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Sample records for radiation induced micronuclei

  1. Micronuclei: sensitivity for the detection of radiation induced damage

    International Nuclear Information System (INIS)

    Di Giorgio, M.; Nasazzi, N.B.; Taja, M.R.

    1998-01-01

    The in vitro cytokinesis-block (CB) micronucleus (MN) assay for human peripheral blood has been used extensively for the assessment of chromosomal damage induced by ionizing radiation and chemicals and considered a suitable biological dosimeter for estimating in vivo whole body exposures, particularly in the case of large scale radiation accidents. One of the major drawbacks of the MN assay is its reduced sensitivity for the detection of damage induced by low doses of low LET radiation, due to the high variability among the spontaneous MN frequencies. It is suggested that age, smoking habit and sex are the main confounding factors that contribute to the observed variability. Previous work in our laboratory, shows a significant positive correlation of the spontaneous and radiation induced MN frequencies with age and smoking habit, the latter being the strongest confounder. These findings led to in vitro studies of the dose-response relationships for smoking and non smoking donors evaluated separately, using 60 Co γ rays. The objectives of the present work are: 1-To increase the amount of data of the dose-response relationships, using γ rays from a 60 Co source, for smoking and non smoking donors, in order to find, if applicable, a correction factor for the calibration curve that takes into account the smoking habit of the individual in the case of accidental overexposure dose assessment, particularly in the low dose range. 2-To establish general conclusions on the current state of the technique. The sample for smoking and non smoking calibration curves was enlarged in the range of 0Gy to 2Gy. The fitting of both curves, performed up to the 2Gy dose, resulted in a linear quadratic model. MN distribution among bi nucleated cells was found to be over dispersed with respect to Poisson distribution, the average ratio of variance to mean being 1.13 for non smokers and 1.17 for smokers. Each fitted calibration curve, for smoking and non smoking donors, fell within the 95

  2. Folic acid deficiency increases chromosomal instability, chromosome 21 aneuploidy and sensitivity to radiation-induced micronuclei

    International Nuclear Information System (INIS)

    Beetstra, Sasja; Thomas, Philip; Salisbury, Carolyn; Turner, Julie; Fenech, Michael

    2005-01-01

    Folic acid deficiency can lead to uracil incorporation into DNA, hypomethylation of DNA, inefficient DNA repair and increase chromosome malsegregation and breakage. Because ionising radiation increases demand for efficient DNA repair and also causes chromosome breaks we hypothesised that folic acid deficiency may increase sensitivity to radiation-induced chromosome breakage. We tested this hypothesis by using the cytokinesis-block micronucleus assay in 10 day WIL2-NS cell cultures at four different folic acid concentrations (0.2, 2, 20, and 200 nM) that span the 'normal' physiological range in humans. The study showed a significant dose-dependent increase in frequency of binucleated cells with micronuclei and/or nucleoplasmic bridges with decreasing folic acid concentration (P < 0.0001, P = 0.028, respectively). These biomarkers of chromosomal instability were also increased in cells irradiated (1.5 Gy γ-rays) on day 9 relative to un-irradiated controls (P < 0.05). Folic acid deficiency and γ-irradiation were shown to have a significant interactive effect on frequency of cells containing micronuclei (two-way ANOVA, interaction P 0.0039) such that the frequency of radiation-induced micronucleated cells (i.e. after subtracting base-line frequency of un-irradiated controls) increased with decreasing folic acid concentration (P-trend < 0.0001). Aneuploidy of chromosome 21, apoptosis and necrosis were increased by folic acid deficiency but not by ionising radiation. The results of this study show that folate status has an important impact on chromosomal stability and is an important modifying factor of cellular sensitivity to radiation-induced genome damage

  3. Antigenotoxic potential of Asparagus racemosus root extract against electron beam radiation induced micronuclei formation in Swiss albino mice

    International Nuclear Information System (INIS)

    Bhandary, B. Satheesh Kumar; Sharmila, K.P.; Suchetha Kumari, N.; Bhat, Vadish S.; Shetty, Jayaram; Peter, Alex John; Jose, Jerish M.; Fernandes, Ronald

    2016-01-01

    To evaluate the antigenotoxic potential of Asparagus Racemosus Root ethanolic extract (ARE) against electron beam radiation induced micronuclei formation in Swiss albino mice. Micronucleus assay was performed in the bone marrow of Swiss albino mice according to the method of Hosseinimehr et al., 2003. The experimental animals were orally administered 200 mg/kg body weight of ARE once daily for 15 consecutive days. At the end of experimental period, the animals were euthanized and the bone marrow was collected from the femur. Control (C), Radiation control (RC) and drug control (DC) group was also maintained. The number of radiation induced Micronucleated Polychromatic Erythrocytes (MnPCE) and Micronucleated Normochromatic Erythrocytes were decreased in the ARE treated mice which was statistically significant (p<0.05) compared to radiation control group. Present findings demonstrate the antigenotoxic potential of ARE against electron beam radiation induced micronuclei formation which may be attributed to scavenging of radiation-induced free radicals

  4. Direct evidence that radiation induced micronuclei of early embryos require a mitosis for expression

    International Nuclear Information System (INIS)

    Mueller, W.U.; Schlusen, I.; Streffer, C.

    1991-01-01

    The naturally synchronous development of early mouse embryos was exploited to address the question, whether micronuclei require a mitosis for expression or whether they can be expressed in the same cell cycle, in which exposure to X-rays or caffeine took place. Experiments with 2-cell and with 4-cell embryos showed that micronulcei are expressed only if a mitosis is completed. There was no indication, even after doses up to 20 Gy, that micronuclei can be expressed before the mitosis was reached, which followed exposure. Furthermore, no nuclear fragmentation pointing to apoptosis could be detected in the cycle, in which cells were exposed. The same results were obtained when caffeine (5 mM) was used as micronucleus inducing agent. (orig.)

  5. Scoring of radiation-induced micronuclei in cytokinesis-blocked human lymphocytes by automated image analysis

    International Nuclear Information System (INIS)

    Verhaegen, F.; Seuntjens, J.; Thierens, H.

    1994-01-01

    The micronucleus assay in human lymphocytes is, at present, frequently used to assess chromosomal damage caused by ionizing radiation or mutagens. Manual scoring of micronuclei (MN) by trained personnel is very time-consuming, tiring work, and the results depend on subjective interpretation of scoring criteria. More objective scoring can be accomplished only if the test can be automated. Furthermore, an automated system allows scoring of large numbers of cells, thereby increasing the statistical significance of the results. This is of special importance for screening programs for low doses of chromosome-damaging agents. In this paper, the first results of our effort to automate the micronucleus assay with an image-analysis system are represented. The method we used is described in detail, and the results are compared to those of other groups. Our system is able to detect 88% of the binucleated lymphocytes on the slides. The procedure consists of a fully automated localization of binucleated cells and counting of the MN within these cells, followed by a simple and fast manual operation in which the false positives are removed. Preliminary measurements for blood samples irradiated with a dose of 1 Gy X-rays indicate that the automated system can find 89% ± 12% of the micronuclei within the binucleated cells compared to a manual screening. 18 refs., 8 figs., 1 tab

  6. Micronuclei Frequency in Radiation Worker

    International Nuclear Information System (INIS)

    Sudprasert, Wanwisa; Jungtanasombut, Amornrat; Pakkong, Pannee

    2009-07-01

    Full text: The purpose of this study is to determine the micronuclei (MN) frequency in peripheral blood lymphocytes of 31 individuals occupationally exposed to radiation compared to 24 controls. The effect of donor gender, age, alcoholic consumption, tea/coffee consumption and radiation burden on MN frequency was studied. The results showed that MN frequencies observed for exposed employees were significantly higher than in controls (p = 0.000). The average MN frequency in control was 39.1 ± 3.7 MN/1000 BN while those of exposed group were 60.9 ± 12.3, 61.6 ± 13.0 and 62.6 ± 11.8 MN/1000 BN for the range of accumulative doses at 0.01-3.00, 3.01-6.00 and 6.01-9.00 mSv, respectively. Moreover, MN frequency showed a positive trend with increased accumulative doses as a linear-quadratic relation (R 2 = 0.4754). No correlation of MN frequency with gender, age and alcoholic consumption could be observed in both exposed and control groups. However, the effect of tea/coffee consumption on MN frequency was clearly observed in the exposed individuals (t-test = -2.018, sig. (2-tailed) = 0.030). These results indicate that the increased MN frequency, an indicator of chromosomal aberration, is associated with occupational exposure to low doses of ionizing radiation

  7. Dose response of micronuclei induced by combination radiation of α-particles and γ-rays in human lymphoblast cells

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Ruiping; He, Mingyuan; Dong, Chen; Xie, Yuexia; Ye, Shuang; Yuan, Dexiao [Institute of Radiation Medicine, Fudan University, No. 2094 Xie-Tu Road, Shanghai 200032 (China); Shao, Chunlin, E-mail: clshao@shmu.edu.cn [Institute of Radiation Medicine, Fudan University, No. 2094 Xie-Tu Road, Shanghai 200032 (China)

    2013-01-15

    Highlights: ► α-Particle induced MN had a biphasic dose–response followed by a bystander model. ► MN dose–response of α- and γ-combination IR was similar to that of α-particle. ► α-Particles followed by γ-rays yielded a synergistic effect on MN induction. ► Low dose γ-rays triggered antagonistic and adaptive responses against α-particle. - Abstract: Combination radiation is a real situation of both nuclear accident exposure and space radiation environment, but its biological dosimetry is still not established. This study investigated the dose–response of micronuclei (MN) induction in lymphocyte by irradiating HMy2.CIR lymphoblast cells with α-particles, γ-rays, and their combinations. Results showed that the dose–response of MN induced by γ-rays was well-fitted with the linear-quadratic model. But for α-particle irradiation, the MN induction had a biphasic phenomenon containing a low dose hypersensitivity characteristic and its dose response could be well-stimulated with a state vector model where radiation-induced bystander effect (RIBE) was involved. For the combination exposure, the dose response of MN was similar to that of α-irradiation. However, the yield of MN was closely related to the sequence of irradiations. When the cells were irradiated with α-particles at first and then γ-rays, a synergistic effect of MN induction was observed. But when the cells were irradiated with γ-rays followed by α-particles, an antagonistic effect of MN was observed in the low dose range although this combination radiation also yielded a synergistic effect at high doses. When the interval between two irradiations was extended to 4 h, a cross-adaptive response against the other irradiation was induced by a low dose of γ-rays but not α-particles.

  8. Discrimination between micronuclei induced by spindle poisons and ...

    African Journals Online (AJOL)

    Discrimination between micronuclei induced by spindle poisons and clastogens by using toad bone marrow polychromatic erythrocytes. ... Egyptian Journal of Biology ... The used chemicals induced high percentages of micronuclei with variable sizes, which clarify the sensitivity of bone marrow cells of Bufo regularis to ...

  9. Oxygen enhancement ratios for glutathione-deficient human fibroblasts determined from the frequency of radiation induced micronuclei

    International Nuclear Information System (INIS)

    Midander, J.

    1982-01-01

    The yield of micronuclei (MN) was determined to study the radiosensitizing effect of oxygen on three human fibroblast strains, characterized by genetically defined differences in their glutathione (GSH) level. Cells were irradiated in paired experiments with x-ray doses of 2.66 and 6.65 gy in their exponential growth phase in a monolayer under oxic and anoxic conditions. Results indicated a reduced oxygen effect for the GSH deficient cells, the reduction of o.e.r. being most pronounced in the case of GSHsup(-/-) cells, when it was close to unity. The o.e.r. value was intermediate for the GSHsup(+/-) in comparison with the two other cell strains. It is concluded that the data indicate a correlation between the cellular content of GSH and the oxygen enhancement of the formation of micronuclei after irradiation. (U.K.)

  10. Influence of age, sex and life style factors (smoking habits) on the spontaneous and radiation induced micronuclei frequencies

    International Nuclear Information System (INIS)

    Di Giorgio, M.; Nasazzi, N.; Heredia, M.L.

    1995-01-01

    Several endpoints have been used for monitoring human populations for environmental or occupational exposure to genotoxic agents, particularly ionizing radiation. The cytokinesis-block micronucleus (MN) assay in peripheral lymphocytes is a reliable method for assessing radiation induced chromosomal damage (DNA breaks and mitotic spindle disturbances) and thus, a suitable dosimeter for estimating in vivo whole body exposures. To further define the use of this assay in Biological Dosimetry, a study to determine the influence of age, sex and life style factors (smoking habit) on the spontaneous and radiation induced MN frequencies was performed. The estimation of MN frequencies was analyzed in lymphocytes cultures from 50 healthy donors aged between 4 and 62 years. On the basis of their smoking habit they were divided into 2 groups. A fraction of the sample was irradiated in vitro with γ rays in the range of 0.35 Gy to 4 Gy. A statistically significant influence on the spontaneous MN frequency was observed (R 2 = 0.59) when the variables age and smoking habit were analyzed and also a statistically significant influence on the radiation induced MN frequency was obtained (R 2 = 0.86) when dose, age and smoking habit were studied. Sex did not influence MN variability significantly but there was a greater dispersion in the results for females when compared to males, possibly due to the loss of X chromosomes. The comparison of the data from smoking donors to non smoking donors supports the convenience of taking into account the smoking habit for estimating in vivo whole body exposure to γ rays for doses below 2 Gy. (author). 8 refs., 3 figs., 1 tab

  11. FREQUENCY OF CHROMOSOMAL ABERRATIONS AND MICRONUCLEI IN HORSE LYMPHOCYTES FOLLOWING IN VITRO EXPOSURE TO LOW DOSE IONISING RADIATION

    Directory of Open Access Journals (Sweden)

    Dunja Rukavina

    2012-07-01

    Full Text Available Ionising radiation is known to cause chromosomal instability, which is observed as increased frequency of chromosomal aberration and micronuclei. These are listed as reliable criteria in biological dosimetry. Numerous experiments conducted on both animal and plant models demonstrated that increase in radiation dosage is followed by increased mutation frequency, and that mutations occur even at the lowest exposure. We used horse blood in vitro irradiated by low doses of ionizing radiation. Cultivation of peripheral blood lymphocytes and micronucleus test were used as biomarkers of genetic damage. The observed aberrations were recorded and classified in accordance with the International System of Cytogenetic Nomenclature. Micronuclei were identified on the basis of criteria proposed by Fenech et al. (8. Analysis of chromosomal aberration showed increased frequency of aberrations in blood cultures exposed to 0,1 Gy and 0,2 Gy compared to the controls. Microscopic analysis of chromosomal damage in in vitro micronucleus test revealed that the applied radiation dose induced micronuclei while no binucleated cells with micronuclei were found in lymphocytes that were not irradiated. In this paper we analysed the influence of low dose ionising radiation on frequency of chromosomal aberration and micronuclei in horse lymphocytes following in vitro exposure to X-rays (0,1 Gy and 0,2 Gy. Key words: chromosomal aberrations, micronuclei, ionising radiation, horse lymphocytes

  12. Quantification of micronuclei in blood lymphocytes of patients exposed to gamma radiation for dose absorbed assessment

    International Nuclear Information System (INIS)

    Barbosa, Isvania Maria Serafim da Silva

    2003-02-01

    Dose assessment in an important step to evaluate biological effects as a result of individual exposure to ionizing radiation. The use of cytogenetic dosimetry based on the quantification of micronuclei in lymphocytes is very important to complement physical dosimetry, since the measurement of absorbed dose cannot be always performed. In this research, the quantification of micronuclei was carried out in order to evaluate absorbed dose as a result of radiotherapy with 60 Co, using peripheral blood samples from 5 patients with cervical uterine cancer. For this purpose, an aliquot of whole blood from the individual patients was added in culture medium RPMI 1640 supplemented with fetal calf serum and phytohaemagglutinin. The culture was incubated for 44 hours. Henceforth, cytochalasin B was added to block the dividing lymphocytes in cytokinesis. The culture was returned to the incubator for further of 28 hours. Thus, cells were harvested, processed and analyzed. Values obtained considering micronuclei frequency after pelvis irradiation with absorption of 0,08 Gy and 1,8 Gy were, respectively, 0,0021 and 0,052. These results are in agreement with some recent researches that provided some standard values related to micronuclei frequency induced by gamma radiation exposure in different exposed areas for the human body. The results presented in this report emphasizes biological dosimetry as an important tool for dose assessment of either total or partial-body exposure to ionizing radiation, mainly in retrospective dose investigation. (author)

  13. Micronuclei Frequencies in Lymphocytes of Nuclear Malaysia Radiation Workers

    International Nuclear Information System (INIS)

    Mohd Rodzi Ali; Aisyah Mohd Yusof; Rahimah Abdul Rahim; Juliana Mahamat Napiah; Yahaya Talib; Shafii Khamis

    2016-01-01

    The objective of the study is to investigate the frequency of cell aberration in lymphocytes of the Nuklear Malaysia radiation workers. A total of 58 blood samples were collected from the radiation workers during their routine medical examination. The donor age range is between 23 to 58 years, 31 male and 27 female. Blood samples were cultured according to the standard protocol recommended by the International Atomic Energy Agency. The mean micronuclei (MN) is 23.5 ± 0.9 MN/ 1000 binucleate, with the median value of 24 MN/ 1000 binucleate. The lowest number of MN was 9, and the highest was 43. There is no correlation between the number of MN in blood and yearly cumulative dose for radiation workers. The results indicate the MN expression due to small radiation exposure is almost negligible in Nuclear Malaysia radiation workers. (author)

  14. Assay of micronuclei in peripheral blood lymphocytes as a biological indicator of radiation dose

    International Nuclear Information System (INIS)

    Sreedevi, B.; Rao, B.S.

    1994-01-01

    Chromosomal aberration analysis (CA) has regularly been used as a biological dosemeter to evaluate suspected overexposures to ionising radiations. Recently, the micronucleus (MN) assay has been suggested as an alternative method. An attempt has been made to explore the dose response parameters of MN assay in cytokinesis-blocked lymphocytes. Whole blood was irradiated with 60 Co gamma rays or 250 kV p X rays. A dose-dependent increase in micronuclei yield was observed. The dose response could be best described by a linear-quadratic relationship for both gamma rays and X rays. The α and β coefficients were found to be 1.9 x 10 -2 Gy -1 and 5.7 x 10 -2 Gy -2 for gamma rays and 6.3 x 10 -2 Gy -1 and 4.3 x 10 -2 Gy -2 for X rays, respectively. In the low dose region X rays were three times more efficient in inducing micronuclei. The background value derived for 25 samples from healthy individuals ranged from 6-18 micronuclei per 1000 cells, with a mean value of 12 ± 4 x 10 -3 . Biological dose estimates for individuals exposed in the range 0.1-1 Gy made by MN and CA methods yielded similar results for doses ≥ 0.5 Gy. Due to the uncertainties in the background incidence of MN, at present this technique cannot provide reliable estimates at low doses. (author)

  15. Effect of Cytosine Arabinoside, 3-Aminobenzamide and Hydroxyurea on the frequencies of radiation-induced micronuclei and aneuploidy in human lymphocytes

    International Nuclear Information System (INIS)

    Cho, Yoon Hee; Kim, Yang Jee; Ha, Sung Whan; Chung, Hai Won; Kang, Chang Mo

    2005-01-01

    This study was carried out to examine the effect of the DNA repair inhibitors, Cytosine Arabinoside(Ara C), 3-Aminobenzamide(3AB) and Hydroxyurea(HU) on the frequencies of radiation-induced MicroNuclei(MNi) and aneuploidy. Irradiated lymphocytes(1-3Gy) were treated with DNA repair inhibitors, Ara C, 3AB and HU for 3 hours and CBMN assay - FISH technique with DNA probe for chromosome 1 and 4 was performed. The frequencies of x-ray induced MNi and aneuploidy of chromosome 1 and 4 were increased in a dose-dependent manner. Ara C, 3AB and HU enhanced the frequencies of radiation-induced MNi and the frequencies of radiation-induced aneuploidy of chromosome 1 and 4 were enhanced by HU and Ara C while no effect was observed by 3AB. The frequency of radiation-induced aneuploidy of chromosome 1 was higher than that of chromosome 4. These results suggest that there are different mechanisms involved in the formation of MNi and aneuploidy by radiation

  16. Effect of Cytosine Arabinoside, 3-Aminobenzamide and Hydroxyurea on the frequencies of radiation-induced micronuclei and aneuploidy in human lymphocytes

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Yoon Hee; Kim, Yang Jee; Ha, Sung Whan; Chung, Hai Won [Seoul National Univ., Seoul (Korea, Republic of); Kang, Chang Mo [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of)

    2005-12-15

    This study was carried out to examine the effect of the DNA repair inhibitors, Cytosine Arabinoside(Ara C), 3-Aminobenzamide(3AB) and Hydroxyurea(HU) on the frequencies of radiation-induced MicroNuclei(MNi) and aneuploidy. Irradiated lymphocytes(1-3Gy) were treated with DNA repair inhibitors, Ara C, 3AB and HU for 3 hours and CBMN assay - FISH technique with DNA probe for chromosome 1 and 4 was performed. The frequencies of x-ray induced MNi and aneuploidy of chromosome 1 and 4 were increased in a dose-dependent manner. Ara C, 3AB and HU enhanced the frequencies of radiation-induced MNi and the frequencies of radiation-induced aneuploidy of chromosome 1 and 4 were enhanced by HU and Ara C while no effect was observed by 3AB. The frequency of radiation-induced aneuploidy of chromosome 1 was higher than that of chromosome 4. These results suggest that there are different mechanisms involved in the formation of MNi and aneuploidy by radiation.

  17. Micronuclei frequency in albino rats exposed to high natural radiation

    International Nuclear Information System (INIS)

    Aneesh, D.; Godwin Wesley, S.

    2013-01-01

    Genotoxicity and DNA damage endpoints are used to evaluate results in the context of cell survival. Genotoxicity in mammalian cells is monitored mostly by using cytokinesis-block micronucleus (CBMN) assay. The score of micronuclei (MN) in peripheral blood lymphocytes can be used as a biomarker and also as a bio-dosimeter of radiation exposure. In the present study the effect of natural radiation on albino rats has been investigated, to find out if there is any increase in MN frequency in peripheral blood lymphocytes. Animals at the age of 2-3 weeks were exposed to natural radiation, at the dose of 10.38 μGyh -1 for a period of 6 months. A parallel control set was also maintained (0.12 μGy h -1 '). Blood samples were collected from both test (exposed to natural radiation) and control rats. Lymphocyte culture was done following 'microculture techniques' for 72 h. Cytochalasin B, at a concentration of 6.0 μg/ml, was added to the lymphocyte cultures at 44 h to block cytokinesis. The frequency of MN was evaluated by scoring a total of 1000 binucleated (BN) cells from one slide. The frequency of MN among the rats exposed to natural radiation was found to be 1.83±0.05 per 1000 BN cells and in the control it was 1.82±0.07 per 1000 BN cells. No statistically significant difference in the MN frequencies of exposed and control groups (p>0.05) was seen. The lower MN frequency in natural radiation exposed rats could be an indication of adaptive response. (author)

  18. Suppressing effects of glucan on micronuclei induced by Co60 in mice

    International Nuclear Information System (INIS)

    Chorvatovicova, D.

    1991-01-01

    The effects of glucan on the frequency of micronuclei in polychromatic erythrocytes of A/Ph mouse bone marrow induced by Co 60 irradiation were examined. Suppressing effect of three glucan derivatives was statistically significant (P 3 substituent (DS 0.89). Intraperitoneal application of glucan has to be done earlier than one hour after irradiation. The suppressive effects of glucans can be explained by their ability to trap OH radicals and so decrease the clastogenic effect of irradiation. The results may be useful for therapeutic application of glucan with radiation therapy. (orig.) [de

  19. Detection of individual radiosensitivity by radiation–induced micronuclei in human peripheral blood lymphocytes and polymorphisms in DNA repair genes

    Energy Technology Data Exchange (ETDEWEB)

    Staynova, A.; Hadjidekova, V.; Popova, L.; Hristova, R. [Radiation Genetics Laboratory, National Centre of Radiobology and Radiation Protection, Sofia (Bulgaria); Savov, A. [National Genetic Laboratory, University Hospital of Obstetrics and Gynecology, Sofia (Bulgaria)

    2013-07-01

    Aim: To investigate the association of two polymorphisms – in XRCC1 gene (Arg399Gln) and in APE1 gene (Asp148Glu) and the radiation induced frequency of micronuclei in human peripheral blood lymphocytes. Material and methods: Genomic DNA from 34 cancer patients and 52 controls were genotyped using PCR–RFLP technique. Micronucleus test (MNT) was performed on 15 cancer patients and 15 controls, before and after in vitro irradiation with 2Gy gamma rays. Results: The data showed that cancer patients had a significantly higher spontaneous frequency of cells with micronuclei than controls (P=0.009). No statistical difference was registered when comparing the mean frequency of cells with micronuclei after in vitro irradiation between these groups. Four subjects were selected as radiosensitive after applying cut–off of the mean frequency of radiation induced micronuclei. Three of them are carriers of the XRCC1 399Gln allele and two of them are carriers of the APE1 148Glu allele. (author)

  20. 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

  1. Dose-dependent micronuclei formation in normal human fibroblasts exposed to proton radiation

    Czech Academy of Sciences Publication Activity Database

    Litvinchuk, Alexandra; Vachelová, Jana; Michaelidesová, Anna; Wagner, Richard; Davídková, Marie

    2015-01-01

    Roč. 54, č. 3 (2015), s. 327-334 ISSN 0301-634X R&D Projects: GA ČR(CZ) GBP108/12/G108; GA MŠk LM2011019 Institutional support: RVO:61389005 Keywords : human fibroblasts * proton radiation * micronuclei assay * biodosimetry Subject RIV: BO - Biophysics Impact factor: 1.923, year: 2015

  2. Suppressing effects of glucan on micronuclei induced by Co sup 60 in mice

    Energy Technology Data Exchange (ETDEWEB)

    Chorvatovicova, D. (Slovak Academy of Sciences, Bratislava (Czechoslovakia). Inst. of Ecobiology)

    1991-10-01

    The effects of glucan on the frequency of micronuclei in polychromatic erythrocytes of A/Ph mouse bone marrow induced by Co{sup 60} irradiation were examined. Suppressing effect of three glucan derivatives was statistically significant (P<0.01) by intravenous application of glucan one hour after irradiation. The most expressive effect was obvious by K{sub 3} substituent (DS 0.89). Intraperitoneal application of glucan has to be done earlier than one hour after irradiation. The suppressive effects of glucans can be explained by their ability to trap OH radicals and so decrease the clastogenic effect of irradiation. The results may be useful for therapeutic application of glucan with radiation therapy. (orig.).

  3. Micronuclei as biomarkers of genotoxicity of gamma radiation in aquatic environments

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Luanna R.S.; Silva, Edvane B.; Melo, Ana M.M.A. [Universidade Federal de Pernambuco (GERAR/DEN/UFPE), Recife, PE (Brazil). Dept. de Energia Nuclear. Grupo de Estudos em Radioprotecao e Radioecologia; Silva, Ronaldo C. da [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Genetica; Amancio, Francisco F. [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Biofisica e Radiobiologia. Lab. de Radiobiologia

    2011-07-01

    Ionizing radiation is a genotoxic agent, inducing gene mutations and cellular death. Several efforts have been defendants in the development of techniques for measurement of radiation damage in biological systems. Among these techniques, micronuclei test has been showing as a great bio marker of DNA damage, being used in environmental monitoring to detect genotoxic agents in the environment. Additionally, organisms as Biomphalaria glabrata, freshwater molluscs, presents itself as an excellent model to assess damage caused by physical and chemical agents, due their biological and environmental characteristics. The snails were divided into groups of 5 individuals exposed to doses of 0 (control), 25, 35, 45 and 55 Gy of {sup 60}Co. After 48 hours of irradiation, the hemo lymph was collected and prepared the slides, which were stained with Giemsa and analyzed the cellular changes in haemocytes Statistical analysis was accomplished through chi-square test, ANOVA and Tukey test (p< 0,05). The results indicated that B. glabrata showed to be sensitive to gamma radiation. The snails irradiated with 35 Gy showed a decrease of haemocytes, while that of 55 Gy increased. Cellular and morphological changes were observed at doses of 35, 45 and 55 Gy and the dose of 55 Gy, the most radiotoxic. (author)

  4. Micronuclei as biomarkers of genotoxicity of gamma radiation in aquatic environments

    International Nuclear Information System (INIS)

    Silva, Luanna R.S.; Silva, Edvane B.; Melo, Ana M.M.A.; Silva, Ronaldo C. da; Amancio, Francisco F.

    2011-01-01

    Ionizing radiation is a genotoxic agent, inducing gene mutations and cellular death. Several efforts have been defendants in the development of techniques for measurement of radiation damage in biological systems. Among these techniques, micronuclei test has been showing as a great bio marker of DNA damage, being used in environmental monitoring to detect genotoxic agents in the environment. Additionally, organisms as Biomphalaria glabrata, freshwater molluscs, presents itself as an excellent model to assess damage caused by physical and chemical agents, due their biological and environmental characteristics. The snails were divided into groups of 5 individuals exposed to doses of 0 (control), 25, 35, 45 and 55 Gy of 60 Co. After 48 hours of irradiation, the hemo lymph was collected and prepared the slides, which were stained with Giemsa and analyzed the cellular changes in haemocytes Statistical analysis was accomplished through chi-square test, ANOVA and Tukey test (p< 0,05). The results indicated that B. glabrata showed to be sensitive to gamma radiation. The snails irradiated with 35 Gy showed a decrease of haemocytes, while that of 55 Gy increased. Cellular and morphological changes were observed at doses of 35, 45 and 55 Gy and the dose of 55 Gy, the most radiotoxic. (author)

  5. The influence of plutonium exposure and lung cancer on the frequency of x-ray-induced micronuclei in dog blood lymphocytes

    International Nuclear Information System (INIS)

    Brooks, A.L.; Rithidech, K.; Muggenburg, B.A.; Lozano, D.; Lundgren, D.L.

    1988-01-01

    This study determined if lung cancer or exposure to an inhaled alpha emitter, plutonium-239, increased the frequency of micronuclei in blood lymphocytes or altered the responsiveness of lymphocytes to induction of micronuclei by subsequent doses of X rays in vitro. Beagle dogs inhaled 1.5 mm ABAD monodisperse 239 PuO 2 aerosols. The exposure resulted in initial lung burdens of 1.8 KBq to 48 KBq and produced cumulative alpha radiation lung doses of 1.4 to 10.4 Gy at the time of this study. Blood lymphocytes were sampled and irradiated with either 0.0 or 2.0 Gy of X rays. The lymphocytes were stimulated to divide by phytohemagglutinin, cytokinesis was blocked with cytochalasin B, and the frequency of micronuclei was determined in binucleated cells. Plutonium inhalation alone produced no significant increase in the frequency of micronuclei in blood lymphocytes. When 2 Gy of X rays ws given to blood lymphocytes of dogs that had inhaled 239 PuO 2 , there was a linear increase in micronuclei frequency as a function of alpha dose to the lungs; micronuclei/binucleated cell = 0.15 +0.2 D, where D is the cumulative alpha-radiation dose to the lung in Gy. Dogs with 239 PuO 2 - induced lung cancer did not have a significant increase in the frequency of X- ray-induced micronuclei relative to dogs exposed to plutonium that did not have lung cancer. These data suggest that inhaled 239 PuO 2 alters the responsiveness of blood lymphocytes to subsequent X-ray exposure. (author)

  6. In vivo variation of micronuclei in BALB/c mice after low and high doses of gamma radiation

    International Nuclear Information System (INIS)

    Strain, D.; Allen, B.J.

    1996-01-01

    Full text: An adaptive response to ionising radiation exists if a low level or priming dose reduces the effect of a subsequent high or challenge dose. This has been demonstrated in vitro using the frequency of micronuclei formation as a measure of radiation-induced DNA damage. The objective of this project was to use the same approach with an animal model to investigate the existence of an in vivo adaptive response. The experimental design involved priming doses of 0.005 or 0.01 Gy and a challenge dose of 4 Gy administered 1, 2, 4, 8 or 16 hours after the priming dose. Ten mice at a time were housed in a perspex animal cage and irradiated using Co-60 gamma radiation. For every time point (1, 2, 4, 8 or 16 hours), there were four treatment groups of 5 mice for statistical analysis. The first group acted as a non-irradiated control (0 Gy). The second group of mice received only the priming dose (0.005 Gy), while the third group of mice received only the challenge dose (4 Gy). The fourth group of mice received both the priming and challenge doses 0.005 Gy + 4 Gy). The process was repeated for the second priming dose of 0.01 Gy. A total of 200 mice were used. The animals were sacrificed by cervical dislocation 24 hours after receiving the challenge dose. Both femora were removed and cleared of adhering muscle tissue. The bone marrow cells of five mice were collected and the nucleated cells removed using filtration through a mixed cellulose column incorporating a self-locking filter. The cell suspension was placed onto microscope slides using a cytocentrifuge, air-dried and then stained for the micronuclei. Then the slides were coded, and reticulocytes were scored for the presence or absence of micronuclei. Approximately 2500 cells were scored for each treatment point, and the number of micronuclei counted ranged from 3 to 125 in this sample size. While it appears that the adaptive response may be present in 2 of 9 groups of mice pre-exposed to 0.005 or 0.01 Gy, this

  7. [The effect of cimeiguo on micronuclei in mice induced by cooking lampblack].

    Science.gov (United States)

    Cui, S; Qiu, D; Li, L; Han, C; Li, Y

    1997-04-01

    The effect of Cimeiguo on micronuclei in mice induced by cooking lampblack is studied. The results show that the number of micronulei induced by cooking lampblack are increased sighificantly (P > 0.01) with dose-response relationship and inhibited by Cimeiguo.

  8. Induction of micronuclei in human and mouse lymphocytes irradiated with gamma radiation and effect of panax ginseng C. A. Meyer

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sung Ho; Oh, Heon; Lee, Song Eun [Chonnam National Univ., Kwangju (Korea, Republic of); Lee, Yun Sil; Kim, Tae Hwan [Korea Cancer Center Hospital, Seoul (Korea, Republic of); Jeong, Kyu Sik [Korea Research Institute of Bioscience and Biotechnology, Taejon (Korea, Republic of); Ryu, Si Yun [Chungnam National Univ., Taejon (Korea, Republic of)

    1997-09-01

    The frequencies of {gamma}-ray-induced micronuclei (MN) in Cytokinesis-Blocked (CB) lymphocytes at several doses were measured in three donors of human and C57BL/6 mice. Measurements performed after irradiation showed a dose-related increases in MN frequency in each of the donors studied. The relative sensitivity of mouse in Spleen Lymphocytes (SLs) compared with human Peripheral Blood Lymphocytes (PBLs) was estimated by best fitting linear-quadratic model based on the radiation-induced MN data over the range from 0 cGy to 400 cGy. In the case of MN frequency with 0.2 per CB cell, the relative sensitivity of mouse SLs was 1.67. Compared with the radiation-induced MN formation in the PBLs of human, the SLs of mouse were more radiosensitive. Using this MN assay with human PBLs and mouse SLs, studies were performed to determine whether the water fraction of ginseng (Panax ginseng C.A.Meyer)against radiation-induced MN in human PBLs after in vitro irradiation (3Gy) and in SLs of C57BL/6 mice after in vivo irradiation (3Gy). The frequency of MN in human PBLs was reduced by water fraction of ginseng (0.5mg/ml of medium) both pre-and post treatment (p<0.01) in vitro. In addition, the frequency of MN in mouse SLs was also reduced by pretreatment of ginseng (2mg/ml of drinking water for 7 days) in vivo.

  9. Frequencies of micronuclei in bank voles from zones of high radiation at Chernobyl, Ukraine

    Energy Technology Data Exchange (ETDEWEB)

    Rodgers, B.E.; Baker, R.J.

    2000-06-01

    A population of Clethrionomys glareolus (bank vole) from a highly radioactive area within the Chernobyl, Ukraine exclusion zone was sampled in June 1997 and in June and October 1998. Internal radiation doses from radiocesium were estimated to be as high as 8 rads/d. Total dose, which takes into account the internal dose form radiostrontium and the surrounding environment, was estimated to be 15 to 20 rads/d. In contrast, individuals from a reference population lying outside of the exclusion zone registered negligible levels of contamination. The authors used the micronucleus test in a double-blind study to analyze blood samples from 58 individuals. They scored more than 600,000 polychromatic erythrocytes (PCEs) but could not reject the null hypothesis that the frequency of micronucleated PCEs in voles exposed to radiation was equal to the frequency in unexposed voles. Results of their study stand in sharp contrast to earlier reports of increased frequencies of micronuclei in rodents exposed to fallout of the Chernobyl accident, but with radiation doses that were orders of magnitude lower than those reported here. Radio resistance and experimental methods are possible explanations for these differences in the results.

  10. Quantification of micronuclei in blood lymphocytes of patients exposed to gamma radiation for dose absorbed assessment; Quantificacao de micronucleos em linfocitos de pacientes expostas a radiacao gama para a avaliacao da dose absorvida

    Energy Technology Data Exchange (ETDEWEB)

    Barbosa, Isvania Maria Serafim da Silva

    2003-02-15

    Dose assessment in an important step to evaluate biological effects as a result of individual exposure to ionizing radiation. The use of cytogenetic dosimetry based on the quantification of micronuclei in lymphocytes is very important to complement physical dosimetry, since the measurement of absorbed dose cannot be always performed. In this research, the quantification of micronuclei was carried out in order to evaluate absorbed dose as a result of radiotherapy with {sup 60}Co, using peripheral blood samples from 5 patients with cervical uterine cancer. For this purpose, an aliquot of whole blood from the individual patients was added in culture medium RPMI 1640 supplemented with fetal calf serum and phytohaemagglutinin. The culture was incubated for 44 hours. Henceforth, cytochalasin B was added to block the dividing lymphocytes in cytokinesis. The culture was returned to the incubator for further of 28 hours. Thus, cells were harvested, processed and analyzed. Values obtained considering micronuclei frequency after pelvis irradiation with absorption of 0,08 Gy and 1,8 Gy were, respectively, 0,0021 and 0,052. These results are in agreement with some recent researches that provided some standard values related to micronuclei frequency induced by gamma radiation exposure in different exposed areas for the human body. The results presented in this report emphasizes biological dosimetry as an important tool for dose assessment of either total or partial-body exposure to ionizing radiation, mainly in retrospective dose investigation. (author)

  11. Micronuclei in cytokinesis-blocked lymphocytes of medical personnel occupationally exposed to ionizing radiation

    International Nuclear Information System (INIS)

    Noditi, M.; Draghia, L.; Popescu, D.; Cincu, E.

    2006-01-01

    Bio monitoring of occupational exposures relies on surveillance of exposure and its biological consequences. The measurement of micronuclei in population of exposed cells is a cytogenetic end point used for estimation purposes. To ensure that only dividing cells are scored, cells are treated with cytochalasin B, which blocks cytokinesis and results in bi nucleated cells. Only the bi nucleated cells are evaluated for the formation of micronuclei. In 2004-2005 there have been analyzed and compared two groups of medical staff occupationally exposed to X-rays by using micronucleus test. The first group consisted in 9 doctors and nurses specialized in interventional cardiology from the Institute of Cardiology - Timisoara, Romania, males and females, smokers and nonsmokers. The mean age was 41.5 years and the mean duration of employment 10.6 years. According to personal dosimeters, some of them have had an overdose exposure. The other group consisted in 19 doctors and nurses from the radiology department of several hospitals from Timisoara with the mean age of 48.3 years and the mean duration of employment of 17.8 years. According to personal dosimeters, none of them have had an overdose exposure. The recorded frequency of micronuclei was 62.6/1000 bi nucleated cells for the interventional cardiology personnel. There have been observed cells with 2, 3 and even 5 micronuclei. For the radiology department personnel the frequency of micronuclei was 15.4/1000 bi nucleated cells and the appearance of cells with more than one micronucleus was exceptional. In general, there was a tendency of accumulation of micronuclei with age but the correlation with the age of employment was rather unclear. Due to low doses exposure confounding factors could exist. For instance, a proportion of micronuclei are formed because of other mutagen factors from the environment or smoking habit. Nevertheless the exposure of interventional cardiology personnel is more consistent and further

  12. Micronuclei in cytokinesis-blocked lymphocytes of medical personnel occupationally exposed to ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Noditi, M.; Draghia, L.; Popescu, D. [Institute of Public Health ' Prof. Dr. Leonida Georgescu' Timisoara (Romania); Cincu, E. [University of Agriculture Sciences of Banat, Timisoara (Romania)

    2006-07-01

    Bio monitoring of occupational exposures relies on surveillance of exposure and its biological consequences. The measurement of micronuclei in population of exposed cells is a cytogenetic end point used for estimation purposes. To ensure that only dividing cells are scored, cells are treated with cytochalasin B, which blocks cytokinesis and results in bi nucleated cells. Only the bi nucleated cells are evaluated for the formation of micronuclei. In 2004-2005 there have been analyzed and compared two groups of medical staff occupationally exposed to X-rays by using micronucleus test. The first group consisted in 9 doctors and nurses specialized in interventional cardiology from the Institute of Cardiology - Timisoara, Romania, males and females, smokers and nonsmokers. The mean age was 41.5 years and the mean duration of employment 10.6 years. According to personal dosimeters, some of them have had an overdose exposure. The other group consisted in 19 doctors and nurses from the radiology department of several hospitals from Timisoara with the mean age of 48.3 years and the mean duration of employment of 17.8 years. According to personal dosimeters, none of them have had an overdose exposure. The recorded frequency of micronuclei was 62.6/1000 bi nucleated cells for the interventional cardiology personnel. There have been observed cells with 2, 3 and even 5 micronuclei. For the radiology department personnel the frequency of micronuclei was 15.4/1000 bi nucleated cells and the appearance of cells with more than one micronucleus was exceptional. In general, there was a tendency of accumulation of micronuclei with age but the correlation with the age of employment was rather unclear. Due to low doses exposure confounding factors could exist. For instance, a proportion of micronuclei are formed because of other mutagen factors from the environment or smoking habit. Nevertheless the exposure of interventional cardiology personnel is more consistent and further

  13. Seven benzimidazole pesticides combined at sub-threshold levels induce micronuclei in vitro

    Science.gov (United States)

    Ermler, Sibylle; Scholze, Martin; Kortenkamp, Andreas

    2013-01-01

    Benzimidazoles act by disrupting microtubule polymerisation and are capable of inducing the formation of micronuclei. Considering the similarities in their mechanisms of action (inhibition of microtubule assembly by binding to the colchicine-binding site on tubulin monomers), combination effects according to the principles of concentration addition might occur. If so, it is to be expected that several benzimidazoles contribute to micronucleus formation even when each single one is present at or below threshold levels. This would have profound implications for risk assessment, but the idea has never been tested rigorously. To fill this gap, we analysed micronucleus frequencies for seven benzimidazoles, including the fungicide benomyl, its metabolite carbendazim, the anthelmintics albendazole, albendazole oxide, flubendazole, mebendazole and oxibendazole. Thiabendazole was also tested but was inactive. We used the cytochalasin-blocked micronucleus assay with CHO-K1 cells according to OECD guidelines, and employed an automated micronucleus scoring system based on image analysis to establish quantitative concentration–response relationships for the seven active benzimidazoles. Based on this information, we predicted additive combination effects for a mixture of the seven benzimidazoles by using the concepts of concentration addition and independent action. The observed effects of the mixture agreed very well with those predicted by concentration addition. Independent action underestimated the observed combined effects by a large margin. With a mixture that combined all benzimidazoles at their estimated threshold concentrations for micronucleus induction, micronucleus frequencies of ~15.5% were observed, correctly anticipated by concentration addition. On the basis of independent action, this mixture was expected to produce no effects. Our data provide convincing evidence that concentration addition is applicable to combinations of benzimidazoles that form micronuclei

  14. Three-dimensional organization of micronuclei induced by colchicine in PtK sub 1 cells

    Energy Technology Data Exchange (ETDEWEB)

    Geraud, G.; Laquerriere, F.; Masson, C.; Arnoult, J.; Labidi, B.; Hernandez-Verdun, D. (Univ. Pierre et Marie Curie, Paris (France))

    1989-03-01

    In PtK{sub 1} cells micronucleated by colchicine, the authors previously demonstrated that some micronuclei contain a single chromosome. Here, they investigated interphase chromosome organization in micronucleated PtK{sub 1} cells using conventional electron microscopy and three-dimensional computer reconstruction. The distribution of micronuclei was not always polarized, but in some cells they formed a ring. When this occurred, centrioles and Golgi apparatus were located inside the ring. On freeze-fracture replicas, they observed that nuclear pore distinction among the micronuclei was heterogeneous, and on thin sections some micronuclei displayed an incomplete nuclear envelope, with gaps in the double membrane and areas without lamina or condensed chromatin. By autoradiography, they showed that the fibrillar dots were not sites of active transcription. They applied three dimensional reconstruction to one micronucleated cell containing 22 micronuclei whose size indicated that each micronucleus probably contained one chromosome. In this cell they demonstrated that only the smallest micronuclei had an incomplete nuclear envelope. The presence in micronuclei of either nucleoli or fibrillar dots was found to be mutually exclusive. Taken together, these findings indicate that in the diploid nuclei of PtK{sub 1} cells, the three-dimensional organization of the nucleolar domain seems to be directly controlled by the X-chromosome.

  15. Micronuclei induced by fast neutrons versus 60Co gamma-rays in human peripheral blood lymphocytes.

    Science.gov (United States)

    Vral, A; Verhaegen, F; Thierens, H; De Ridder, L

    1994-03-01

    Here we compared the effectiveness of neutrons ( = 5.5 MeV) versus 60Co gamma-rays in producing micronuclei (MN) in human lymphocytes. To obtain dose-response data, blood samples of six donors were irradiated with doses ranging from 0.1 to 5 Gy for gamma-rays and 0.1-3 Gy for neutrons. A linear dependence of MN yield with dose was found for fast neutrons while for gamma-rays a nonlinear dependence existed. For both radiation qualities no significant interindividual differences were found. Derived relative biological effectiveness values decreased with increasing dose. The MN frequency distributions were overdispersed with respect to the Poisson distribution, with neutrons showing higher dispersion values than with gamma-rays. To compare the repair kinetics of both radiation qualities split-dose experiments were performed. A dose of 4 Gy gamma-rays (3 Gy neutrons) was delivered either as a single exposure or in two equal fractions separated by time intervals ranging from 30 min to 10 h (30 min to 7 h for neutrons). The data showed for gamma-rays a significant decline (30% +/- 10%) in MN yield with interfraction time due to repair of DNA damage. This repair is a continuous process starting almost immediately after the first of the two doses and lasting 3-5 h. For fast neutrons no decline was observed indicating irreparable damage.

  16. Dose assessment by quantification of chromosome aberrations and micronuclei in peripheral blood lymphocytes from patients exposed to gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Silva-Barbosa, Isvania; Pereira-MagnataI, Simey; Amaral, Ademir [Pernambuco Univ., Recife, PE (Brazil). Dept. de Energia Nuclear. Grupo de Estudos em Radioprotecao e Radioecologia - GERAR; Sotero, Graca [Fundacao de Hematologia e Hemoterapia, Recife, PE (Brazil); Melo, Homero Cavalcanti [Hospital do Cancer, Recife, PE (Brazil). Centro de Radioterapia de Pernambuco]. E-mail: isvania@uol.com.br

    2005-07-15

    Scoring of unstable chromosome aberrations (dicentrics, rings and fragments) and micronuclei in circulating lymphocytes are the most extensively studied biological means for estimating individual exposure to ionizing radiation (IR), which can be used as complementary methods to physical dosimetry or when the latter cannot be performed. In this work, the quantification of the frequencies of chromosome aberrations and micronuclei were carried out based on cytogenetic analyses of peripheral blood samples from 5 patients with cervical uterine cancer following radiotherapy in order to evaluate the absorbed dose as a result of partial-body exposure to 60Co source. Blood samples were collected from each patient in three phases of the treatment: before irradiation, 24 h after receiving 0.08 Gy and 1.8 Gy, respectively. The results presented in this report emphasize biological dosimetry, employing the quantification of chromosome aberrations and micronuclei in lymphocytes from peripheral blood, as an important methodology of dose assessment for either whole or partial-body exposure to IR.

  17. Induction of micronuclei and binucleated cells by treatment with radiation and cisplatin in CHO cells

    International Nuclear Information System (INIS)

    Rodilla, V.; Seymour, C.B.; Mothersill, C.; Pertusa, J.; Pellicer, J.A.

    1991-01-01

    The frequencies of CHO cells with micronuclei in the cisplatin-treated cultures showed an increase reaching a maximum 48 hours after treatment. Within the next 48 hours a slight decrease in the frequencies was observed. In γ-irradiated cultures (1.2 Gy/min at 80 cm source-skin distance) the maximum in micronuclei-induction was reached at 24 hours post-irradiation, decreasing thereafter. Cultures receiving both treatments showed a similar curve, with a peak at 24 hours, decreasing thereafter. (UK)

  18. Comparative investigations of sodium arsenite, arsenic trioxide and cadmium sulphate in combination with gamma-radiation on apoptosis, micronuclei induction and DNA damage in a human lymphoblastoid cell line

    International Nuclear Information System (INIS)

    Hornhardt, Sabine; Gomolka, Maria; Walsh, Linda; Jung, Thomas

    2006-01-01

    In the field of radiation protection the combined exposure to radiation and other toxic agents is recognised as an important research area. To elucidate the basic mechanisms of simultaneous exposure, the interaction of the carcinogens and environmental toxicants cadmium and two arsenic compounds, arsenite and arsenic trioxide, in combination with gamma-radiation in human lymphoblastoid cells (TK6) were investigated. Gamma-radiation induced significant genotoxic effects such as micronuclei formation, DNA damage and apoptosis, whereas arsenic and cadmium had no significant effect on these indicators of cellular damage at non-toxic concentrations. However, in combination with gamma-radiation arsenic trioxide induced a more than additive apoptotic rate compared to the sum of the single effects. Here, the level of apoptotic cells was increased, in a dose-dependent way, up to two-fold compared to the irradiated control cells. Arsenite did not induce a significant additive effect at any of the concentrations or radiation doses tested. On the other hand, arsenic trioxide was less effective than arsenite in the induction of DNA protein cross-links. These data indicate that the two arsenic compounds interact through different pathways in the cell. Cadmium sulphate, like arsenite, had no significant effect on apoptosis in combination with gamma-radiation at low concentrations and, at high concentrations, even reduced the radiation-induced apoptosis. An additive effect on micronuclei induction was observed with 1 μM cadmium sulphate with an increase of up to 80% compared to the irradiated control cells. Toxic concentrations of cadmium and arsenic trioxide seemed to reduce micronuclei induction. The results presented here indicate that relatively low concentrations of arsenic and cadmium, close to those occurring in nature, may interfere with radiation effects. Differences in action of the two arsenic compounds were identified

  19. Stress induced by premature chromatin condensation triggers chromosome shattering and chromothripsis at DNA sites still replicating in micronuclei or multinucleate cells when primary nuclei enter mitosis.

    Science.gov (United States)

    Terzoudi, Georgia I; Karakosta, Maria; Pantelias, Antonio; Hatzi, Vasiliki I; Karachristou, Ioanna; Pantelias, Gabriel

    2015-11-01

    Combination of next-generation DNA sequencing, single nucleotide polymorphism array analyses and bioinformatics has revealed the striking phenomenon of chromothripsis, described as complex genomic rearrangements acquired in a single catastrophic event affecting one or a few chromosomes. Via an unproven mechanism, it is postulated that mechanical stress causes chromosome shattering into small lengths of DNA, which are then randomly reassembled by DNA repair machinery. Chromothripsis is currently examined as an alternative mechanism of oncogenesis, in contrast to the present paradigm that considers a stepwise development of cancer. While evidence for the mechanism(s) underlying chromosome shattering during cancer development remains elusive, a number of hypotheses have been proposed to explain chromothripsis, including ionizing radiation, DNA replication stress, breakage-fusion-bridge cycles, micronuclei formation and premature chromosome compaction. In the present work, we provide experimental evidence on the mechanistic basis of chromothripsis and on how chromosomes can get locally shattered in a single catastrophic event. Considering the dynamic nature of chromatin nucleoprotein complex, capable of rapid unfolding, disassembling, assembling and refolding, we first show that chromatin condensation at repairing or replicating DNA sites induces the mechanical stress needed for chromosome shattering to ensue. Premature chromosome condensation is then used to visualize the dynamic nature of interphase chromatin and demonstrate that such mechanical stress and chromosome shattering can also occur in chromosomes within micronuclei or asynchronous multinucleate cells when primary nuclei enter mitosis. Following an aberrant mitosis, chromosomes could find themselves in the wrong place at the wrong time so that they may undergo massive DNA breakage and rearrangement in a single catastrophic event. Specifically, our results support the hypothesis that premature chromosome

  20. Effect of doxorubicin on cell survival and micronuclei formation in HeLa cells exposed to different doses of gamma-radiation

    International Nuclear Information System (INIS)

    Jagetia, G.C.; Nayak, V.

    2000-01-01

    Purpose: The present study was undertaken to obtain an insight into the combined effects of doxorubicin with radiation on the cell survival and micronuclei induction in HeLa cells. Material and Methods: HeLa S3 cells were allowed to grow till they reached plateau phase, inoculated with 10 μg/ml doxorubicin hydrochloride and then exposed to 0, 0.5, 1, 2 and 3 Gy γ-radiation. Clonogenicity of cell was measured using the colony forming assay, micronuclei formation using the micronucleus assay. Results: The treatment of HeLa cells with doxorubicin (adriamycin) for 2 hours before exposure to different doses of γ-radiation resulted in a significant and dose-dependent decline in the cell survival and cell proliferation when compared to the PBS+irradiation group. Conversely, the frequency of micronuclei increased in a dose-related manner in both the PBS+irradiation and doxorubicin+irradiation groups. The pretreatment of HeLa cells with doxorubicin before irradiation to various doses of γ-rays resulted in a significant elevation in the frequency of micronuclei when compared with the concurrent PBS+irradiation group. The dose-response relationship for both PBS+irradiation and doxorubicin+irradiation groups was linear. The correlation between cell survival and micronuclei induction was also determined for PBS or doxorubicin+irradiation group, where the clonogenicity of cells declined with the increase in micronuclei formation. The correlation between cell survical and micronuclei induction was linear quadratic for both PBS+irradiation and doxorubicin+irradiation groups. Conclusion: From our study it can be concluded that combination treatment with doxorubicin and radiation increased the genotoxic effect of the either treatment given alone. (orig.) [de

  1. Frequencies of micronuclei in lymphocytes and complete blood picture of radiation worker at Al-Twuathia Site Iraq

    International Nuclear Information System (INIS)

    Amel, J.M.; Abdulsahib, K. A.; Abdullah, A.G.; Haider, Y.L.; Ali, H.F.

    2012-12-01

    The present study aims to use the frequency of micronuclei in lymphocyte and complete blood picture as a bio markers for detection of the effects of the low radiation doses in to decommissioning to radioactive contamination (Lama and Geo- Pilot) as a result of work, during January 2009 to November 2011 present study including collected 113 blood samples, including (103 male and female) aged (25 - 65) year for the exam of compete blood picture analysis, included 69 blood samples as first time before work in Al-Twuathia site, 22 blood samples as a second and third exam. While the cytogenetic analysis including 78 male blood samples aged (35 - 63) year, included 30 blood samples as first time be for work in Al-Twuathia site, 30 blood samples as a second exam and 18 blood samples as third exam, as well as 50 blood samples which are not smokers and alcohol as control group which including (40 male and 10 female) aged (30 - 55 year). Three cytogenetic parameter were employed such as frequency of micronuclei, mitotic index an nuclear and nuclear division index, which used for detection of biological effects of ionizing radiation. Also the current study included the detection of the effect of radiation in complete blood picture analysis of workers at Al-Tuwaitha site, which included (Hb, PCV, WBC count, differential count of WBCs, platelets count of WBCs, platelets count and ESR). From the study no significant differences in the rate of micronuclei and division index of workers in the first and second examination compared with the group of workers in the third exam, while observed a significant increase slightly at level (P <0.05) in these rates compared with the control group, as well as were recorded no significant differences in the rate of mitotic index for workers compared with the control group. Also, found no significant difference in complete blood picture analysis for workers compared with the control group. In conclusion, the significant slightly increase at the

  2. Improvement of techniques for the detection of radio-induced micronuclei in human blood lymphocytes

    Energy Technology Data Exchange (ETDEWEB)

    Voisin, P.; Paillole, N.

    1995-12-31

    Scoring of micronuclei in cytokinesis-blocked peripheral human lymphocytes, after an accidental overexposure, seems an easier and faster alternative for biological dosimetry than conventional cytogenetics (dicentric chromosomes). Several variations of the cytokinesis-block micronucleus assay have been tested, in order to obtain a sufficient number of micronuclei in bi-nucleated cells by the shortest time possible for operational purposes. The methods differ in the use of hypotonic treatment as well as culture time (48 to 72 h), amount of blood and materials used. We have compared frequencies of bi-nucleated cells and micronuclei in normal lymphocytes and after {gamma}-({sup 60}Co) irradiation in vitro with {sup 60}Co for doses up to 6 Gy. Main results and the final choice of the technique are presented. (authors). 3 refs., 3 figs.

  3. Improvement of techniques for the detection of radio-induced micronuclei in human blood lymphocytes

    International Nuclear Information System (INIS)

    Voisin, P.; Paillole, N.

    1995-01-01

    Scoring of micronuclei in cytokinesis-blocked peripheral human lymphocytes, after an accidental overexposure, seems an easier and faster alternative for biological dosimetry than conventional cytogenetics (dicentric chromosomes). Several variations of the cytokinesis-block micronucleus assay have been tested, in order to obtain a sufficient number of micronuclei in bi-nucleated cells by the shortest time possible for operational purposes. The methods differ in the use of hypotonic treatment as well as culture time (48 to 72 h), amount of blood and materials used. We have compared frequencies of bi-nucleated cells and micronuclei in normal lymphocytes and after γ-( 60 Co) irradiation in vitro with 60 Co for doses up to 6 Gy. Main results and the final choice of the technique are presented. (authors). 3 refs., 3 figs

  4. Urban air pollution induces micronuclei in peripheral erythrocytes of mice in vivo

    International Nuclear Information System (INIS)

    Soares, S.R.C.; Bueno-Guimaraes, H.M.; Ferreira, C.M.; Rivero, D.H.R.F.; Castro, I. de; Garcia, M.L.B.; Saldiva, P.H.N.

    2003-01-01

    In this study, we explored the role of chronic exposure to urban air pollution in causing DNA damage (micronuclei frequency in peripheral erythrocytes) in rodents in vivo. Mice (n=20) were exposed to the urban atmosphere of Sao Paulo for 120 days (February to June 1999) and compared to animals (n=20) maintained in the countryside (Atibaia) for the same period. Daily levels of inhalable particles (PM10), CO, NO 2 , and SO 2 , were available for Sao Paulo. Occasional measurements of CO and O 3 were made in Atibaia, showing negligible levels of pollution in the area. The frequency of micronuclei (repeated-measures ANOVA) increased with aging, the highest values obtained for the 90th day of experiment (P 2 (P<0.001), and PM10 (P<0.001). Our results support the concept that urban levels of air pollution may cause somatic mutations

  5. Micronuclei induced by municipal landfill leachate in mouse bone marrow cells in vivo

    International Nuclear Information System (INIS)

    Li Guangke; Sang Nan; Zhao Youcai

    2004-01-01

    The induction of micronuclei (MN) in polychromatic erythrocytes (PCE) of mouse bone marrow by municipal landfill leachate was studied in vivo. Results showed that mouse exposure via drinking water containing various concentrations of leachate caused a significant increase of MN frequencies in a concentration (Chemical oxygen demand measured with potassium dichromate oxidation, COD Cr )-dependent manner. MN induction in female and male mice was different at higher concentrations. This implies that leachate is a genotoxic agent in mammalian cells and that exposure to leachate in an aquatic environment may pose a potential genotoxic risk to human beings

  6. Micronuclei frequency in circulating erythrocytes from rainbow trout (Oncorhynchus mykiss) subjected to radiation, an image analysis and flow cytometric study

    International Nuclear Information System (INIS)

    Schultz, N.; Norrgren, L.; Grawe, J.; Johannisson, A.; Medhage, O.

    1993-01-01

    Rainbow trout (oncorhynchus mykiss) were exposed to a single X-ray dose of 4 Gy. The frequency of micronuclei in the peripheral erythrocytes was investigated at regular intervals up to 58 days after the exposure. A flow cytometric method and a semi-automatic image analysis method were used to estimate the micronuclei frequency. The results show that both methods can detect an increased frequency of micronuclei in peripheral erythrocytes from exposed fish. However, the semi-automatic image analysis method was the most stable and sensitive. (Author)

  7. Two structurally distinct inhibitors of glycogen synthase kinase 3 induced centromere positive micronuclei in human lymphoblastoid TK6 cells.

    Science.gov (United States)

    Mishima, Masayuki; Tanaka, Kenji; Takeiri, Akira; Harada, Asako; Kubo, Chiyomi; Sone, Sachiko; Nishimura, Yoshikazu; Tachibana, Yukako; Okazaki, Makoto

    2008-08-25

    Glycogen synthase kinase 3 (GSK3) is an attractive novel pharmacological target. Inhibition of GSK3 is recently regarded as one of the viable approaches to therapy for Alzheimer's disease, cancer, diabetes mellitus, osteoporosis, and bipolar mood disorder. Here, we have investigated the aneugenic potential of two potent and highly specific inhibitors of GSK3 by using an in vitro micronucleus test with human lymphoblastoid TK6 cells. One inhibitor was a newly synthesized maleimide derivative and the other was a previously known aminopyrimidine derivative. Both compounds elicited statistically significant and concentration-dependent increases in micronucleated cells. One hundred micronuclei (MN) of each were analyzed using centromeric DNA staining with fluorescence in situ hybridization. Both the two structurally distinct compounds induced centromere-positive micronuclei (CMN). Calculated from the frequency of MN cells and the percentage of CMN, CMN cell incidence after treatment with the maleimide compound at 1.2 microM, 2.4 microM, and 4.8 microM was 11.6, 27.7, and 56.3 per 1000 cells, respectively; the negative control was 4.5. CMN cell incidence after the treatment with the aminopyrimidine compound at 1.8 microM, 3.6 microM, and 5.4 microM was 6.7, 9.8 and 17.2 per 1000 cells, respectively. Both compounds exhibited concentration-dependent increase in the number of mitotic cells. The frequency of CMN cells correlated well with mitotic cell incidence after treatment with either compound. Furthermore, both inhibitors induced abnormal mitotic cells with asymmetric mitotic spindles and lagging anaphase chromosomes. These results lend further support to the hypothesis that the inhibition of GSK3 activity affects microtubule function and exhibits an aneugenic mode of action.

  8. The insecticide buprofezin induces morphological transformation and kinetochore-positive micronuclei in cultured Syrian hamster embryo cells in the absence of detectable DNA damage.

    Science.gov (United States)

    Herrera, L A; Ostrosky-Wegman, P; Schiffmann, D; Chen, Q Y; Ziegler-Skylakakis, K; Andrae, U

    1993-11-01

    The insecticide buprofezin was examined for its genotoxicity in cultured Syrian hamster embryo cells in order to better understand the mechanisms underlying the genotoxicity of the compound in mammalian cells. Exposure to buprofezin concentrations of 12.5-100 microM did not significantly affect the colony-forming ability of the cells, but did result in increased frequencies of morphologically transformed colonies. Treatment with buprofezin did not cause a detectable induction of DNA repair synthesis, an indicator of DNA damage, but significantly increased the frequency of micronuclei. Immunostaining of the cells with antikinetochore antibody (CREST antibody) showed that essentially all of the buprofezin-induced micronuclei were kinetochore-positive. The results suggest that morphological transformation of Syrian hamster embryo cells by buprofezin results from an interaction of the compound or a metabolite of it with the mitotic apparatus rather than from DNA damage.

  9. Estimation and comparison of baseline frequencies of micronuclei among the new-borns from natural high background radiation and control areas of Kerala coast in south India

    International Nuclear Information System (INIS)

    Das, Birajalaxmi; Karuppasamy, C.V.; Thampi, M.V.

    1994-01-01

    Based on the studies it is concluded that the elevated level of natural radiation has no significant effect of micronucleus formation in high background radiation area (HBRA) new-borns as compared to control area. It is also in agreement with the results of cytogenetic investigations on new-borns from HBRA and control area using chromosome aberration analysis method. The significance, if any, of the slightly lower micronuclei (MN) frequency observed in HBRA, is not clear at this stage. Further investigations on a larger number of new-borns from both the areas are necessary in order to draw firm conclusions. It appears that, this is the first attempt to estimate the baseline frequency of MN among the new-borns from a natural high background radiation area. (author). 9 refs

  10. Induction of micronuclei by X radiation and various chemical agents in red blood cells of Pleurodeles waltl. Uptake, release and excretion of one of them: benzo(a)pyrene

    International Nuclear Information System (INIS)

    Grinfeld, S.

    1983-11-01

    The first part of the study is concerned with the effects of X radiation and of various substances dissolved in the breeding water (carbaryl, N-nitrosocarbaryl, benzo(a)pyrene, formol, cafeine, colchicine...) on the formation of micronuclei in red blood cells of Pleurodele larvae. The curves of the dose-effect relationships and of the kinetics of micronuclei formation are established for X radiation and benzo(a)pyrene. In the second part, a scintigraphic study concerning benzo(a)pyrene uptake, release and excretion by larvae, is presented. This study enables the dose-effect curve and the kinetics of micronuclei formation for this substance, to be interpreted. This study must allow the development of a cytogenetic test for the detection of radiomimetic substances in aqueous medium. Pleurodele is proposed as a new animal for the study of genetic toxicology [fr

  11. MICRONUCLEI: A PROGNOSTIC TOOL

    OpenAIRE

    Ankit; Rinky; Manisha; Sonalika; Anand; Sanyog

    2014-01-01

    Squamous cell carcinoma is one the most common oral mucosal malignant tumor, diagnosis of oral squamous cell carcinoma rarely presents difficulty, it is the cancer staging and histo pathological grading that are more important for prognosis, micronuclei are good prognostic indicator. Micronuclei screening can be done easily by exfoliative cytology, one of the most valuable diagnostic method other than routine histopathology (H and E-stained sections) and immunohistochemist...

  12. Chromosomal aberrations, micronuclei and nuclear buds induced in human lymphocytes by 2,4-dichlorophenoxyacetic acid pesticide formulation

    International Nuclear Information System (INIS)

    Zeljezic, Davor; Garaj-Vrhovac, Vera

    2004-01-01

    Pesticides of worldwide application are used in agriculture in vast amounts each year, of which herbicides are the most prominent class. Phenoxyacetic herbicides constitute one of the largest groups of herbicides sold in the world. Among them, for many years 2,4-dichlorophenoxyacetic acid (2,4-D) has been the one most used. In this study we used Deherban A[reg], a commercial formulation of 2,4-D to determine its possible genotoxic effect on human lymphocytes in vitro by chromosomal aberration analysis and micronucleus assay including the scoring of nuclear buds. Two different concentrations of pesticide formulation were used so that final concentrations of 2,4-D were 0.4 and 4 μg/ml, both in the presence and in the absence of the liver microsomal fraction as metabolic activator. Both concentrations of pesticide caused an increase in chromatid and chromosome breaks, number of micronuclei and number of nuclear buds. Presence of the S9 mix additionally elevated the number of chromatid breaks and micronuclei in treated lymphocytes

  13. Frequency of micronuclei in individuals from high level natural radiation areas of Kerala in India, as a function of age and gender

    International Nuclear Information System (INIS)

    Karuppasamy, C.V.; Ramachandran, E.N.; Vivek Kumar, P.R.; Anil Kumar, V.; Sudheer, K.R.; Jaikishan, G.; Jagateesan, C.K.; Seshadri, M.

    2012-01-01

    The genotoxic effects of chronic low level radiation exposure in humans may be studied by estimating the frequency of micronuclei (MN) in whole blood samples. Frequency of MN is also known to be affected by age, gender and smoking habit of individuals. In this study we have evaluated the frequency of MN in subjects from high level natural radiation areas (HLNRA) of Kerala. Radioactivity in this area is primarily due to the presence of 8-10% of thorium ( 232 Th) in the monazite, which is 1% of the beach sand. Peripheral blood samples were obtained from 105 subjects by venipuncture using heparinised vacuette tubes, after obtaining informed consent. Age of the subjects ranged between 22 and 80. Of these subjects, 68 belong to HLNRA and consisted of 50 males and 18 females. Thirty seven subjects belong to normal level natural radiation areas (NLNRA) and consisted of 27 males and 10 females. Whole blood cultures were set up for the MN test using the cytokinesis-block methodology. Frequency of MN was calculated per 1000 binucleated cells. Data on the frequency of MN was analyzed after log transformation, as the results were not normally distributed. The basal frequency of micronuclei in the 105 subjects studied was 13.59 ± 7.49 (Mean ± S.D.) with a range of 2-37. Multiple regression analysis in all samples showed significant influence of age (P=0.02) and gender (P=0.007) on the frequency of MN. However, the frequency of MN was comparable (P=0.3) between NLNRA (12.97 ± 7.84) and HLNRA subjects (13.92 ± 7.34). In this study, 75% (N=21) of females were in the age group of 35-55. Frequency of MN was significantly (Th=0.05) higher among females (17.80 ± 7.56) compared to males belonging to age group of 35-55 (14.09 ± 6.95). Further, in subgroup analysis, in male subjects (N=77) frequency of MN was significantly influenced by age (P=0.03) and not by smoking habit (P=0.11) or residential area (NLNRA/HLNRA, P=0.7). In female subjects (N=28) frequency of MN was not

  14. Cell cycle kinetics and in vivo micronuclei induction in rat rhabdomyosarcoma tumors using a monoclonal antibody to BrdUrd and cell sorting

    International Nuclear Information System (INIS)

    Nuesse, M.; Afzal, S.M.J.; Carr, B.C.; Kavanau, K.S.; Tenforde, T.S.; Curtis, S.B.

    1986-01-01

    The aim of the experiments reported here was to investigate the applicability of the BrdUrd/DNA technique to a rat rhabdomyosarcoma tumor system growing in vivo and to study radiation-induced changes in the progression of cells through the cell cycle. Details of this technique are described elsewhere. In addition, the induction of micronuclei in tumor cells irradiated in vivo with x-rays or peak neon ions was studied. Micronuclei found in interphase cells after irradiation represent genetic material that is lost from the genome of the cells during mitosis. The formation of micronuclei that can mainly be ascribed to acentric chromosome or chromatid fragments occurs only after cells go through one or more cell divisions. Cycling cells in the tumors were, therefore, continuously labeled with BrdUrd, and micronuclei induction was measured only in tetraploid cycling tumor cells using the flow cytometric cell sorting technique

  15. Ultraviolet-induced formation of micronuclei and sister chromatid exchange in cultured fibroblasts of patients with cutaneous malignant melanoma

    International Nuclear Information System (INIS)

    Roser, M.; Boehm, A.O.; Oldigs, M.; Weichenthal, M.; Reimers, U.; Schmidt-Preuss, U.; Breitbart, E.W.; Ruediger, H.W.

    1989-01-01

    Genetically enhanced sensitivity to ultraviolet (UV) radiation may play an important role in the development of cutaneous malignant melanoma (CMM). This was studied in cultured fibroblasts of 26 CMM patients and controls by micronucleus (MN) test and sister chromatid exchange (SCE) after UV irradiation (375 J/m2). Sister chromatid exchange and MN formation were used as parameters to detect the UV-induced genotoxic damage in the individual cell strains. We found that the UV-induced level of MN was significantly increased in CMM patients (p = 0.0005), being most pronounced in the familial cases (p = 0.0001). Ultraviolet-induced SCE was also elevated in CMM patients (p = 0.001), but there was no difference between familial and nonfamilial cases. The present findings indicate that genetic predisposition contributes to the development of CMM in a subset of CMM patients and may be due to an enhanced susceptibility to UV light

  16. Incidence of Micronuclei inversly relates with apoptosis in human circulating lymphocytes

    International Nuclear Information System (INIS)

    Jocksic, G.; Djurovic, B.; Petrovic, S.

    2004-01-01

    In this study relationship between chromosome aberrations, micronuclei, radiosensitivity and apoptosis of circulating lymphocytes of radiation workers was evaluated. Exposed group comprises 34 individuals, radiology sts, of mean age 43,35±6.02; with 14.9±5.2 years of occupational exposition to ionizing radiation. In 10 out of 34 exchange aberrations were found (dicentrics and ring chromosomes). According to chromosomal findings exposed groups was divided on two subgroups:>> dicentric positive >dicentric negative > dicentric positive >dicentric >dicentric >dicentric >dicentric >dicentric<< negative respectively. Baseline micronuclei correlates negatively with apoptosis in both exposed groups (r=0.55m p<0.45) suggesting that chronical exposure to low doses of ionizing radiation disturb the balance between pro apoptotic and anti apoptotic signals in cells. Results of our study have shown that effects of radiation-induced cytotoxicity could be characterised employing flow cytometry as precise method for measuring degradation of internucleosaomal DNA. Inversly relationship between baseline micronuclei and percent of lymphocytes undergoing apoptosis is the most important finding in this study, suggesting that assay can discriminate differences in radiation-induced cytotoxicity between individuals occupationally exposed to low doses of ionising radiation. (Author)

  17. Effects of γ (60Co) and β (90Sr) radiations in Chinese hamster ovarian cells (CHO-K1): induction of micronuclei and cell death

    International Nuclear Information System (INIS)

    Murakami, Daniella

    2003-01-01

    Among various types of ionising radiation, the beta emitter radionuclides are involved in many sectors of human activity, such as nuclear medicine, nuclear industries and biomedicine, with a consequent increased risk of accidental, occupational or therapeutic exposure. Despite their recognized importance, there is little information about the effect of beta particles at the cellular level when compared to other types of ionizing radiation. Thus, the objective of the present study was to evaluate the genotoxic and cytotoxic effects of 90 Sr, a pure, highly energetic beta source, on CHO-K1 cells and to compare them with data obtained with 60 Co. CHO-K1 cells irradiated with different doses (1.0, 2.5, 5.0, 7.5 Gy) of 60 Co (0.34 Gy.min -1 ) and 90 Sr (0.23 Gy.min -1 ) were processed for analysis of clonogenic death, induction of micronuclei (MN) and necrotic and apoptotic death. The survival curves obtained for both types of radiation were better fitted by the linear-quadratic model and were similar. However, the cytogenetic results showed that both the proportion of micronucleated cells and the magnitude of radioinduced lesions demonstrated by the analysis of MN distribution were significantly higher in cells irradiated with 60 Co than in cells irradiated with 90 Sr, whereas 90 Sr was more damaging than 60 Co in terms of cell death induction. Necrosis was the major type of death observed in CHO-K1 cells. The data obtained suggest that the low incidence of micronucleated cells after exposure to 90 Sr may be a consequence of selective elimination of severely damaged cells from the population by the necrotic process at a higher rate than observed with 60 Co exposure. The data obtained also demonstrated the need to use several parameters for a better estimate of cellular sensitivity to the action of genotoxic agents, which would be important in terms of radiobiology, oncology and therapeutics. (author)

  18. Radiation-induced pneumothorax

    International Nuclear Information System (INIS)

    Epstein, D.M.; Littman, P.; Gefter, W.B.; Miller, W.T.; Raney, R.B. Jr.

    1983-01-01

    Pneumothorax is an uncommon complication of radiation therapy to the chest. The proposed pathogenesis is radiation-induced fibrosis promoting subpleural bleb formation that ruptures resulting in pneumothorax. We report on two young patients with primary sarcomas without pulmonary metastases who developed spontaneous pneumothorax after irradiation. Neither patient had antecedent radiographic evidence of pulmonary fibrosis

  19. Use of 2-color flow cytometry to assess radiation induced geotoxic damage on CHO-KI cells

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, Luma Ramirez de; Bonfim, Leticia; Vieira, Daniel Perez, E-mail: lrcarvalho@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2017-11-01

    The micronucleus assay is an important technique used to evaluate genotoxic damage of chemical or physical agents (as ionizing radiations) on cells, based on quantification of cells bearing micronuclei, which are fragments derived from damage (breakage) of the DNA. Currently, this technique was updated to an automated approach that relies on plasma membrane dissolution to analyze fluorescent dye-labelled nuclei and micronuclei by flow cytometry. Cell suspensions were irradiated in PBS by a {sup 60}Co source in doses between 0 and 16Gy, and incubated by 48h. Cell membranes were lysed in the presence of SYTOX Green and EMA dyes, so EMA-stained nuclei could be discriminated as from dead cells, and nuclei and micronuclei could be quantified. Amounts of micronuclei (percent of events) in the samples, were found to be proportional to radiation doses, and could be fitted to a linear-quadratic model (R² = 0.993). Only higher doses (8 and 16Gy) and positive control could induce relevant increases in micronucleus amounts. The incorporation EMA showed an increase in irradiated cells. Mid to high doses (4, 8 and 16Gy) induced reduction of cell proliferation. Experiments showed the suitability of the technique to replace traditional microscopy analysis in evaluation of the effects of ionizing radiations on cells, with possibility to use in biological dosimetry. (author)

  20. The chromosome damage induced by x-ray radiation doses. Comparison between dicentric chromosomes, micronuclei and Sister Chromatid Exchanges analyses. Valoracion de dao cromosomico originado por una dosis de rayos X. Comparacion de los analisis de cromosomas dicentricos, micronucleos e intercambios entre cromatidas hermanas

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, J.L.; Losada, C.; Losada, G.; Veiras, C. (Centro Oncologico de Galicia. La Corua (Spain)); Goyanes, V.J. (Hospital ' ' Teresa Herrera' ' . La Corua (Spain))

    1993-01-01

    Exposure to ionizing radiations is a well-known source of chromosome damage. Here we present a comparison among three different methodologies employed to recognize cytogenetic damage, after an acute exposure of human lymphocytes to 3 Gy of X-rays (100kVp). Scoring of dicentric chromosomes, present in first mitosis ''in vitro'', was the method of preference as dicentrics increased 937.5 times with respect to background. Micronucleus scoring in binucleated-cytokinesis blocked cells showed an increase of 32.5 times, while it was only of 1.46 times when Sister Chromatid Exchanges (SCEs) were analyzed. The estimated probability of an acentric fragment becoming a micronucleus was around 0.25. Intercellular distribution of dicentrics agree with Poisson, while micronucleus were overdispersed. When analyzed at second cycle after damage induction, the dicentrics yield as well as the level of cells with unstable cromosome aberrations, decreased around a half. Finally, SCEs level was similar in cells with or without unstable structural chromosome aberrations. (Author)

  1. Radiation-induced apoptosis

    International Nuclear Information System (INIS)

    Ohyama, Harumi

    1995-01-01

    Apoptosis is an active process of gene-directed cellular self-destruction that can be induced in many cell types via numerous physiological and pathological stimuli. We found that interphasedeath of thymocytes is a typical apoptosis showing the characteristic features of apoptosis including cell shrinkage, chromatin condensation and DNA degradation. Moderate dose of radiation induces extensive apoptosis in rapidly proliferating cell population such as the epithelium of intestinal crypt. Recent reports indicate that the ultimate form of radiation-induced mitotic death in several cells is also apoptosis. One of the hallmarks of apoptosis is the enzymatic internucleosomal degradation of chromatin DNA. We identified an endonuclease responsible for the radiation-induced DNA degradation in rat thymocytes. The death-sparing effects of interrupting RNA and protein synthesis suggested a cell genetic program for apoptosis. Apoptosis of thymocytes initiated by DNA damage, such as radiation and radio mimetic substance, absolutely requires the protein of p53 cancer suppresser gene. The cell death induced by glucocorticoid, or aging, has no such requirement. Expression of oncogene bcl-2 rescues cells from the apoptosis. Massive apoptosis in radiosensitive cells induced by higher dose radiation may be fatal. It is suggested that selective apoptotic elimination of cells would play an important role for protection against carcinogenesis and malformation through removal of cells with unrepaired radiation-induced DNA damages. Data to evaluate the significance of apoptosis in the radiation risk are still poor. Further research should be done in order to clarify the roles of the cell death on the acute and late effects of irradiation. (author)

  2. Effects on micronuclei formation of 60-Hz electromagnetic field exposure with ionizing radiation, hydrogen peroxide, or c-Myc overexpression.

    Science.gov (United States)

    Jin, Yeung Bae; Kang, Ga-Young; Lee, Jae Seon; Choi, Jong-Il; Lee, Ju-Woon; Hong, Seung-Cheol; Myung, Sung Ho; Lee, Yun-Sil

    2012-04-01

    Epidemiological studies have demonstrated a possible correlation between exposure to extremely low-frequency magnetic fields (ELF-MF) and cancer. However, this correlation has yet to be definitively confirmed by epidemiological studies. The principal objective of this study was to assess the effects of 60 Hz magnetic fields in a normal cell line system, and particularly in combination with various external factors, via micronucleus (MN) assays. Mouse embryonic fibroblast NIH3T3 cells and human lung fibroblast WI-38 cells were exposed for 4 h to a 60 Hz, 1 mT uniform magnetic field with or without ionizing radiation (IR, 2 Gy), H(2)O(2) (100 μM) and cellular myelocytomatosis oncogene (c-Myc) activation. The results obtained showed no significant differences between the cells exposed to ELF-MF alone and the unexposed cells. Moreover, no synergistic effects were observed when ELF-MF was combined with IR, H(2)O(2), and c-Myc activation. Our results demonstrate that ELF-MF did not enhance MN frequency by IR, H(2)O(2) and c-Myc activation.

  3. The Induction of Chromosome Aberrations and Micronuclei in Human Peripheral Blood Lymphocytes at Low Doses of Radiation

    CERN Document Server

    Shmakova, N L; Krasavin, E A; Melnikova, L A; Fadeeva, T A

    2003-01-01

    The chromosome damage induced by the low doses of gamma-irradiation with ^{60}Co and X-rays in peripheral blood lymphocytes has been studied using different cytogenetic assays. Isolated lymphocytes were exposed to 0.01-1.0 Gy, simulated by PHA, and analysed for chromosome aberrations by the metaphase and the anaphase methods, by the micronucleus assay. Despite the quantitative differences in the amount of chromosome damage revealed by different methods, all of them demonstrated complex nonlinear dose dependence of the frequency of aberrant cells and aberrations. At the dose range of 0.01-0.05 Gy the cells showed the highest radiosensitivity; at 0.05-0.5 Gy the dose-independent induction of chromosome damage was revealed. At the doses of 0.5-1.0 Gy the dose-effect curves became linear with the decreased slope compared with the initial one (by a factor of 5 to 10 for different criteria) reflecting a higher radioresistance of the cells. These data confirm the idea that the direct linear extrapolation of high-dos...

  4. Failure of antimony trioxide to induce micronuclei or chromosomal aberrations in rat bone-marrow after sub-chronic oral dosing.

    Science.gov (United States)

    Kirkland, David; Whitwell, James; Deyo, James; Serex, Tessa

    2007-03-05

    Antimony trioxide (Sb2O3, CAS 1309-64-4) is widely used as a flame retardant synergist in a number of household products, as a fining agent in glass manufacture, and as a catalyst in the manufacture of various types of polyester plastics. It does not induce point mutations in bacteria or mammalian cells, but is able to induce chromosomal aberrations (CA) in cultured cells in vitro. Although no CA or micronuclei (MN) have been induced after acute oral dosing of mice, repeated oral dosing for 14 or 21 days resulted in increased CA in one report, but did not result in increased MN in another. In order to further investigate its in vivo genotoxicity, Sb2O3 was dosed orally to groups of rats for 21 days at 250, 500 and 1000 mg/kg day. There were no clinical signs of toxicity in the Sb2O3-exposed animals except for some reductions in body-weight gain in the top dose group. Toxicokinetic measurements in a separate study confirmed bone-marrow exposure, and at higher levels than would have been achieved by single oral dosing. Large numbers of cells were scored for CA (600 metaphases/sex group) and MN (12,000 PCE/sex group) but frequencies of CA or MN in Sb2O3-treated rats were very similar to controls, and not biologically or statistically different, at all doses. These results provide further indication that Sb2O3 is not genotoxic to the bone marrow of rodents after 21 days of oral administration at high doses close to the maximum tolerated dose.

  5. Effect of radiosensitizer BSO on the incidence of micronuclei in cultured cells

    International Nuclear Information System (INIS)

    Jin Yizun; Cai Rongmei; Ding Li; Shen Zhifen; Xu Liming; Yang Jiakuan

    1992-01-01

    The effects of BSO, a potent radiosensitizing and chemical sensitizing chemical, on the incidence of micronuclei in four different cell lines have been studied using the cytokinesis-block (CB) method. The number of micronuclei in cultured human peripheral lymphocytes, Chinese hamster cells and human breast cancer cells were not affected by 0.1-2 mmol/L BSO treatment alone. However, significant increase in the incidence of micronuclei in these cells could be detected when BSO was used in combination with γ-irradiation. Linear relationship between the incidence of micronuclei and the radiation dose was observed

  6. Radiation-induced myelopathy

    Energy Technology Data Exchange (ETDEWEB)

    Gaenshirt, H [Heidelberg Univ. (F.R. Germany). Neurologische Klinik

    1975-10-01

    12 cases of radiation-induced myelopathy after /sup 60/Co teletherapy are reported on. Among these were 10 thoracal lesions, one cerviothoracal lesion, and one lesion of the medulla oblongata. In 9 cases, Hodgkin's disease had been the primary disease, tow patients had been irradiated because of suspected vertebral metastases of cancer of the breast, and one patient had suffered from a glomus tumour of the petrous bone. The spinal doses had exceeded the tolerance doses recommended in the relevant literature. There was no close correlation between the radiation dose and the course of the disease. The latency periods between the end of the radiotherapy and the onset of the neurological symptons varied from 6 to 16 mouths and were very constant in 7 cases with 6 to 9 months. The segmental height of the lesion corresponded to the level of irradiation. The presenting symptons of radiation-induced myelopathy are buruing dysaesthesias and Brown-Sequard's paralysis which may develop into transverse lesion of the cord with paraplegia still accompanied by dissociated perception disorders. The disease developed intermittently. Disturbances of the bladder function are frequent. The fluid is normal in most cases. Myelographic examinations were made in 8 cases. 3 cases developed into stationary cases exhibiting. Brown-Sequard syndrome, while 9 patients developed transverse lesion of the cord with paraplegia. 3 patients have died; antopsy findings are given for two of these. In the pathogenesis of radiation-induced myelopathy, the vascular factor is assumed to be of decisive importance.

  7. Radioprotective Effect of Achillea millefolium L Against Genotoxicity Induced by Ionizing Radiation in Human Normal Lymphocytes

    Directory of Open Access Journals (Sweden)

    Somayeh Shahani

    2015-04-01

    Full Text Available The radioprotective effect of Achillea millefolium L (ACM extract was investigated against genotoxicity induced by ionizing radiation (IR in human lymphocytes. Peripheral blood samples were collected from human volunteers and incubated with the methanolic extract of ACM at different concentrations (10, 50, 100, and 200 μg/mL for 2 hours. At each dose point, the whole blood was exposed in vitro to 2.5 Gy of X-ray and then the lymphocytes were cultured with mitogenic stimulation to determine the micronuclei in cytokinesis-blocked binucleated cell. Antioxidant capacity of the extract was determined using free radical-scavenging method. The treatment of lymphocytes with the extract showed a significant decrease in the incidence of micronuclei binucleated cells, as compared with similarly irradiated lymphocytes without any extract treatment. The maximum protection and decrease in frequency of micronuclei were observed at 200 μg/mL of ACM extract which completely protected genotoxicity induced by IR in human lymphocytes. Achillea millefolium extract exhibited concentration-dependent radical-scavenging activity on 1,1-diphenyl-2-picryl hydrazyl free radicals. These data suggest that the methanolic extract of ACM may play an important role in the protection of normal tissues against genetic damage induced by IR.

  8. 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

  9. 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.

  10. Radiation induced genomic instability

    International Nuclear Information System (INIS)

    Morgan, W.

    2003-01-01

    This presentation will focus on delayed genetic effects occurring in the progeny of cells after exposure to ionizing radiation. We have developed a model system for investigating those genetic effects occurring multiple generations after radiation exposure. The presentation will describe some of the delayed effects observed after radiation exposures including delayed chromosomal rearrangements, and recombination events as determined by a plasmid based assay system. We will present new data on how changes in gene expression as measured by differential display and DNA microarray analysis provides a mechanism by which cells display a memory of irradiation, and introduce candidate genes that may play a role in initiating and perpetuation the unstable phenotype. These results will be discussed in terms of the recently described non-targeted Death Inducing Effect (DIE) where by secreted factors from clones of unstable cells can elicit effects in non irradiated cells and may serve to perpetuate the unstable phenotype in cells that themselves were not irradiated

  11. 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

  12. Effect of misonidazole (Ro-07-0582) on the incidence of micronuclei in irradiated Ehrlich tumour ascites cells

    Energy Technology Data Exchange (ETDEWEB)

    Olinici, C D; Mustea, I [Institute of Oncology, Cluj (Romania)

    1978-12-01

    Misonidazole (1-(2-nitro-1-imidazole)-3-methoxy-2-propanol) was injected intraperitoneally into mice on the fifth day of development of Ehrlich ascites tumours. The animals were then /sup 60/Co ..gamma..-irradiated (100 to 400 R) and killed at 24 to 72 hours post-irradiation. Ascites tumour cells from the mice were stained by the Feulgen reaction and the incidence of micronuclei determined. Pretreatment with misonidazole induced an increase in the incidence of micronuclei in the irradiated tumour cells. This increase was most conspicuous at higher radiation doses and at 48 hours post-irradiation. The results suggest the possibility of using the micronucleus assay for the screening of substances with radio-sensitizing potential. The method would be especially suitable for the study of tumours irradiated in vivo with high doses of radiation, since cytogenetic methods present difficulties under these conditions.

  13. Radiation-induced cancer

    International Nuclear Information System (INIS)

    Dutrillaux, B.; CEA Fontenay-aux-Roses, 92

    1998-01-01

    The induction of malignant diseases is one of the most concerning late effects of ionising radiation. A large amount of information has been collected form atomic bomb survivors, patients after therapeutic irradiation, occupational follow-up and accidentally exposed populations. Major uncertainties persist in the (very) low range i.e, population and workers radioprotection. A review of the biological mechanisms leading to cancer strongly suggests that the vast majority of radiation-induced malignancies arise as a consequence of recessive mutations can be unveiled by ageing, this process being possibly furthered by constitutional or acquired genomic instability. The individual risk is likely to be very low, probably because of the usual dose level. However, the magnitude of medical exposure and the reliance of our societies on nuclear industry are so high that irreproachable decision-making processes and standards for practice are inescapable. (author)

  14. 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)

  15. Hypersensitivity of Allium cepa seedling roots to X-rays for production of micronuclei

    International Nuclear Information System (INIS)

    Hori, Takayoshi; Hanmoto, Hidehiro; Fujishige, Ikuko; Inoue, Toshihiro; Taniguchi, Kenji; Itoh, Tetsuo; Fujikawa, Kazuo; Yonezawa, Yoshihiko.

    1995-01-01

    Seedling roots of onion (Allium cepa) were irradiated with various doses of X-rays. Following irradiation, the roots were incubated at 23-25degC for 24 hr, i.e., approximate time for one mitotic cycle, and then fixed, stained and macerated in a 7:3 mixture of acetic dahlia (prepared by dissolving a 0.5 g sample of dahlia violet into 100 ml of 30% acetate) and 1 N HCl for 10-15 min. Terminal 1-2 mm of the root tips were squashed on slides, one root each, and microscopically inspected for the presence of more than one nucleus in the cells. The additional nuclei, which were smaller than the normal, were scored as micronuclei. The frequency of micronuclei increased with dose over the control level (∼0.2x10 -3 ) to a high level of 140x10 -3 at 1 Gy. The frequency recorded at 1 Gy was about two fold higher as compared with the frequency reported by Evans et al. (1959) for micronuclei induced by γ-rays at a comparable dose in the root tip cells of Vica faba seedlings, probably reflecting relatively higher DNA content per cell in Allium somatic cells. We thus may conclude that root-tip meristematic cells of Allium seedlings are hypersensitive to the induction of micronuclei by X-rays. The Allium micronucleus assay may be useful as a system not only for quantitating chromosome damage by low-level radiation but also for detecting environmental mutagens. (author)

  16. Biological dosimetry of X-rays by micronuclei study

    International Nuclear Information System (INIS)

    Gomez, E.; Silva, A.; Navlet, J.

    1991-01-01

    Biological dosimetry consists of estimating absorbed doses for people exposed to radiation by mean biological methods. Several indicators used are based in hematological, biochemical an cytogenetics data, although nowadays without doubt, the cytogenetic method is considered to be the most reliable, in this case, the study of micronuclei in peripheral blood lymphocytes cytokinetic blocked can be related to absorbed dose through an experimental calibration curve. An experimental dose-response curve, using micronuclei assay for X-rays at 250 kVp, 43,79 rads/min and temperature 37 degree celsius has been produced. Experimental data is fitted to model Y=c+ α D+β D 2 where. Y is the number micronuclei per cell and D the dose. the curve is compared with those produced elsewhere

  17. Biological Dosimetry of X-rays by micronuclei study

    International Nuclear Information System (INIS)

    Gomez, E.; Silva, A.; Navlet, J.

    1991-01-01

    Biological dosimetry consists of estimating absorbed doses for people exposed to radiation by mean biological methods. Several indicators used are based in haematological, biochemical an cytogenetics data, although nowadays without doubt, the cytogenetic method is considered to be the most reliable, in this case, the study of micronuclei in peripheral blood lymphocytes citokinetics blocked can be related to absorbed dose through an experimental calibration curve. An experimental dose-response curve, using micronuclei assay for X-rays at 250 kVp, 43,79 rads/min and temperature 37 degree centigree has been produced. Experimental data is fitted to model Y=C+ αD+BD''2 where Y is the number of micronuclei per cell and D the dose. The curve is compared with those produced elsewhere. (Author) 24 refs

  18. [Induction of micronuclei in peripheral blood and bone marrow reticulocytes of male mice after subchronic exposure to x-rays and bisphenol A].

    Science.gov (United States)

    Radzikowska, Joanna; Gajowik, Aneta; Dobrzyńska, Małgorzata

    2012-01-01

    Ionizing radiation and xenoestrogens are widely present in the human environment. Bisphenol A (BPA) is used to manufacture polycarbonate plastics, epoxy and polyester resins. BPA is present in a great variety of products including: baby bottles, compact disks, thermal paper, safety helmets, bullet resistant laminate, plastic windows, car parts, adhesives, protective coatings, powder paints, polycarbonate bottles and containers, the sheathing of electrical and electronic parts, dental fillings. Food and beverage cans are protected from rusting and corrosion by the application of epoxy resins as inner coatings. Human activities involving the use of radiation and radioactive materials in industry, agriculture and research cause radiation exposure in addition to natural exposure coming from cosmic rays and naturally occurring radioactive substances. The aim of the study was to estimate the effects of bisphenol A, X-rays and combined exposure to X-rays and bisphenol A on the induction of micronuclei in the peripheral blood and in bone marrow reticulocytes of laboratory mice. Pzh-Sfis male mice were exposed for 8 weeks. Animals were treated with bisphenol A diluted in drinking water (5 mg/kg bw, 10 mg/kg bw, 20 mg/kg bw), irradiated 0.05 Gy of X-rays or exposed to a combination of both (0.05 Gy + 5 mg/kg bw BPA). The samples of peripheral blood were taken at 1, 4 and 8 week following the start of exposure, whereas the bone marrow after the end of experiment, only. The induction of micronuclei in reticulocytes were evaluated by using fluorescence microscope. Bisphenol A as well as ionizing radiation stimulated induction of micronuclei in peripheral blood and bone marrow reticulocytes. After the irradiation the level of micronuclei increased, whereas after exposure to BPA decreased related to time expired from beginning of experiment. Combined exposure of ionizing radiation and bisphenol A induced significantly higher frequency of micronuclei compared to the effect

  19. Radiation-induced nondisjunction

    International Nuclear Information System (INIS)

    Uchida, I.A.

    1979-01-01

    The methodology and results of epidemiological studies of the effects of preconception diagnostic x-rays of the abdomen on chromosome segregation in humans are described. The vast majority of studies show the same positive, though not significant, trend to increased nondisjunction among the offspring of irradiated women. The results of the various studies, however, cannot be pooled because of differing methodologies used. Abnormal chromosome segregation during mitotic division has been inducted experimentally by the in vitro exposure of human lymphocytes to a low dose of 50 R gamma irradiation. First meiotic nondisjunction has been successfully induced by whole body exposure of female mice to a low dose of radiation. The question of time-related repair of the mechanism involved in chromosome segregation is raised

  20. 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

  1. Radiation-induced thermoacoustic imaging

    International Nuclear Information System (INIS)

    Bowen, T.

    1984-01-01

    This invention provides a new technique for obtaining information non-invasively on the composition and structures of a material or body by detecting radiation-induced thermoacoustic image features. This is accomplished by utilizing the acoustic wave generated by sudden thermal stress. The sudden thermal stress is induced by a pulse of radiation which deposits energy causing a rapid, but very small, rise of temperature (typically, ΔT approximately 10sup(-6) - 10sup(-5) deg C). The radiation may be ionizing radiation, such as high energy electrons, photons (x-rays), neutrons, or other charged particles or it may be non-ionizing radiation, such as R.F. and microwave electromagnetic radiation and ultrasonic radiation. The choice of radiation depends on the nature of the body to be imaged and the type of information desired

  2. 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)

  3. 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)

  4. Evaluation of radiation-induced genotoxicity on human melanoma cells (SK-MEL-37) by flow cytometry

    International Nuclear Information System (INIS)

    Bonfim, Leticia; Carvalho, Luma Ramirez de; Vieira, Daniel Perez

    2017-01-01

    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 "6"0Co 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)

  5. 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)

  6. Radiation-induced enteropathy

    Energy Technology Data Exchange (ETDEWEB)

    Sher, M.E.; Bauer, J. (Mount Sinai Hospital, New York, NY (USA))

    1990-02-01

    The incidence of chronic radiation enteritis appears to have risen in recent years due to the increasing utilization of radiotherapy for abdominal and pelvic malignancies. The etiology, pathogenesis, and management of radiation enteritis are discussed. Two case reports exemplify the progressive nature of the disease. Case 1 demonstrates the classical picture of multiple exacerbations and remissions of partial small bowel obstruction and the eventual need for surgical management ten years after radiation therapy. Case 2 presents the more severe sequelae of an acute perforation with a 14-yr latency period. Predisposing factors in the progression of radiation injury include excessive radiation, underlying cardiovascular disease, fixation of the bowel, and an asthenic habitus. In both cases, radiation injury was localized to a discrete segment of bowel; therefore, resection with a primary end-to-end anastomosis was performed. In addition, diseased bowel was eliminated and, therefore, would not cause further complications such as intractable bleeding or fistula formation. The review focuses on current knowledge which may be applied to the treatment and prevention of radiation enteritis.

  7. 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.

  8. RNA polymerase activity in PtK1 micronuclei containing individual chromosomes: an in vitro and in situ study

    International Nuclear Information System (INIS)

    Labidi, B.; Gregoire, M.; Frackowiak, S.; Hernandez-Verdun, D.; Bouteille, M.

    1987-01-01

    Micronuclei have been induced by colchicine in rat kangaroo (Potorous tridactylis) PtK1 cells. The synthesis of RNA was investigated both in isolated micronuclei by quantifying RNA polymerase activities at different ionic strengths with or without inhibitors, and in micronucleated cells by radioautography after [ 3 H]uridine pulse labeling. In vitro transcription shows that isolated micronuclei are able to take up [ 3 H]UTP. The rate curves of incorporation are close to those of isolated diploid nuclei, though the level of incorporation was relatively lower (65-70%) than control nuclei. This indicates that micronuclei react to the ionic environment and to inhibitors in the same manner as described for many species of isolated diploid nuclei. The labelling distributions plotted from radioautographs show that micronuclei were able to efficiently incorporate the hot precursor. Furthermore, for short pulses there is no homogeneity in the labelling density among the different micronuclei and there is no correlation between the labelling intensity and the size of micronuclei. After 60-min pulse time, there is an enhanced uptake of [ 3 H]uridine and all the micronuclei exhibit considerable labelling, although less than control cells. Thus, the micronuclei exhibit some characteristic RNA transcriptional activity in situ as well as after isolation. This material should be a particular interesting model with which to study the physiological activity and the role of each individual interphasic chromosome

  9. Basic reactions induced by radiation

    International Nuclear Information System (INIS)

    Charlesby, A.

    1980-01-01

    This paper summarises some of the basic reactions resulting from exposure to high energy radiation. In the initial stages energy is absorbed, but not necessarily at random, giving radical and ion species which may then react to promote the final chemical change. However, it is possible to intervene at intermediate stages to modify or reduce the radiation effect. Under certain conditions enhanced reactions are also possible. Several expressions are given to calculate radiation yield in terms of energy absorbed. Some analogies between radiation-induced reactions in polymers, and those studied in radiobiology are outlined. (author)

  10. Bystander Effect Induced by UV Radiation; why should we be interested? 

    Directory of Open Access Journals (Sweden)

    Maria Widel

    2012-11-01

    Full Text Available The bystander effect, whose essence is an interaction of cells directly subjected to radiation with adjacent non-subjected cells, via molecular signals, is an important component of ionizing radiation action. However, knowledge of the bystander effect in the case of ultraviolet (UV radiation is quite limited. Reactive oxygen and nitrogen species generated by UV in exposed cells induce bystander effects in non-exposed cells, such as reduction in clonogenic cell survival and delayed cell death, oxidative DNA damage and gene mutations, induction of micronuclei, lipid peroxidation and apoptosis. Although the bystander effect after UV radiation has been recognized in cell culture systems, its occurrence in vivo has not been studied. However, solar UV radiation, which is the main source of UV in the environment, may induce in human dermal tissue an inflammatory response and immune suppression, events which can be considered as bystander effects of UV radiation. The oxidative damage to DNA, genomic instability and the inflammatory response may lead to carcinogenesis. UV radiation is considered one of the important etiologic factors for skin cancers, basal- and squamous-cell carcinomas and malignant melanoma. Based on the mechanisms of actions it seems that the UV-induced bystander effect can have some impact on skin damage (carcinogenesis?, and probably on cells of other tissues. The paper reviews the existing data about the UV-induced bystander effect and discusses a possible implication of this phenomenon for health risk. 

  11. Radiation-induced cataract

    International Nuclear Information System (INIS)

    Martignoni, K.

    1986-01-01

    Dose assessments for cataract threshold doses are available based on epidemiological studies of radiotherapy patients, survivors of the nuclear bombing of Hiroshima and Nagasaki, and of persons with occupational exposure to radiation. According to these, short-term application of low-level LET radiation of a dose ranging between 0.5 and 2.0 Gy may suffice to cause a cataract in the course of a few months or years which results in inpairment of vision (UNSCEAR, 1982). In fractionated irradiation, cataractogenic threshold dose increases to 4 Sv at treatment times between 3 weeks and 3 months, and to more than 5 Sv at more than 3 months (ICRP 41). Densely ionizing radiation must be assumed to have threshold doses between 2 and 20 Sv. An ICRP assessment (ICRP Publ. No. 41, 1984) gives a threshold dose of more than 8 Sv for a vision-impairing cataract if these was protracted irradiation at a low-level dose rate. Concerning radiation protection, a maximum lens dose of 150 mSv per annum was recommended which should not be exceeded. This indicates a maximum of 7.5 Sv of exposure throughout a period of 50 years of working life. (orig./HP) [de

  12. Cytogenetic Monitoring By Use Of The Micronucleus Assay Among Nuclear Malaysia Radiation Workers-A Preliminary Result

    International Nuclear Information System (INIS)

    Rahimah Abdul Rahim; Mohd Rodzi Ali; Noraisyah Mohd Yusof; Juliana Mahamad Napiah; Yahaya Talib; Rehir Dahalan

    2014-01-01

    Biological dosimetry based on the analysis of micronuclei in the cytokinesis-block micronucleus (CBMN) assay can be used as an alternative method for scoring dicentric chromosomes in the field of radiation protection. Bio dosimetry is mainly performed, in addition to physical dosimetry, with the aim of individual dose assessment. Aim of this study was to assess occupationally induced chromosomal damage in radiation workers exposed to ionizing radiation. The CBMN assay was used in the peripheral blood lymphocytes of 50 exposed workers. Number of bi-nucleated cell and micronuclei were scored and statistical analysis was done to see the effect and correlation of micronuclei with gender, age and time of worked. In conclusion, scoring of micronuclei is a useful cytogenetic monitoring for radiation workers. (author)

  13. Peculiarities of radiation induced craniopharyngioma

    Energy Technology Data Exchange (ETDEWEB)

    Sataev, N.M. (Uzbekskij Nauchno-Issledovatel' skij Inst. Onkologii i Radiologii, Tashkent (USSR))

    1982-03-01

    Due to intracranial implantation of a radiosource in rabbit brain craniopharyngioma appeared. Its specific feature is grandular differentiation of embryonal epithelium of residuals of hypophysical (craniopharyngial) passage and the presence of focuses of blood vessel tumor degeneration of hemangioma type in its stroma. It is suggested that radiation craniopharyngioma is developed along the way of epigenetic changes of cellular elements of embryonal epithelium induced by radiation.

  14. Peculiarities of radiation induced craniopharyngioma

    International Nuclear Information System (INIS)

    Sataev, N.M.

    1982-01-01

    Due to intracranial implantation of a radiosource in rabbit brain craniopharyngioma appeared. Its specific feature is grandular differentiation of embryonal epithelium of residuals of hypophysical (craniopharyngial) passage and the presence of focuses of blood vessel tumor degeneration of hemangioma type in its stroma. It is suggested that radiation craniopharyngioma is developed along the way of epigenetic changes of cellular elements of embryonal epithelium induced by radiation

  15. Micronuclei in lymphocytes from currently active uranium miners

    International Nuclear Information System (INIS)

    Zoelzer, Friedo; Freitinger Skalicka, Zuzana; Havrankova, Renata; Hon, Zdenek; Rosina, Jozef; Navratil, Leos; Skopek, Jiri

    2012-01-01

    Micronuclei can be used as markers of past radiation exposure, but only few studies have dealt with uranium miners. In this paper, we report on micronuclei in lymphocytes from individuals currently working at Rozna, Czech Republic, the last functioning uranium mine in the European Union. A modified micronucleus-centromere test was applied to assess the occurrence of micronuclei in stimulated lymphocytes, as well as their content in terms of whole chromosomes or fragments. Compared with unexposed individuals, the miners had higher frequencies of micronucleus-containing lymphocytes and higher percentages of micronuclei without centromeres, and the differences were significant for both parameters (0.74 ± 0.60 vs. 0.50 ± 0.42, p = 0.017 and 49 ± 44 vs. 12 ± 21, p = 0.0002; means ± standard deviations). There were also significant correlations between one or other of these parameters on the one hand and various dose values on the other, in particular with a 'retrievable' dose, that is, a dose whose effect should still be recognisable in lymphocytes assuming a half-life of 3 years. The 'retrievable' dose at which a doubling of the micronucleus frequency was observed was around 35 mSv, corresponding to a total dose of 90 mSv received while working in the mines. Altogether, our data show that the micronucleus-centromere test is a valuable tool for the assessment of past radiation exposure in uranium miners. The scatter in the data is of course far too great to allow individual dosimetry, but for groups of a few dozen exposed individuals, the method can be used to monitor doses clearly below 100 mSv. (orig.)

  16. Induction and prevention of micronuclei and chromosomal aberrations in cultured human lymphocytes exposed to the light of halogen tungsten lamps.

    Science.gov (United States)

    D'Agostini, F; Caimo, A; De Filippi, S; De Flora, S

    1999-07-01

    Previous studies have shown that the light emitted by halogen tungsten lamps contains UV radiation in the UV-A, UV-B and UV-C regions, induces mutations and irreparable DNA damage in bacteria, enhances the frequency of micronuclei in cultured human lymphocytes and is potently carcinogenic to the skin of hairless mice. The present study showed that the light emitted by an uncovered, traditional halogen lamp induces a significant, dose-related and time-related increase not only in micronuclei but also in chromosome-type aberrations, such as breaks, and even more in chromatid-type aberrations, such as isochromatid breaks, exchanges and isochromatid/chromatid interchanges, all including gaps or not, in cultured human lymphocytes. All these genotoxic effects were completely prevented by shielding the same lamp with a silica glass cover, blocking UV radiation. A new model of halogen lamp, having the quartz bulb treated in order to reduce the output of UV radiation, was considerably less genotoxic than the uncovered halogen lamp, yet induction of chromosomal alterations was observed at high illuminance levels.

  17. Radiation-induced myelomatosis

    International Nuclear Information System (INIS)

    Cuzick, J.

    1981-01-01

    It is well known that radiation can cause myeloid leukemia. However, no excess of chronic lymphocytic leukemia has been observed. Myelomatosis, like chronic lymphocytic leukemia, is a tumor of B lymphocytes. To determine whether this disease has a radiogenic origin, we surveyed all cohorts of persons exposed to radiation for which data on cancer-related mortaility are available. An excess of myeloma was found in most cohorts. However, a striking deficit was found in two groups irradiated intensely for uterine neoplasms (three cases observed, 10.71 expected; P = 0.012). All other groups combined had a highly significant excess (50 observed, 22.21 expected; P = 2 x 10 -7 ). The largest relative risk appeared among persons receiving internal doses of α-particles (14 observed, 3.24 expected; P = 2 x 10 -5 ), but a significant excess (13 observed, 6.33 expected; P = 0.026) was also found in patients receiving only therapeutic or diagnostic γ-rays or x-rays. Most cases occurred 15 to 25 years after exposure

  18. Radiation induced emulsion polymerization

    International Nuclear Information System (INIS)

    Stannett, V.T.; Stahel, E.P.

    1990-01-01

    High energy radiation is particularly favored for the initiation of emulsion polymerization. The yield of free radicals, for example, from the radiolysis of the aqueous phase, is high; G(radical) values of 5-7. In addition, the rather special kinetics associated with emulsion polymerization lead, in general, to very large kinetic chain lengths, even with 'non-ideal' monomers such as vinyl acetate. Together, high polymerization rates at low doses become possible. There are some important advantages of radiation polymerization compared with chemical initiators, such as potassium persulfate. Perhaps the most important among them is the temperature independence of the initiation step. This makes low temperature polymerization very accessible. With monomers such as vinyl acetate, where chain termination to monomer is predominant, low temperatures lead to often highly desirable higher molecular weights. With styrene, the classical ideally behaved monomer, there are the advantages such as, for example, the feasibility of using cationic monomers. These and some attendant disadvantages are discussed in detail, including pilot plant studies

  19. 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.)

  20. Micronuclei, nucleoplasmic bridges, and nuclear buds induced in human lymphocytes by the fungicide signum and its active ingredients (boscalid and pyraclostrobin).

    Science.gov (United States)

    Çayır, Akin; Coskun, Munevver; Coskun, Mahmut

    2014-05-01

    The aim of this study was to investigate the genotoxic and cytotoxic potential of the Signum fungicide and its active ingredients (boscalid and pyraclostrobin) on human peripheral blood lymphocytes using the cytokinesis-block micronucleus (CBMN) assay. Micronuclei (MNi), nucleoplasmic bridges (NPBs), nuclear bud (NBUDs) formations, and the cytokinesis-block proliferation index (CBPI) were evaluated in treated lymphocytes in Go (cells were treated and then kept in culture without stimulation for 24 h) and proliferation phases (cells were treated after 44 h culture in medium containing phytohemagglutinin). MN formation in lymphocytes treated in G0 statistically increased at doses of 2, 6, and 25 μg/mL signum; 0.5 and 2 μg/mL boscalid; and 0.5, 1.5, and 2 μg/mL pyraclostrobin; while NPB formation increased at a dose of 0.25 μg/mL pyraclostrobin. All concentrations of each fungicide did not statistically increase NBUD formation, while the cytotoxicity increased the dependent on concentration in lymphocytes treated in G0 . Doses of 0.5, 1, 1.5, and 3 μg/mL signum; 0.5, 1, and 1.5 μg/mL boscalid; and 0.75 μg/mL pyraclostrobin statistically increased the MN formation in proliferating lymphocytes. NPB formation increased in proliferating lymphocytes at doses of 1, 1.5, 2, and 3 μg/mL signum and at a dose of 0.75 μg/mL pyraclostrobin. In addition, a dose of 0.75 μg/mL pyraclostrobin increased NBUD frequencies. Cytotoxicity increased with increasing concentrations of each fungicide. It is concluded that signum, boscalid, and pyraclostrobin may be genotoxic and cytotoxic in vitro human peripheral blood lymphocytes in consideration of each of the two protocols. © 2012 Wiley Periodicals, Inc. Environ Toxicol 29: 723-732, 2014. Copyright © 2012 Wiley Periodicals, Inc., a Wiley company.

  1. Fracture induced electromagnetic radiation

    International Nuclear Information System (INIS)

    Frid, V; Rabinovitch, A; Bahat, D

    2003-01-01

    In our laboratory, we combine accurate electromagnetic radiation (EMR) measurements during fracture of rocks (carbonate and igneous) and transparent materials (glass, PMMA and glass ceramics) with careful fractographic methods. A critical analysis of experimental observations, accumulated here during the last decade together with supporting material from the works of other authors are used in this study to demonstrate the failure of all current models to explain the properties of EMR arising from fracture. The basic elements of a new model are proposed. These are (a) the EMR amplitude increases as long as the crack continues to grow, since new atomic bonds are severed and their contribution is added to the EMR. As a result, the atoms on both sides of the bonds are moved to 'non-equilibrium' positions relative to their steady state ones and begin to oscillate collectively in a manner similar to Debye model bulk oscillations - 'surface vibrational optical waves'; (b) when the crack halts, the waves and the EMR pulse amplitude decay by relaxation. These basic elements are already enough to describe the characteristics of the experimentally obtained isolated individual EMR pulses. These characteristics include the shape of the EMR pulse envelope, and the frequency, time duration and rise - fall time of the pulse

  2. Fracture induced electromagnetic radiation

    Energy Technology Data Exchange (ETDEWEB)

    Frid, V [Geological and Environmental Sciences Department, Deichmann Rock Mechanics Laboratory of the Negev, Ben Gurion University of the Negev, Beer Sheva (Israel); Rabinovitch, A [Physics Department, Deichmann Rock Mechanics Laboratory of the Negev, Ben Gurion University of the Negev, Beer Sheva (Israel); Bahat, D [Geological and Environmental Sciences Department, Deichmann Rock Mechanics Laboratory of the Negev, Ben Gurion University of the Negev, Beer Sheva (Israel)

    2003-07-07

    In our laboratory, we combine accurate electromagnetic radiation (EMR) measurements during fracture of rocks (carbonate and igneous) and transparent materials (glass, PMMA and glass ceramics) with careful fractographic methods. A critical analysis of experimental observations, accumulated here during the last decade together with supporting material from the works of other authors are used in this study to demonstrate the failure of all current models to explain the properties of EMR arising from fracture. The basic elements of a new model are proposed. These are (a) the EMR amplitude increases as long as the crack continues to grow, since new atomic bonds are severed and their contribution is added to the EMR. As a result, the atoms on both sides of the bonds are moved to 'non-equilibrium' positions relative to their steady state ones and begin to oscillate collectively in a manner similar to Debye model bulk oscillations - 'surface vibrational optical waves'; (b) when the crack halts, the waves and the EMR pulse amplitude decay by relaxation. These basic elements are already enough to describe the characteristics of the experimentally obtained isolated individual EMR pulses. These characteristics include the shape of the EMR pulse envelope, and the frequency, time duration and rise - fall time of the pulse.

  3. Micronucleus assay for radiation workers

    International Nuclear Information System (INIS)

    Balasem, A.N.; Ali, A.S.K.

    1997-01-01

    Micronucleus assay was performed on 49 radiation workers and 22 healthy volunteers. Radiation workers were subdivided into two groups according to their employments durations in the radiation field. Group a consisted of 18 radiation workers who have been in this work between 5 and 22 years. Group b included 31 employees who have been classified as radiation workers for 1 to 4.5 years. Statistical analysis showed significant variations between the yields of micronuclei in groups A and B as well as between group A and a group of healthy controls. Meanwhile no significant difference was noticed between the yields of micronuclei in group B and the corresponding values in the healthy controls. The possible effect of age in the induction of micronuclei was discussed and a comparison with the yield of chromosomal aberrations was described. It seems that cytokinesis- blocking method may be used to detect the radiation-induced micronuclei in workers exposed occupationally to ionizing radiation in levels below the maximum permissible limit of 0.05 Sv per year

  4. Radiation-induced chromosomal instability

    International Nuclear Information System (INIS)

    Ritter, S.

    1999-01-01

    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/μm) 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.)

  5. Diseases induced by ionising radiation

    International Nuclear Information System (INIS)

    1984-11-01

    An interim report is presented by the Industrial Injuries Advisory Council in accordance with Section 141 of the Social Security Act 1975 on the question whether the terms of prescription for occupational diseases induced by ionising radiation should be amended to cover a wider range of conditions. A lack of persuasive statistical data has prevented reliable estimates of health risks of radiation workers in the UK to be made. However the report gives details of the progress made so far and the difficulties encountered. (U.K.)

  6. Radiation-induced micronucleus frequencies in female peripheral blood lymphocytes collected during the first and second half of the menstrual cycle

    International Nuclear Information System (INIS)

    Krol, M.; Lankoff, A.; Buraczewska, I.; Derezinska, E.; Wojcik, A.

    2007-01-01

    Biological dosimetry relies on the assessment of dose in peripheral blood lymphocytes (PBL) of a victim. Variability in the individual radiosensitivity of PBL has an impact on the precision of dose estimate and radiation-induced micronuclei show a strong individual variability. A factor which can influence the radiosensitivity of PBL is the hormonal status of female donors, which shows a regular pattern during the menstrual cycle. The aim of the present investigation was to verify whether the position within the menstrual cycle has an impact on the level of micronuclei in PBL. Blood was collected from 19 donors during the first and second half of the menstrual cycle and exposed to 2 Gy. Although statistically significant differences between the MN frequencies in PBL collected during the different time points were observed in the case of some donors, no reproducible trend that could find application in biological dosimetry could be detected. (authors)

  7. The relative biological effectiveness of a high energy neutron beam for micronuclei induction in T-lymphocytes of different individuals

    Energy Technology Data Exchange (ETDEWEB)

    Slabbert, J.P., E-mail: jps@tlabs.ac.z [NRF iThemba LABS (Laboratory for Accelerated Based Sciences), Somerset West (South Africa); Dept. of Medical Imaging and Clinical Oncology, University of Stellenbosch (South Africa); August, L. [NRF iThemba LABS (Laboratory for Accelerated Based Sciences), Somerset West (South Africa); Vral, A. [Dept. of Basic Medical Sciences, Ghent University (Belgium); Symons, J. [NRF iThemba LABS (Laboratory for Accelerated Based Sciences), Somerset West (South Africa)

    2010-12-15

    In assessing the radiation risk of personnel exposed to cosmic radiation fields as it pertains to radiological damage during travel in civilian aircrafts, it is particularly important to know the relative biological effectiveness (RBE) for high energy neutrons. It has been the subject of numerous investigations in recent years using different neutron energies and cytogenetic examinations. Variations in the radiosensitivity of white blood cells for different individuals are likely to influence the estimate of the relative biological effectiveness for high energy neutrons. This as such observations have been noted in the response of different cancer cell lines with varying inherent sensitivities. In this work the radiosensitivities of T-lymphocytes of different individuals to the p(66)/Be neutron beam at iThemba LABS were measured using micronuclei formations and compared to that noted following exposure to {sup 60}Co {gamma}-rays. The principle objective of this investigation was to establish if a relationship between neutron RBE and variation in biological response to {sup 60}Co {gamma}-rays for lymphocytes from different individuals could be determined. Peripheral blood samples were collected from four healthy donors and isolated lymphocytes were exposed to different doses of {sup 60}Co {gamma}-rays (1-5 Gy) and p(66)/Be neutrons (0.5-2.5 Gy). One sample per donor was not exposed to radiation and served as a control. Lymphocytes were stimulated using PHA and cultured to induce micronuclei in cytokinesis-blocked cells. Micronuclei yields were numerated using fluorescent microscopy. Radiosensitivities and RBE values were calculated from the fitted parameters describing the micronuclei frequency dose response data. Dissimilar dose response curves for different donors were observed reflecting varying inherent sensitivities to both neutron and gamma radiation. A clear reduction in the dose limiting RBE{sub M} is noted for donors with lymphocytes more sensitive to

  8. Radiation induced estane polymer crosslinking

    International Nuclear Information System (INIS)

    Fletcher, M.; Foster, P.

    1997-01-01

    The exposure of polymeric materials to radiation has been known to induce the effects of crosslinking and degradation. The crosslinking phenomena comes about when two long chain polymers become linked together by a primary bond that extends the chain and increases the viscosity, molecular weight and the elastic modules of the polymer. This process has been observed in relatively short periods of time with fairly high doses of radiation, on the order of several megarads/hour. This paper address low dose exposure over long periods of time to determine what the radiation effects are on the polymeric binder material in PBX 9501. An experimental sample of binder material without explosives will be placed into a thermal and radiation field produced from a W-48 put mod 0. Another sample will be placed in a thermal environment without the radiation. The following is the test plan that was submitted to the Pantex process. The data presented here will be from the first few weeks of exposure and this test will be continued over the next few years. Subsequent data will hopefully be presented in the next compatibility and aging conference

  9. Induction of micronuclei by irradiation with neutrons produced from 600 MeV protons

    CERN Document Server

    Diehl-Marshall, I

    1980-01-01

    Chromosome damage can be detected by the observation of micronuclei . Because its sensitivity, the micronuclei induciton in meristems of Vicia faba bean roots has been selected to determine the radiation damage produced by doses ranging from 1 to 82 cGy of neutrons. The average number of miconuclei found between 24 and 48 hours after irradiation was plotted as a funciton of dose. The RBE values, using as reference radiation 60 Co y-rays, ranged from 3.5 for a neutron dose of 82 cGy to 18 for a neutron of 1 cGy. Even higher RBE values were deduced at low doses from the evaluation of cells containing multiple micronuclei.

  10. Protective Effect of Anthocyanins from Lingonberry on Radiation-induced Damages

    Directory of Open Access Journals (Sweden)

    Shuang-Qi Tian

    2012-12-01

    Full Text Available There is a growing concern about the serious harm of radioactive materials, which are widely used in energy production, scientific research, medicine, industry and other areas. In recent years, owing to the great side effects of anti-radiation drugs, research on the radiation protectants has gradually expanded from the previous chemicals to the use of natural anti-radiation drugs and functional foods. Some reports have confirmed that anthocyanins are good antioxidants, which can effectively eliminate free radicals, but studies on the immunoregulatory and anti-radiation effects of anthocyanins from lingonberry (ALB are less reported. In this experiment, mice were given orally once daily for 14 consecutive days before exposure to 6 Gy of gamma-radiation and were sacrificed on the 7th day post-irradiation. The results showed that the selected dose of extract did not lead to acute toxicity in mice; while groups given anthocyanins orally were significantly better than radiation control group according to blood analysis; pretreatment of anthocyanins significantly (p < 0.05 enhanced the thymus and spleen indices and spleen cell survival compared to the irradiation control group. Pretreatment with anthocyanins before irradiation significantly reduced the numbers of micronuclei (MN in bone marrow polychromatic erythrocytes (PCEs. These findings indicate that anthocyanins have immunostimulatory potential against immunosuppression induced by the radiation.

  11. Radiation induced sulfur dioxide removal

    International Nuclear Information System (INIS)

    Chmielewski, A.G.

    2000-01-01

    The biggest source of air pollution is the combustion of fossil fuels, were pollutants such as particulate, sulfur dioxide (SO 2 ), nitrogen oxides (NO x ), and volatile organic compounds (VOC) are emitted. Among these pollutants, sulfur dioxide plays the main role in acidification of the environment. The mechanism of sulfur dioxide transformation in the environment is partly photochemical. This is not direct photooxidation, however, but oxidation through formed radicals. Heterogenic reactions play an important role in this transformation as well; therefore, observations from environmental chemistry can be used in air pollution control engineering. One of the most promising technologies for desulfurization of the flue gases (and simultaneous denitrification) is radiation technology with an electron accelerator application. Contrary to the nitrogen oxides (NO x ) removal processes, which is based on pure radiation induced reactions, sulfur dioxide removal depends on two pathways: a thermochemical reaction in the presence of ammonia/water vapor and a radiation set of radiochemical reactions. The mechanism of these reactions and the consequent technological parameters of the process are discussed in this paper. The industrial application of this radiation technology is being implemented in an industrial pilot plant operated by INCT at EPS Kaweczyn. A full-scale industrial plant is currently in operation in China, and two others are under development in Japan and Poland. (author)

  12. Lycopene: An antioxidant and radioprotector against γ-radiation-induced cellular damages in cultured human lymphocytes

    International Nuclear Information System (INIS)

    Srinivasan, M.; Devipriya, N.; Kalpana, K.B.; Menon, Venugopal P.

    2009-01-01

    The present study aimed to evaluate the radioprotective effect of lycopene, a naturally occurring dietary carotenoid on γ-radiation-induced toxicity. The cellular changes were estimated by using lipid peroxidative indices like thiobarbituric acid reactive substances (TBARS), hydroperoxides (HP), the antioxidants superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and reduced glutathione (GSH). The DNA damage was analyzed by cytokinesis blocked micronucleus assay (CBMN), dicentric aberration (DC) and translocation frequency. The γ-radiation at different doses (1, 2 and 4 Gy) resulted in a significant increase in the number of micronuclei (MN), DC, translocation frequency, TBARS and HP level, whereas the levels of GSH and antioxidant enzymes were significantly decreased when compared with normal control. The maximum damage to lymphocytes was observed at 4 Gy irradiation. Lycopene pretreatment (1, 5 and 10 μg/ml) significantly decreased the frequency of MN, DC and translocation when compared with γ-radiation control. The levels of TBARS, HP were also decreased and activities of SOD, CAT and GPx were significantly increased along with GSH levels when compared with γ-radiation control. The dose of 5 μg/ml of lycopene was found to be more effective than the other two doses. Thus, our result shows that pretreatment with lycopene offers protection to normal lymphocytes against γ-radiation-induced cellular damage.

  13. Lack of specificity of chromosome breaks resulting from radiation-induced genomic instability in Chinese hamster cells

    International Nuclear Information System (INIS)

    Trott, K.-R.; Teibe, A.

    1998-01-01

    In V79 Chinese hamster cells, radiation-induced genomic instability results in a persistently increased frequency of micronuclei, dicentric chromosomes and apoptosis and in decreased colony-forming ability. These manifestations of radiation-induced genomic instability may be attributed to an increased rate of chromosome breakage events many generations after irradiation. This chromosomal instability does not seem to be a property which has been inflicted on individual chromosomes at the time of irradiation. Rather, it appears to be secondary to an increased level of non-specific clastogenic factors in the progeny of most if not all irradiated cells. This conclusion is drawn from the observations presented here, that all the chromosomes in surviving V79 cells are involved in the formation of dicentric chromosome aberrations 1 or 2 weeks after irradiation with about equal probability if corrections are made for chromosome length. (orig.)

  14. Micronuclei in breast aspirates. Is scoring them helpful?

    Directory of Open Access Journals (Sweden)

    A Hemalatha

    2014-01-01

    Conclusion: An increase in micronuclei values was seen from fibroadenoma to infiltrating ductal carcinoma. Micronuclei scoring can be used as a biomarker on fine needle aspiration cytology smears of breast carcinoma.

  15. Protective effect of red wine on the frequency of micronuclei in human lymphocytes irradiated in vitro

    International Nuclear Information System (INIS)

    Stankovic, M.; Joksic, G.

    2000-01-01

    The present investigation was undertaken to study the effect of red wines 'Cabernet Sauvignon' on the micronuclei formation in human lymphocytes. Blood samples of healthy volunteers were irratiated in vitro using 60 Co as a source of radiation, dose of 2Gy. Irradiated samples, as well as unirradiated controls, were treated with concentrations of red wine ranged from 100-500 ml/2x106 cells. Obtained results demonstrated significant decrease of the micronuclei frequency (t=9.14; p0.05) in treated samples versus untreated controls. The results of our study demonstrated radioprotective effect of red wine

  16. Impact of Lutein Intervention in Mice on the Radiation Induced Clastogenic Changes

    Directory of Open Access Journals (Sweden)

    Vidya Vasudeva

    2017-10-01

    Full Text Available One of the genetic effects of radiation is that it may lead to formation of single or double strand breaks in DNA which can be observed in differentially stained polychromatic or normochromatic erythrocytes (PCE and NCE respectively. In pursuit of finding a natural radioprotector to treat the radiation induced damages; lutein, a carotenoid pigment is one such approach. Swiss albino mice are administered with the compound (lutein/gallic acid/DMSO with respective controls for 15 consecutive days after which they are irradiated. The whole blood is drawn for comet assay and the femur of the leg is removed to flush out the content of the bone marrow in BSA for the micronucleus assay. The comet slides are observed under the fluorescent microscope and the PCE/NCE or micronucleated PCEs or NCEs are scored blindly. Lutein in the present study has effectively reduced the olive moment and the tail moment. However, % DNA in tail has been maintained to normal levels in comparison to its control indicating lesser extent of damage to the genetic material. The percent micronucleated NCE (MnNCE has been decreased in the group treated with lutein prior to radiation. The % MnPCE and the PCE/(PCE + NCE ratio has been increased in all the irradiated groups; however lutein treatment has not drastically increased the formation of micronuclei in comparison to its control. This indicates that lutein shows a protective effect against the radiation induced cytogenetic damages in Swiss albino mice.

  17. 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

  18. Possible radioprotective effect of folic acid supplementation on low dose ionizing radiation-induced genomic instability in vitro.

    Science.gov (United States)

    Padula, Gisel; Ponzinibbio, María Virginia; Seoane, Analia I

    2016-08-01

    Ionizing radiation (IR) induces DNA damage through production of single and double-strand breaks and reactive oxygen species (ROS). Folic acid (FA) prevents radiation-induced DNA damage by modification of DNA synthesis and/or repair and as a radical scavenger. We hypothesized that in vitro supplementation with FA will decrease the sensitivity of cells to genetic damage induced by low dose of ionizing radiation. Annexin V, comet and micronucleus assays were performed in cultured CHO cells. After 7 days of pre-treatment with 0, 100, 200 or 300 nM FA, cultures were exposed to radiation (100 mSv). Two un-irradiated controls were executed (0 and 100 nM FA). Data were statistically analyzed with X2-test and linear regression analysis (P 0.05). We observed a significantly decreased frequency of apoptotic cells with the increasing FA concentration (P <0.05). The same trend was observed when analyzing DNA damage and chromosomal instability (P <0.05 for 300 nM). Only micronuclei frequencies showed significant differences for linear regression analysis (R2=94.04; P <0.01). Our results have demonstrated the radioprotective effect of folic acid supplementation on low dose ionizing radiation-induced genomic instability in vitro; folate status should be taken into account when studying the effect of low dose radiation in environmental or occupational exposure.

  19. Radiation-induced centers in inorganic glasses

    International Nuclear Information System (INIS)

    Brekhovskikh, S.M.; Tyul'nin, V.A.

    1988-01-01

    The nature, structure and formation mechanisms of radiation-induced colour centers, EPR, luminescence, generated ionizing radiation in nonorganic oxide glasses are considered. Experimental material covering both fundamental aspects of radiation physics and glass chemistry, and aspects intimately connected with the creation of new materials with the given radiation-spectral characteristics, with possibilities to prepare radiation-stable and radiation-sensitive glasses is systematized and generalized. Considerable attention is paid to the detection of radiation-induced center binding with composition, glass structures redox conditions for their synthesis. Some new possibilities of practical application of glasses with radiation-induced centers, in particular, to record optical information are reflected in the paper

  20. cGAS Conducts Micronuclei DNA Surveillance.

    Science.gov (United States)

    de Oliveira Mann, Carina C; Kranzusch, Philip J

    2017-10-01

    DNA damage elicits a potent proinflammatory immune response. A collection of four papers now reveals that micronuclear DNA is a new cell intrinsic immunostimulatory molecule, and that accumulation of the immune sensor cyclic GMP-AMP synthase (cGAS) in micronuclei leads to a cell-cycle-dependent proinflammatory response following DNA damage. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Protective effect of mild endoplasmic reticulum stress on radiation-induced bystander effects in hepatocyte cells

    Science.gov (United States)

    Xie, Yuexia; Ye, Shuang; Zhang, Jianghong; He, Mingyuan; Dong, Chen; Tu, Wenzhi; Liu, Peifeng; Shao, Chunlin

    2016-01-01

    Radiation-induced bystander effect (RIBE) has important implications for secondary cancer risk assessment during cancer radiotherapy, but the defense and self-protective mechanisms of bystander normal cells are still largely unclear. The present study found that micronuclei (MN) formation could be induced in the non-irradiated HL-7702 hepatocyte cells after being treated with the conditioned medium from irradiated hepatoma HepG2 cells under either normoxia or hypoxia, where the ratio of the yield of bystander MN induction to the yield of radiation-induced MN formation under hypoxia was much higher than that of normoxia. Nonetheless, thapsigargin induced endoplasmic reticulum (ER) stress and dramatically suppressed this bystander response manifested as the decrease of MN and apoptosis inductions. Meanwhile, the interference of BiP gene, a major ER chaperone, amplified the detrimental RIBE. More precisely, thapsigargin provoked ER sensor of PERK to initiate an instantaneous and moderate ER stress thus defensed the hazard form RIBE, while BiP depletion lead to persistently destroyed homeostasis of ER and exacerbated cell injury. These findings provide new insights that the mild ER stress through BiP-PERK-p-eIF2α signaling pathway has a profound role in protecting cellular damage from RIBE and hence may decrease the potential secondary cancer risk after cancer radiotherapy. PMID:27958308

  2. 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.

  3. RAD9 deficiency enhances radiation induced bystander DNA damage and transcriptomal response

    International Nuclear Information System (INIS)

    Ghandhi, Shanaz A; Ponnaiya, Brian; Panigrahi, Sunil K; Hopkins, Kevin M; Cui, Qingping; Hei, Tom K; Amundson, Sally A; Lieberman, Howard B

    2014-01-01

    Radiation induced bystander effects are an important component of the overall response of cells to irradiation and are associated with human health risks. The mechanism responsible includes intra-cellular and inter-cellular signaling by which the bystander response is propagated. However, details of the signaling mechanism are not well defined. We measured the bystander response of Mrad9 +/+ and Mrad9 −/− mouse embryonic stem cells, as well as human H1299 cells with inherent or RNA interference-mediated reduced RAD9 levels after exposure to 1 Gy α particles, by scoring chromosomal aberrations and micronuclei formation, respectively. In addition, we used microarray gene expression analyses to profile the transcriptome of directly irradiated and bystander H1299 cells. We demonstrated that Mrad9 null enhances chromatid aberration frequency induced by radiation in bystander mouse embryonic stem cells. In addition, we found that H1299 cells with reduced RAD9 protein levels showed a higher frequency of radiation induced bystander micronuclei formation, compared with parental cells containing inherent levels of RAD9. The enhanced bystander response in human cells was associated with a unique transcriptomic profile. In unirradiated cells, RAD9 reduction broadly affected stress response pathways at the mRNA level; there was reduction in transcript levels corresponding to genes encoding multiple members of the UVA-MAPK and p38MAPK families, such as STAT1 and PARP1, suggesting that these signaling mechanisms may not function optimally when RAD9 is reduced. Using network analysis, we found that differential activation of the SP1 and NUPR1 transcriptional regulators was predicted in directly irradiated and bystander H1299 cells. Transcription factor prediction analysis also implied that HIF1α (Hypoxia induced factor 1 alpha) activation by protein stabilization in irradiated cells could be a negative predictor of the bystander response, suggesting that local hypoxic stress

  4. Genotoxicity of nanomaterials: DNA damage and micronuclei induced by carbon nanotubes and graphite nanofibres in human bronchial epithelial cells in vitro.

    Science.gov (United States)

    Lindberg, Hanna K; Falck, Ghita C-M; Suhonen, Satu; Vippola, Minnamari; Vanhala, Esa; Catalán, Julia; Savolainen, Kai; Norppa, Hannu

    2009-05-08

    Despite the increasing industrial use of different nanomaterials, data on their genotoxicity are scant. In the present study, we examined the potential genotoxic effects of carbon nanotubes (CNTs; >50% single-walled, approximately 40% other CNTs; 1.1 nm x 0.5-100 microm; Sigma-Aldrich) and graphite nanofibres (GNFs; 95%; outer diameter 80-200 nm, inner diameter 30-50 nm, length 5-20 microm; Sigma-Aldrich) in vitro. Genotoxicity was assessed by the single cell gel electrophoresis (comet) assay and the micronucleus assay (cytokinesis-block method) in human bronchial epithelial BEAS 2B cells cultured for 24h, 48h, or 72h with various doses (1-100 microg/cm(2), corresponding to 3.8-380 microg/ml) of the carbon nanomaterials. In the comet assay, CNTs induced a dose-dependent increase in DNA damage at all treatment times, with a statistically significant effect starting at the lowest dose tested. GNFs increased DNA damage at all doses in the 24-h treatment, at two doses (40 and 100 microg/cm(2)) in the 48-h treatment (dose-dependent effect) and at four doses (lowest 10 microg/cm(2)) in the 72-h treatment. In the micronucleus assay, no increase in micronucleated cells was observed with either of the nanomaterials after the 24-h treatment or with CNTs after the 72-h treatment. The 48-h treatment caused a significant increase in micronucleated cells at three doses (lowest 10 microg/cm(2)) of CNTs and at two doses (5 and 10 microg/cm(2)) of GNFs. The 72-h treatment with GNFs increased micronucleated cells at four doses (lowest 10 microg/cm(2)). No dose-dependent effects were seen in the micronucleus assay. The presence of carbon nanomaterial on the microscopic slides disturbed the micronucleus analysis and made it impossible at levels higher than 20 microg/cm(2) of GNFs in the 24-h and 48-h treatments. In conclusion, our results suggest that both CNTs and GNFs are genotoxic in human bronchial epithelial BEAS 2B cells in vitro. This activity may be due to the fibrous nature

  5. 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

  6. Role of ROS-mediated autophagy in radiation-induced bystander effect of hepatoma cells.

    Science.gov (United States)

    Wang, Xiangdong; Zhang, Jianghong; Fu, Jiamei; Wang, Juan; Ye, Shuang; Liu, Weili; Shao, Chunlin

    2015-05-01

    Autophagy plays a crucial role in cellular response to ionizing radiation, but it is unclear whether autophagy can modulate radiation-induced bystander effect (RIBE). Here, we investigated the relationship between bystander damage and autophagy in human hepatoma cells of HepG2. HepG2 cells were treated with conditioned medium (CM) collected from 3 Gy γ-rays irradiated hepatoma HepG2 cells for 4, 12, or 24 h, followed by the measurement of micronuclei (MN), intracellular reactive oxygen species (ROS), mitochondrial membrane potential (MMP), and protein expressions of microtubule-associated protein 1 light chain 3 (LC3) and Beclin-1 in the bystander HepG2 cells. In some experiments, the bystander HepG2 cells were respectively transfected with LC3 small interfering RNA (siRNA), Beclin-1 siRNA or treated with 1% dimethyl sulfoxide (DMSO). Additional MN and mitochondrial dysfunction coupled with ROS were induced in the bystander cells. The expressions of protein markers of autophagy, LC3-II/LC3-I and Beclin-1, increased in the bystander cells. The inductions of bystander MN and overexpressions of LC3 and Beclin-1 were significantly diminished by DMSO. However, when the bystander cells were transfected with LC3 siRNA or Beclin-1 siRNA, the yield of bystander MN was significantly enhanced. The elevated ROS have bi-functions in balancing the bystander effects. One is to cause MN and the other is to induce protective autophagy.

  7. 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

  8. Modulation of ionizing radiation induced oxidative imbalance by semi-fractionated extract of Piper betle

    Science.gov (United States)

    Verma, Savita; Dutta, Ajaswrata; Sankhwar, Sanghmitra; Shukla, Sandeep Kumar

    2010-01-01

    The study was planned to evaluate modulatory effect of aqueous extract of Piper betle leaf (PBL) on ionizing radiation mediated oxidative stress leading to normal tissues damage during radiotherapy and other radiation exposures. The total polyphenols and flavonoids known as free radical scavenger (chelators) were measured in the extract. To ascertain antioxidant potential of PBL extract, we studied free radical scavenging, metal chelation, reducing power, lipid peroxidation inhibition and ferric reducing antioxidant properties (FRAP ) using in vitro assays. Mice were exposed to varied radiation doses administered with the same extract prior to irradiation to confirm its oxidative stress minimizing efficacy by evaluating ferric reducing ability of plasma, reduced glutathione, lipid peroxidation and micro-nuclei frequency. PBL extract was effective in scavenging DPPH (up to 92% at 100 µg/ml) and superoxide radicals (up to 95% at 80 µg/ml), chelated metal ions (up to 83% at 50 µg/ml) and inhibited lipid peroxidation (up to 45.65% at 500 µg/ml) in a dose dependant manner using in vitro model. Oral administration of PBL extract (225 mg/kg body weight) 1 hr before irradiation in mice significantly enhanced (p < 0.01) radiation abated antioxidant potential of plasma and GSH level in all the observed organs. The treatment with extract effectively lowered the radiation induced lipid peroxidation at 24 hrs in all the selected organs with maximum inhibition in thymus (p < 0.01). After 48 hrs, lipid peroxidation was maximally inhibited in the group treated with the extract. Frequency of radiation induced micronucleated cells declined significantly (34.78%, p < 0.01) at 24 hrs post-irradiation interval by PBL extract administration. The results suggest that PBL extract has high antioxidant potential and relatively non-toxic and thus could be assertively used to mitigate radiotherapy inflicted normal tissues damage and also injuries caused by moderate doses of radiation

  9. The different radiation response and radiation-induced bystander effects in colorectal carcinoma cells differing in p53 status.

    Science.gov (United States)

    Widel, Maria; Lalik, Anna; Krzywon, Aleksandra; Poleszczuk, Jan; Fujarewicz, Krzysztof; Rzeszowska-Wolny, Joanna

    2015-08-01

    Radiation-induced bystander effect, appearing as different biological changes in cells that are not directly exposed to ionizing radiation but are under the influence of molecular signals secreted by irradiated neighbors, have recently attracted considerable interest due to their possible implication for radiotherapy. However, various cells present diverse radiosensitivity and bystander responses that depend, inter alia, on genetic status including TP53, the gene controlling the cell cycle, DNA repair and apoptosis. Here we compared the ionizing radiation and bystander responses of human colorectal carcinoma HCT116 cells with wild type or knockout TP53 using a transwell co-culture system. The viability of exposed to X-rays (0-8 Gy) and bystander cells of both lines showed a roughly comparable decline with increasing dose. The frequency of micronuclei was also comparable at lower doses but at higher increased considerably, especially in bystander TP53-/- cells. Moreover, the TP53-/- cells showed a significantly elevated frequency of apoptosis, while TP53+/+ counterparts expressed high level of senescence. The cross-matched experiments where irradiated cells of one line were co-cultured with non-irradiated cells of opposite line show that both cell lines were also able to induce bystander effects in their counterparts, however different endpoints revealed with different strength. Potential mediators of bystander effects, IL-6 and IL-8, were also generated differently in both lines. The knockout cells secreted IL-6 at lower doses whereas wild type cells only at higher doses. Secretion of IL-8 by TP53-/- control cells was many times lower than that by TP53+/+ but increased significantly after irradiation. Transcription of the NFκBIA was induced in irradiated TP53+/+ mainly, but in bystanders a higher level was observed in TP53-/- cells, suggesting that TP53 is required for induction of NFκB pathway after irradiation but another mechanism of activation must operate in

  10. Radiation-induced gene responses

    International Nuclear Information System (INIS)

    Woloschak, G.E.; Paunesku, T.; Shearin-Jones, P.; Oryhon, J.

    1996-01-01

    In the process of identifying genes that are differentially regulated in cells exposed to ultraviolet radiation (UV), we identified a transcript that was repressed following the exposure of cells to a combination of UV and salicylate, a known inhibitor of NF-kappaB. Sequencing this band determined that it has identify to lactate dehydrogenase, and Northern blots confirmed the initial expression pattern. Analysis of the sequence of the LDH 5' region established the presence of NF-kappaB, Sp1, and two Ap-2 elements; two partial AP- 1; one partial RE, and two halves of E-UV elements were also found. Electromobility shift assays were then performed for the AP-1, NF- kappaB, and E-UV elements. These experiments revealed that binding to NF-kappaB was induced by UV but repressed with salicylic acid; UV did not affect AP-1 binding, but salicylic acid inhibited it alone or following UV exposure; and E-UV binding was repressed by UV, and salicylic acid had little effect. Since the binding of no single element correlated with the expression pattern of LDH, it is likely that multiple elements govern UV/salicylate-mediated expression

  11. Diseases induced by ionizing radiation

    International Nuclear Information System (INIS)

    Anon.

    1991-01-01

    The instruction sheet for medical examinations presents information on clinical symptoms and diagnostic procedures relating to the following cases: 1. Acute radiation injury due to whole-body exposure; 2. acute, local radiation injury due to partial body exposure; 3. chronic general affections due to whole-body exposure; 4. chronic, local affections due to partial body exposure; 5. delayed radiation effects. (HP) [de

  12. The Estimation of Human Genome Radiosensitivity-Applicability in Radiation Protection

    International Nuclear Information System (INIS)

    Joksic, G.; Nikolic, M.; Vuckovic, M.

    1997-01-01

    The individual variability in response to radiation was examined in a group of 77 healthy individuals, 35-45 years aged, employing Cytochalasin-blocking micronucleus test. Blood samples were irradiated by the most explored therapeutical gamma dose of 2 Gy ( 60 Co) in vitro. The results of our examination demonstrated statistically significant difference in the yield of spontaneously occurring micronuclei between genders of the same age group, while in the yields of induced micronuclei no statistical significance was observed. Out of 77 persons, 4% showed extreme radiosensitivity, while 2% showed extreme radioresistance. Since both extremes are genetically controlled, such genomes could easily be recognized employing CB micronuclei test. It would be useful to perform this type of analysis instead of 'null control' chromosomal aberration analysis for all professionals working in ionizing radiation zone. Persons with such genetic predisposition should be advised to work out of ionizing radiation zone. (author)

  13. Induction of micronuclei in the root tip cells of Haplopappus germinating seeds by fission neutrons and X rays

    International Nuclear Information System (INIS)

    Hanmoto, Hidehiro; Yonezawa, Yoshihiko; Itoh, Tetsuo; Kondo, Sohei.

    1992-01-01

    Seeds of Haplopappus gracilis (2n=4), an annual Compositae, were soaked in water for 24 hr and then irradiated with fission neutrons from the 1-wattage reactor, UTR-KINKI, or X rays. The root tip cells were inspected at 48 hr post-irradiation for evidence of chromosome damage using micronucleus as endpoint. The frequency of neutron-induced micronuclei increased almost linearly as the dose increased up to as much as 1.2 Gy. X-ray-induced micronuclei showed an exponential dose-response relation. From dose-response data, we estimated that the dose necessary to induce micronuclei at a frequency of 5 per 1,000 cells was 1.2 Gy for neutrons and 8.6 Gy for X rays. Thus, to induce chromosome damage in the somatic cells of germinating Haplopappus seeds, fission neutrons were much more effective than X rays. (author)

  14. 3 cases of radiation-induced sarcoma

    International Nuclear Information System (INIS)

    Shiba, Keiichiro; Fukuma, Hisatoshi; Beppu, Yasuo; Hirota, Teruyuki; Shinohara, Norio.

    1982-01-01

    Criteria for the diagnosis of radiation-induced sarcoma have been previously described. All cases must have a history of irradiation and the second neoplasm must have arisen in the area of the radiation field. A latent period of several years must have elapsed after irradiation before clinical evidence of a second malignant neoplasm. Most important thing is that, all suspected cases must have been proved histologically. We have experienced 3 cases of radiation-induced sarcoma, they were 42-years-old man who developed an osteosarcoma of the lumbar spine at the field of postoperative irradiation for seminoma 7 years previously, 69-years-old woman who developed a malignant fibrous histiocytoma of the buttock at the field of radical radiation for uterine carcinoma 7 years previously and 59-years-old woman who developed an extraskeletal osteosarcoma of the abdominal wall at the field of postoperative irradiation for uterine sarcoma 7 years previously. The last case is very rare and only 8 cases of radiation-induced extraskeletal osteosarcoma have been reported. Since there has been a definite trend in the treatment of cancer toward employing radiation for more favorable cases, in addition to technical improvements in the administration of radiotherapy and more modern equipment, survival data may have been altered considerably in many malignant tumors. Accordingly, more radiation-induced tumors may be encountered in the future. The clinical presentation and histopathology of these radiation-induced sarcomas are presented with a review of the literature. (author)

  15. Radiation induced sarcomas of bone following therapeutic radiation

    International Nuclear Information System (INIS)

    Kim, J.H.; Chu, F.C.H.; Woodward, H.Q.; Huvos, A.

    1983-01-01

    Because of new therapeutic trends of multi-modality and the importance of late effects, we have updated our series of radiation induced bone sarcomas seen at Memorial Sloan-Kettering Cancer Center over the past four decades. A total of 37 cases of bone sarcoma arising from normal bone in the irradiated field was analyzed. The median for latent period from irradiation to diagnosis of bone sarcoma was 11 years with a minimum latent period of four years. The median radiation dose for the bone sarcoma was 6000 rad in 6 weeks with a minimum total radiation dose of 3000 rad in 3 weeks. We have found nine patients who developed bone sarcomas in the radiation field after successful treatment of Hodgkin's disease. Criteria for radiation induced bone sarcomas and the magnitude of the risk of bone sarcomas are briefly discussed

  16. Radiation-induced thyroid disease

    International Nuclear Information System (INIS)

    Maxon, H.R.

    1985-01-01

    Ionizing radiation has been demonstrated to result in a number of changes in the human thyroid gland. At lower radiation dose levels (between 10 and 1500 rads), benign and malignant neoplasms appear to be the dominant effect, whereas at higher dose levels functional changes and thyroiditis become more prevalent. In all instances, the likelihood of the effect is related to the amount and type of radiation exposure, time since exposure, and host factors such as age, sex, and heredity. The author's current approach to the evaluation of patients with past external radiation therapy to the thyroid is discussed. The use of prophylactic thyroxine (T4) therapy is controversial. While T4 therapy may not be useful in preventing carcinogenesis when instituted many years after radiation exposure, theoretically T4 may block TSH secretion and stimulation of damaged cells to undergo malignant transformation when instituted soon after radiation exposure

  17. Radiation induced bystander effect on hepatoma HepG2 cells under hypoxia condition

    International Nuclear Information System (INIS)

    Zhang Jianghong; Jin Yizun; Shao Chunlin; Prise KM

    2009-01-01

    Objective: To investigate radiation induced bystander effect and its mechanism on hepatoma HepG2 cells under hypoxia condition. Methods: Non-irradiated bystander hepatoma cells were co-cultured with irradiated cells or treated with the conditioned medium (CM) from irradiated cells, then micronuclei (MN) were measured for both irradiated cells and bystander cells. Results: The MN yield of irradiated HepG2 cells under hypoxic condition was significantly lower than that under normoxia, the oxygen enhancement ratio of HepG2 cells of MN was 1.6. For both hypoxic and normoxic condition, the MN yield of bystander cells were obviously enhanced to a similar high level after co-culturing with irradiated cells or with CM treatment, and it also correlated with the irradiation dose. When the hypoxic HepG2 cells were treated with either DMSO, a scavenger of reactive oxygen species (ROS), or aminoguanidine, an iNOS inhibitor, the yield of bystander MN was partly diminished, and the reducing rate of DMSO was 42.2%-46.7%, the reducing rate of aminoguanidine was 42% . Conclusion: ROS, NO and their downstream signal factors are involved in the radiation induced bystander effect of hypoxic HepG2 cells. (authors)

  18. Better flocculants by radiation induced polymerization

    International Nuclear Information System (INIS)

    Laizier, J.; Gaussens, G.

    1978-01-01

    The use of radiation induced polymerization should theoritically allow to prepare better flocculants. The testings of several products prepared by such a process shows that better properties are indeed obtained: better efficiencies, lower amounts needed, better overall properties [fr

  19. 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)

  20. Radiation-induced degradation of pollutants

    International Nuclear Information System (INIS)

    Proksch, E.

    1988-01-01

    This article outlines the fundamentals of radiation-induced degradation of noxious substances in drinking water and waste water and discusses the relevant literature. Radiation methods present a number of advantages and disadvantages, which should carefully be considered in each case. In many cases, there seems to be merit in combining the radiation method with other techniques, as e.g. ozone treatement and biodegradation. 30 refs., 3 figs. (Author)

  1. Application of radiation-induced apoptosis in radiation oncology and radiation protection

    International Nuclear Information System (INIS)

    Crompton, N.E.A.; Emery, G.C.; Ozsahin, M.; Menz, R.; Knesplova, L.; Larsson, B.

    1997-01-01

    A rapid assay of the ability of lymphocytes to respond to radiation-induced damage is presented. Age and genetic dependence of radiation response have been quantified. The assay is sensitive to low doses of radiation. Its ability to assess the cytotoxic response of blood capillaries to radiation has been evaluated. (author)

  2. Protection of ionizing radiation-induced cytogenetic damage by hydroalcoholic extract of Cynodon dactylon in Chinese hamster lung fibroblast cells and human peripheral blood lymphocytes.

    Science.gov (United States)

    Rao, Bola Sadashiva Satish; Upadhya, Dinesh; Adiga, Satish Kumar

    2008-01-01

    The radiomodulatory potential of hydroalcoholic extract of a medicinal plant Cynodon dactylon (family: Poaceae) against radiation-induced cytogenetic damage was analyzed using Chinese hamster lung fibroblast (V79) cells and human peripheral blood lymphocytes (HPBLs) growing in vitro. Induction of micronuclei was used as an index of cytogenetic damage, evaluated in cytokinesis blocked binucleate cells. The hydroalcoholic Cynodon dactylon extract (CDE) rendered protection against the radiation-induced DNA damage, as evidenced by the significant (p<0.001) reduction in micronucleated binucleate cells (MNBNC%) after various doses of CDE treatment in V79 cells and HPBLs. The optimum dose of CDE (40 and 50 microg/ml in HPBLs and V79 cells, respectively) with the greatest reduction in micronuclei was further used in combination with various doses of gamma radiation (0.5, 1, 2, 3, and 4 Gy) exposed 1 h after CDE treatment. A linear dose-dependent MNBNC% increase in radiation alone group was observed, while 40/50 microg/ml CDE significantly resulted in the reduction of MNBNC%, compared to the respective radiation alone groups. CDE resulted in a dose-dependent increase in free radical scavenging ability against various free radicals, viz., 2, 2-diphenyl-2-picryl-hydrazyl (DPPH); 2, 2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS); superoxide anion (O2*-); hydroxyl radical (OH*) and nitric oxide radical (NO*) generated in vitro. Also, an excellent (70%) inhibition of lipid peroxidation in vitro was observed at a dose of 300 microg/ml CDE, attaining the saturation point at higher doses. The present findings demonstrated the radioprotective effect of CDE, also rendering protection against radiation-induced genomic instability and DNA damage. The observed radioprotective effect may be partly attributed to the free radical scavenging and antilipid peroxidative potential of CDE.

  3. Does occupational exposure to ionizing radiation induce adaptation

    International Nuclear Information System (INIS)

    Djurovic, B.; Selakovic, V.; Radjen, S.; Radakovic, S.; Spasic-Jokic, V.

    2008-01-01

    Full text: Even the most of personnel occupationally exposed (OE) to ionizing radiation (IR) is exposed to very low doses (LD), some harmful effects can be noticed. IR can affect the cell structure in two ways: directly and indirectly-inducing radiolysis of water and production of reactive oxygen species (ROS) similar to endogenously induced. In the low- LET exposure almost 70 % of absorbed energy is spent for ROS production. Over-production of ROS can cause oxidative stress. DNA is the main target of induced ROS. It is also experimentally showed that many important cell protective mechanisms, such is adaptation, are dependent of ROS concentration produced by low doses. The aim of this paper is to investigate if occupational exposure to LD induce over-production of ROS, and influence the activity of protective enzymes and radiosensitivity as well as induce adaptation. Our subjects were medical workers occupationally exposed to IR (44) and not-exposed (33), matched in gender, age, habits-dietary, alcohol consumption, smoking. Occupational exposure was calculated on the basis of individual TL-dose records. Besides the standard medical examination, micronucleus test, superoxide production and lipid peroxidation index, expressed as malonaldehyde (MDA) production, were performed by standard procedures as well as measurements of activity of the superoxide dismutase (SOD) and glutathione (GSH). Half of each sample were put in a sterile plastic test-tube placed in a plexiglas container 15 x 15 cm, and irradiated by 60 Co source of γ-ray at room temperature. Employed radiation dose was 2 Gy, dose-rate 0.45 Gy/min and distance from the source 74 cm. All blood samples were frozen at -70 C degrees, and kept till analyses which were performed at the same time. Our results confirm: significantly higher incidence of micronuclei in OE (.31±10 vs 17±8, p=0.00) with significant increase after irradiation in each group and lack of differences in radiosensitivity between groups

  4. Radiation-induced renovascular hypertension

    International Nuclear Information System (INIS)

    Staab, G.E.; Tegtmeyer, C.J.; Constable, W.C.

    1976-01-01

    Radiation is known to produce changes in the small vessels and interstitium of the kidneys resulting in hypertension. Two cases of renal artery stenosis and resultant hypertension secondary to abdominal irradiation are reported and the literature is reviewed

  5. 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

  6. Radiation- induced aneuploidy in mammalian germ cells

    International Nuclear Information System (INIS)

    Tease, C.

    1989-01-01

    The ability of ionizing radiation to induce aneuploidy in mammalian germ cells has been investigated experimentally in the laboratory mouse using a variety of cytogenetic and genetic methods. These studies have provided unambiguous evidence of induced nondisjunction in both male and female germ cells when the effect of irradiation is screened in meiotic cells or preimplantation embryos. In contrast, however, cytogenetic analyses of post-implantation embryos and genetic assays for induced chromosome gains have not found a significant radiation effect. These apparently contradictory findings may be reconciled if (a) radiation induces tertiary rather than primary trisomy, or (b) induces embryo-lethal genetic damage, such as deletions, in addition to numerical anomalies. Either or both of these explanations may account for the apparent loss during gestation of radiation-induced trisomic embryos. Extrapolating from the information so far available, it seems unlikely that environmental exposure to low doses if low dose rate radiation will result in a detectable increase in the rate of aneuploidy in the human population. (author)

  7. 'BioQuaRT' project: design of a novel in situ protocol for the simultaneous visualisation of chromosomal aberrations and micronuclei after irradiation at microbeam facilities

    International Nuclear Information System (INIS)

    Patrono, C.; Testa, A.; Monteiro Gil, O.; Giesen, U.; Langner, F.; Rabus, H.; Pinto, M.

    2015-01-01

    The aim of the 'BioQuaRT' (Biologically weighted Quantities in Radiotherapy) project is to develop measurement techniques for characterising charged particle track structure on different length scales, and to correlate at the cellular level the track structure properties with the biological effects of radiation. This multi-scale approach will allow characterisation of the radiation qualities used in radiotherapy and the related biological effects. Charged-particle microbeam facilities were chosen as the platforms for all radiobiology experiments in the 'BioQuaRT' project, because they allow targeting single cells (or compartments of a cell) with a predefined number of ionising particles and correlating the cell-by-cell induced damage with type and energy of the radiation and with the number of ions per cell. Within this project, a novel in situ protocol was developed for the analysis of the mis-repaired and/or unrepaired chromosome damage induced by charged-particle irradiations at the Physikalisch-Technische Bundesanstalt (PTB) ion microbeam facility. Among the cytogenetic biomarkers to detect and estimate radiation-induced DNA damage in radiobiology, chromosomal aberrations and micronuclei were chosen. The characteristics of the PTB irradiation system required the design of a special in situ assay: specific irradiation dishes with a base made from a bio-foil 25-μm thick and only 3000-4000 cells seeded and irradiated per dish. This method was developed on Chinese hamster ovary (CHO) cells, one of the most commonly used cell lines in radiobiology in vitro experiments. The present protocol allows the simultaneous scoring of chromosome aberrations and micronuclei on the same irradiated dish. Thanks to its versatility, this method could also be extended to other radiobiological applications besides the single-ion microbeam irradiations. (authors)

  8. Radiation-induced liver damage

    International Nuclear Information System (INIS)

    Marcial, V.A.; Santiago-Delpin, E.A.; Lanaro, A.E.; Castro-Vita, H.; Arroyo, G.; Moscol, J.A.; Gomez, C.; Velazquez, J.; Prado, K.

    1977-01-01

    Due to the recent increase in the use of radiation therapy in the treatment of cancer with or without chemotherapy, the risk of liver radiation damage has become a significant concern for the radiotherapist when the treated tumour is located in the upper abdomen or lower thorax. Clinically evident radiation liver damage may result in significant mortality, but at times patients recover without sequelae. The dose of 3000 rads in 3 weeks to the entire liver with 5 fractions per week of 200 rads each, seems to be tolerated well clinically by adult humans. Lower doses may lead to damage when used in children, when chemotherapy is added, as in recent hepatectomy cases, and in the presence of pre-existent liver damage. Reduced fractionation may lead to increased damage. Increased fractionation, limitation of the dose delivered to the entire liver, and restriction of the high dose irradiation volume may afford protection. With the aim of studying the problems of hepatic radiation injury in humans, a project of liver irradiation in the dog is being conducted. Mongrel dogs are being conditioned, submitted to pre-irradiation studies (haemogram, blood chemistry, liver scan and biopsy), irradiated under conditions resembling human cancer therapy, and submitted to post-irradiation evaluation of the liver. Twenty-two dogs have been entered in the study but only four qualify for the evaluation of all the study parameters. It has been found that dogs are susceptible to liver irradiation damage similar to humans. The initial mortality has been high mainly due to non-radiation factors which are being kept under control at the present phase of the study. After the initial experiences, the study will involve variations in total dose and fractionation, and the addition of anticoagulant therapy for possible prevention of radiation liver injury. (author)

  9. Radiation-induced transgenerational instability.

    Science.gov (United States)

    Dubrova, Yuri E

    2003-10-13

    To date, the analysis of mutation induction has provided an irrefutable evidence for an elevated germline mutation rate in the parents directly exposed to ionizing radiation and a number of chemical mutagens. However, the results of numerous publications suggest that radiation may also have an indirect effect on genome stability, which is transmitted through the germ line of irradiated parents to their offspring. This review describes the phenomenon of transgenerational instability and focuses on the data showing increased cancer incidence and elevated mutation rates in the germ line and somatic tissues of the offspring of irradiated parents. The possible mechanisms of transgenerational instability are also discussed.

  10. Replication of somatic micronuclei in bovine enucleated oocytes

    Directory of Open Access Journals (Sweden)

    Canel Natalia

    2012-11-01

    Full Text Available Abstract Background Microcell-mediated chromosome transfer (MMCT was developed to introduce a low number of chromosomes into a host cell. We have designed a novel technique combining part of MMCT with somatic cell nuclear transfer, which consists of injecting a somatic micronucleus into an enucleated oocyte, and inducing its cellular machinery to replicate such micronucleus. It would allow the isolation and manipulation of a single or a low number of somatic chromosomes. Methods Micronuclei from adult bovine fibroblasts were produced by incubation in 0.05 μg/ml demecolcine for 46 h followed by 2 mg/ml mitomycin for 2 h. Cells were finally treated with 10 μg/ml cytochalasin B for 1 h. In vitro matured bovine oocytes were mechanically enucleated and intracytoplasmatically injected with one somatic micronucleus, which had been previously exposed [Micronucleus- injected (+] or not [Micronucleus- injected (−] to a transgene (50 ng/μl pCX-EGFP during 5 min. Enucleated oocytes [Enucleated (+] and parthenogenetic [Parthenogenetic (+] controls were injected into the cytoplasm with less than 10 pl of PVP containing 50 ng/μl pCX-EGFP. A non-injected parthenogenetic control [Parthenogenetic (−] was also included. Two hours after injection, oocytes and reconstituted embryos were activated by incubation in 5 μM ionomycin for 4 min + 1.9 mM 6-DMAP for 3 h. Cleavage stage and egfp expression were evaluated. DNA replication was confirmed by DAPI staining. On day 2, Micronucleus- injected (−, Parthenogenetic (− and in vitro fertilized (IVF embryos were karyotyped. Differences among treatments were determined by Fisher′s exact test (p≤0.05. Results All the experimental groups underwent the first cell divisions. Interestingly, a low number of Micronucleus-injected embryos showed egfp expression. DAPI staining confirmed replication of micronuclei in most of the evaluated embryos. Karyotype analysis revealed that all Micronucleus-injected embryos had

  11. Radiation-induced brain injury: A review

    Directory of Open Access Journals (Sweden)

    Michael eRobbins

    2012-07-01

    Full Text Available 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

  12. 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

  13. Carcinogenesis induced by low-dose radiation

    Directory of Open Access Journals (Sweden)

    Piotrowski Igor

    2017-11-01

    Full Text Available Although the effects of high dose radiation on human cells and tissues are relatively well defined, there is no consensus regarding the effects of low and very low radiation doses on the organism. Ionizing radiation has been shown to induce gene mutations and chromosome aberrations which are known to be involved in the process of carcinogenesis. The induction of secondary cancers is a challenging long-term side effect in oncologic patients treated with radiation. Medical sources of radiation like intensity modulated radiotherapy used in cancer treatment and computed tomography used in diagnostics, deliver very low doses of radiation to large volumes of healthy tissue, which might contribute to increased cancer rates in long surviving patients and in the general population. Research shows that because of the phenomena characteristic for low dose radiation the risk of cancer induction from exposure of healthy tissues to low dose radiation can be greater than the risk calculated from linear no-threshold model. Epidemiological data collected from radiation workers and atomic bomb survivors confirms that exposure to low dose radiation can contribute to increased cancer risk and also that the risk might correlate with the age at exposure.

  14. Radiation-induced polymerization and radiation effect on polymers

    International Nuclear Information System (INIS)

    Seguchi, Tadao

    1977-12-01

    The processes of radiation-induced polymerization of monomers and also radiation effects on polymers have been studied by instrumental analyses of electron spin resonance (ESR), nuclear magnetic resonance (NMR) and electron microscopy. In radiation-induced polymerization, graft-copolymerization and absorbed state polymerization were taken up. For graft-copolymerization, monomers such as methylmethacrylate and butadiene were made to react with irradiated polyethylene, and behaviors of the initiating radicals and propagating radicals were followed under the reaction by ESR. For absorbed state polymerization, acrylonitrile/zeolite and methylmethacrylate/zeolite were chosen. Absorbed monomers were irradiated at 77 0 K and polymerized at room temperature. Active species and the concentrations were measured by ESR and the yields of polymer were observed by NMR. In radiation effect on polymers, polyvinylfluoride, polyvinylidenfluoride and polytetrafluoroethylene were taken up. Active species trapped in the polymer matrixes were identified and decay and reactivity of the species were also studied. On the basis of information from the electron microscopy and x-ray analysis, radiation effects on these polymers are described. In polytetrafluoroethylene produced by radiation polymerization, the relation between morphology and polymerization conditions and also the process of crystallization during polymerization were studied. (auth.)

  15. Biological Dosimetry of X-rays by micronuclei study; Dosimetria Biologica de rayos-X mediante el estudio de micronucleos

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, E.; Silva, A.; Navlet, J.

    1991-07-01

    Biological dosimetry consists of estimating absorbed doses for people exposed to radiation by mean biological methods. Several indicators used are based in haematological, biochemical an cytogenetics data, although nowadays without doubt, the cytogenetic method is considered to be the most reliable, in this case, the study of micronuclei in peripheral blood lymphocytes citokinetics blocked can be related to absorbed dose through an experimental calibration curve. An experimental dose-response curve, using micronuclei assay for X-rays at 250 kVp, 43,79 rads/min and temperature 37 degree centigree has been produced. Experimental data is fitted to model Y=C+ {alpha}D+BD''2 where Y is the number of micronuclei per cell and D the dose. The curve is compared with those produced elsewhere. (Author) 24 refs.

  16. Biological Dosimetry of X-rays by micronuclei study; Dosimetria Biologica de rayos-X mediante el estudio de micronucleos

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, E; Silva, A; Navlet, J

    1991-07-01

    Biological dosimetry consists of estimating absorbed doses for people exposed to radiation by mean biological methods. Several indicators used are based in haematological, biochemical an cytogenetics data, although nowadays without doubt, the cytogenetic method is considered to be the most reliable, in this case, the study of micronuclei in peripheral blood lymphocytes citokinetics blocked can be related to absorbed dose through an experimental calibration curve. An experimental dose-response curve, using micronuclei assay for X-rays at 250 kVp, 43,79 rads/min and temperature 37 degree centigree has been produced. Experimental data is fitted to model Y=C+ {alpha}D+BD''2 where Y is the number of micronuclei per cell and D the dose. The curve is compared with those produced elsewhere. (Author) 24 refs.

  17. Radiation-induced breast cancer

    International Nuclear Information System (INIS)

    Price, J.L.

    1977-01-01

    Concern is expressed over a recent U.K. newspaper report (The Times, 21 January 1977, 5) on the possible hazards of mammography, as women may over-react to the extent of refusing mammography. The problems of radiation risk estimates, particularly at low dose levels, are very briefly reviewed. Recent improvements in mammography techniques have minimised the radiation hazard. Conflicting reports of the mortality rates following mammography screening programmes are discussed. In England and Wales, breast cancer is the commonest cause of death in women aged 35 to 54, and it would be unfortunate if the possible benefits of screening were denied to this age group before the latest mammographic techniques have been fully evaluated. (U.K.)

  18. Radiation-induced breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Price, J L [Hammersmith Hospital, London (UK). Postgraduate Medical School

    1977-03-12

    Concern is expressed over a recent U.K. newspaper report (The Times, 21 January 1977, 5) on the possible hazards of mammography, as women may over-react to the extent of refusing mammography. The problems of radiation risk estimates, particularly at low dose levels, are very briefly reviewed. Recent improvements in mammography techniques have minimised the radiation hazard. Conflicting reports of the mortality rates following mammography screening programmes are discussed. In England and Wales, breast cancer is the commonest cause of death in women aged 35 to 54, and it would be unfortunate if the possible benefits of screening were denied to this age group before the latest mammographic techniques have been fully evaluated.

  19. Radiation-induced cerebrovascular complications

    International Nuclear Information System (INIS)

    Naito, Haruko; Koizumi, Nobuhiko; Nihei, Kenji; Taguchi, Nobuyuki; Tanaka, Haruki.

    1982-01-01

    A 3-year-old boy with non-Hodgkin malignant lymphoma came to complete remission after combined chemotherapy, intrathecal methotrexate, and whole brain irradiation of 2,400 rad. Two years after diagnosis, he developed it hemiparesis. CT scan showed cerebral infarction and hydrocephalus, and angiography revealed obstruction of the left middle cerebral artery. He survived with marked neurological deficits and no relapse of lymphoma. The literature was reviewed concerning complications after radiation to the brain. (Kondo, M.)

  20. Effect of space flight on the frequency of micronuclei and expression of stress-responsive proteins in cultured mammalian cells

    Energy Technology Data Exchange (ETDEWEB)

    Ikenaga, Mituo; Hirayama, Jun; Kato, Tomohisa [Kyoto Univ. (Japan). Radiation Biology Center] [and others

    2002-12-01

    Results of past space experiments suggest that the biological effect of space radiation could been hanced under microgravity in some cases, especially ininsects. To examine if such a synergistic effect of radiation and microgravity also exists in human cells, frequencies of chromosome instability and cellular levels of several stress-responsive proteins were analyzed incultured human and rodent cells afterspace flight. Human (MCF7 and ataxia telangiectasia(AT)2KY), mouse (m5S) and hamster (Syrian hamster embryo (SHE)) cell lines were loaded on the Space Shuttle Discovery (STS-95 mission) and grown during a 9-daymission. After landing, the micronuclei resulting from abnormal nuclear division and accumulationof stress-responsive proteins such as p53 and mitogen-activated protein kinases (MAPKs), which are involved in radiation-induced signal transduction cascades, were analyzed. The frequencies of micronucleiin all the four mammalian cell strains tested were not significantly different between flight and ground control samples. Also, the cellular amounts of p53, p21 (WAF1/SDI1/CIP1) and activated (phosphorylated) forms of three distinct MAPKs in MCF7 and m5S cells of flight samples were similar to those of ground control samples. These results indicated that anyeffect of space radiation, microgravity, or combination of both were not detectable, at least under thepresent experimental conditions. (author)

  1. An integrated model for radiation induced cancer

    International Nuclear Information System (INIS)

    Hall, E.J.; Varma, M.

    1994-01-01

    Risk estimates for radiation induced cancer are based on epidemiological data, principally the Japanese A bomb survivors. These estimates for radiation are better known than for any other environmental pollutant, but they do not relate directly to exposure to low doses and low dose rate. Recent rapid advances in molecular genetics, coupled with steady gains in cellular biology, radiation physics and chemistry led to the notion that the time may not be far off when it may be possible to arrive at human cancer risk estimates entirely from laboratory data. Whether risk estimates based on laboratory data will ever replace estimates based on epidemiological studies is an open question. What is clear is that laboratory data can supplement the present risk estimates by providing information on the relative effectiveness of high LET radiations, the importance of dose rate and dose protraction, and by identifying subpopulations which are unusually sensitive or resistant to radiation carcinogenesis. (author)

  2. 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

  3. Radiation induced peroxidation in model lipid systems

    International Nuclear Information System (INIS)

    Dahlan, K.Z.B.H.M.

    1981-08-01

    In the studies of radiation induced lipid peroxidation, lecithin-liposomes and aqueous micellar solutions of sodium linoleate (or linoleic acid) have been used as models of lipid membrane systems. The liposomes and aqueous linoleate micelles were irradiated in the presence of O 2 and N 2 O/O 2 (80/20 v/v). The peroxidation was initiated using gamma radiation from 60 Co radiation source and was monitored by measuring the increase in absorbance of conjugated diene at 232 nm and by the thiobarbituric acid (TBA) test. The oxidation products were also identified by GLC and GLC-MS analysis. (author)

  4. A report on radiation-induced gliomas

    International Nuclear Information System (INIS)

    Salvati, M.; Artico, M.; Caruso, R.; Rocchi, G.; Orlando, E.R.; Nucci, F.

    1991-01-01

    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

  5. The genetics of radiation-induced osteosarcoma

    International Nuclear Information System (INIS)

    Rosemann, M.; Kuosaite, V.; Nathrath, M.; Atkinson, M.J.

    2002-01-01

    Individual genetic variation can influence susceptibility to the carcinogenic effects of many environmental carcinogens. In radiation-exposed populations those individuals with a greater genetically determined susceptibility would be at greater risk of developing cancer. To include this modification of risk into radiation protection schemes it is necessary to identify the genes responsible for determining individual sensitivity. Alpha-particle-induced osteosarcoma in the mouse has been adopted as a model of human radiation carcinogenesis, and genome-wide screens have been conducted for allelic imbalance and genetic linkage. These studies have revealed a series of genes involved in determining the sensitivity to radiogenic osteosarcoma formation. (author)

  6. 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.)

  7. Radiation-induced brain damage in children

    International Nuclear Information System (INIS)

    Oi, Shizuo; Kokunai, Takashi; Ijichi, Akihiro; Matsumoto, Satoshi; Raimondi, A.J.

    1990-01-01

    The nature and sequence of the radiation-induced changes in the brain were studied postmortem in 34 children with glioma, 22 of whom underwent central nervous system radiation therapy. Twenty received whole-brain or whole-neuroaxis radiation at a total mean dosage of 4063 cGy. Brain tissue alternations were analyzed histologically by means of various staining methods, including immunohistochemical techniques. The histological features of irradiated brains were compared with those of non-irradiated brains. Microscopic findings included demyelination (seven cases), focal necrosis (six cases), cortical atrophy (four cases), endothelial proliferation (four cases), and telangiectatic vascular proliferation with vascular thickening and oozing of a thick fluid (one case). Such findings were rare in non-irradiated patients. Demyelination was observed earliest in a patient who died 5 months after radiation therapy and was more common after 9 months. Focal necrosis was first observed 9 months post-irradiation but was more advanced and extensive after 1 year. Calcified foci were found only after 60 months. Various vascular changes such as vascular thickening and thrombosis suggested ischemic insult to the brain as a late effect of radiation injury. The results of this study suggest that the immature brain may be more sensitive to radiation than is the adult brain, and that the manifestations of radiation-induced injury depend on the time elapsed after irradiation. (author)

  8. Radiation Induced Precipitation in Iron

    Energy Technology Data Exchange (ETDEWEB)

    Solly, B

    1964-02-15

    Foils of iron have been neutron-irradiated in the Swedish re- search reactor R2 to integrated doses in the range 10{sup 17} - 10{sup 19} nvt (> 1 MeV) and examined by transmission electron microscopy. Features have been observed having diffraction contrast similar to that of the prismatic dislocation loops formed in f.c.c. metals by the collapse of point-defect clusters. The features have been shown to be due to precipitation of impurities at radiation damage centres in the iron matrix.

  9. Radiation Induced Precipitation in Iron

    International Nuclear Information System (INIS)

    Solly, B.

    1964-02-01

    Foils of iron have been neutron-irradiated in the Swedish re- search reactor R2 to integrated doses in the range 10 17 - 10 19 nvt (> 1 MeV) and examined by transmission electron microscopy. Features have been observed having diffraction contrast similar to that of the prismatic dislocation loops formed in f.c.c. metals by the collapse of point-defect clusters. The features have been shown to be due to precipitation of impurities at radiation damage centres in the iron matrix

  10. 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.)

  11. The different radiation response and radiation-induced bystander effects in colorectal carcinoma cells differing in p53 status

    Energy Technology Data Exchange (ETDEWEB)

    Widel, Maria, E-mail: maria.widel@polsl.pl [Biosystems Group, Institute of Automatic Control, Silesian University of Technology, 16 Akademicka Street, 44-100 Gliwice (Poland); Lalik, Anna; Krzywon, Aleksandra [Biosystems Group, Institute of Automatic Control, Silesian University of Technology, 16 Akademicka Street, 44-100 Gliwice (Poland); Poleszczuk, Jan [College of Inter-faculty Individual Studies in Mathematics and Natural Sciences, University of Warsaw, 93 Zwirki i Wigury Street, 02-089 Warsaw (Poland); Department of Integrated Mathematical Oncology, H. Lee Moffitt Cancer Center & Research Institute, Tampa, Florida (United States); Fujarewicz, Krzysztof; Rzeszowska-Wolny, Joanna [Biosystems Group, Institute of Automatic Control, Silesian University of Technology, 16 Akademicka Street, 44-100 Gliwice (Poland)

    2015-08-15

    Highlights: • We tested radiation response and bystander effect on HCT116p53+/+ and p53−/− cells. • The p53+/+ cells developed premature senescence in exposed and bystander neighbors. • Directly exposed and bystander p53−/− cells died profoundly through apoptosis. • Interleukins 6 and 8 were differently generated by both cell lines. • NFκB path was activated mainly in p53+/+ hit cells, in p53 −/− in bystanders only. - Abstract: Radiation-induced bystander effect, appearing as different biological changes in cells that are not directly exposed to ionizing radiation but are under the influence of molecular signals secreted by irradiated neighbors, have recently attracted considerable interest due to their possible implication for radiotherapy. However, various cells present diverse radiosensitivity and bystander responses that depend, inter alia, on genetic status including TP53, the gene controlling the cell cycle, DNA repair and apoptosis. Here we compared the ionizing radiation and bystander responses of human colorectal carcinoma HCT116 cells with wild type or knockout TP53 using a transwell co-culture system. The viability of exposed to X-rays (0–8 Gy) and bystander cells of both lines showed a roughly comparable decline with increasing dose. The frequency of micronuclei was also comparable at lower doses but at higher increased considerably, especially in bystander TP53-/- cells. Moreover, the TP53-/- cells showed a significantly elevated frequency of apoptosis, while TP53+/+ counterparts expressed high level of senescence. The cross-matched experiments where irradiated cells of one line were co-cultured with non-irradiated cells of opposite line show that both cell lines were also able to induce bystander effects in their counterparts, however different endpoints revealed with different strength. Potential mediators of bystander effects, IL-6 and IL-8, were also generated differently in both lines. The knockout cells secreted IL-6 at

  12. The different radiation response and radiation-induced bystander effects in colorectal carcinoma cells differing in p53 status

    International Nuclear Information System (INIS)

    Widel, Maria; Lalik, Anna; Krzywon, Aleksandra; Poleszczuk, Jan; Fujarewicz, Krzysztof; Rzeszowska-Wolny, Joanna

    2015-01-01

    Highlights: • We tested radiation response and bystander effect on HCT116p53+/+ and p53−/− cells. • The p53+/+ cells developed premature senescence in exposed and bystander neighbors. • Directly exposed and bystander p53−/− cells died profoundly through apoptosis. • Interleukins 6 and 8 were differently generated by both cell lines. • NFκB path was activated mainly in p53+/+ hit cells, in p53 −/− in bystanders only. - Abstract: Radiation-induced bystander effect, appearing as different biological changes in cells that are not directly exposed to ionizing radiation but are under the influence of molecular signals secreted by irradiated neighbors, have recently attracted considerable interest due to their possible implication for radiotherapy. However, various cells present diverse radiosensitivity and bystander responses that depend, inter alia, on genetic status including TP53, the gene controlling the cell cycle, DNA repair and apoptosis. Here we compared the ionizing radiation and bystander responses of human colorectal carcinoma HCT116 cells with wild type or knockout TP53 using a transwell co-culture system. The viability of exposed to X-rays (0–8 Gy) and bystander cells of both lines showed a roughly comparable decline with increasing dose. The frequency of micronuclei was also comparable at lower doses but at higher increased considerably, especially in bystander TP53-/- cells. Moreover, the TP53-/- cells showed a significantly elevated frequency of apoptosis, while TP53+/+ counterparts expressed high level of senescence. The cross-matched experiments where irradiated cells of one line were co-cultured with non-irradiated cells of opposite line show that both cell lines were also able to induce bystander effects in their counterparts, however different endpoints revealed with different strength. Potential mediators of bystander effects, IL-6 and IL-8, were also generated differently in both lines. The knockout cells secreted IL-6 at

  13. Radiation-induced heart disease

    Energy Technology Data Exchange (ETDEWEB)

    Stroobandt, R; Knieriem, H J; De Wolf, L; Joossens, J V

    1975-01-01

    A 45-year old woman underwent a radical mastectomy in 1965 for carcinoma of the left breast with metastasis in the left axillar lymph nodes. Fifty per cent of the heart received 4,000 rads during postoperative X-ray therapy. Patient developed radiopneumonia and symptoms of acute pericarditis in 1967. Constrictive pericarditis developed gradually from 1972 on. A pericardiectomy was performed in June 1974 and a thickened pericardium could be removed. Light and electron microscopic examination of a surgical biopsy of the left ventricular epi-myocardium revealed epicardial fibrosis, interstitial fibrosis of the myocardium and perivascular fibrosis. The diagnosis of post-radiation pericarditis was made. The myocardial involvement may be responsible for the subsequent clinical course.

  14. Radiation-induced valvular heart disease.

    Science.gov (United States)

    Gujral, Dorothy M; Lloyd, Guy; Bhattacharyya, Sanjeev

    2016-02-15

    Radiation to the mediastinum is a key component of treatment with curative intent for a range of cancers including Hodgkin's lymphoma and breast cancer. Exposure to radiation is associated with a risk of radiation-induced heart valve damage characterised by valve fibrosis and calcification. There is a latent interval of 10-20 years between radiation exposure and development of clinically significant heart valve disease. Risk is related to radiation dose received, interval from exposure and use of concomitant chemotherapy. Long-term outlook and the risk of valve surgery are related to the effects of radiation on mediastinal structures including pulmonary fibrosis and pericardial constriction. Dose prediction models to predict the risk of heart valve disease in the future and newer radiation techniques to reduce the radiation dose to the heart are being developed. Surveillance strategies for this cohort of cancer survivors at risk of developing significant heart valve complications are required. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  15. Radiation-induced Genomic Instability and Radiation Sensitivity

    Energy Technology Data Exchange (ETDEWEB)

    Varnum, Susan M.; Sowa, Marianne B.; Kim, Grace J.; Morgan, William F.

    2013-01-19

    The obvious relationships between reactive oxygen and nitrogen species, mitochondrial dysfunction, inflammatory type responses and reactive chemokines and cytokines suggests a general stress response induced by ionizing radiation most likely leads to the non-targeted effects described after radiation exposure. We argue that true bystander effects do not occur in the radiation therapy clinic. But there is no question that effects outside the target volume do occur. These “out of field effects” are considered very low dose effects in the context of therapy. So what are the implications of non-targeted effects on radiation sensitivity? The primary goal of therapy is to eradicate the tumor. Given the genetic diversity of the human population, lifestyle and environment factors it is likely some combination of these will influence patient outcome. Non-targeted effects may contribute to a greater or lesser extent. But consider the potential situation involving a partial body exposure due to a radiation accident or radiological terrorism. Non-targeted effects suggest that the tissue at risk for demonstrating possible detrimental effects of radiation exposure might be greater than the volume actually irradiated.

  16. Radiation-induced cancers in man

    International Nuclear Information System (INIS)

    Hirose, Fumio

    1978-01-01

    Radiation-induced cancers in man were divided into three groups, a group in which cancers occurred after atomic bomb exposure, a group in which cancers occurred in radiologists and other medical specialists, and a group in which cancers occurred after exposure to diagnostic radiation, and they were summarized. In atomic bomb survivors leukemia, thyroid cancer, salivary gland cancer, lung cancer, and breast cancer occurred so frequently. In addition to them, mortality ratios by malignant lymphoma, stomach cancer, esophageal cancer, and by cancer of urinary tract were increased. The incidence of leukemia was decreased in those who treated radiation owing to the development of the protection of occupational exposure, and the incidence of radiation-induced cancers was decreased in patients owing to the improvement of therapy. However, a new problem has arisen as to the occurrence of cancers after medical exposure, such as various histological types of cancers after the treatment of skin diseases on the head, and breast cancer after the treatment of pneumothorax. Dose-to-effect relation, hereditary factors, effect of age, immunological influences and endocrine actions were also studied in each radiation-induced cancer. (Ichikawa, K.)

  17. Study on radiation-inducible genes

    International Nuclear Information System (INIS)

    Lim, Sang Yong; Kim, Dong Ho; Joe, Min Ho; Park, Hae Jun; Song, Hyu Npa

    2012-01-01

    Radiation-inducible genes of E. coli, which is a model strain for bacterial study, and Salmonella, which is a typical strain for pathogenic bacteria were compared through omic analysis. Heat shock response genes and prophage genes were induced by radiation in Salmonella, not in E. coli. Among prophage genes tested, STM2628 showed the highest activation by radiation, and approximately 1 kb promoter region was turned out to be necessary for radiation response. To screen an artificial promoter showing activation by 2 Gy, the high-throughput screening method using fluorescent MUG substrate was established. The use of bacteria as anticancer agents has attracted interest. In this study, we tried to develop tumor targeting bacteria in which the radiation-inducible promoter activate a transgene encoding a cytotoxic protein. To do this, a tumor-targeting hfq Salmonella mutant strain was constructed, and we found that its virulence decreased. For outward secretion of anticancer protein produced inside bacteria, the signal peptide of SspH1 was determined and the signal peptide was proven to be able to secrete an anticancer protein. Tumor xenograft mouse model was secured, which can be used for efficiency evaluation of bacterial tumor therapy

  18. Radiation-induced heart injury. Radiopathological study

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Y; Niibe, H [Gunma Univ., Maebashi (Japan). School of Medicine

    1975-11-01

    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 interval 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.

  19. Study on radiation-inducible genes

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Sang Yong; Kim, Dong Ho; Joe, Min Ho; Park, Hae Jun; Song, Hyu Npa

    2012-01-15

    Radiation-inducible genes of E. coli, which is a model strain for bacterial study, and Salmonella, which is a typical strain for pathogenic bacteria were compared through omic analysis. Heat shock response genes and prophage genes were induced by radiation in Salmonella, not in E. coli. Among prophage genes tested, STM2628 showed the highest activation by radiation, and approximately 1 kb promoter region was turned out to be necessary for radiation response. To screen an artificial promoter showing activation by 2 Gy, the high-throughput screening method using fluorescent MUG substrate was established. The use of bacteria as anticancer agents has attracted interest. In this study, we tried to develop tumor targeting bacteria in which the radiation-inducible promoter activate a transgene encoding a cytotoxic protein. To do this, a tumor-targeting hfq Salmonella mutant strain was constructed, and we found that its virulence decreased. For outward secretion of anticancer protein produced inside bacteria, the signal peptide of SspH1 was determined and the signal peptide was proven to be able to secrete an anticancer protein. Tumor xenograft mouse model was secured, which can be used for efficiency evaluation of bacterial tumor therapy.

  20. Radiation-induced cancers in man

    Energy Technology Data Exchange (ETDEWEB)

    Hirose, F [Hiroshima Univ. (Japan). Research Inst. for Nuclear Medicine and Biology

    1978-07-01

    Radiation-induced cancers in man were divided into three groups, a group in which cancers occurred after atomic bomb exposure, a group in which cancers occurred in radiologists and other medical specialists, and a group in which cancers occurred after exposure to diagnostic radiation, and they were summarized. In atomic bomb survivors leukemia, thyroid cancer, salivary gland cancer, lung cancer, and breast cancer occurred so frequently. In addition to them, mortality ratios by malignant lymphoma, stomach cancer, esophageal cancer, and by cancer of urinary tract were increased. The incidence of leukemia was decreased in those who treated radiation owing to the development of the protection of occupational exposure, and the incidence of radiation-induced cancers was decreased in patients owing to the improvement of therapy. However, a new problem has arisen as to the occurrence of cancers after medical exposure, such as various histological types of cancers after the treatment of skin diseases on the head, and breast cancer after the treatment of pneumothorax. Dose-to-effect relation, hereditary factors, effect of age, immunological influences and endocrine actions were also studied in each radiation-induced cancer.

  1. Radiation Induced Polymerization of Pyrrole

    International Nuclear Information System (INIS)

    Sarada Idris; Ratnam, C.T.; Ahmad Ashrif Abu Bakar

    2016-01-01

    We demonstrate the polymerization of pyrrole by gamma irradiation. The pyrrole films were exposed to gamma ray from cobalt 60 source at doses ranging from 0 to 150 kGy. The films were subjected to structural and morphological analyses by using FTIR, SEM and AFM techniques. Similar studies were also made on pristine pyrrole film which serve as control. Results revealed that pyrrole has been successfully polymerized through irradiation induced reactions. The SEM images depicted the formation of cauliflower shape upon gamma irradiation. The structural changes of pyrrole also evidenced by FTIR spectra. Surface topography and roughness of pyrrole before and after gamma irradiation found to show significant differences. (author)

  2. Study on radiation-inducible genes

    International Nuclear Information System (INIS)

    Lim, Sang Yong; Kim, Dong Ho; Joe, Min Ho; Song, Hyu Npa

    2012-01-01

    Transcription of previously identified radiation-inducible genes, uscA and cyoA, was examined responding to radiation. The putative promoter regions of both genes were cloned into pRS415 vector containing lacZ, and the core promoter region necessary for radiation response were determined through promoter deletion method. To investigate the role of uscA, which is assumed to be small RNA related with radiation response, a deletion mutant strain of uscA was constructed. However, uscA deletion did not affect bacterial survival against radiation exposure. The use of bacteria as anticancer agents has attracted interest. In this study, we tried to develop tumor targeting bacteria in which the radiation-inducible promoter activate a transgene encoding a cytotoxic protein. For outward secretion of anticancer protein produced inside bacteria, the N-terminal 140 amino acid of SspH1 was found to function as a secretion signal peptide. To create an attenuated tumor-targeting bacteria, Salmonella ptsI mutant strain was constructed, and we found that its virulence decreased. Finally, the tumor-targeting ability of ptsI mutant was verified by the use of in-vivo imaging analysis

  3. 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

  4. Cell cycle arrest induced by radiation

    International Nuclear Information System (INIS)

    Okaichi, Yasuo; Matsumoto, Hideki; Ohnishi, Takeo

    1994-01-01

    It is known that various chemical reactions, such as cell cycle arrest, DNA repair and cell killing, can occur within the cells when exposed to ionizing radiation and ultraviolet radiation. Thus protein dynamics involved in such chemical reactions has received considerable attention. In this article, cell cycle regulation is first discussed in terms of the G2/M-phase and the G1/S-phase. Then, radiation-induced cell cycle arrest is reviewed. Cell cycle regulation mechanism involved in the G2 arrest, which is well known to occur when exposed to radiation, has recently been investigated using yeasts. In addition, recent study has yielded a noticeable finding that the G1 arrest can occur with intracellular accumulation of p53 product following ionization radiation. p53 is also shown to play an extremely important role in both DNA repair and cell killing due to DNA damage. Studies on the role of genes in protein groups induced by radiation will hold promise for the elucidation of cell cycle mechanism. (N.K.) 57 refs

  5. Study on radiation-inducible genes

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Sang Yong; Kim, Dong Ho; Joe, Min Ho; Song, Hyu Npa

    2012-01-15

    Transcription of previously identified radiation-inducible genes, uscA and cyoA, was examined responding to radiation. The putative promoter regions of both genes were cloned into pRS415 vector containing lacZ, and the core promoter region necessary for radiation response were determined through promoter deletion method. To investigate the role of uscA, which is assumed to be small RNA related with radiation response, a deletion mutant strain of uscA was constructed. However, uscA deletion did not affect bacterial survival against radiation exposure. The use of bacteria as anticancer agents has attracted interest. In this study, we tried to develop tumor targeting bacteria in which the radiation-inducible promoter activate a transgene encoding a cytotoxic protein. For outward secretion of anticancer protein produced inside bacteria, the N-terminal 140 amino acid of SspH1 was found to function as a secretion signal peptide. To create an attenuated tumor-targeting bacteria, Salmonella ptsI mutant strain was constructed, and we found that its virulence decreased. Finally, the tumor-targeting ability of ptsI mutant was verified by the use of in-vivo imaging analysis.

  6. Radiation induced genetic damage in Aspergillus nidulans

    International Nuclear Information System (INIS)

    Georgiou, J.T.

    1984-01-01

    The mechanism by which ionizing radiation induces genetic damage in haploid and diploid conidia of Aspergillus nidulans was investigated. Although the linear dose-response curves obtained following low LET irradiation implied a 'single-hit' action of radiation, high LET radiations were much more efficient than low LET radiations, which suggests the involvement of a multiple target system. It was found that the RBE values for non-disjunction and mitotic crossing-over were very different. Unlike mitotic crossing-over, the RBE values for non-disjunction were much greater than for cell killing. This suggests that non-disjunction is a particularly sensitive genetical endpoint that is brought about by damage to a small, probably non-DNA target. Radiosensitisers were used to study whether radiation acts at the level of the DNA or some other cellular component. The sensitisation to electrons and/or X-rays by oxygen, and two nitroimidazoles (metronidazole and misonidazole) was examined for radiation induced non-disjunction, mitotic crossing-over, gene conversion, point mutation and cell killing. It was found that these compounds sensitised the cells considerably more to genetic damage than to cell killing. (author)

  7. 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

  8. Visual sensations induced by Cherenkov radiation

    International Nuclear Information System (INIS)

    McNulty, P.J.; Pease, V.P.; Bond, V.P.

    1975-01-01

    Pulses of relativistic singly charged particles entering the eyeball induce a variety of visual phenomena by means of Cerenkov radiation generated during their passage through the vitreous. These phenomena are similar in appearance to many of the visual sensations experienced by Apollo astronauts exposed to the cosmic rays in deep space

  9. Reducing radiation induced emesis in abdominal radiotherapy

    International Nuclear Information System (INIS)

    Griffin, K.

    1994-01-01

    In patients with seminoma testes, a comparison was made between radiation induced emesis suffered by patients receiving 'dogleg' radiotherapy with those suffered by patients who received para-aortic radiotherapy. The same comparisons were made between the effects suffered by those patients who received the anti-emetic, Ondansetron, and those suffered by patients who received conventional anti-emetics. (UK)

  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. Radiation-induced mutations and plant breeding

    International Nuclear Information System (INIS)

    Naqvi, S.H.M.

    1985-01-01

    Ionizing radiation could cause genetic changes in an organism and could modify gene linkages. The induction of mutation through radiation is random and the probability of getting the desired genetic change is low but can be increased by manipulating different parameters such as dose rate, physical conditions under which the material has been irradiated, etc. Induced mutations have been used as a supplement to conventional plant breeding, particularly for creating genetic variability for specific characters such as improved plant structure, pest and disease resistance, and desired changes in maturity period; more than 200 varieties of crop plants have been developed by this technique. The Pakistan Atomic Energy Commission has used this technique fruitfully to evolve better germplasm in cotton, rice, chickpea, wheat and mungbean; some of the mutants have become popular commercial varieties. This paper describes some uses of radiation induced mutations and the results achieved in Pakistan so far

  12. Environmental lead exposure increases micronuclei in children

    DEFF Research Database (Denmark)

    Kapka, Lucyna; Baumgartner, Adolf; Siwińska, Ewa

    2007-01-01

    The objective of this pilot study was to investigate the contribution of environmental exposures to lead in the development of cytogenetic damage detected as the frequency of micronuclei (MN) in children. The other aim was to apply the MN assay in combination with fluorescence in situ hybridization...... age from an unexposed recreational area. Exposure to lead was assessed by determination of lead concentrations in blood (PbB) by atomic absorption spectrophotometry, whereas the level of selenium (Se) in serum was detected by using graphite furnace atomic-absorption spectrometry. The frequency of MN...... was determined by the cytokinesis-block MN assay and fluorescence in situ hybridization performed using a specific pan-centromeric probe. Environmental exposure to lead resulted in significantly increased levels of PbB (5.29 +/- 2.09 versus 3.45 +/- 1.20 microg/dl in controls), although the average level...

  13. Cataracts induced by microwave and ionizing radiation

    International Nuclear Information System (INIS)

    Lipman, R.M.; Tripathi, B.J.; Tripathi, R.C.

    1988-01-01

    Microwaves most commonly cause anterior and/or posterior subcapsular lenticular opacities in experimental animals and, as shown in epidemiologic studies and case reports, in human subjects. The formation of cataracts seems to be related directly to the power of the microwave and the duration of exposure. The mechanism of cataractogenesis includes deformation of heat-labile enzymes, such as glutathione peroxide, that ordinarily protect lens cell proteins and membrane lipids from oxidative damage. Oxidation of protein sulfhydryl groups and the formation of high-molecular-weight aggregates cause local variations in the orderly structure of the lens cells. An alternative mechanism is thermoelastic expansion through which pressure waves in the aqueous humor cause direct physical damage to the lens cells. Cataracts induced by ionizing radiation (e.g., X-rays and gamma rays) usually are observed in the posterior region of the lens, often in the form of a posterior subcapsular cataract. Increasing the dose of ionizing radiation causes increasing opacification of the lens, which appears after a decreasing latency period. Like cataract formation by microwaves, cataractogenesis induced by ionizing radiation is associated with damage to the lens cell membrane. Another possible mechanism is damage to lens cell DNA, with decreases in the production of protective enzymes and in sulfur-sulfur bond formation, and with altered protein concentrations. Until further definitive conclusions about the mechanisms of microwaves and ionizing radiation induced cataracts are reached, and alternative protective measures are found, one can only recommend mechanical shielding from these radiations to minimize the possibility of development of radiation-induced cataracts. 74 references

  14. 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

  15. Radiation-induced brain injury: A review

    Energy Technology Data Exchange (ETDEWEB)

    Greene-Schloesser, Dana; Robbins, Mike E.; Peiffer, Ann M.; Shaw, Edward G. [Department of Radiation Oncology, Wake Forest School of Medicine,, Winston-Salem, NC (United States); Brain Tumor Center of Excellence, Wake Forest School of Medicine,, Winston-Salem, NC (United States); Wheeler, Kenneth T. [Brain Tumor Center of Excellence, Wake Forest School of Medicine,, Winston-Salem, NC (United States); Department of Radiology, Wake Forest School of Medicine,, Winston-Salem, NC (United States); Chan, Michael D., E-mail: mrobbins@wakehealth.edu [Department of Radiation Oncology, Wake Forest School of Medicine,, Winston-Salem, NC (United States); Brain Tumor Center of Excellence, Wake Forest School of Medicine,, Winston-Salem, NC (United States)

    2012-07-19

    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

  16. 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

  17. Toxic clinical hypoxic radiation sensitizers plus radiation-induced toxicity

    International Nuclear Information System (INIS)

    Richmond, R.C.

    1984-01-01

    The operational definition espoused twelve years ago that clinical hypoxic radiation sensitizers should be nontoxic interferes with the recognition and research of useful radiation sensitizers. Eight years ago the toxic antitumor drug cis-dichlorodiammineplatinum(II) was reported to be a hypoxic radiation sensitizer and the selective antitumor action of this drug was stressed as potentially creating tumor-targeted radiation sensitization. This rationale of oxidative antitumor drugs as toxic and targeted clinical sensitizers is useful, and has led to the study reported here. The antitumor drug cis-(1,1-cyclobutane-dicarboxylato)diammineplatinum(II), or JM-8, is being tested in clinical trials. Cells of S. typhimurium in PBS in the presence of 0.2mM JM-8 are found to be sensitized to irradiation under hypoxic, but not oxic, conditions. JM-8 is nontoxic to bacteria at this concentration, but upon irradiation the JM-8 solution becomes highly toxic. This radiation induced toxicity of JM-8 preferentially develops from hypoxic solution, and thus contributes to the rationale of hypoxic tumor cell destruction

  18. Genotoxic potential evaluation of a cosmetic insoluble substance by the micronuclei assay.

    Science.gov (United States)

    Dayan, N; Shah, V; Minko, T

    2011-01-01

    An optical brightener (OB) powder (INCI: sodium silicoaluminate (and) glycidoxypropyl trimethyloxysilane/PEI-250 cross fluorescent brightener 230 salt (and) polyvinylalcohol crosspolymer) that is used in cosmetic facial products was tested for its genotoxic potential using the micronuclei test (MNT). It is a solid dry powder with an average size of 5 microns that is insoluble but dispersible in water. This study describes the exposure of cell culture to positive controls with and without enzymatic activation and to the test compound in different concentrations. We evaluated three end points: microscopic observation and quantification of micronuclei formation, and cell viability and proliferation. Both positive controls induced significant changes that were observed under the microscope and quantified. Based on its chemical nature, it was not anticipated that the test substance will degrade under the conditions of the experiments. However, the test is required to make sure that when solublized, impurities that may be present, even at trace levels, will not induce a genotoxic effect. The test compound did not promote micronuclei formation or change the viability or proliferation rate of cells. During this study we faced challenges such as solubilization and correlating viability data to genotoxicity data. These are described in the body of the paper. We believe that with the emergence of the 7(th) European amendment that bans animal testing, sharing these data and the study protocol serves as a key in building the understanding of the utilization of in vitro studies in the safety assessment of cosmetic ingredients.

  19. 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)

  20. Molecular epidemiology of radiation-induced carcinogenesis

    International Nuclear Information System (INIS)

    Trosko, J.E.

    1996-01-01

    The role of ionizing radiation in carcinogenesis is discussed. Every cell contains proto-oncogenes, which if damaged may lead to cell transformation. Every cell also contains tumor suppressor genes, which guard against transformation. Thus, transformation would seem to require a double injury to the DNA in a cell. Ionizing radiation is known to be a relatively weak mutagen, but a good clastogen (inducer of chromosome breaks, deletions and rearrangements). Ionizing radiation may therefore be a 'promoter' of cancer, i.e. a stimulant of the clonal expansion of transformed cells, if it kills enough cells to induce compensatory hyperplasia - i.e. rapid growth of cells. Ionizing radiation may be a 'progressor', if it deactivates tumor suppressor genes tending to suppress the growth of existing clones of transformed cells resulting from any of numerous causes. It may therefore be an oversimplification to say that radiation causes cancer; rather, it seems to be a weak initiator, an indirect promoter, and a late-stage progressor. 2 figs

  1. 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.

  2. 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.

  3. Radiation-induced reactions in polydimethyl siloxanes

    International Nuclear Information System (INIS)

    Menhofer, H.

    1988-01-01

    The dissertation reports an investigation into the behaviour of polydimethyl soloxanes (PDMS) subject to the radiation field of a 60 Co-γ radiation source at different irradiation conditions. Several different analytical methods have been applied for the detection of chemical changes in the material and their effects on the polymeric segment mobility. Application of the ESR-spintrap technique identifies the primary radicals x CH 3 , -Si x , and -Si-CH 2 x , induced by the radiolysis of the PDMS. The individual rates of radical formation have been found to be strongly dependent on temperature. (orig./LU) [de

  4. 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

  5. The nature and principles of the radiation-induced cancerogenesis

    International Nuclear Information System (INIS)

    Lips'ka, A.YI.; Serkyiz, Ya.Yi.

    2004-01-01

    The paper represents the analysis of the authors and literary data concerning the nature and principles of the radiation-induced neoplasms. The mechanisms of the radiation-induced cancerogenesis development are not clear understood. The experimental data altogether do not allow developing the mathematical model of the radiation-induced cancerogenesis at the molecular level. This model has to take into account all necessary indices including radiation factor and the state of the organism. The general principles of the radiation-induced cancerogenesis have been formulated in the present review. It is possible to use these principles in order to predict and calculate the risks of the radiation-induced neoplasms

  6. The use of unstable chromosome aberrations and micronuclei in the individual biomonitoring: a comparative study

    International Nuclear Information System (INIS)

    Fernandes, Thiago de Salazar e

    2005-02-01

    Biodosimetry is based on the investigation of radioinduced biological effects in order to correlate them with the absorbed dose. The quantification of unstable chromosome aberrations and micronuclei, in peripheral blood lymphocytes, are two methods commonly used in biodosimetry. In this context, the aim of this research was to compare these methods in the biomonitoring of health care professionals occupationally exposed to ionizing radiation. In parallel, the technique of C-banding was evaluated for quality control of unstable chromosome aberrations analyses. Thus, samples of peripheral blood from health care professionals of three hospitals from Recife (Brazil) were collected, and the lymphocytes cultures were carried out based on the cytogenetic classical technique. It was pointed out that analysis of micronuclei is faster than the unstable chromosome aberrations ones, which suggests the use of the former in preliminary evaluation in cases of suspected accidental exposure. C-banding technique was efficient, as confirmatory test, in the identification of dicentrics and rings during the analyses of unstable chromosome aberrations, being able to be applied in the quality control in biodosimetry. The comparison between the individual work conditions with the frequencies of unstable aberrations and micronuclei obtained from cytogenetic analysis, resulted in the change of behavior of the professionals involved in this research, with a better observance of the radioprotection standards. (author)

  7. 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

  8. 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...

  9. 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

  10. 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

  11. Radiation-induced conductivity of polynaphthoyl benzimidazole

    Energy Technology Data Exchange (ETDEWEB)

    Tiutnev, A P; Berlin, A M; Saenko, V S; Rusanov, A L; Korshak, V V

    1985-01-01

    The nonstationary radiation-induced conductivity of polynaphthoyl benzimidazole, synthesized by single-stage high-temperature catalytic polycondensation, is investigated experimentally. It is shown that the radiation-induced conductivity of this material is characterized by an anomalous (non-Gaussian) transfer of excess charge carriers. The activation energy of the delayed component (0.1 ms after pulse termination) is determined to be 0.12 eV; the volt-ampere characteristic of this component is nonlinear, with the coefficient of nonlinearity increasing with the intensity of the external electric field. Experimental results are interpreted on the basis of the phenomenological theory of jump conductivity proposed by Zviagin. 15 references.

  12. 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

  13. Heat pump processes induced by laser radiation

    Science.gov (United States)

    Garbuny, M.; Henningsen, T.

    1980-01-01

    A carbon dioxide laser system was constructed for the demonstration of heat pump processes induced by laser radiation. The system consisted of a frequency doubling stage, a gas reaction cell with its vacuum and high purity gas supply system, and provisions to measure the temperature changes by pressure, or alternatively, by density changes. The theoretical considerations for the choice of designs and components are dicussed.

  14. Radiation-induced structural changes, (2)

    International Nuclear Information System (INIS)

    Ogasawara, M.; Matsuyama, T.

    1992-11-01

    This seminar is aimed at understanding both the physical and chemical aspects of the structural changes of materials induced by photons or ionizing radiation. The seminar was held on December 19th, 1991 and from February 13 to 14th, 1992 in this institute. The most active areas of the material science, in addition to the previous subjects, such as organic superconductors, silicon-based polymers, and fullerenes were included in this seminar. (J.P.N.)

  15. 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)

  16. Role of neurotensin in radiation-induced hypothermia in rats

    International Nuclear Information System (INIS)

    Kandasamy, S.B.; Hunt, W.A.; Harris, A.H.

    1991-01-01

    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

  17. Ultraviolet Radiation-Induced Cytogenetic Damage in White, Hispanic and Black Skin Melanocytes: A Risk for Cutaneous Melanoma

    Energy Technology Data Exchange (ETDEWEB)

    Dasgupta, Amrita [Hampton University Skin of Color Research Institute, Hampton, VA 23668 (United States); Katdare, Meena, E-mail: mkatdare@gmail.com [Hampton University Skin of Color Research Institute, Hampton, VA 23668 (United States); Department of Dermatology, Eastern Virginia Medical School, Norfolk, VA 23507 (United States)

    2015-08-14

    Cutaneous Melanoma (CM) is a leading cause of cancer deaths, with reports indicating a rising trend in the incidence rate of melanoma among Hispanics in certain U.S. states. The level of melanin pigmentation in the skin is suggested to render photoprotection from the DNA-damaging effects of Ultraviolet Radiation (UVR). UVR-induced DNA damage leads to cytogenetic defects visualized as the formation of micronuclei, multinuclei and polymorphic nuclei in cells, and a hallmark of cancer risk. The causative relationship between Sun exposure and CM is controversial, especially in Hispanics and needs further evaluation. This study was initiated with melanocytes from White, Hispanic and Black neonatal foreskins which were exposed to UVR to assess their susceptibility to UVR-induced modulation of cellular growth, cytogenetic damage, intracellular and released melanin. Our results show that White and Hispanic skin melanocytes with similar levels of constitutive melanin are susceptible to UVR-induced cytogenetic damage, whereas Black skin melanocytes are not. Our data suggest that the risk of developing UVR-induced CM in a skin type is correlated with the level of cutaneous pigmentation and its ethnic background. This study provides a benchmark for further investigation on the damaging effects of UVR as risk for CM in Hispanics.

  18. Ultraviolet Radiation-Induced Cytogenetic Damage in White, Hispanic and Black Skin Melanocytes: A Risk for Cutaneous Melanoma

    International Nuclear Information System (INIS)

    Dasgupta, Amrita; Katdare, Meena

    2015-01-01

    Cutaneous Melanoma (CM) is a leading cause of cancer deaths, with reports indicating a rising trend in the incidence rate of melanoma among Hispanics in certain U.S. states. The level of melanin pigmentation in the skin is suggested to render photoprotection from the DNA-damaging effects of Ultraviolet Radiation (UVR). UVR-induced DNA damage leads to cytogenetic defects visualized as the formation of micronuclei, multinuclei and polymorphic nuclei in cells, and a hallmark of cancer risk. The causative relationship between Sun exposure and CM is controversial, especially in Hispanics and needs further evaluation. This study was initiated with melanocytes from White, Hispanic and Black neonatal foreskins which were exposed to UVR to assess their susceptibility to UVR-induced modulation of cellular growth, cytogenetic damage, intracellular and released melanin. Our results show that White and Hispanic skin melanocytes with similar levels of constitutive melanin are susceptible to UVR-induced cytogenetic damage, whereas Black skin melanocytes are not. Our data suggest that the risk of developing UVR-induced CM in a skin type is correlated with the level of cutaneous pigmentation and its ethnic background. This study provides a benchmark for further investigation on the damaging effects of UVR as risk for CM in Hispanics

  19. Adaptive response in human blood lymphocytes exposed to non-ionizing radiofrequency fields: resistance to ionizing radiation-induced damage.

    Science.gov (United States)

    Sannino, Anna; Zeni, Olga; Romeo, Stefania; Massa, Rita; Gialanella, Giancarlo; Grossi, Gianfranco; Manti, Lorenzo; Vijayalaxmi; Scarfì, Maria Rosaria

    2014-03-01

    The aim of this preliminary investigation was to assess whether human peripheral blood lymphocytes which have been pre-exposed to non-ionizing radiofrequency fields exhibit an adaptive response (AR) by resisting the induction of genetic damage from subsequent exposure to ionizing radiation. Peripheral blood lymphocytes from four healthy donors were stimulated with phytohemagglutinin for 24 h and then exposed for 20 h to 1950 MHz radiofrequency fields (RF, adaptive dose, AD) at an average specific absorption rate of 0.3 W/kg. At 48 h, the cells were subjected to a challenge dose (CD) of 1.0 or 1.5 Gy X-irradiation (XR, challenge dose, CD). After a 72 h total culture period, cells were collected to examine the incidence of micronuclei (MN). There was a significant decrease in the number of MN in lymphocytes exposed to RF + XR (AD + CD) as compared with those subjected to XR alone (CD). These observations thus suggested a RF-induced AR and induction of resistance to subsequent damage from XR. There was variability between the donors in RF-induced AR. The data reported in our earlier investigations also indicated a similar induction of AR in human blood lymphocytes that had been pre-exposed to RF (AD) and subsequently treated with a chemical mutagen, mitomycin C (CD). Since XR and mitomycin-C induce different kinds of lesions in cellular DNA, further studies are required to understand the mechanism(s) involved in the RF-induced adaptive response.

  20. Polyploidy and chromosomal aberrations induced by mutagens in open flowering sterile mutants of spring barley

    Energy Technology Data Exchange (ETDEWEB)

    Manzyuk, V T; Kozachenko, M R; Kirichenko, V V

    1975-01-01

    Two types of aberration in meiosis were observed which induced sterility in chemical and radiational mutations of spring wheat: asynapsis and absence of cytokinesis, and chromosomal aberrations in the form of bridges and fragments. Gamma-mutants have many more chromosomal aberrations in the form of fragments, bridges and cells with micronuclei than do chemical mutants. The percent of tetrads with micronuclei is 1.5-2 times greater than the number of dyads with such nuclei. We obtained an original gamma-mutant exhibiting depolyploidization and polyploidization in the mother cells; we also observed cells possessing chromosomal associations of n, 2n, 4n, 68, 8n and greater.

  1. Generation of micronuclei during interphase by coupling between cytoplasmic membrane blebbing and nuclear budding.

    Directory of Open Access Journals (Sweden)

    Koh-ichi Utani

    Full Text Available Micronucleation, mediated by interphase nuclear budding, has been repeatedly suggested, but the process is still enigmatic. In the present study, we confirmed the previous observation that there are lamin B1-negative micronuclei in addition to the positive ones. A large cytoplasmic bleb was found to frequently entrap lamin B1-negative micronuclei, which were connected to the nucleus by a thin chromatin stalk. At the bottom of the stalk, the nuclear lamin B1 structure appeared broken. Chromatin extrusion through lamina breaks has been referred to as herniation or a blister of the nucleus, and has been observed after the expression of viral proteins. A cell line in which extrachromosomal double minutes and lamin B1 protein were simultaneously visualized in different colors in live cells was established. By using these cells, time-lapse microscopy revealed that cytoplasmic membrane blebbing occurred simultaneously with the extrusion of nuclear content, which generated lamin B1-negative micronuclei during interphase. Furthermore, activation of cytoplasmic membrane blebbing by the addition of fresh serum or camptothecin induced nuclear budding within 1 to 10 minutes, which suggested that blebbing might be the cause of the budding. After the induction of blebbing, the frequency of lamin-negative micronuclei increased. The budding was most frequent during S phase and more efficiently entrapped small extrachromosomal chromatin than the large chromosome arm. Based on these results, we suggest a novel mechanism in which cytoplasmic membrane dynamics pulls the chromatin out of the nucleus through the lamina break. Evidence for such a mechanism was obtained in certain cancer cell lines including human COLO 320 and HeLa. The mechanism could significantly perturb the genome and influence cancer cell phenotypes.

  2. Investigation of micronuclei induction in human peripheral blood lymphocytes exposed in vitro to EMF RF

    International Nuclear Information System (INIS)

    Kolomiets, Irina A.; Triapitsina, Galina A.; Polevik, Nikolai D.; Pryakhin, Evgeny A.

    2008-01-01

    Full text: The widespread application of cellular phones is of great concern in view possible consequences for human health. The aim of this study is to assess the capability of electromagnetic fields (EMF) RF with frequency 925 MHz and modulation 217 Hz to induce genotoxic effects as evaluated by the in vitro micronucleus assay on peripheral blood lymphocytes. The flasks of peripheral blood samples collected from healthy volunteers (5 men and 5 women) were placed just on the oscillator of emitting antenna. The signals were produced by the laboratory research plant and were evaluated at four specific absorption rates (SARs) - 0; 0.29; 1.2; 8.1 W/kg. SARs were determined by the calorimetric method. Phytohaemagglutinin stimulated lymphocytes were exposed three times for 10 minutes in the G o (the first 30 minutes after the beginning of cultivation), S (24 hours later), G 2 -M (after 48 hours from the beginning of cultivation) stages of the cell cycle. 72-hours cultures of lymphocytes were examined to determine the extent of micronuclei. The Mann-Whitney U-test was used to evaluate the significance for comparison. The data indicated a significant increase of micronuclei in human lymphocytes exposed to EMF RF (6.5 ± 0.51 0/00; 7.1 ± 0.66 0/00; 7.0 ± 0.50 0/00) in comparison with sham-exposed lymphocytes (3.0 ± 0.60 0/00). There was not revealed a dose-dependent increase of micronuclei in human lymphocytes. It was suggested that the increase of micronuclei in lymphocytes is explicated by a particularity of EMF RF just near the oscillator of emitting antenna. (author)

  3. Three cases of radiation-induced cancer in oral regions

    International Nuclear Information System (INIS)

    Kawamura, Hiroshi; Shinoki, Kunihiko; Endo, Yoshitaka; Fujita, Yasushi; Hayashi, Susumu

    1985-01-01

    Three cases of radiation-induced cancer in the oral regions were reported with relation to radiation therapy. One was the general radiation-induced cancer following radiotherapy for the hemangioma. The other two cases, which belonged in the B-1 group of Sakai and his coworker's diagnostic criteria for radiation-induced cancer, were those occurring after radiotherapy for the malignant tumors. Due to the relatively high dosage exposure by the patient in the radiotherapy it is necessary to look out the latency of the radiation-induced cancer. After radiotherapy, careful and periodical observation is important for immediate treatment in an early stage for the radiation-induced cancer to have a favorable prognosis. In addition careful observation of the changes after radiotherapy helps in discovering the precancerous lesions from the therapy. For the radiation-induced cancer, surgical treatment would be the best, however, radiation therapy is also effective in certain cases. (author)

  4. Effect of oxygen on formation of micronuclei and binucleated cells and cell survival in γ-irradiated 3T3 cells

    International Nuclear Information System (INIS)

    Zhang Peng; Zheng Xiulong

    1991-01-01

    Formation of micronuclei and binucleate cells and their relationships with cell survival were studied in the aerobically- and anaerobically-irradiated 3T3 cells. The results showed taht frequency of micronuclei, percentage of micronucleus cells and percentage of binucleate cells increased linearly with the radiation dose in certain range. Oxygen enhancement ratios (OER) of micronucleus frequency, percentage of micronucleus cells, percentage of binucleate cells and cell survival were 2.02, 1.96, 1.87 and 1.83 respectively. The percentage of micronucleus cells or the percentage of micronucleus cells plus binucleate cells correlated negatively well with cell survival. The mechanism of oxygen effect in the radiation response of 3T3 cells and the significance of formation of micronuclei and binucleate cells were discussed

  5. Breast cancer induced by protracted radiation exposures

    International Nuclear Information System (INIS)

    Elkind, M.M.

    1997-01-01

    The experience at Hiroshima/Nagasaki demonstrated that breast cancer can be induced by single doses of ionizing radiation following latencies of 10-40 years. Several epidemiological studies, usually involving ancillary low-LET radiation to the breast, have demonstrated that breast cancer can be induced by protracted exposures, with similar latencies, and with similar dependencies on dose. Radiobiologically these results suggest that the target cells involved were deficient in repair of low-LET damage even when the protraction was over months to years. Since three-quarters of breast tumors originate in the ducts where their proliferation is controlled by menstrual-cycle timed estrogen/progesterone secretions, these cells periodically were in cycle. Thus, the two main elements of a conceptual model for radon-induced lung cancer -- kinetics and deficient repair -- are satisfied. The model indicates that breast cancer could be the cumulative effect of protracted small exposures, the risk from any one of which ordinarily would be quite small. (author)

  6. Heterogeneity in 2-deoxy-D-glucose-induced modifications in energetics and radiation responses of human tumor cell lines

    International Nuclear Information System (INIS)

    Dwarkanath, Bilikere S.; Zolzer, Frido; Chandana, Sudhir; Bauch, Thomas; Adhikari, Jawahar S.; Muller, Wolfgang U.; Streffer, Christian; Jain, Viney

    2001-01-01

    Purpose: The glucose analog and glycolytic inhibitor, 2-deoxy-D-glucose (2-DG), has been shown to differentially enhance the radiation damage in tumor cells by inhibiting the postirradiation repair processes. The present study was undertaken to examine the relationship between 2-DG-induced modification of energy metabolism and cellular radioresponses and to identify the most relevant parameter(s) for predicting the tumor response to the combined treatment of radiation + 2-DG. Methods and Materials: Six human tumor cell lines (glioma: BMG-1 and U-87, squamous cell carcinoma: 4451 and 4197, and melanoma: MeWo and Be-11) were investigated. Cells were exposed to 2 Gy of Co-60 γ-rays or 250 kVP X-rays and maintained under liquid-holding conditions 2-4 h to facilitate repair. 2-DG (5 mM, equimolar with glucose) that was added at the time of irradiation was present during the liquid holding. Glucose utilization, lactate production (enzymatic assays), and adenine nucleotides (high performance liquid chromatography and capillary isotachophoresis) were investigated as parameters of energy metabolism. Induction and repair of DNA damage (comet assay), cytogenetic damage (micronuclei formation), and cell death (macrocolony assay) were analyzed as parameters of radiation response. Results: The glucose consumption and lactate production of glioma cell lines (BMG-1 and U-87) were nearly 2-fold higher than the squamous carcinoma cell lines (4197 and 4451). The ATP content varied from 3.0 to 6.5 femto moles/cell among these lines, whereas the energy charge (0.86-0.90) did not show much variation. Presence of 2-DG inhibited the rate of glucose usage and glycolysis by 30-40% in glioma cell lines and by 15-20% in squamous carcinoma lines, while ATP levels reduced by nearly 40% in all the four cell lines. ATP:ADP ratios decreased to a greater extent (∼40%) in glioma cells than in squamous carcinoma 4451 and MeWo cells; in contrast, presence of 2-DG reduced ADP:AMP ratios by 3-fold in

  7. Studies on radiation-induced graft polymerization

    International Nuclear Information System (INIS)

    Omichi, Hideki

    1978-09-01

    Radiation-induced graft polymerization is used extensively to improve physical properties of polymers, but few processes are now commercialized. The reason for this is partly inadequate basic research on the reaction and partly the difficulty in developing the grafting process with large radiation source. Firstly, new techniques are proposed of studying kinetics of the graft polymerization in heterogeneous system. Based on the grafting yield, the molecular weight of graft chains, and the amount of radicals given by ESR and activation analysis, kinetic parameters are obtained and the reaction mechanism of grafting process is discussed. Secondly, the development of grafting process of poly (vinyl chloride)-butadiene is described. By study of the reaction, process design, construction and operation of the pilot plant, and economic analysis of the process, this process with 60 Co gamma ray sources is shown to be industrially promising. (author)

  8. Radiation-induced mutations in mammals

    International Nuclear Information System (INIS)

    Ehling, U.H.

    1993-01-01

    The aims of the proposed project are to provide a better basis for extrapolation of animal data to man. Genetic endpoint, strain and species comparisons are made, which will provide critical experimental data regarding strategies in extrapolating laboratory animal data to man. Experiments were conducted to systematically compare the spontaneous and radiation-induced mutation rates for recessive specific-locus, dominant cataract and enzyme activity alleles in the mouse as well as a comparison of the mutation rate in the mouse and hamster for dominant cataract and enzyme activity alleles. The comparison of the radiation-dose response for recessive specific-locus and dominant cataract mutations are extended. Selected mutations are characterized at the genetic, biochemical and molecular levels. (R.P.) 5 refs., 3 tabs

  9. 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

  10. Radiation induced mutations for plant selection

    International Nuclear Information System (INIS)

    Brunner, H.

    1994-01-01

    The successful use of plant breeding for improving crops requires the existence of genetic variation of useful traits. Unfortunately, the desired variation is often lacking. However, radiation can be used to induce mutations and thereby generate genetic variation from which desired mutants may be selected. Mutation induction has become a proven way of creating variation within a crop variety. It offers the possibility of inducing desired attributes that either cannot be expressed in nature or have been lost during evolution. More than 1700 mutant cultivars of crop plants with significantly improved attributes such as increased yield, improved quality, disease and stress resistance, have been released worldwide in the last thirty years. The Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture has contributed to these achievements through the promotion of research and development in mutation breeding techniques using nuclear and related biotechnological methods and the provision of in plant breeding is then transferred to Member States of the IAEA and the FAO through training in mutation breeding methods and the provision of technical advice. Moreover, radiation treatment services are provided to foster applications of nuclear techniques in crop improvement programmes of member states and more specifically to render direct support to plant breeders by efficient generation of mutations. Plant materials are standardized prior to radiation exposure to warrant reproducibility of the induced effects within practical limits and a radiosensitivity test is implemented to affirm useful doses for applied objectives of a request. This review deals with irradiation methods applied at the IAEA laboratories for the efficient induction of mutations in seeds, vegetative propagules and tissue and cell cultures and the establishment of genetically variable populations upon which selection of desired traits can be based. 3 tabs., 18 refs. (author)

  11. Radiation-induced sensitisation of stainless steels

    International Nuclear Information System (INIS)

    Norris, D.I.R.

    1987-01-01

    The book contains the proceedings of a symposium on radiation-induced sensitization of stainless steels, which took place at Berkeley, United Kingdom, 1986. The purpose of the symposium was to examine the mechanism leading to inter-granular corrosion of 20%Cr/25% Ni/Nb stainless steel cladding of AGR fuel following irradiation. Nine papers are presented, of which three are theoretical, two papers are based upon corrosion studies of 20%Cr/25%Ni/Nb steel, and the remaining are concerned with compositional redistribution and its measurement. (U.K.)

  12. Radiation-induced diploid spermatids in mice

    International Nuclear Information System (INIS)

    Hacker-Klom, U.; Heiden, Th.; Otto, F.J.; Goehde, W.; Mauro, F.

    1989-01-01

    Diploid elongated spermatids of mice were enriched by flow cytometry and cell sorting using a new type of sorter (Partec). The sorted abnormal spermatids were identified morphologically and by nuclear area integration. The radiation-induced increase in the frequency of diploid elongated spermatids was monitored with time following acute X-ray exposure of mice. Dose-response curves for acute 60 Co-gamma and 14 MeV neutron irradiations yielded an RBE value of 4.3 for the doubling of the control level. (author)

  13. Radiation-induced diploid spermatids in mice

    Energy Technology Data Exchange (ETDEWEB)

    Hacker-Klom, U; Heiden, Th; Otto, F J; Goehde, W; Mauro, F

    1989-05-01

    Diploid elongated spermatids of mice were enriched by flow cytometry and cell sorting using a new type of sorter (Partec). The sorted abnormal spermatids were identified morphologically and by nuclear area integration. The radiation-induced increase in the frequency of diploid elongated spermatids was monitored with time following acute X-ray exposure of mice. Dose-response curves for acute /sup 60/Co-gamma and 14 MeV neutron irradiations yielded an RBE value of 4.3 for the doubling of the control level. (author).

  14. Radiation-induced creep and swelling

    International Nuclear Information System (INIS)

    Heald, P.T.

    1977-01-01

    The physical basis for radiation induced creep and swelling is reviewed. The interactions between the point defects and dislocations are recalled since these interactions are ultimately responsible for the observable deformation phenomena. Both the size misfit interaction and the induced inhomogeneity interaction are considered since the former gives rise to irradiation swelling while the latter, which depends on both internal and external stresses, results in irradiation creep. The defect kinetics leading to the deformation processes are discussed in terms of chemical rate theory. The rate equations for the spatially averaged interstitial and vacancy concentrations are expressed in terms of the microstructural sink strengths and the solution of these equations leads to general expressions for the deformation rates

  15. Radiation-induced lesions of the aorta

    Energy Technology Data Exchange (ETDEWEB)

    Doessing, M; Rasmussen, S [Medical Department C, Diakonissestiftelsen, Copenhagen (Denmark); Fischer-Hansen, B; Walbom-Joergensen, S

    1977-04-09

    A description is given of pathological changes detected in the aortic arch of a 21-year-old man. The patient died from an acute myocardial infarction 16 months after a dose of 3696 rads to a mantle field for Hodgkin's disease confined to the midcervical lymph nodes on the left side of the neck. Histological examination of the exposed part of the aortic arch showed the wall to be focally thickened owing to a pronounced fibrosis of the luminal third of the wall. The elastic lamellae in this area were reduced in number, broken up, and haphazardly arranged. The intima appeared normal. There was no leucocytic infiltration, no proliferation of vasa vasorum and no significant adventitial fibrosis. It is suggested that these noncharacteristic changes may have been early radiation-induced lesions which later might induce fibrotic scarring with perhaps clinically evident disease.

  16. Allogeneic radiation chimeras induced in SPF mice

    International Nuclear Information System (INIS)

    Sado, Toshihiko; Kamisaku, Hitoko

    1977-01-01

    During the past two decades much has been learned concerning the immunobiology of bone marrow chimeras induced in experimental animals as well as in man. However, from the basic as well as clinical points of view, there still remain many unsolved questions yet to be resolved. In this presentation, we discussed some of our recent results on the immunobiology of radiation chimeras induced in specific-pathogen-free (SPF) mice. These included the following: (a) contribution of graft versus host reaction (GVHR) as well non- GVHR mediated immunologic mechanism(s) to the expression of immunologic dysfunctions observed in allogeneic and certain semiallogeneic chimeras, (b) existence of immunoregulatory mechanism as a basis for the apparent lack of immunologic reactivity (tolerance) to the host- as well as to the donor-type alloantigens in situ in successful allogeneic bone marrow chimeras, and (c) the effect of microflora of the environment on the stability of such immunoregulatory mechanisms and its possible mechanism of action. (auth.)

  17. Induction of adaptive response in human blood lymphocytes exposed to radiofrequency radiation.

    Science.gov (United States)

    Sannino, Anna; Sarti, Maurizio; Reddy, Siddharth B; Prihoda, Thomas J; Vijayalaxmi; Scarfì, Maria Rosaria

    2009-06-01

    The incidence of micronuclei was evaluated to assess the induction of an adaptive response to non-ionizing radiofrequency (RF) radiation in peripheral blood lymphocytes collected from five different human volunteers. After stimulation with phytohemagglutinin for 24 h, the cells were exposed to an adaptive dose of 900 MHz RF radiation used for mobile communications (at a peak specific absorption rate of 10 W/kg) for 20 h and then challenged with a single genotoxic dose of mitomycin C (100 ng/ml) at 48 h. Lymphocytes were collected at 72 h to examine the frequency of micronuclei in cytokinesis-blocked binucleated cells. Cells collected from four donors exhibited the induction of adaptive response (i.e., responders). Lymphocytes that were pre-exposed to 900 MHz RF radiation had a significantly decreased incidence of micronuclei induced by the challenge dose of mitomycin C compared to those that were not pre-exposed to 900 MHz RF radiation. These preliminary results suggested that the adaptive response can be induced in cells exposed to non-ionizing radiation. A similar phenomenon has been reported in cells as well as in animals exposed to ionizing radiation in several earlier studies. However, induction of adaptive response was not observed in the remaining donor (i.e., non-responder). The incidence of micronuclei induced by the challenge dose of mitomycin C was not significantly different between the cells that were pre-exposed and unexposed to 900 MHz RF radiation. Thus the overall data indicated the existence of heterogeneity in the induction of an adaptive response between individuals exposed to RF radiation and showed that the less time-consuming micronucleus assay can be used to determine whether an individual is a responder or non-responder.

  18. Radiation induced micrencephaly in guinea pigs

    International Nuclear Information System (INIS)

    Wagner, L.K.; Johnston, D.A.; Felleman, D.J.

    1991-01-01

    A brain weight deficit of about 70 mg was induced at doses of approximately 75-mGy and a deficit of 60 mg was induced at 100 mGy. This confirms the effects projected and observed by Wanner and Edwards. Although the data do not demonstrate a clear dose-response relationship between the 75-mGy and 100-mGy groups, the data are statistically consistent with a dose-response effect because of the overlapping confidence intervals. The lack of a statistically significant observation is most likely related to the small difference in doses and the limited numbers of animals examined. There are several factors that can influence the brain weight of guinea pig pups, such as caging and housing conditions, the sex of the animal, and litter size. These should be taken into account for accurate analysis. Dam weight did not appear to have a significant effect. The confirmation of a micrencephalic effect induced x rays at doses of 75-mGy during this late embryonic stage of development is consistent with the findings of small head size induced in those exposed prior to the eight week of conception at Hiroshima. This implies a mechanism for micrencephaly different from those previously suggested and lends credence to a causal relation between radiation and small head size in humans at low doses as reported by Miller and Mulvihill. 16 refs., 13 tabs

  19. 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)

  20. Radiation induced color in topaz crystals

    International Nuclear Information System (INIS)

    Castagnet, A.C.; Rocca, H.C.C.; Rostilato, M.E.C.M.

    1989-08-01

    The presence of defects and impurities in the crystal lattice alters the eletric field distribution within the crystal, allowing the electrons to occupy energy levels in the forbbiden band. Ionizing radiation supply the required energy to permit the electrons originaly bound to lattice atoms, to occupy effectively those intermediate levels, forming color centers. Dependig upon the nature and energy of the radiation, it is possible to produce defects in regions of the crystal, generating color centers. Based on these premises, a technique to induce color in originally colorless topaz, by using the IEA-R1 nuclear reactor, was developed at Engineering and Industrial Application Department (TE). Samples were irradiated inside iron capsules coated with cadmium foils. The iron, and principaly the cadmium, absorb the thermal neutrons that could activate crystal impurities generating long-lived radioisotopes. The epithermal neutrons that overpass the iron and cadmium barriers interact with the crystal atoms, causing lattice defects which give rise to color center, by subsequent ionization processes. The procedure used at TE induces permanent blue color, in natural colorless topaz. (author) [pt

  1. Radiation induced changes in the airway - anaesthetic implications

    African Journals Online (AJOL)

    Adele

    CASE REPORT. Southern African Journal of Anaesthesia & Analgesia - May 2004. 19. Radiation ... Summary: Radiation induces a variety of changes in the airway that can potentially lead to difficult intubation. ... Mask holding and ventilation is.

  2. 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...

  3. 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

  4. Micronuclei rate in workers of Novi Han radioactive waste repository

    International Nuclear Information System (INIS)

    Atamasova, P.; Hadjidekova, V.

    2003-01-01

    A cytogenetic study has been carried out by the micronucleus test of lymphocytes from the peripheral blood of 30 workers from the Novi Han radioactive waste repository. The results are compared to the results of a control group of 6 persons from the administrative staff, and to outside group of 39 healthy persons. All persons are questioned through a special questionnaire about their occupational, medical, and social status. The rate of the cells with micronuclei and the total number of the micronuclei are analysed in the peripheral blood lymphocytes using the cytogenesis-block micronucleus test. The comparison of the results does not show an increase of the lymphocytes with micronuclei in the workers

  5. Radiological protection effect on vanillin derivative VND3207 radiation-induced cytogenetic damage in mouse bone marrow cells

    International Nuclear Information System (INIS)

    Wang Chuangao; Wang Li; Zhou Pingkun; Wang Zhongwen; Hu Yongzhe; Jin Haiming; Zhang Xueqing; Chen Ying

    2010-01-01

    Objective: To study the protection of vanillin derivative VND3207 on the cytogenetic damage of mouse bone marrow cell induced by ionizing radiation. Methods: BALB/c mice were randomly divided into five groups: normal control group, 2 Gy dose irradiation group, and three groups of 2 Gy irradiation with VND3207 protection at doses of 10, 50 and 100 mg/kg, respectively. VND3207 was given by intragastric administration once a day for five days. Two hours after the last drug administration, the mice were irradiated with 2 Gy γ-rays. The changes of polychromatophilic erythroblasts micronuclei (MN), chromosome aberration (CA) and mitosis index (MI) of mouse bone marrow cells were observed at 24 and 48 h after irradiation. Results: Under the protection of VND3207 at the dosages 10, 50, 100 μmg/kg, the yields of poly-chromatophilic erythroblasts MN and CA of bone marrow cells were significantly decreased (t=2.36-4.26, P<0.05), and the marrow cells MI remained much higher level compared with the irradiated mice without drug protection (t=2.58, 2.01, P<0.05). The radiological protection effect was drug dose-dependent, and the administration of VND3207 at the dosage of 100 mg/kg resulted in reduction by 50 % and 65% in the yields of MN and CA, respectively. Conclusions: VND3207 had a good protection effect of on γ-ray induced cytogentic damage of mouse bone marrow cells. (authors)

  6. Enhancement of Temozolomide and radiation induced damage in malignant glioma cell lines by 2-deoxy-D-glucose

    International Nuclear Information System (INIS)

    Kumari, Kalyani; Shyam, Sai; Chandrasekhar Sagar, B.K.; Jagath Lal, G.; Kalia, Vijay Kumar

    2014-01-01

    Malignant Gliomas are the most common and aggressive CNS tumors. The current standard treatment includes surgery, followed by Temozolomide (TMZ)-Radiotherapy. It leads to increased survival as compared to radiotherapy alone. However hematological toxicities are also increased by the combination treatments. Therefore, it is important to carry out further preclinical studies, to develop more effective treatment for these tumors. 2-deoxy-D-Glucose (2-DG), an inhibitor of glycolytic energy metabolism, has been shown earlier to differentially inhibit growth and survival of tumor cells in vitro. It also increases tumor regression in experimental models; and has been used in a few clinical studies as radiosensitizer. In the present study, effects of combining 2-DG with TMZ on radiation induced damage were studied in established malignant glioma cell lines (U251MG and U87MG); and primary cultures derived from malignant glioma biopsies. Exponentially growing cells were exposed to drugs and radiation. Drugs were removed 4 hours later and cultures were processed further for different assays of damage. Effects on proliferation response, viability and total cellular damage (TCD; micronuclei + apoptosis) were studied after post-treatment growth for 1, 2, 4 or 6 days. Our results showed that combination of 2-DG with TMZ ± Radiation significantly inhibited tumor cell proliferation up to 6 days, at low drug concentrations in primary as well as in established cell lines. The TCD at 24 and 48 hours after Gamma irradiation was also significantly increased by the combination of drugs as compared to individual treatments. Experiments to study proliferation kinetics by flow cytometry and cell survival are in progress. These studies suggest that 2-DG significantly enhances the cytotoxic effect of TMZ + radiation without increasing toxic side effects. Therefore, combining 2-DG with TMZ+ radiation therapy could be a potential strategy to improve the therapeutic outcome for Malignant

  7. Incidence of micronuclei in human peripheral blood lymphocytes exposed to modulated and unmodulated 2450 MHz radiofrequency fields.

    Science.gov (United States)

    Vijayalaxmi; Reddy, Abhishek B; McKenzie, Raymond J; McIntosh, Robert L; Prihoda, Thomas J; Wood, Andrew W

    2013-10-01

    Peripheral blood samples from four healthy volunteers were collected and aliquots were exposed in vitro for 2 h to either (i) modulated (wideband code division multiple access, WCDMA) or unmodulated continuous wave (CW) 2450 MHz radiofrequency (RF) fields at an average specific absorption rate of 10.9 W/kg or (ii) sham-exposed. Aliquots of the same samples that were exposed in vitro to an acute dose of 1.5 Gy ionizing gamma-radiation (GR) were used as positive controls. Half of the aliquots were treated with melatonin (Mel) to investigate if such treatment offers protection to the cells from the genetic damage, if any, induced by RF and GR. The cells in all samples were cultured for 72 h and the lymphocytes were examined to determine the extent of genetic damage assessed from the incidence of micronuclei (MN). The results indicated the following: (i) the incidence of MN was similar in incubator controls, and those exposed to RF/sham and Mel alone; (ii) there were no significant differences between WCDMA and CW RF exposures; (iii) positive control cells exposed to GR alone exhibited significantly increased MN; and (iv) Mel treatment had no effect on cells exposed to RF and sham, while such treatment significantly reduced the frequency of MN in GR-exposed cells. Copyright © 2013 Wiley Periodicals, Inc.

  8. 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 - .

  9. Radiation-induced bone neoplasma in facial cranium

    Energy Technology Data Exchange (ETDEWEB)

    Zomer-Drozda, J; Buraczewska-Lipinska, H; Buraczewski, J [Instytut Onkologii, Warsaw (Poland)

    1976-01-01

    Radiation-induced bone neoplasms in the region of facial cranium account for about 40% of all radiation-induced tumours of bones, although the number of cases with lesions irradiated in this area is proportionally much lower than the number of cases treated with radiotherapy in other parts of the body. Four personal cases of radiation-induced tumours with complicated course are reported. Attention is called to the value of radiological investigations in the diagnosis of bone diseases and in differential diagnosis of radiation-induced tumours of bones.

  10. Gamma-irradiated onions as a biological indicator of radiation dose

    International Nuclear Information System (INIS)

    Vaijapurkar, S.G.; Agarwal, Deepshikha; Chaudhuri, S.K.; Ram Senwar, Kana; Bhatnagar, P.K.

    2001-01-01

    Post-irradiation identification and dose estimation are required to assess the radiation-induced effects on living things in any nuclear emergency. In this study, radiation-induced morphological/cytological changes i.e., number of root formation and its length, shooting length, reduction in mitotic index, micronuclei formation and chromosomal aberrations in the root tip cells of gamma-irradiated onions at lower doses (50-2000 cGy) are reported. The capabilities of this biological species to store the radiation-induced information are also studied

  11. The induction of micronuclei in X-irradiated Beagle dog lymphocytes

    International Nuclear Information System (INIS)

    Rithidech, K.; Lozano, D.; Brooks, A.L.

    1988-01-01

    We developed a simple, sensitive, and reproducible method using the micronucleus assay in dog blood lymphocytes for detecting genotoxic effects of ionizing radiation. Micronuclei (MM) are expressed in cells that have undergone 1 cell division. Thus, it was important to determine the optimum culture condition and sampling time to obtain a maximum number of such cells. To identify cells that have divided, cytochalasin B was added to block cytokinesis. Cells were harvested at 72, 76, or 94 h after incubation with different concentrations of phytohaemagglutinin (PHA) 15 or 16. After optimizing the culture time and PHA concentration, the system was calibrated by evaluating the dose response for the induction of MN by X rays. Blood samples were drawn, X-irradiated (0.0, 0.5, 1.0, 2.0, or 4.0 Gy), grown in optimum culture medium, harvested at 94 h after incubation, and the frequency of MN analyzed in binucleated cells. The dose-response relationship was fit by a quadratic model; micronuclei/binucleated cell = 0.017 + 0.046D + 0.0093D 2 , where D = dose. The MN assay in dog blood lymphocytes provides a sensitive and reliable technique for measuring genotoxic damage in a large animal model. The MN assay will be very useful for evaluating genotoxic effects of hazardous agents after both chronic and acute exposures and for estimating radiation dose. (author)

  12. Reductive effects of poria cocos on radiation-induced damage

    International Nuclear Information System (INIS)

    Oh, Heon; Park, Hae-Ran; Jo, Sung-Kee; Kim, Sung-Ho

    2002-01-01

    In order to screen a radioprotective material from nontoxic natural products, the effects of Poria cocos (PC), known as a blood tonic of traditional Oriental herbs, were investigated in HL-60 cells and ICR mice. The water extract of PC was administrated to mice and then the mice were irradiated with - rays. The jejunal crypt survival, endogenous spleen colony formation and apoptosis in jejunal crypt cells were investigated in mice irradiated with 12 Gy, 6.5 Gy, 2 Gy of -rays, respectively. The administration of the PC extract protected the jejunal crypts (p<0.005) and decreased the apoptosis frequency (p<0.05). The formation of endogenous spleen colony was increased but not significantly. The micronuclei (MN) formation and the alkaline single-cell gel electrophoresis (SCGE; comet assay) were investigated in HL- 60 cells irradiated 2 Gy of -rays. The frequency of MN was decreased (p<0.001) and the tail movement, which was a marker of DNA strand breaks in the SCGE, was decreased in groups treated with PC extract (p<0.01) before exposure to-irradiation. These results indicated that PC protects stem cells and reduces DNA damage induced by -rays. Therefore, Poria cocos might be a useful radioprotector, especially since it is a relatively nontoxic product

  13. Retinoic acid-treated pluripotent stem cells undergoing neurogenesis present increased aneuploidy and micronuclei formation.

    Directory of Open Access Journals (Sweden)

    Rafaela C Sartore

    Full Text Available The existence of loss and gain of chromosomes, known as aneuploidy, has been previously described within the central nervous system. During development, at least one-third of neural progenitor cells (NPCs are aneuploid. Notably, aneuploid NPCs may survive and functionally integrate into the mature neural circuitry. Given the unanswered significance of this phenomenon, we tested the hypothesis that neural differentiation induced by all-trans retinoic acid (RA in pluripotent stem cells is accompanied by increased levels of aneuploidy, as previously described for cortical NPCs in vivo. In this work we used embryonal carcinoma (EC cells, embryonic stem (ES cells and induced pluripotent stem (iPS cells undergoing differentiation into NPCs. Ploidy analysis revealed a 2-fold increase in the rate of aneuploidy, with the prevalence of chromosome loss in RA primed stem cells when compared to naïve cells. In an attempt to understand the basis of neurogenic aneuploidy, micronuclei formation and survivin expression was assessed in pluripotent stem cells exposed to RA. RA increased micronuclei occurrence by almost 2-fold while decreased survivin expression by 50%, indicating possible mechanisms by which stem cells lose their chromosomes during neural differentiation. DNA fragmentation analysis demonstrated no increase in apoptosis on embryoid bodies treated with RA, indicating that cell death is not the mandatory fate of aneuploid NPCs derived from pluripotent cells. In order to exclude that the increase in aneuploidy was a spurious consequence of RA treatment, not related to neurogenesis, mouse embryonic fibroblasts were treated with RA under the same conditions and no alterations in chromosome gain or loss were observed. These findings indicate a correlation amongst neural differentiation, aneuploidy, micronuclei formation and survivin downregulation in pluripotent stem cells exposed to RA, providing evidence that somatically generated chromosomal

  14. Ion beam induced luminescence: Relevance to radiation induced bystander effects

    Science.gov (United States)

    Ahmad, S. B.; McNeill, F. E.; Byun, S. H.; Prestwich, W. V.; Seymour, C.; Mothersill, C. E.

    2012-10-01

    The aim of this work is quantify the light emitted as a result of charged particle interaction in materials which may be of relevance to radiation induced "bystander effects" studies. We have developed a system which employs single photon counting to measure the light emitted from samples irradiated under vacuum by a charged particle beam. The system uses a fast photomultiplier tube with a peak cathode response at 420 nm. It has been tested in a proof-of-principle experiment using polystyrene targets. Light output, as a result of irradiation, was measured. The luminescence yield appears to have a non-linear behavior with the incident ion fluence: it rises exponentially to an asymptotic value. The target was irradiated with beam energies varying from 1 to 2 MeV and showed saturation at or before an incident fluence rate of 3 × 1013 H+/cm2 s. The average saturation value for the photon output was found to be 40 × 106 cps. Some measurements were performed using filters to study the emission at specific wavelengths. In the case of filtered light measurements, the photon output was found to saturate at 28 × 103, 10 × 106, and 35 × 106 cps for wavelengths of 280 ± 5 nm, 320 ± 5 nm and 340 ± 5 nm respectively. The light output reaches a maximum value because of damage induced in the polymer. Our measurements indicate a "damage cross section" of the order of 10-14 cm2. The average radiant intensity was found to increase at wavelengths of 280 and 320 nm when the proton energy was increased. This was not found to occur at 340 nm. In conclusion, the light emission at specific wavelengths was found to depend upon the incident proton fluence and the proton energy. The wavelengths of the emitted light measured in this study have significance for the understanding of radiation induced bystander effects.

  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 structural changes. 3

    International Nuclear Information System (INIS)

    Kondo, Yasuhiro; Matsuyama, Tomochika; Ogasawara, Masaaki

    1993-05-01

    This meeting is the fourth of series meetings on the structural change in materials induced by ionizing radiation. The present meeting was organized to discuss specifically on the x-ray storage phosphors such as BaFBr:Eu 2+ or RbI x Br 1-x :Tl and to get a clear understanding of the present status of the research on the storage mechanisms, nature of the rare earth impurities, and the optical properties of BaFBr. It was also expected that all the participants became aware of unsolved problems in these storage materials and that some of them would start research work on the storage phosphors. Therefore this report was edited mainly to provide basic knowledge correlated with the storage phosphors and related phenomena rather than to report simply on the experimental results. (J.P.N.)

  17. Ionizing radiation-induced cell death

    International Nuclear Information System (INIS)

    Szumiel, I.

    1994-01-01

    Selected aspects of radiation-induced cell death, connected with signal transduction pathways are reviewed. Cell death is defined as insufficiency of the cellular signal transducing system to maintain the cell's physiological functions. The insufficiency may be due to impaired signal reception and/or transduction, lack or erroneous transcription activation, and eventual cellular ''misexpression'' of the signal. The molecular basis of this insufficiency would be damage to genomic (but also other cellular) structures and closing of specific signalling pathways or opening of others (like those leading to apoptosis). I describe experimental data that suggest an important role of RAS/NFI and p53/p105 Rb proteins in cell cycle control-coupled responses to DNA damage. (Author)

  18. Radiation-induced segregation in model alloys

    Science.gov (United States)

    Ezawa, T.; Wakai, E.; Oshima, R.

    2000-12-01

    The dependence of the size factor of solutes on radiation-induced segregation (RIS) was studied. Ni-Si, Ni-Co, Ni-Cu, Ni-Mn, Ni-Pd, and Ni-Nb binary solid solution alloys were irradiated with electrons in a high voltage electron microscope at the same irradiation conditions. A focused beam and a grain boundary were utilized to generate a flow of point defects to cause RIS. From the concentration profile obtained by an energy dispersive X-ray analysis, the amount of RIS was calculated. The amount of RIS decreased as the size of the solute increased up to about 10%. However, as the size increased further, the amount of RIS increased. This result shows that RIS is not simply determined by the size effect rule.

  19. Radiation-induced grafting onto wool

    International Nuclear Information System (INIS)

    Muller-Schulte, D.

    1979-10-01

    Radiation-induced grafting tests were done on single wool fibres. Different vinyl monomers were used for this purpose and they were grafted in twenty different solvents which were selected for their swelling effiency and solvent parameters. The tests were done once with and once without the addition of water. The presence of water causes the polymer uptake to increase considerably. Formic acid/methanol and methanol were found to be the most suitable solvent systems, as they have the highest hydrogen-bond interaction effiency. The moisture uptake of wool depends on the hydrophily and hydrophoby of the grafted polymers. The single-fibre tests serve as a basis for analogous grafting tests on wool fabrics. The permanent- press was improved by graftng with hydrophoric polymers and polymers with a high glass-transition temperature [af

  20. 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).

  1. Naturally occurring and radiation-induced tumors in SPF mice, and genetic influence in radiation leukemogenesis

    International Nuclear Information System (INIS)

    Kasuga, T.

    1979-01-01

    The data obtained so far in this study point to a strong genetic influence not only on the types and incidence of naturally occurring and radiation-induced tumors but also on radiation leukemogenesis. (Auth.)

  2. Radiation induced mutations in Phaseolus vulgaris L

    International Nuclear Information System (INIS)

    Al-Rubeai, M.A.F.

    1982-01-01

    A selection of various macro- and micro-mutations was undertaken in the M2 generation of Phaseolus vulgaris cultivars after seed exposure to acute gamma radiation doses of 2.5, 5, 7, 10 and 15 Kr. The chlorophyll mutation was positively correlated with dose. Nevertheless, the highest frequency was at 7 Kr. Several interesting morphological mutants were observed. There were dwarf, stiff stem, shiny small leaf, narrow leaf and green giant mutants. Two selected micromutants were superior in seed yield capacity to their parents. The high yields were related to the high number of pods per plant. In 'The Prince' (seed color: red with beige marbling) several mutants with seeds of black color marbled with beige were selected. These seeds gave M3 segregants exhibiting a range of seed colors including white. Many of these M3 plants were short, early flowering and highly sterile. The work demonstrated that the pigmentation character can readily be changed, and confirmed that the variability induced by radiation can be exploited to obtain desirable mutations. (Author) [pt

  3. Radiation-Induced Mutation and Crop Improvement

    International Nuclear Information System (INIS)

    Lee, Y. I.; Song, H. S.; Kim, J. S.; Shin, I. C.; Lee, S. J.

    1987-01-01

    Radiation induced mutations have not only been used directly as a cultivar in crop plants, but also indirectly as a genetic resource that is essential to conventional plant breeding. M 1 plant survivals of three rice cultivars treated with gamma rays of 200-350 Gy varied from 30-40%. The survival of the Sawing variety was less sensitive to radiation, but its fertility was more sensitive in comparison with Seomjin and Sponging. Various dwarf or semi-dwarf mutants and early=matured mutants have been selected in the M 2 and M 3 generations of the three rice cultivars irradiated with gamma rays. Other desirable mutants also have been selected, such as high-yielding, high-tailoring and disease-resistant. The genetic nature of most of the selected short calm and earliness mutants was fixed in M 2 or M 3 generations. Dwarfism of IEAR 308 and Monogynol 10 were found to have a single recessive gene. However, the dwarf of IEAR 308 has a recessive deficit phenomenon. The highest genetic heritability of plant height was observed in the cross combination of Monogynol 10 Χ Pawling

  4. Radiation induced mutations for breeding of sorghum

    Energy Technology Data Exchange (ETDEWEB)

    Bretaudeau, A [Rural Polytechnic Inst., Katibougou, Koulikoro (Mali)

    1997-07-01

    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.

  5. 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)

  6. 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

  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. Micronuclei in red blood cells of armored catfish Hypostomus ...

    African Journals Online (AJOL)

    SERVER

    2008-04-03

    Apr 3, 2008 ... with micronuclei and 17 ± 0.005 mg/kg of total chrome in tissues, detected through atomic absorption spectrophotometry. .... and human cell lines, DNA damage induction by potas- .... Effects of metallic ion toxicity on human ...

  9. Evaluation of spontaneous and radiation-induced micronucleus frequency in cultured human peripheral blood lymphocytes depending on age and sex

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, H. J.; Kang, C. M.; Chung, H. C. [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of)] (and others)

    2002-12-15

    The goal of this study was to provide data on the dose-dependent production of MicroNucleus (MN) in human lymphocytes irradiated with {sup 60}Co {gamma}-rays and 50MeV neutron, and to evaluate predictive markers of intrinsic radiosensitivity in individuals for monitoring occupational or environmental radiation exposure. For the dose-response study, heparinized whole blood of 10 healthy volunteers was irradiated with {sup 60}Co {gamma}-rays employing of 0.25-8Gy. The MNs were observed all doses, and the numerical changes according to doses. In dose-response curves fit linear-quadratic form (alpha =0.31{+-}0.049, beta =0.0022{+-}0.0022) for {gamma}-rays, but (alpha=0.99{+-}0.528, beta =0.0093{+-}0.0047) for neutron. Neutrons were than {gamma}-rays effective in producing MN with dose-dependent manner. The frequency of MN varies with dose. The RBE (Relative Biological Effectiveness) for micronuclei was 2.370.17. Further studies were carried out to provide evidence for the existence of individual variations in age-dependent responses to radiation. Spontaneous and radiation-induced MN varies greatly among individuals, and little is known about the molecular mechanisms of this variability. It was shown that the increased level of spontaneous cell with MN was observed with increasing age. The relationship between radiosensitivity and the increased spontaneous level of MN may be in inverse proportion. These studies indicated that the MN assay have a high potential as a rapid, sensitive and accurate method which can be used to monitor a large population exposed to radiation for rapid triage in the case of a large-scale accident.

  10. Evaluation of spontaneous and radiation-induced micronucleus frequency in cultrued human peripheral blood lymphocytes depending on age and sex

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, H. J.; Kang, C. M.; Chung, H. C. [Korea Cancer Center Hospital, Seoul (Korea, Republic of)] [and others

    2002-07-01

    The goal of this study was to provide data on the dose-dependent production of micronucleus (MN) in human lymphocytes irradiated with {sub 60} Co {gamma} -rays and 50MeV neutron, and to evaluate predictive markers of intrinsic radiosensitivity in individuals for monitoring occupational or environmental radiation exposure. For the dose-response study, heparinized whole blood of 10 healthy volunteers was irradiated with {sub 60} Co {gamma} -rays employing of 0.25-8Gy. The MNs were observed all doses, and the numerical changes according to doses. In dose-response curves fit linear- quadratic form (alpha =0.31{+-}0.049, beta =0.0022{+-}0.0022) for {gamma} -rays, but (alpha =0.99{+-}0.528, beta =0.0093{+-}0.0047) for neutron. Neutrons were than {gamma} -rays effective in producing MN with dose-dependent manner. The frequency of MN varies with dose. The RBE for micronuclei was 2.37{+-}0.17. Further studied are carried out to provide evidence for the existence of individual variations in age-dependent responses to radiation. Spontaneous and radiation-induced MN varies greatly between individuals, and little is known about the molecular mechanisms of this variability. It was shown that the increased level of spontaneous cell with MN was observed with increasing age. The relationship between radiosensitivity and the increased spontaneous level of MN may be in inverse proportion. These studies indicates that the MN assay have a high potential as a rapid, sensitive and accurate method which can be used to monitor a large population exposed to radiation for rapid triage in the case of a large-scale accident.

  11. 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

  12. 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 ...

  13. 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 ...

  14. 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.

  15. Radioprotective effect of Haberlea rhodopensis (Friv.) leaf extract on gamma-radiation-induced DNA damage, lipid peroxidation and antioxidant levels in rabbit blood.

    Science.gov (United States)

    Georgieva, Svetlana; Popov, Borislav; Bonev, Georgi

    2013-01-01

    Different concentrations of H. rhodopensis total extract (HRE; 0.03, 0.06 and 0.12 g/kg body weight) were injected im, into rabbits 2 h before collecting the blood samples. The whole blood samples were exposed in vitro to 2.0 Gy 60Co gamma-radiation. The radiation-induced changes were estimated by using the chromosome aberration test (CA) and cytokinesis blocked micronucleus assay (CBMN) in peripheral lymphocytes, and by determining the malondialdehyde levels (MDA) in blood plasma and the superoxide dismutase (SOD) and catalase (CAT) activity in erythrocytes. Radiation significantly increased the chromosome aberration and micronuclei frequencies as well as MDA levels and decreased the antioxidant enzyme activity. On the other hand, the HRE pretreatment significantly decreased the CA, MN frequencies and MDA levels and increased the SOD and CAT activity in a concentration dependent manner. The most effective was the highest concentration of HRE (0.12 g/kg body weight). The results suggest that HRE as a natural product with a nantioxidant capacity could play a modulatory role against the cellular damage induced by gamma-irradiation. The possible mechanism involved in the radioprotective potential of HRE is discussed.

  16. Radioprotective effect of Haberlea rhodopensis (Friv.) leaf extract on γ-radiation-induced DNA damage, lipid peroxidation and antioxidant levels in rabbit blood

    International Nuclear Information System (INIS)

    Georgieva, Svetlana; Bonev, Georgi; Popov, Borislav

    2013-01-01

    Different concentrations of H. rhodopensis total extract (HRE; 0.03, 0.06 and 0.12 g/kg body weight) were injected im, into rabbits 2 h before collecting the blood samples. The whole blood samples were exposed in vitro to 2.0 Gy 60 Co γ-radiation. The radiation-induced changes were estimated by using the chromosome aberration test (CA) and cytokinesis blocked micronucleus assay (CBMN) in peripheral lymphocytes, and by determining the malondialdehyde levels (MDA) in blood plasma and the superoxide dismutase (SOD) and catalase (CAT) activity in erythrocytes. Radiation significantly increased the chromosome aberration and micronuclei frequencies as well as MDA levels and decreased the antioxidant enzyme activity. On the other hand, the HRE pretreatment significantly decreased the CA, MN frequencies and MDA levels and increased the SOD and CAT activity in a concentration dependent manner. The most effective was the highest concentration of HRE (0.12 g/kg body weight). The results suggest that HRE as a natural product with an antioxidant capacity could play a modulatory role against the cellular damage induced by γ-irradiation. The possible mechanism involved in the radioprotective potential of HRE is discussed. (author)

  17. A case of radiation-induced osteosarcoma of the maxilla

    International Nuclear Information System (INIS)

    Tanaka, Rie; Asato, Ryo; Tanaka, Shinzo; Hiratsuka, Yasuyuki; Ito, Juichi

    2003-01-01

    Radiation-induced osteosarcoma in the head and neck region is very rare. A 68-year-old female, who had been treated with radiation for malignant lymphoma of the right maxillary sinus, presented with right cheek swelling. Imaging examinations demonstrated a huge mass occupying the right nasal cavity and paranasal sinuses. Total maxillectomy was performed, and the tumor was histologically diagnosed as osteosarcoma. Diagnosis and treatment for radiation-induced osteosarcoma in the head and neck is discussed. (author)

  18. A case of radiation-induced osteosarcoma of the maxilla

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Rie [Shimada City Hospital, Shizuoka (Japan); Asato, Ryo; Tanaka, Shinzo; Hiratsuka, Yasuyuki; Ito, Juichi [Kyoto Univ. (Japan). Faculty of Medicine

    2003-02-01

    Radiation-induced osteosarcoma in the head and neck region is very rare. A 68-year-old female, who had been treated with radiation for malignant lymphoma of the right maxillary sinus, presented with right cheek swelling. Imaging examinations demonstrated a huge mass occupying the right nasal cavity and paranasal sinuses. Total maxillectomy was performed, and the tumor was histologically diagnosed as osteosarcoma. Diagnosis and treatment for radiation-induced osteosarcoma in the head and neck is discussed. (author)

  19. 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

  20. Radiation risk assessment in professionals working in dental radiology area using buccal micronucleus cytome assay.

    Science.gov (United States)

    Sadatullah, Syed; Dawasaz, Ali Azhar; Luqman, Master; Assiry, Ali A; Almeshari, Ahmed A; Togoo, Rafi Ahmad

    2013-11-01

    The aim of this study was to assess the incidence of micronuclei (MN) in buccal mucosal cells of professionals working in radiology area to determine the risk of stochastic effects of radiation. All the professionals and students working in King Khalid University - College of Dentistry radiology area were included in the Risk Group (RG = 27). The Control Group (CG = 27) comprised of healthy individual matching the gender and age of the RG. Buccal mucosal scraping from all the 54 subjects of RG and CG were stained with Papanicolaou stain and observed under oil immersion lens (×100) for the presence of micronuclei (MN) in the exfoliated epithelial cells. There was no significant difference between the incidence of MN in RG and CG (p = >0.05) using t-test. Routine radiation protection protocol does minimize the risk of radiation induced cytotoxicity, however, screening of professionals should be carried out at regular intervals.

  1. 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)

  2. Ion beam induced luminescence: Relevance to radiation induced bystander effects

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, S.B., E-mail: ahmad.rabilal@gmail.com [Medical Physics and Applied Radiation Sciences, University of McMaster, Hamilton, Ontario (Canada); McNeill, F.E., E-mail: fmcneill@mcmaster.ca [Medical Physics and Applied Radiation Sciences, University of McMaster, Hamilton, Ontario (Canada); Byun, S.H., E-mail: soohyun@mcmaster.ca [Medical Physics and Applied Radiation Sciences, University of McMaster, Hamilton, Ontario (Canada); Prestwich, W.V., E-mail: prestwic@mcmaster.ca [Medical Physics and Applied Radiation Sciences, University of McMaster, Hamilton, Ontario (Canada); Seymour, C., E-mail: seymouc@mcmaster.ca [Medical Physics and Applied Radiation Sciences, University of McMaster, Hamilton, Ontario (Canada); Mothersill, C.E., E-mail: mothers@mcmaster.ca [Medical Physics and Applied Radiation Sciences, University of McMaster, Hamilton, Ontario (Canada)

    2012-10-01

    The aim of this work is quantify the light emitted as a result of charged particle interaction in materials which may be of relevance to radiation induced 'bystander effects' studies. We have developed a system which employs single photon counting to measure the light emitted from samples irradiated under vacuum by a charged particle beam. The system uses a fast photomultiplier tube with a peak cathode response at 420 nm. It has been tested in a proof-of-principle experiment using polystyrene targets. Light output, as a result of irradiation, was measured. The luminescence yield appears to have a non-linear behavior with the incident ion fluence: it rises exponentially to an asymptotic value. The target was irradiated with beam energies varying from 1 to 2 MeV and showed saturation at or before an incident fluence rate of 3 Multiplication-Sign 10{sup 13} H{sup +}/cm{sup 2} s. The average saturation value for the photon output was found to be 40 Multiplication-Sign 10{sup 6} cps. Some measurements were performed using filters to study the emission at specific wavelengths. In the case of filtered light measurements, the photon output was found to saturate at 28 Multiplication-Sign 10{sup 3}, 10 Multiplication-Sign 10{sup 6}, and 35 Multiplication-Sign 10{sup 6} cps for wavelengths of 280 {+-} 5 nm, 320 {+-} 5 nm and 340 {+-} 5 nm respectively. The light output reaches a maximum value because of damage induced in the polymer. Our measurements indicate a 'damage cross section' of the order of 10{sup -14} cm{sup 2}. The average radiant intensity was found to increase at wavelengths of 280 and 320 nm when the proton energy was increased. This was not found to occur at 340 nm. In conclusion, the light emission at specific wavelengths was found to depend upon the incident proton fluence and the proton energy. The wavelengths of the emitted light measured in this study have significance for the understanding of radiation induced bystander effects.

  3. Modulation of Ionizing Radiation Induced Oxidative Imbalance by Semi-Fractionated Extract of Piper betle: An In Vitro and In Vivo Assessment

    Directory of Open Access Journals (Sweden)

    Savita Verma

    2010-01-01

    Full Text Available The study was planned to evaluate modulatory effect of aqueous extract of Piper betle leaf (PBL on ionizing radiation mediated oxidative stress leading to normal tissues damage during radiotherapy and other radiation exposures. The total polyphenols and flavonoids known as free radical scavenger (chelators were measured in the extract. To ascertain antioxidant potential of PBL extract, we studied free radical scavenging, metal chelation, reducing power, lipid peroxidation inhibition and ferric reducing antioxidant properties (FRAP using in vitro assays. Mice were exposed to varied radiation doses administered with the same extract prior to irradiation to confirm its oxidative stress minimizing efficacy by evaluating ferric reducing ability of plasma, reduced glutathione, lipid peroxidation and micro-nuclei frequency. PBL extract was effective in scavenging DPPH (up to 92% at 100 µg/ml and superoxide radicals (up to 95% at 80 µg/ml, chelated metal ions (up to 83% at 50 µg/ml and inhibited lipid peroxidation (up to 45.65% at 500 µg/ml in a dose dependant manner using in vitro model. Oral administration of PBL extract (225 mg/kg body weight 1 hr before irradiation in mice significantly enhanced (p < 0.01 radiation abated antioxidant potential of plasma and GSH level in all the observed organs. The treatment with extract effectively lowered the radiation induced lipid peroxidation at 24 hrs in all the selected organs with maximum inhibition in thymus (p < 0.01. After 48 hrs, lipid peroxidation was maximally inhibited in the group treated with the extract. Frequency of radiation induced micronucleated cells declined significantly (34.78%, p < 0.01 at 24 hrs post-irradiation interval by PBL extract administration. The results suggest that PBL extract has high antioxidant potential and relatively non-toxic and thus could be assertively used to mitigate radiotherapy inflicted normal tissues damage and also injuries caused by moderate doses of

  4. Modulation of ionizing radiation induced oxidative imbalance by semi-fractionated extract of Piper betle: an in vitro and in vivo assessment.

    Science.gov (United States)

    Verma, Savita; Gupta, Manju Lata; Dutta, Ajaswrata; Sankhwar, Sanghmitra; Shukla, Sandeep Kumar; Flora, Swaran J S

    2010-01-01

    The study was planned to evaluate modulatory effect of aqueous extract of Piper betle leaf (PBL) on ionizing radiation mediated oxidative stress leading to normal tissues damage during radiotherapy and other radiation exposures. The total polyphenols and flavonoids known as free radical scavenger (chelators) were measured in the extract. To ascertain antioxidant potential of PBL extract we studied free radical scavenging, metal chelation, reducing power, lipid peroxidation inhibition and ferric reducing antioxidant properties (FRAP) using in vitro assays. Mice were exposed to varied radiation doses administered with the same extract prior to irradiation to confirm its oxidative stress minimizing efficacy by evaluating ferric reducing ability of plasma, reduced glutathione, lipid peroxidation and micro-nuclei frequency. PBL extract was effective in scavenging DPPH (up to 92% at 100 microg/ml) and superoxide radicals (up to 95% at 80 microg/ml), chelated metal ions (up to 83% at 50 microg/ml) and inhibited lipid peroxidation (up to 55.65% at 500 microg/ml) in a dose dependant manner using in vitro model. Oral administration of PBL extract (225 mg/kg body weight) 1 hr before irradiation in mice significantly enhanced (p < 0.01) radiation abated antioxidant potential of plasma and GSH level in all the observed organs. The treatment with extract effectively lowered the radiation induced lipid peroxidation at 24 hrs in all the selected organs with maximum inhibition in thymus (p < 0.01). After 48 hrs, lipid peroxidation was maximally inhibited in the group treated with the extract. Frequency of radiation induced micronucleated cells declined significantly (34.78%, p < 0.01) at 24 hrs post-irradiation interval by PBL extract administration. The results suggest that PBL extract has high antioxidant potential and relatively non-toxic and thus could be assertively used to mitigate radiotherapy inflicted normal tissues damage and also injuries caused by moderate doses of

  5. Comparative data in the radiation-induced yields of cytogenetic alterations

    International Nuclear Information System (INIS)

    Koeteles, G.J.

    1993-01-01

    The need of biological indicators of radiation injuries is growing for various conditions of exposures like external or internal, acute or chronic. The search for such indicators did not result in techniques fulfilling yet all these requirements. So far, the dielectric chromosome aberration analysis can be used as the most reliable assay in radiation accidents. In the recent years several laboratories including ours have initiated research to apply a more simple cytogenetic technique, i.e. the detection of micronuclei in lymphocytes. The fairly consequent dose-effect relationships obtained by several laboratories made the technique rather promising, especially after the modification recommended to recognize interphase cells after their first mitotic divisions. In this presentation dose-effect relationships of formations of various cytogenetic abnormalities are compared with special emphasis on their applicabilities in dose assessments in radiation accidents. Basically, the materials and methods were as published earlier

  6. Indomethacin attenuation of radiation-induced hyperthermia does not modify radiation-induced motor hypoactivity

    Energy Technology Data Exchange (ETDEWEB)

    Ferguson, J.L.; Kandasamy, S.B.; Harris, A.H.; Davis, H.D.; Landauer, M.R. [Armed Forces Radiobiology Research Inst., Bethesda, MD (United States)

    1996-09-01

    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 {mu}sec 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)

  7. 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)

  8. 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

  9. Radiation-induced cancer in laryngectomized patients

    International Nuclear Information System (INIS)

    Miyahara, Hiroshi; Tsuruta, Yoshihiro; Sato, Takeo; Yoshino, Kunitoshi; Umatani, Katunori

    1991-01-01

    Three patients developed hypopharyngo-cervical esophageal carcinoma, 6.5, 13, and 12 years after total laryngectomy. The first patient had received irradiation (60 Gy) for hypopharyngeal carcinoma. The recurrent tumor was removed with total pharyngolaryngoesophagectomy and reconstruction was performed with a local skin flap. After 6 years and 6 months, she developed progressive dysphagia. A new cervical esophageal skin cancer was diagnosed by pharyngoesophagography and treated. The second patient had had total laryngectomy for laryngeal carcinoma and received irradiation (100 Gy) post-operatively. After 13 years, he developed progressive dysphagia. Pharyngoesophagography revealed cervical esophageal carcinoma. The third patient had received irradiation for laryngeal carcinoma (60 Gy) and underwent total laryngectomy because of recurrence. After 12 years she developed dysphagia, and was treated for hypopharyngeal carcinoma. These three patients seemed to have radiation-induced carcinoma. Patients treated with total laryngectomy and irradiation who later complain of progressive dysphagia should be examined carefully to differentiate between postoperative stenosis due to scarring and a new carcinoma. (author)

  10. Radiation-induced cranial nerve palsy

    International Nuclear Information System (INIS)

    Berger, P.S.; Bataini, J.P.

    1977-01-01

    Twenty-five patients with 35 cranial nerve palsies were seen at the Fondation Curie during follow-up after radical radiotherapy for head and neck tumors. The twelfth nerve was involved in 19 cases, the tenth in nine, and the eleventh in five; the fifth and second nerves were involved once each and in the same patient. The twelfth nerve was involved alone in 16 patients and the tenth nerve alone in three, with multiple nerves involved in the remaining six patients. The palsy was noted from 12 to 145 months after diagnosis of the tumor. The latency period could be correlated with dose so that the least square fit equation representing NSD vs delay is NSD = 2598--Delay (in months) x 4.6, with a correlation coefficient of -0.58. The distinction between tumor recurrence and radiation-induced nerve palsy is critical. It can often be inferred from the latency period but must be confirmed by observation over a period of time

  11. Radiation induced cancer: risk assessment and prevention

    International Nuclear Information System (INIS)

    Shore, R.E.

    1984-01-01

    A number of factors have to be considered in defining the cancer risk from ionizing radiation. These include the radiation sensitivity of the target tissue(s), the temporal pattern of risk, the shape of the dose-incidence curve, the effects of low dose rates, host susceptibility factors, and synergism with other environmental exposures. For the population as a whole the largest sources of radiation exposure are natural background radiation and medical/dental radiation. Radiation exposures in the medical field make up the largest volume of occupational exposures as well. Although new technologies offer opportunities to lower exposures, worker training, careful exposure monitoring with remedial feedback, and monitoring to prevent unnecessary radiodiagnostic procedures may be even more important means of reducing radiation exposure. Screening of irradiated populations can serve a useful preventive function, but only for those who have received very high doses

  12. Spontaneous micronucleus frequencies in human peripheral blood lymphocytes as a screening test for an individual variation in a different population and radiation-induced micronucleus induction

    International Nuclear Information System (INIS)

    Kang, Chang-Mo; Jeon, Hye-Jeong; Cho, Chul-Koo

    2004-01-01

    Our studies were to evaluate the role of epigenetic factors in the variation of radiosensitivity on human peripheral blood lymphocytes by measuring the frequencies of micronucleus (MN) from 293 healthy subjects of different population for assessing the radiation health risk in Korea. We analyzed the frequencies of both spontaneous and in vitro 60 Co γ-rays or 50MeV neutron-induced MNs. The frequencies of spontaneous NMs not only vary greatly between individuals, but also working or living areas. The increased levels of cells with spontaneous MNs were observed with an increasing age. The frequencies of spontaneous MNs were significantly higher in females than in males. For both sexes, MN frequency was significantly and positively correlated with age. Age and gender are the most important demographic variables impacting on the MN index. Donors who had ever smoked showed significantly increased frequencies of MNs compared to nonsmokers. The main lifestyle factors influencing the MN index in the subjects are correlated significantly and positively with smoke while measuring the spontaneous frequencies of micronuclei. Therefore, it is evident that with regard to the application of MN assay all future studies to evaluate the association between radiosensitivity and susceptibility for radiation health risks in different populations should take into account the effect of age, gender and lifestyle. For the dose-response study, the induced MNs were observed at all doses, and the numerical changes according to doses. The dose-response curves were fitted with a linear-quadratic forms of the dose, and the results were different for γ-rays and neutrons significantly. Neutrons were more effective than γ-rays in producing MN with a dose-dependent manner. The frequency of MN varies with dose. The RBE for a micronuclei was 2.37 ± 0.17. The results suggested that the MN assay have a high potential to ensure appropriate quality control and a standard documentation protocol, which

  13. Radiation induced mitotic delay and stimulation of growth

    International Nuclear Information System (INIS)

    Feldmann, A.

    1974-01-01

    The mechanisms responsible for the radiation induced mitotic delay and stimulation of growth are discussed in connection with the results of studies in Lemna minor and Lepidium sativum. The action of temperature seems to be of major importance. As many authors suggest that various chemical agents and slight intoxications also affect mitosis in a way similar to that induced by ionizing radiation, the radiation induced stimulation has lost its specific character and approaches might be found for further investigations of this phenomenon. (MG) [de

  14. Differential Micronuclei Induction in Human Lymphocyte Cultures by Imidacloprid in the Presence of Potassium Nitrate

    Directory of Open Access Journals (Sweden)

    Polychronis Stivaktakis

    2010-01-01

    Full Text Available Humans are exposed to pesticides as a consequence of their application in farming or their persistence in a variety of media, including food, water, air, soil, plants, animals, and smoke. The interaction of pesticides with environmental factors may result in the alteration of their physicochemical properties. Square wave cathodic stripping voltammetry (SW-CSV, a technique that simulates electrodynamically the cellular membrane, is used to investigate whether the presence of potassium nitrate (KNO3 in the culture medium interferes with the genotoxic behavior of imidacloprid. The cytokinesis block micronuclei (CBMN method is used to evaluate imidacloprid's genotoxicity in the absence or presence of KNO3 in the culture medium and, as a consequence, its adsorption by lymphocytes. Comparing micronuclei (MN frequencies in control and imidacloprid-treated blood cell cultures, statistically significant differences were not detected. KNO3 did not induce MN frequencies compared to control. Statistically significant differences in MN frequencies were observed when blood cell cultures were treated with imidacloprid in the presence of increasing concentrations of KNO3. SW-CSV revealed that by increasing KNO3 molarity, imidacloprid's concentration in the culture medium decreased in parallel. This finding indicates that imidacloprid is adsorbed by cellular membranes. The present study suggests a novel role of a harmless environmental factor, such as KNO3, on the genotoxic behavior of a pesticide, such as imidacloprid. KNO3 rendered imidacloprid permeable to lymphocytes, resulting in elevated MN frequencies.

  15. 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.

  16. Radiation-induced neuropathies: collateral damage of improved cancer prognosis

    International Nuclear Information System (INIS)

    Pradat, Pierre-Francois; Maisonobe, Thierry; Psimaras, Dimitri; Lenglet, Timothee; Porcher, Raphael; Lefaix, J.L.; Delenian, S.

    2012-01-01

    Because of the improvement of cancer prognosis, long-term damages of treatments become a medical and public health problem. Among the iatrogenic complications, neurological impairment is crucial to consider since motor disability and pain have a considerable impact on quality of life of long cancer survivors. However, radiation-induced neuropathies have not been the focus of great attention. The objective of this paper is to provide an updated review about the radiation-induced lesions of the peripheral nerve system. Radiation-induced neuropathies are characterized by their heterogeneity in both symptoms and disease course. Signs and symptoms depend on the affected structures of the peripheral nerve system (nerve roots, nerve plexus or nerve trunks). Early-onset complications are often transient and late complications are usually progressive and associated with a poor prognosis. The most frequent and well known is delayed radiation-induced brachial plexopathy, which may follow breast cancer irradiation. Radiation-induced lumbosacral radiculoplexopathy is characterized by pure or predominant lower motor neuron signs. They can be misdiagnosed, confused with amyotrophic lateral sclerosis (ALS) or with leptomeningeal metastases since nodular MRI enhancement of the nerve roots of the cauda equina and increased cerebrospinal fluid protein content can be observed. In the absence of specific markers of the link with radiotherapy, the diagnosis of post-radiation neuropathy may be difficult. Recently, a posteriori conformal radiotherapy with 3D dosimetric reconstitution has been developed to link a precise anatomical site to unexpected excess irradiation. The importance of early diagnosis of radiation-induced neuropathies is underscored by the emergence of new disease-modifying treatments. Although the pathophysiology is not fully understood, it is already possible to target radiation-induced fibrosis but also associated factors such as ischemia, oxidative stress and

  17. Computer modelling of radiation-induced bystander effect

    International Nuclear Information System (INIS)

    Khvostunov, Igor K.; Nikjoo, Hooshang

    2002-01-01

    Radiation-induced genomic instability and bystander effects are now well established consequences of exposure of living cells to ionising radiation. It has been observed that cells not directly hit by radiation tracks may still exhibit radiation effects. We present a quantitative modelling of the radiation-induced bystander effect based on a diffusion model of spreading the bystander signal. The model assumes the bystander factor to be a protein of low molecular weight, given out by the hit cell, diffusing in the medium and reacting with non-hit cells. The model calculations successfully predict the results of cell survival in an irradiated conditioned medium. The model predicts the shape of dose-effect relationship for cell survival and oncogenic transformation induced by broad-beam and micro-beam irradiation by alpha-particles. (author)

  18. Novel features of radiation-induced segregation and radiation-induced precipitation in austenitic stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Jiao, Z., E-mail: zjiao@umich.edu [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, MI 48109 (United States); Was, G.S. [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, MI 48109 (United States)

    2011-02-15

    Three stainless steel alloys, high-purity 304 (HP304), high-purity 304 with high Si (HP304 + Si) and commercial purity 304 (CP304), were irradiated with 2 MeV protons to a dose of 5 dpa at 360 deg. C and subsequently examined using atom probe tomography (APT) and scanning transmission electron microscopy-energy dispersive X-ray spectrometry (STEM-EDS). Several novel features of radiation-induced segregation and radiation-induced precipitation were observed. There is a significant variation in the composition of enriched and depleted elements in the grain boundary plane and along the dislocation loop core. Boron segregation to the grain boundary prior to irradiation is not affected by the irradiation. Phosphorus segregation is enhanced by irradiation. Carbon depletes at the grain boundary and may be affected by co-segregation with Cr. APT and STEM-EDS measurements are in excellent agreement for almost all the elements studied. The segregation behavior of elements at dislocations mirrors that at the grain boundary, but at a lower magnitude, except for Si. Ni/Si-rich clusters formed in irradiated HP304 + Si and CP304 are probably the precursors of {gamma}' or other Si- and Ni-rich phases. Copper depletion was observed at both the grain boundary and the dislocation loops. Regions adjacent to the depleted zones were sites for Cu cluster formation, which were also spatially correlated with Ni/Si-rich clusters.

  19. Induced Compton scattering effects in radiation transport approximations

    International Nuclear Information System (INIS)

    Gibson, D.R. Jr.

    1982-01-01

    In this thesis the method of characteristics is used to solve radiation transport problems with induced Compton scattering effects included. The methods used to date have only addressed problems in which either induced Compton scattering is ignored, or problems in which linear scattering is ignored. Also, problems which include both induced Compton scattering and spatial effects have not been considered previously. The introduction of induced scattering into the radiation transport equation results in a quadratic nonlinearity. Methods are developed to solve problems in which both linear and nonlinear Compton scattering are important. Solutions to scattering problems are found for a variety of initial photon energy distributions

  20. Induced Compton-scattering effects in radiation-transport approximations

    International Nuclear Information System (INIS)

    Gibson, D.R. Jr.

    1982-02-01

    The method of characteristics is used to solve radiation transport problems with induced Compton scattering effects included. The methods used to date have only addressed problems in which either induced Compton scattering is ignored, or problems in which linear scattering is ignored. Also, problems which include both induced Compton scattering and spatial effects have not been considered previously. The introduction of induced scattering into the radiation transport equation results in a quadratic nonlinearity. Methods are developed to solve problems in which both linear and nonlinear Compton scattering are important. Solutions to scattering problems are found for a variety of initial photon energy distributions

  1. 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

  2. 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.

  3. Simulating Space Radiation-Induced Breast Tumor Incidence Using Automata.

    Science.gov (United States)

    Heuskin, A C; Osseiran, A I; Tang, J; Costes, S V

    2016-07-01

    Estimating cancer risk from space radiation has been an ongoing challenge for decades primarily because most of the reported epidemiological data on radiation-induced risks are derived from studies of atomic bomb survivors who were exposed to an acute dose of gamma rays instead of chronic high-LET cosmic radiation. In this study, we introduce a formalism using cellular automata to model the long-term effects of ionizing radiation in human breast for different radiation qualities. We first validated and tuned parameters for an automata-based two-stage clonal expansion model simulating the age dependence of spontaneous breast cancer incidence in an unexposed U.S. We then tested the impact of radiation perturbation in the model by modifying parameters to reflect both targeted and nontargeted radiation effects. Targeted effects (TE) reflect the immediate impact of radiation on a cell's DNA with classic end points being gene mutations and cell death. They are well known and are directly derived from experimental data. In contrast, nontargeted effects (NTE) are persistent and affect both damaged and undamaged cells, are nonlinear with dose and are not well characterized in the literature. In this study, we introduced TE in our model and compared predictions against epidemiologic data of the atomic bomb survivor cohort. TE alone are not sufficient for inducing enough cancer. NTE independent of dose and lasting ∼100 days postirradiation need to be added to accurately predict dose dependence of breast cancer induced by gamma rays. Finally, by integrating experimental relative biological effectiveness (RBE) for TE and keeping NTE (i.e., radiation-induced genomic instability) constant with dose and LET, the model predicts that RBE for breast cancer induced by cosmic radiation would be maximum at 220 keV/μm. This approach lays the groundwork for further investigation into the impact of chronic low-dose exposure, inter-individual variation and more complex space radiation

  4. Radiation-induced camptocormia and dropped head syndrome. Review and case report of radiation-induced movement disorders

    International Nuclear Information System (INIS)

    Seidel, Clemens; Kuhnt, Thomas; Kortmann, Rolf-Dieter; Hering, Kathrin

    2015-01-01

    In recent years, camptocormia and dropped head syndrome (DHS) have gained attention as particular forms of movement disorders. Camptocormia presents with involuntary forward flexion of the thoracolumbar spine that typically increases during walking or standing and may severely impede walking ability. DHS is characterized by weakness of the neck extensors and a consecutive inability to extend the neck; in severe cases the head is fixed in a ''chin to chest position.'' Many diseases may underlie these conditions, and there have been some reports about radiation-induced camptocormia and DHS. A PubMed search with the keywords ''camptocormia,'' ''dropped head syndrome,'' ''radiation-induced myopathy,'' ''radiation-induced neuropathy,'' and ''radiation-induced movement disorder'' was carried out to better characterize radiation-induced movement disorders and the radiation techniques involved. In addition, the case of a patient developing camptocormia 23 years after radiation therapy of a non-Hodgkin's lymphoma of the abdomen is described. In total, nine case series of radiation-induced DHS (n = 45 patients) and - including our case - three case reports (n = 3 patients) about radiogenic camptocormia were retrieved. Most cases (40/45 patients) occurred less than 15 years after radiotherapy involving extended fields for Hodgkin's disease. The use of wide radiation fields including many spinal segments with paraspinal muscles may lead to radiation-induced movement disorders. If paraspinal muscles and the thoracolumbar spine are involved, the clinical presentation can be that of camptocormia. DHS may result if there is involvement of the cervical spine. To prevent these disorders, sparing of the spine and paraspinal muscles is desirable. (orig.) [de

  5. Low-dose radiation-induced endothelial cell retraction

    International Nuclear Information System (INIS)

    Kantak, S.S.; Onoda, J.M.; Diglio, C.A.; Harper Hospital, Detroit, MI

    1993-01-01

    The data presented here are representative of a series of studies designed to characterize low-dose radiation effects on pulmonary microvascular endothelium. Data suggest that post-irradiation lung injuries (e.g. oedema) may be induced with only a single fraction of therapeutic radiation, and thus microscopic oedema may initiate prior to the lethal effects of radiation on the microvascular endothelium, and much earlier than would be suggested by the time course for clinically-detectable oedema. (author)

  6. Skin aspergillosis induced in the region of radiation ulcer

    International Nuclear Information System (INIS)

    Niimura, Yumiko; Nakauchi, Yohichi; Ushijima, Tsugako

    1980-01-01

    A case of skin aspergillosis in the region of radiation ulcer which was caused by Aspergillus fumigatus was reported. The patient was a 51 year-old man. This fungal infection was probably induced by a local factor, that is, chronic radiation ulcer. Histological findings suggested that Aspergillus fumigatus which increased saprophytically at the beginning possessed parasitic nature gradually, invaded into connective tissues in the deep layer of true skin, and made radiation ulcer more intractable. (Tsunoda, M.)

  7. Radiation-Induced Bystander Response: Mechanism and Clinical Implications

    OpenAIRE

    Suzuki, Keiji; Yamashita, Shunichi

    2014-01-01

    Significance: Absorption of energy from ionizing radiation (IR) to the genetic material in the cell gives rise to damage to DNA in a dose-dependent manner. There are two types of DNA damage; by a high dose (causing acute or deterministic effects) and by a low dose (related to chronic or stochastic effects), both of which induce different health effects. Among radiation effects, acute cutaneous radiation syndrome results from cell killing as a consequence of high-dose exposure.

  8. Radiation-induced nitration of organic compounds in aqueous solutions

    International Nuclear Information System (INIS)

    Ershov, B.G.; Gordeev, A.V.; Bykov, G.L.

    2009-01-01

    Radiation-induced nitration of organic compounds in aqueous solutions was studied. It was found that γ-irradiation of solutions containing acetic and nitric acid and/or their salts gives nitromethane. Dependences of the product yield on the absorbed dose and the contents of components were established. The mechanism of radiation nitration involving radicals is discussed. (author)

  9. Seven cases of radiation-induced cutaneous squamous cell carcinoma

    International Nuclear Information System (INIS)

    Sugita, Kazunari; Yamamoto, Osamu; Suenaga, Yoshinori

    2000-01-01

    We report 7 cases of radiation-induced skin cancer. The diagnosis was based on the history of radiotherapy for benign skin diseases (5 cases) and of occupational exposures to medical doctors (2 cases). All cases were squamous cell carcinomas which arose from chronic radiodermatitis. The estimated latent period of these tumors ranged from 6 to 64 years, with an average of 29.9 years. After surgical treatments of the lesions, no local recurrences were observed in all cases. Benign skin diseases had sometimes been treated with low-energy radiation before the 1960s. Considering the estimated latent period, the peak time point of developing risk of radiation-induced skin cancer by such treatment has been already passed, however, the danger of it should not be ignored in future. In association with multiplicity of radiation usage, occupational exposure of radiation may develop the risk of occurrence of skin cancer in future. Therefore, we should recognize that radiation-induced skin cancer is not in the past. In the cases of chronic skin diseases showing warty keratotic growth, erosion and ulcer, we should include chronic radio-dermatitis in the differential diagnosis. It is necessary to recall all patients about the history of radiotherapy or radiation exposure. Rapid histopathological examination is mandatory because of the suspicion of radiation-induced skin cancer. (author)

  10. Seven cases of radiation-induced cutaneous squamous cell carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Sugita, Kazunari; Yamamoto, Osamu; Suenaga, Yoshinori [Univ. of Occupational and Environmental Health, Kitakyushu, Fukuoka (Japan). School of Medicine

    2000-09-01

    We report 7 cases of radiation-induced skin cancer. The diagnosis was based on the history of radiotherapy for benign skin diseases (5 cases) and of occupational exposures to medical doctors (2 cases). All cases were squamous cell carcinomas which arose from chronic radiodermatitis. The estimated latent period of these tumors ranged from 6 to 64 years, with an average of 29.9 years. After surgical treatments of the lesions, no local recurrences were observed in all cases. Benign skin diseases had sometimes been treated with low-energy radiation before the 1960s. Considering the estimated latent period, the peak time point of developing risk of radiation-induced skin cancer by such treatment has been already passed, however, the danger of it should not be ignored in future. In association with multiplicity of radiation usage, occupational exposure of radiation may develop the risk of occurrence of skin cancer in future. Therefore, we should recognize that radiation-induced skin cancer is not in the past. In the cases of chronic skin diseases showing warty keratotic growth, erosion and ulcer, we should include chronic radio-dermatitis in the differential diagnosis. It is necessary to recall all patients about the history of radiotherapy or radiation exposure. Rapid histopathological examination is mandatory because of the suspicion of radiation-induced skin cancer. (author)

  11. Potassium cyanate-induced modification of toxic and mutagenic effects of gamma-radiation and benzo(A)-pyrene

    International Nuclear Information System (INIS)

    Serebryanyj, A.M.; Sal'nikova, L.E.; Bakhitova, L.M.; Pashin, Yu.V.; AN SSSR, Moscow

    1989-01-01

    In experiments with CHO-AT3-2 cell culture, a study was made of the effect of potassium cyanate (KNCO) on the effect of gamma-radiation and benzo(a)pyrene (BP) by the following tests: cell viability, induction of cells with micronuclei and fragmentated nuclei and mutations by thymidinekinase (TK) and Na + /K + -ATPase loci. Some tests have revealed the increase in the effect of gamma-radiation and BP produced by potassium cyanate. It is suggested that sensitizing effects are related to repair system inhibition and/or changes in the cell chromatin structure produced by KNCO

  12. Radiation-induced mutation breeding of papaya

    Energy Technology Data Exchange (ETDEWEB)

    Chan, Y. K. [Horticulture Research Centre, Malaysian Agricultural Research and Development Institute (MARDI), Kuala Lumpur (Malaysia)

    2009-05-15

    Irradiation-induced mutation breeding of papaya commenced at the Malaysian Agricultural Research and Development Institute (MARDI) in August, 2000. This research was initiated under a Coordinated Research Project (CRP - D23023) with assistance from the International Atomic Energy Agency (IAEA). In the preliminary dosimetry study, seeds from two local papaya varieties, Sekaki and Eksotika were irradiated, either as dry seeds or as pre-soaked seeds (soaked overnight in water and surface-dried) with radiation doses ranging from 0 to 300 Gy. 100 Gy dose was lethal for all wet presoaked seeds while dry seed did not show loss of viability, even at 300 Gy. From the growth data it was estimated that dose of 525 Gy reduced shoot elongation by 50%, and this dose was recommended for mass irradiation of dry seeds. For wet, pre-soaked seeds results indicated that 42.5 Gy was the optimal dose for mass irradiation. At this dose, both seeds germination and seedlings growth were reduced by 50%. In a massive irradiation experiment 2,000 Eksotika seeds were irradiated at 42.5 Gy (pre-soaked) and another 2,000 at 525 Gy (dry). In the M2 population, numerous physiological defects were observed, including stem splitting, leaf variegation and puckering, and crinkled dwarfs. In the M3 population, a wide variability was recorded for a number of traits. M3 seedlings derived from presoaked seeds irradiated a low 42.5 Gy dose presented a high number of plants that were shorter and more vigorous in leaf development compared to those irradiated at 525 Gy and to non-irradiated control seedlings. The distribution patterns of M3 progenies for nine quantitative field characters showed great variation, often exceeding the limits of the control population. There appears to be good prospects in improving Eksotika papaya especially in the development of dwarf trees with lower fruit bearing stature, higher total soluble solids in fruits and larger fruit size. Several M2 and M3 putative mutants also

  13. Characterization of radiation-induced Apoptosis in rodent cell lines

    International Nuclear Information System (INIS)

    Guo, Min; Chen, Changhu; Ling, C.C.

    1997-01-01

    For REC:myc(ch1), Rat1 and Rat1:myc b cells, we determined the events in the development of radiation-induced apoptosis to be in the following order: cell division followed by chromatin condensation, membrane blebbing, loss of adhesion and the uptake of vital dye. Experimental data which were obtained using 4 He ions of well defined energies and which compared the dependence of apoptosis and clonogenic survival on 4 He range strongly suggested that in our cells both apoptosis and loss of clonogenic survival resulted from radiation damage to the cell nucleus. Corroboratory evidence was that BrdU incorporation sensitized these cells to radiation-induced apoptosis. Comparing the dose response for apoptosis and the clonogenic survival curves for Rat1 and Rat1:myc b cells, we concluded that radiation-induced cell inactivation as assayed by clonogenic survival, and that a modified linear-quadratic model, proposed previously, modeled such a contribution effectively. In the same context, the selective increase in radiation-induced apoptosis. Comparing the dose response for apoptosis and the clonogenic survival curves for Rat1 and Rat1:myc b cells, we concluded that radiation-induced apoptosis contributed to the overall radiation-induced cell inactivation as assayed by clonogenic survival, and that a modified linear-quadratic model, proposed previously, modeled such a contribution effectively. In the same context, the selective increase in radiation-induced apoptosis during late S and G 2 phases reduced the relative radioresistance observed for clonogenic survival during late S and G 2 phases. 30 refs., 8 figs

  14. Radiation-induced coronary artery disease

    International Nuclear Information System (INIS)

    Dunsmore, L.D.; LoPonte, M.A.; Dunsmore, R.A.

    1986-01-01

    This report describes three patients who developed myocardial infarction at an untimely age, 4 to 12 years after radiation therapy for Hodgkin's disease. These cases lend credence to the cause and effect relation of such therapy to coronary artery disease

  15. 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

  16. Comparison of Radiation-Induced Bystander Effect in QU-DB Cells after Acute and Fractionated Irradiation: An In Vitro Study.

    Science.gov (United States)

    Soleymanifard, Shokouhozaman; Bahreyni Toossi, Mohammad Taghi; Kamran Samani, Roghayeh; Mohebbi, Shokoufeh

    2016-01-01

    Radiation effects induced in non-irradiated cells are termed radiation-induced bystander effects (RIBE). The present study intends to examine the RIBE response of QU-DB bystander cells to first, second and third radiation fractions and compare their cumulative outcome with an equal, single acute dose. This experimental study irradiated three groups of target cells for one, two and three times with(60)Co gamma rays. One hour after irradiation, we transferred their culture media to non-irradiated (bystander) cells. We used the cytokinesis block micronucleus assay to evaluate RIBE response in the bystander cells. The numbers of micronuclei generated in bystander cells were determined. RIBE response to single acute doses increased up to 4 Gy, then decreased, and finally at the 8 Gy dose disappeared. The second and third fractions induced RIBE in bystander cells, except when RIBE reached to the maximum level at the first fraction. We split the 4 Gy acute dose into two fractions, which decreased the RIBE response. However, fractionation of 6 Gy (into two fractions of 3 Gy or three fractions of 2 Gy) had no effect on RIBE response. When we split the 8 Gy acute dose into two fractions we observed RIBE, which had disappeared following the single 8 Gy dose. The impact of dose fractionation on RIBE induced in QU-DB cells de- pended on the RIBE dose-response relationship. Where RIBE increased proportion- ally with the dose, fractionation reduced the RIBE response. In contrast, at high dos- es where RIBE decreased proportionally with the dose, fractionation either did not change RIBE (at 6 Gy) or increased it (at 8 Gy).

  17. γ-radiation induced tetracycline removal in an aqueous solution

    International Nuclear Information System (INIS)

    Zhou Fei; Guo Zhaobing; Zhang Chaozhi; Lin Mingyue; Wu Menglong; Zhao Yongfu

    2012-01-01

    Degradation effect of tetracycline (TC) by γ-radiation was investigated in an aqueous solution. The effects of initial concentrations of TC, pH values, combining with H 2 O 2 or CH 3 OH on degradation of TC were studied. Results showed that TC can be effectively degradated by γ-irradiation in an aqueous solution. Degradation of TC could be remarkably improved both in acid solution and alkaline solution, especially when pH value was 9.0. In addition, H 2 O 2 could gently promote degradation of TC induced by γ-radiation. While, CH 3 OH markedly restrained degradation of TC induced by γ-radiation. The degradation mechanism of TC was supposed by results of quantum chemical calculations and LC-MS. Results proved that degradation of TC induced by γ-radiation was mainly ascribed to · OH oxidation. (authors)

  18. Effect of dose on radiation-induced conductivity in polymers

    International Nuclear Information System (INIS)

    Tyutnev, A.P.; Saenko, V.S.; Pozhidaev, E.D.; Ikhsanov, R.Sh.

    2007-01-01

    Numerical simulation of radiation-induced conductivity in polymers upon long-term irradiation on the basis of the generalized Rose-Fowler-Vaisberg model, which allows for both dipolar carrier transport and generation of radiation traps during irradiation, was performed. The unusual properties of radiation-induced conductivity, such as the appearance of a maximum on current transients, the absence of a steady state, and a substantial difference between these curves for the first and subsequent irradiation, are rationalized in terms of the formation of free radicals, the major feature of radiolysis in the chemical aspect. This interpretation does not require the involvement of degradation or crosslinking processes, unlike other interpretations that appear in the literature. With the use of low-density polyethylene as an example, it was shown that radiation-induced conductivity both upon pulse and continuous irradiation can satisfactorily be described with the unified set of parameters of the generalized Rose-Fowler-Vaisberg model [ru

  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. Radiation-induced gene amplification in rodent and human cells

    International Nuclear Information System (INIS)

    Luecke-Huhle, C.; Gloss, B.; Herrlich, P.

    1990-01-01

    Ionizing and UV radiations induce amplification of SV40 DNA sequences integrated in the genome of Chinese hamster cells and increase amplification of the dihydrofolate reductase (DHFR) gene during methotrexate selection in human skin fibroblasts of a patient with ataxia telangiectasia. Various types of external (60-Co-γ-rays, 241-Am-α-particles, UV) or internal radiation (caused by the decay of 125 I incorporated into DNA in form of I-UdR) were applied. By cell fusion experiments it could be shown that SV40 gene amplification is mediated by one or several diffusible trans-acting factors induced or activated in a dose dependent manner by all types of radiation. One of these factors binds to a 10 bp sequence within the minimal origin of replication of SV40. In vivo competition with an excess of a synthetic oligonucleotide comprising this sequence blocks radiation-induced amplification. (author) 25 refs.; 8 figs

  1. Free radicals in wood induced by γ-radiation

    International Nuclear Information System (INIS)

    Xu Honglin; Zhang Wenhui

    1994-01-01

    The free radicals in wood induced by γ-radiation were studied by electron spin resonance. The fine structure of the ESR signal from sawdust samples irradiated could be resolved into various radicals. These free radicals have a very long lifetime. The major spectrum for the free radicals will exponentially increased along with the radiation dose according to Y 1-Exp(-α a D). The intensity of radiation radicals is dependent on tree species. The stronger the intensity of mechanic free radicals is, the stronger the intensity of radiation free radicals

  2. Perspectives in the paradigm of radiation-induced carcinogenesis

    International Nuclear Information System (INIS)

    Sugakhara, T.; Vatanabe, M.; Niva, O.; Nikajdo, O.

    1995-01-01

    Carcinogenesis is analysed as a multistage process consisting of initiation, promotion and progression. This model includes the mutation of oncogenes and the loss of hetrezygosity by tumor-suppressor genes. The threshold concept of radiation cancerogenesis is proposed, under which ionizing radiation can induce in somatic cell genetic effects a s result of DNA damage and epigenetic changes as well. The epigenetic changes (through DNA or cytoplasma) can be stabilized as mutations observed in many cancer cells and play a dominant role in radiation cancerogenesis induction. The ration of epigenetic and genetic effects largely depends on radiation doses

  3. Non-targeted bystander effects induced by ionizing radiation

    International Nuclear Information System (INIS)

    Morgan, William F.; Sowa, Marianne B.

    2007-01-01

    Radiation-induced bystander effects refer to those responses occurring in cells that were not subject to energy deposition events following ionizing radiation. These bystander cells may have been neighbors of irradiated cells, or physically separated but subject to soluble secreted signals from irradiated cells. Bystander effects have been observed in vitro and in vivo and for various radiation qualities. In tribute to an old friend and colleague, Anthony V. Carrano, who would have said 'well what are the critical questions that should be addressed, and so what?', we review the evidence for non-targeted radiation-induced bystander effects with emphasis on prevailing questions in this rapidly developing research field, and the potential significance of bystander effects in evaluating the detrimental health effects of radiation exposure

  4. 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

  5. Radiation induces aerobic glycolysis through reactive oxygen species

    International Nuclear Information System (INIS)

    Zhong, Jim; Rajaram, Narasimhan; Brizel, David M.; Frees, Amy E.; Ramanujam, Nirmala; Batinic-Haberle, Ines; Dewhirst, Mark W.

    2013-01-01

    Background and purpose: Although radiation induced reoxygenation has been thought to increase radiosensitivity, we have shown that its associated oxidative stress can have radioprotective effects, including stabilization of the transcription factor hypoxia inducible factor 1 (HIF-1). HIF-1 is known to regulate many of the glycolytic enzymes, thereby promoting aerobic glycolysis, which is known to promote treatment resistance. Thus, we hypothesized that reoxygenation after radiation would increase glycolysis. We previously showed that blockade of oxidative stress using a superoxide dismutase (SOD) mimic during reoxygenation can downregulate HIF-1 activity. Here we tested whether concurrent use of this drug with radiotherapy would reduce the switch to a glycolytic phenotype. Materials and methods: 40 mice with skin fold window chambers implanted with 4T1 mammary carcinomas were randomized into (1) no treatment, (2) radiation alone, (3) SOD mimic alone, and (4) SOD mimic with concurrent radiation. All mice were imaged on the ninth day following tumor implantation (30 h following radiation treatment) following injection of a fluorescent glucose analog, 2-[N-(7-nitrobenz-2-oxa-1,3-diaxol-4-yl)amino]-2-deoxyglucose (2-NBDG). Hemoglobin saturation was measured by using hyperspectral imaging to quantify oxygenation state. Results: Mice treated with radiation showed significantly higher 2-NBDG fluorescence compared to controls (p = 0.007). Hemoglobin saturation analysis demonstrated reoxygenation following radiation, coinciding with the observed increase in glycolysis. The concurrent use of the SOD mimic with radiation demonstrated a significant reduction in 2-NBDG fluorescence compared to effects seen after radiation alone, while having no effect on reoxygenation. Conclusions: Radiation induces an increase in tumor glucose demand approximately 30 h following therapy during reoxygenation. The use of an SOD mimic can prevent the increase in aerobic glycolysis when used

  6. Radiations - induced disorders in ovarian function

    International Nuclear Information System (INIS)

    Saleh, S.; Roushdy, H.M.; Abdel-Aziz, M.T.; Eldenshary, A.E.; Abdel-Khalek, A.; Ramadan, L.A.

    1988-01-01

    The effect of whole body gamma radiation exposure (7.5 and 6.5 Gy) on the secretory activity and the structure of the ovaries was investigated. The parameters studied were serum levels of oestrogen, progesterone, Lh and FSH, beside histopathological studies of the ovaries of femaler rats. These were measured on the next day after radiation exposure and then after one two oestrus cycles. Whole body gamma - irradiation of females rats at two levels of exposure progressively decreased the level of oestrogen and progesterone while increased the level of LH and FSH as compared with the control. moreover, the changes in the ovaries were demonstrated in the histopathological investigation. Keywords: Radiation exposure - ovarian function - hormone radioimmunoassay - oestrogen - progesterone - LH - FSH

  7. Radiation-induced emesis in monkeys

    International Nuclear Information System (INIS)

    Mattsson, J.L.; Yochmowitz, M.G.

    1980-01-01

    To determine the emesis ED 50 for 60 Co radiation, 15 male rhesus monkeys were exposed to whole-body radiation doses ranging from 350 to 550 rad midline tissue dose. An up-and-down sequence of exposures was used. Step size between doses was 50 rad, and dose rate was 20 rad/min. There had been no access to food for 1 to 2 h. The ED 50 +- SE was found to be 446 +- 27 rad. To determine the effect of motion on emesis ED 50 , six more monkeys were exposed to 60 Co radiation as above, except that the chair in which they were seated was oscillated forward and backward 5 to 15 0 (pitch axis) at a variable rate not exceeding 0.3 Hz. Radioemesis ED 50 +- SE with motion was 258 +- 19 rad, a value significantly lower (P < 0.01) than for stationary monkeys

  8. Radiation-induced changes in carboxymethylated chitosan

    International Nuclear Information System (INIS)

    Huang Ling; Peng Jing; Zhai Maolin; Li Jiuqiang; Wei Genshuan

    2007-01-01

    This study focuses on the radiation effect of γ-ray on carboxymethylated chitosan (CM-chitosan) in solid state. The changes in molecular weight of CM-chitosan with absorbed dose were monitored by viscosity method. Experimental results indicated that random chain scissions took place under irradiation. Radiation chemical yield (G d ) of CM-chitosan in solid state with N 2 -saturated was 0.49, which showed CM-chitosan has high radiation stability. Biomaterials composed of CM-chitosan can be thought to sterilize with low absorbed dose. FTIR and UV spectra showed that main chain structures of CM-chitosan were retained, carbonyl/carboxyl groups were formed and partial amino groups were eliminated in high absorbed dose. XRD patterns identified that the degradation of CM-chitosan occurred mostly in amorphous region

  9. Radiation induced cancer risk, detriment and radiation protection

    International Nuclear Information System (INIS)

    Sinclair, W.K.

    1992-01-01

    Recommendations on radiation protection limits for workers and for the public depend mainly on the total health detriment estimated to be the result of low dose ionizing radiation exposure. This detriment includes the probability of a fatal cancer, an allowance for the morbidity due to non-fatal cancer and the probability of severe hereditary effects in succeeding generations. In a population of all ages, special effects on the fetus particularly the risk of mental retardation at defined gestational ages, should also be included. Among these components of detriment after low doses, the risk of fatal cancer is the largest and most important. The estimates of fatal cancer risk used by ICRP in the 1990 recommendations were derived almost exclusively from the study of the Japanese survivors of the atomic bombs of 1945. How good are these estimates? Uncertainties associated with them, apart from those due to limitations in epidemiological observation and dosimetry, are principally those due to projection forward in time and extrapolation from high dose and dose rate to low dose and dose rate, each of which could after the estimate by a factor of 2 or so. Recent estimates of risk of cancer derived directly from low dose studies are specific only within very broad ranges of risk. Nevertheless, such studies are important as confirmation or otherwise of the estimates derived from the atomic bomb survivors. Recent U.S. British and Russian studies are examined in this light. (author)

  10. Transcriptomic network analysis of micronuclei-related genes: a case study

    DEFF Research Database (Denmark)

    van Leeuwen, D. M.; Pedersen, Marie; Knudsen, Lisbeth E.

    2011-01-01

    checkpoint and aneuploidy. The MN-related gene network was tested against a transcriptomics case study associated with MN measurements. In this case study, transcriptomic data from children and adults differentially exposed to ambient air pollution in the Czech Republic were analysed and visualised......Mechanistically relevant information on responses of humans to xenobiotic exposure in relation to chemically induced biological effects, such as micronuclei (MN) formation can be obtained through large-scale transcriptomics studies. Network analysis may enhance the analysis and visualisation...... of such data. Therefore, this study aimed to develop a 'MN formation' network based on a priori knowledge, by using the pathway tool MetaCore. The gene network contained 27 genes and three gene complexes that are related to processes involved in MN formation, e.g. spindle assembly checkpoint, cell cycle...

  11. Radiation-induced hondrosarcoma - a clinical case from our practice

    International Nuclear Information System (INIS)

    Marinova, L.; Georgiev, R.; Mihaylova, I.

    2013-01-01

    We present a clinical case of radiation - induced occipital extracerebral chondrosarcoma in 36 years old young man. The patient had undergone two brain operations 8 years ago due to oligodendroglioma in the left temporo - parietal area. These surgical interventions were partial and subtotal tumor extirpation, followed by local radiotherapy to the brain to a total dose of 56Gy. The necessity of immunohistochemistry (IHH) analysis for pathologic differential diagnosis in high grade brain and peripheral tumors was discussed. In this particular case a precise differential diagnosis between peripheral chondrosarcoma and Ewing sarcoma/pPNET is needed. important risk factors for the development of radiation-induced brain tumors and chondrosarcoma, extremely rarely diagnosed, was discussed. A very accurate precising of the treatment radiation dose is needed in young patients with malignant brain tumors, not only in the surrounding healthy brain tissues, but also in other tissues, such as skin, subcutaneous layer and bone. The exceeding of the radiation dose in the bone above 45-50 Gy, increases the risk of radiation - induced sarcoma with latent period over 8 years. Key words: Hondrosarcoma. Radiotherapy. Radiation-induced Sarcoma. Complex Treatment. Immunohistochemistry

  12. Origin of nuclear buds and micronuclei in normal and folate-deprived human lymphocytes

    International Nuclear Information System (INIS)

    Lindberg, Hanna K.; Wang Xu; Jaerventaus, Hilkka; Falck, Ghita C.-M.; Norppa, Hannu; Fenech, Michael

    2007-01-01

    Micronuclei are formed from chromosomes and chromosomal fragments that lag behind in anaphase and are left outside daughter nuclei in telophase. They may also be derived from broken anaphase bridges. Nuclear buds, micronucleus-like bodies attached to the nucleus by a thin nucleoplasmic connection, have been proposed to be generated similarly to micronuclei during nuclear division or in S-phase as a stage in the extrusion of extra DNA, possibly giving rise to micronuclei. To better understand these phenomena, we have characterized the contents of 894 nuclear buds and 1392 micronuclei in normal and folate-deprived 9-day cultures of human lymphocytes using fluorescence in situ hybridization with pancentromeric and pantelomeric DNA probes. Such information has not earlier been available for human primary cells. Surprisingly, there appears to be no previous data on the occurrence of telomeres in micronuclei (or buds) of normal human cells in general. Our results suggest that nuclear buds and micronuclei have partly different mechanistic origin. Interstitial DNA without centromere or telomere label was clearly more prevalent in nuclear buds (43%) than in micronuclei (13%). DNA with only telomere label or with both centromere and telomere label was more frequent in micronuclei (62% and 22%, respectively) than in nuclear buds (44% and 10%, respectively). Folate deprivation especially increased the frequency of nuclear buds and micronuclei harboring telomeric DNA and nuclear buds harboring interstitial DNA but also buds and micronuclei with both centromeric and telomeric DNA. According to the model we propose, that micronuclei in binucleate lymphocytes primarily derive from lagging chromosomes and terminal acentric fragments during mitosis. Most nuclear buds, however, are suggested to originate from interstitial or terminal acentric fragments, possibly representing nuclear membrane entrapment of DNA that has been left in cytoplasm after nuclear division or excess DNA that

  13. Radiation-induced life shortening. Annex K

    International Nuclear Information System (INIS)

    1982-01-01

    The purpose of this Annex is to review the cumulative evidence in the field of non-neoplastic long-term effects of whole-body irradiation. In particular, the existence and extent of life-span shortening in irradiated animals and man, and the relationships of life shortening to the physical and biological variables which may influence this effect of radiation are examined.

  14. Radiation-induced cerebellar chondrosarcoma. Case report

    International Nuclear Information System (INIS)

    Bernstein, M.; Perrin, R.G.; Platts, M.E.; Simpson, W.J.

    1984-01-01

    The authors report a case of chondrosarcoma arising in the cerebellum 16 years after treatment of a cerebellar malignant astrocytoma by subtotal resection and irradiation. It is thought that the chondrosarcoma arising within the intracranial cavity was a probable consequence of previous ionizing radiation

  15. 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.).

  16. Crack velocity measurement by induced electromagnetic radiation

    International Nuclear Information System (INIS)

    Frid, V.; Rabinovitch, A.; Bahat, D.

    2006-01-01

    Our model of electromagnetic radiation (EMR) emanated from fracture implies that EMR amplitude is proportional to crack velocity. Soda lime glass samples were tested under uniaxial tension. Comparison of crack velocity observed by Wallner line analysis and the peak amplitude of EMR signals registered during the test, showed very good correlation, validating this proportionality

  17. Radiation recall dermatitis induced by trastuzumab

    Directory of Open Access Journals (Sweden)

    Emre Kaynak

    2014-12-01

    Full Text Available Radiation recall phenomenon is an acute, egzematous reaction that develops throughout a previously irradiated area, precipitated by the administration of docetaxel, doxorubicin, gemcitabine and paclitaxel. We report a 52-year-old woman with breast cancer who received locoregional radiotherapy followed by trastuzumab monotherapy. Three day after the first cycle of trastuzumab monotherapy, dermatitis developed in the previously irradiated skin.

  18. Crack velocity measurement by induced electromagnetic radiation

    Energy Technology Data Exchange (ETDEWEB)

    Frid, V. [Deichmann Rock Mechanics Laboratory of the Negev, Geological and Environmental Sciences Department, Ben Gurion University of the Negev, Beer Sheva (Israel)]. E-mail: vfrid@bgu.ac.il; Rabinovitch, A. [Deichmann Rock Mechanics Laboratory of the Negev, Physics Department, Ben Gurion University of the Negev, Beer Sheva (Israel); Bahat, D. [Deichmann Rock Mechanics Laboratory of the Negev, Geological and Environmental Sciences Department, Ben Gurion University of the Negev, Beer Sheva (Israel)

    2006-07-31

    Our model of electromagnetic radiation (EMR) emanated from fracture implies that EMR amplitude is proportional to crack velocity. Soda lime glass samples were tested under uniaxial tension. Comparison of crack velocity observed by Wallner line analysis and the peak amplitude of EMR signals registered during the test, showed very good correlation, validating this proportionality.

  19. Vacuum alignment and radiatively induced Fermi scale

    Directory of Open Access Journals (Sweden)

    Alanne Tommi

    2017-01-01

    Full Text Available We extend the discussion about vacuum misalignment by quantum corrections in models with composite pseudo-Goldstone Higgs boson to renormalisable models with elementary scalars. As a concrete example, we propose a framework, where the hierarchy between the unification and the Fermi scale emerges radiatively. This scenario provides an interesting link between the unification and Fermi scale physics.

  20. Hyperprolactinemia from radiation-induced hypothalamic hypopituitarism

    International Nuclear Information System (INIS)

    Corkill, G.; Hanson, F.W.; Gold, E.M.; White, V.A.

    1980-01-01

    In 1975 Samaan et al., described the effects of radiation damage of the hypothalamus in 15 patients with head and neck cancer. Shalet et al., in 1977 described endocrine morbidity in adults who as children had been irradiated for brain tumors. This report describes instances of hyperprolactinemia and associated hypothalamic, pituitary, and thyroid dysfunction following irradiation of a young adult female for brain neoplasia

  1. [Induced thymus aging: radiation model and application perspective for low intensive laser radiation].

    Science.gov (United States)

    Sevost'ianova, N N; Trofimov, A V; Lin'kova, N S; Poliakova, V O; Kvetnoĭ, I M

    2010-01-01

    The influence of gamma-radiation on morphofunctional state of thymus is rather like as natural thymus aging. However gamma-radiation model of thymus aging widely used to investigate geroprotectors has many shortcomings and limitations. Gamma-radiation can induce irreversible changes in thymus very often. These changes are more intensive in comparison with changes, which can be observed at natural thymus aging. Low intensive laser radiation can not destroy structure of thymus and its effects are rather like as natural thymus aging in comparison with gamma-radiation effects. There are many parameters of low intensive laser radiation, which can be changed to improve morphofunctional thymus characteristics in aging model. Using low intensive laser radiation in thymus aging model can be very perspective for investigations of aging immune system.

  2. Radiation-induced tumors of the nervous system

    International Nuclear Information System (INIS)

    Bernstein, M.; Laperriere, N.

    1991-01-01

    Therapeutic and nontherapeutic ionizing radiation has long been recognized as a putative carcinogenic agent, but the evidence that radiation causes tumors is circumstantial at worst and statistically significant at best. There are no distinct histological, biochemical, cytogenetic, or clinical criteria that can be used to determine if an individual tumor was caused directly by previous irradiation of the anatomic area. Additional supportive evidence for radiation-induced tumors includes a position correlation between radiation dose and tumor incidence (usually in the low dose range) and experimental induction of the same neoplasm in appropriate animal models. even if these criteria are fulfilled, coincidental development of a second tumor can never be discounted in an individual patient, particularly if there is an underlying diathesis to develop multiple tumors of different histology, such as in Recklinghausen's disease, or if there is an strong family history for the development of neoplastic disease. In this paper, the authors critically evaluate the available evidence to support the hypothesis that radiation induces tumors in the nervous system. The current concepts of radiation carcinogenesis are discussed and are followed by a discussion of animal data and clinical experience in humans. Finally, a brief discussion on treatment of radiation-induced nervous system tumors is presented

  3. Flow cytometric detection of micronuclei by combined staining of DNA and membranes

    International Nuclear Information System (INIS)

    Wessels, J.M.; Nuesse, M.

    1995-01-01

    A new staining method is presented for flow cytometric measurement of micronuclei (MN) in cell cultures and human lymphocytes using membrane-specific fluorescent dyes in addition to DNA staining. Several combinations of fluorescent membrane and DNA dyes were studied for a better discrimination of MN from debris in a suspension of nuclei and micronuclei. For staining of membranes, the lipophilic dyes 2-hydroxyethyl-7,12,17-tris(methoxyethyl)porphycene (HEPn) and 1,6-diphenyl-1,3,5-hexatriene (DPH) were used in combination with ethidium bromide (EB), proflavine (PF), and Hoechst 33258 (HO). Due to their spectral properties, HO or EB combined with HEPn were not as suitable for the discrimination of MN from debris as was HEPn in combination with PF. With HEPn in combination with PF, however, additional noise was found at low fluorescence intensities, probably due to free fluorescent dye molecules in the solution. The optimal simultaneous staining of membranes and DNA was obtained using a combination of DPH and EB. The induction of MN in Chinese hamster and mouse NIH-3T3 cells by UV-B illumination was studied with this new staining technique. UV-B illumination (280-360 nm) induced MN in both cell lines. Chinese hamster cells were found to be more sensitive to these wavelengths. Illumination with wavelengths above 360 nm did not induce MN in either cell line. The results obtained from human lymphocytes using the combination of EB or DPH were comparable to the results obtained with the combination of EB and HO. 23 refs., 7 figs

  4. Plasma induced DNA damage: Comparison with the effects of ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Lazović, S.; Maletić, D.; Puač, N.; Malović, G.; Petrović, Z. Lj. [Institute of Physics, University of Belgrade, Pregrevica 118, 11080 Belgrade (Serbia); Leskovac, A.; Filipović, J.; Joksić, G. [Department of Physical Chemistry, Vinča Institute of Nuclear Sciences, University of Belgrade, 11001 Belgrade (Serbia)

    2014-09-22

    We use human primary fibroblasts for comparing plasma and gamma rays induced DNA damage. In both cases, DNA strand breaks occur, but of fundamentally different nature. Unlike gamma exposure, contact with plasma predominantly leads to single strand breaks and base-damages, while double strand breaks are mainly consequence of the cell repair mechanisms. Different cell signaling mechanisms are detected confirming this (ataxia telangiectasia mutated - ATM and ataxia telangiectasia and Rad3 related - ATR, respectively). The effective plasma doses can be tuned to match the typical therapeutic doses of 2 Gy. Tailoring the effective dose through plasma power and duration of the treatment enables safety precautions mainly by inducing apoptosis and consequently reduced frequency of micronuclei.

  5. Radiation-Induced Differentiation in Human Lung Fibroblast

    International Nuclear Information System (INIS)

    Park, Sa-Rah; Ahn, Ji-Yeon; Han, Young-Soo; Shim, Jie-Young; Yun, Yeon-Sook; Song, Jie-Young

    2007-01-01

    One of the most common tumors in many countries is lung cancer and patients with lung cancer may take radiotherapy. Although radiotherapy may have its own advantages, it can also induce serious problems such as acute radiation pneumonitis and pulmonary fibrosis. Pulmonary fibrosis is characterized by excessive production of α-SMA and accumulation of extracellular matrix (ECM) such as collagen and fibronectin. There has been a great amount of research about fibrosis but the exact mechanism causing the reaction is not elucidated especially in radiation-induced fibrosis. Until now it has been known that several factors such as transforming growth factor (TGF-β), tumor necrosis factor (TNF), interleukin (IL)-1, IL-6, platelet-derived growth factor (PDGF) and fibroblast growth factor (FGF) are related to fibrosis. Among them TGF-β with Smad signaling is known to be the main stream and other signaling molecules such as MAPK, ERK and JNK (3) also participates in the process. In addition to those above factors, it is thought that more diverse and complicate mechanisms may involve in the radiationinduced fibrosis. Therefore, to investigate the underlying mechanisms in radiation induced fibrosis, first of all, we confirmed whether radiation induces trans differentiation in human normal lung fibroblasts. Here, we suggest that not only TGF-β but also radiation can induce trans differentiation in human lung fibroblast WI-38 and IMR-90

  6. Characterization of radiation-induced emesis in the ferret

    International Nuclear Information System (INIS)

    King, G.L.

    1988-01-01

    Forty-eight ferrets (Mustela putorius furo) were individually head-shielded and radiated with bilateral 60 Co gamma radiation at 100 cGy min-1 at doses ranging between 49 and 601 cGy. The emetic threshold was observed at 69 cGy, the ED50 was calculated at 77 cGy, and 100% incidence of emesis occurred at 201 cGy. With increasing doses of radiation, the latency to first emesis after radiation decreased dramatically, whereas the duration of the prodromal period increased. Two other sets of experiments suggest that dopaminergic mechanisms play a minor role in radiation-induced emesis in the ferret. Twenty-two animals were injected either intravenously or subcutaneously with 30 to 300 micrograms/kg of apomorphine. Fewer than 50% of the animals vomited to 300 micrograms/kg apomorphine; central dopaminergic receptor activation was apparent at all doses. Another eight animals received 1 mg/kg domperidone prior to either 201 (n = 4) or 401 (n = 4) cGy radiation and their emetic responses were compared with NaCl-injected-irradiated controls (n = 8). At 201 cGy, domperidone significantly reduced only the total time in emetic behavior. At 401 cGy, domperidone had no salutary effect on radiation-induced emesis. The emetic responses of the ferret to radiation and apomorphine are compared with these responses in other vomiting species

  7. 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)

  8. Radiation-induced pseudotumor following therapy for soft tissue sarcoma

    Energy Technology Data Exchange (ETDEWEB)

    Moore, Lacey F.; Kransdorf, Mark J. [Mayo Clinic, Department of Radiology, Jacksonville, FL (United States); Buskirk, Steven J. [Mayo Clinic, Department of Radiation Oncology, Jacksonville, FL (United States); O' Connor, Mary I. [Mayo Clinic, Department of Orthopedic Surgery, Jacksonville, FL (United States); Menke, David M. [Mayo Clinic, Department of Pathology, Jacksonville, FL (United States)

    2009-06-15

    The purpose of this study was to describe the prevalence and imaging appearance of radiation induced pseudotumors in patients following radiation therapy for extremity soft tissue sarcomas. We retrospectively reviewed the serial magnetic resonance (MR) images of 24 patients following radiation therapy for extremity soft tissue sarcomas. A total of 208 exams were reviewed (mean, 8.7 exams per patient) and included all available studies following the start of radiation therapy. Exams were analyzed for the identification of focal signal abnormalities within the surgical bed suggesting local tumor recurrence. Histopathologic correlation was available in nine patients suspected of having local tumor recurrence. Additional information recorded included patient demographics, tumor type and location, radiation type, and dose. The study group consisted of 12 men and 12 women, having an average age of 63 years (range, 39-88 years). Primary tumors were malignant fibrous histiocytoma (n = 13), leiomyosarcoma (n = 6), liposarcoma (n = 3), synovial sarcoma (n = 1), and extraskeletal chondrosarcoma (n = 1). All lesions were high-grade sarcomas, except for two myxoid liposarcomas. Average patient radiation dose was 5,658 cGy (range, 4,500-8,040 cGy). Average follow-up time was 63 months (range, 3-204 months). Focal signal abnormalities suggesting local recurrence were seen in nine (38%) patients. Three of the nine patients with these signal abnormalities were surgically proven to have radiation-induced pseudotumor. The pseudotumors developed between 11 and 61 months following the initiation of radiation therapy (mean, 38 months), with an average radiation dose of 5,527 cGy (range, 5,040-6,500 cGy). MR imaging demonstrated a relatively ill-defined ovoid focus of abnormal signal and intense heterogeneous enhancement with little or no associated mass effect. MR imaging of radiation-induced pseudotumor typically demonstrates a relatively ill-defined ovoid mass-like focus of intense

  9. Radiation-induced transformations of cellulose ethers

    International Nuclear Information System (INIS)

    Nud'ga, L.A.; Petropavlovskii, G.S.; Plisko, E.A.; Isakova, O.V.; Ershov, B.G.

    1988-01-01

    The purpose of this investigation was to study the transformation which take place under the action of γ-radiation in a number of cellulose ethers containing both saturated (carboxymethyl, hydroxyethyl) and unsaturated (allyl, methacryloyl) groups. Irradiation was carried out on a 60 Co unit in air at 77 and 300 K; the dose rate was 37 and 50 kGy/h respectively. The EPR spectra of γ-irradiated hydroxyethyl- and allylhydroxyethylcelluloses are identical. Under the action of γ-radiation extensive changes took place in cellulose ethers which are exhibited in degradation or the formation of three-dimensional structures and are accompanied by a change in the functional composition. The efficiency in the formation of radicals and their localization are determined by the nature and number of substituents in the cellulose ethers

  10. Simulation of radiation-induced defects

    CERN Document Server

    Peltola, Timo

    2015-09-14

    Mainly due to their outstanding performance the position sensitive silicon detectors are widely used in the tracking systems of High Energy Physics experiments such as the ALICE, ATLAS, CMS and LHCb at LHC, the world's largest particle physics accelerator at CERN, Geneva. The foreseen upgrade of the LHC to its high luminosity (HL) phase (HL-LHC scheduled for 2023), will enable the use of maximal physics potential of the facility. After 10 years of operation the expected fluence will expose the tracking systems at HL-LHC to a radiation environment that is beyond the capacity of the present system design. Thus, for the required upgrade of the all-silicon central trackers extensive measurements and simulation studies for silicon sensors of different designs and materials with sufficient radiation tolerance have been initiated within the RD50 Collaboration. Supplementing measurements, simulations are in vital role for e.g. device structure optimization or predicting the electric fields and trapping in the silicon...

  11. Chromosomal instability induced by ionizing radiation

    International Nuclear Information System (INIS)

    Morgan, W.F.; Marder, B.A.; Day, J.P.

    1995-01-01

    There is accumulating evidence indicating genomic instability can manifest multiple generations after cellular exposure to DNA damaging agents. For instance, some cells surviving exposure to ionizing radiations show delayed reproductive cell death, delayed mutation and / or delayed chromosomal instability. Such instability, especially chromosome destabilization has been implicated in mutation, gene amplification, cellular transformation, and cell killing. To investigate chromosomal instability following DNA damage, we have used fluorescence in situ hybridization to detect chromosomal rearrangements in a human/hamster somatic hybrid cell line following exposure to ionizing radiation. Delayed chromosomal instability was detected when multiple populations of uniquely arranged metaphases were observed in clonal isolates raised from single cells. The relationship between delayed chromosomal destabilization and other endpoints of genomic instability, namely; delayed mutation and gene amplification will be discussed, as will the potential cytogenetic and molecular mechanisms contributing to delayed chromosomal instability

  12. Radiation induced growth of micro crystallites

    International Nuclear Information System (INIS)

    Meisel, D.

    1991-01-01

    Generation of colloidal particles during the radiolysis of aqueous solutions was already observed in the early days of radiation chemistry. Systematic studies using radiation chemistry techniques as synthetic tools in the preparation of colloidal particles, primarily metallic particles, were begun approximately a decade ago in conjunction since they were found to catalyze multi-electron redox processes. A large number of metallic colloidal particles were then synthesized, including silver, gold, platinum, iridium, nickel, cadmium, and others. More recently, attention has turned to semiconductor colloidal particles. The stimulus to these studies is the observation of quantum size effects in small semiconductor particles that exhibit hybrid properties between those of the molecular species and the solid state bulk material. In the following we discuss our own observations on the evolution of semiconductor particles whose growth has been initiated by pulse radiolysis. 13 refs., 2 figs

  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. 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

  15. Radiation-induced spindle cell sarcoma: A rare case report

    Directory of Open Access Journals (Sweden)

    Khan Mubeen

    2009-01-01

    Full Text Available Ionizing radiation has been known to induce malignant transformation in human beings. Radiation-induced sarcomas are a late sequel of radiation therapy. Most sarcomas have been reported to occur after exposure to a radiation dose of 55 Gray (Gy and above, with a dose ranging from 16 to 112 Gys. Spindle cell sarcomas, arising after radiotherapy given to treat the carcinoma of head and neck region is a very uncommon sequel. This is a rare case report of spindle cell sarcoma of left maxilla, in a 24-year-old male, occurring as a late complication of radiotherapy with Cobalt-60 given for the treatment of retinoblastoma of the left eye 21 years back.

  16. 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

  17. 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

  18. 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

  19. Radiation-induced Pulmonary Damage in Lung Cancer Patients

    International Nuclear Information System (INIS)

    Chung, Su Mi; Choi, Ihl Bohng; Kang, Mi Mun; Kim, In Ah; Shinn, Kyung Sub

    1993-01-01

    Purpose: A retrospective analysis was performed to evaluate the incidence of radiation induced lung damage after the radiation therapy for the patients with carcinoma of the lung. Method and Materials: Sixty-six patients with lung cancer (squamous cell carcinoma 27, adenocarcinoma 14, large cell carcinoma 2, small cell carcinoma 13, unknown 10) were treated with definitive, postoperative or palliative radiation therapy with or without chemotherapy between July 1987 and December 1991. There were 50 males and 16 females with median age of 63 years(range: 33-80 years). Total lung doses ranged from 500 to 6,660 cGy (median 3960 cGy) given in 2 to 38 fractions (median 20) over a range of 2 to 150 days (median 40 days) using 6 MV or 15 MV linear accelerator. To represent different fractionation schedules of equivalent biological effect, the estimated single dose(ED) model, ED=D·N-0.377·T-0.058 was used in which D was the lung dose in cGy, N was the number of fractions, and T was the overall treatment time in days. The range of ED was 370 to 1357. The endpoint was a visible increase in lung density within the irradiated volume on chest X-ray as observed independently by three diagnostic radiologists. Patients were grouped according to ED, treatment duration, treatment modality and age, and the percent incidence of pulmonary damage for each group was determined. Result: In 40 of 66 patients, radiation induced change was seen on chest radiographs between 11 days and 314 days after initiation of radiation therapy. The incidence of radiation pneumonitis was increased according to increased ED, which was statistically significant (p=0.001). Roentgenographic charges consistent with radiation pneumonitis were seen in 100% of patients receiving radiotherapy after lobectomy or pneumonectomy, which was not statistically significant. In 32 patients who also received chemotherapy, there was no difference in the incidence of radiation induced charge between the group with radiation

  20. Radiation induced desynaptic mutants in barley

    International Nuclear Information System (INIS)

    Srivastava, H.M.

    1974-01-01

    Spontaneous occurrence of asynapsis and desynapsis has been frequently reported in a number of crop plants (Beadle 1930, 1933; Beasley and Brown 1942; Li et al. 1945; Magoon et al. 1961; Miller 1963) and other angiospermic texa (Calarier 1955; Chennaveraiah and Krisnappa 1968; Ehrenberg 1949; Johnson 1941, 1944; Roy and Jha 1958). However, there are only a few reports of induced asynapsis or desynapsis (Gottschalk and Baquar 1971; Martini and Bozzini 1966). The present paper deals with the morphology and meiotic behavior of gamma-ray induced barley mutants showing high degree of desynapsis resulting in partial to complete sterility. (author)

  1. 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

  2. Inhibition of radiation-induced polyuria by histamine receptor antagonists

    Energy Technology Data Exchange (ETDEWEB)

    Donlon, M.A.; Melia, J.A.; Helgeson, E.A.; Wolfe, W.W.

    1986-03-01

    In previous studies the authors have demonstrated that gamma radiation results in polyuria, which is preceded by polydypsia. This suggests that the increased thirst elicited by radiation causes increased urinary volume (UV). Histamine, which is released following radiation exposure, also elicits drinking by nonirradiated rats when administered exogenously. In this study the authors have investigated both the role of water deprivation and the effect of histamine receptor antagonists (HRA) on radiation-induced polyuria. Sprague-Dawley rats were housed individually in metabolic cages. Water was allowed ad libitum except in deprivation experiments where water was removed for 24 hr immediately following radiation. Cimetidine (CIM), an H2 HRA, and dexbromopheniramine (DXB), an H1 HRA, were administered i.p. (16 and 1 mg/kg, respectively) 30 min prior to irradiation (950 rads from a cobalt source). UV was determined at 24-hr intervals for 3 days preceding irradiation and 24 hr postirradiation. UV in DXB treated rats was significantly reduced 24 hr postirradiation (CON = 427 +/- 54%; DXB = 247 +/- 39% of preirradiated CON) compared to postirradiation control values. CIM did not affect postirradiation UV. These data suggest that radiation-induced polyuria is caused by polydypsia which is, in part, mediated by histamine induced by an H1 receptor.

  3. Inhibition of radiation-induced polyuria by histamine receptor antagonists

    International Nuclear Information System (INIS)

    Donlon, M.A.; Melia, J.A.; Helgeson, E.A.; Wolfe, W.W.

    1986-01-01

    In previous studies the authors have demonstrated that gamma radiation results in polyuria, which is preceded by polydypsia. This suggests that the increased thirst elicited by radiation causes increased urinary volume (UV). Histamine, which is released following radiation exposure, also elicits drinking by nonirradiated rats when administered exogenously. In this study the authors have investigated both the role of water deprivation and the effect of histamine receptor antagonists (HRA) on radiation-induced polyuria. Sprague-Dawley rats were housed individually in metabolic cages. Water was allowed ad libitum except in deprivation experiments where water was removed for 24 hr immediately following radiation. Cimetidine (CIM), an H2 HRA, and dexbromopheniramine (DXB), an H1 HRA, were administered i.p. (16 and 1 mg/kg, respectively) 30 min prior to irradiation (950 rads from a cobalt source). UV was determined at 24-hr intervals for 3 days preceding irradiation and 24 hr postirradiation. UV in DXB treated rats was significantly reduced 24 hr postirradiation (CON = 427 +/- 54%; DXB = 247 +/- 39% of preirradiated CON) compared to postirradiation control values. CIM did not affect postirradiation UV. These data suggest that radiation-induced polyuria is caused by polydypsia which is, in part, mediated by histamine induced by an H1 receptor

  4. Submandibular salivary gland transfer prevents radiation-induced xerostomia

    International Nuclear Information System (INIS)

    Jha, Naresh; Seikaly, Hadi; McGaw, Timothy; Coulter, Linda

    2000-01-01

    Background: Xerostomia is a significant morbidity of radiation therapy in the management of head and neck cancers. We hypothesized that the surgical transfer of one submandibular salivary gland to submental space, outside the proposed radiation field, prior to starting radiation treatment, would prevent xerostomia. Methods: We are conducting a prospective clinical trial where the submandibular gland is transferred as part of the surgical intervention. The patients are followed clinically, with salivary flow studies and University of Washington quality of life questionnaire. Results: We report early results of 16 patients who have undergone this procedure. Seven patients have finished and 2 patients are currently undergoing radiation treatment. In 2 patients, no postoperative radiation treatment was indicated. Two patients are waiting to start radiation treatment and 2 patients refused treatment after surgery. The surgical transfer was abandoned in 1 patient. All of the transferred salivary glands were positioned outside the proposed radiation fields and were functional. The patients did not complain of any xerostomia and developed only minimal oral mucositis. There were no surgical complications. Conclusions: Surgical transfer of a submandibular salivary gland to the submental space (outside the radiation field) preserves its function and prevents the development of radiation-induced xerostomia

  5. Radiation-induced malignant tumors of skin and their histogenesis

    International Nuclear Information System (INIS)

    Li Guomin; Chen Yunchi; Yang Yejing

    1987-01-01

    Seven cases of radiation-induced malignant tumors and 60 cases of chronic radiation damage of skin are reported. Severe hyperplasia, false epitheliomatoid hyperpiasia and atypical proliferation of epithelia and atypical proliferation of fibrohistocytes were the main changes found in chronic radiation damage of skin. The development of malignant tumors from chronic radiation damage of skin can be divided into 4 periods: necrotic and degenerative change period, benign proliferative period, atypical proliferative period and malignant change period. The incidence of hyperplastic changes of skin is related to the time elapse after irradiation and the integrated dose of radiation. The longer the duration after irradiation and the larger the integrated dose are, the higher will be the incidence of hyperplastic changes

  6. Radiological-morphological synopsis of radiation-induced lung fibrosis

    International Nuclear Information System (INIS)

    Bublitz, G.

    1977-01-01

    As delayed radiation damage after treatment of bronchial carcinoma and mamma carcinoma, fibroses occur as a reaction of the tissues. They have become a clinical-functional syndrome because of their uniform clinicaL-radiological symptomatology and pathophysiology. Pulmonary fibrosis as delayed radiation damage has a special importance with its two different radiation effects on connective tissue: a) on existing structures, b) delayed alterations of the connective tissue. As seen from experiments on lungs of men and rats, radiation-induced alterations can be measured by testing the different solubilities of the collagen types. In addition to the pathologically disordered collagen production, 9 weeks after the irradiation the radiation fibrosis leads to an isolated increase of insoluble collagen corresponding to the formation of metabolism-resistant fibrils. (MG) [de

  7. Radiation-induced cationic curing of vinyl ethers

    International Nuclear Information System (INIS)

    Lapin, S.C.

    1992-01-01

    Recently there has been an increasing interest in nonacrylate radiation-curable coatings. Vinyl ethers are particularly reactive under cationic polymerization reaction conditions. The high efficiency of the photoacid initiators combined with the high reactivity of vinyl ether monomers makes this a potentially very useful system. This chapter discusses the preparation of vinyl ethers, introduces vinyl ether-functional monomers and oligomers, describes radiation-induced cationic polymerization of vinyl ethers, and discusses various coating systems. Throughout the chapter, an emphasis is placed on radiation-curable coating applications. 64 refs., 5 figs., 11 tabs

  8. Radiation-induced life-shortening and premature aging

    International Nuclear Information System (INIS)

    Walburg, H.E. Jr.

    1975-01-01

    Data from a number of studies on irradiated laboratory animals showed that almost none of the characteristic lesions associated with senescence that were studied adequately reflects a radiation effect analogous to premature aging. In fact, most of the age-related changes showed no effect of radiation at all, and many of those that did (for example, graying of hair, sterility, cataract formation) did not appear to be due to similar mechanisms. It is concluded that, in the light of more recent information, the hypothesis of radiation-induced premature aging requires reassessment. (80 references) (CH)

  9. Mechanistic issues for modeling radiation-induced segregation

    International Nuclear Information System (INIS)

    Simonen, E.P.; Bruemmer, S.M.

    1993-03-01

    Model calculations of radiation-induced chromium depletion and radiation-induced nickel enrichment at grain boundaries are compared to measured depletions and enrichments. The model is calibrated to fit chromium depletion in commercial purity 304 stainless steel irradiated in boiling water reactor (BWR) environments. Predicted chromium depletion profiles and the dose dependence of chromium concentration at grain boundaries are in accord with measured trends. Evaluation of chromium and nickel profiles in three neutron, and two ion, irradiation environments reveal significant inconsistencies between measurements and predictions

  10. Radiation induced ionic polymerisation and grafting of vinyl monomers

    International Nuclear Information System (INIS)

    Stannett, V.T.

    1981-01-01

    Some special aspects of the radiation induced ionic polymerisation and grafting of vinyl monomers will be described. In particular the effects of solvents on the cationic polymerisation of the vinyl ethers will be discussed in detail. The unequivocal free ion nature of the polymerisation makes such information of considerable general interest. Estimates of the propagation rate constants with free cation polymerisation in solvents of different dielectric constants and solvation powers will be presented. Finally, some observations on the radiation induced graft polymerisation of ethyl vinyl ether to poly(vinyl chloride) and to polypropylene will be presented. (author)

  11. Radiation-induced osteosarcoma of the calvaria; Case report

    Energy Technology Data Exchange (ETDEWEB)

    Sugita, Yasuo; Shigemori, Minoru; Miyagi, Jun; Ochiai, Satoshi; Lee, Souichi; Watanabe, Toshinori; Abe, Hitoshi; Morimatsu, Minoru [Kurume Univ., Fukuoka (Japan). School of Medicine

    1992-01-01

    The authors report a case of radiation-induced calvarial osteosarcoma. A 58-year-old female received subtotal removal of the pituitary adenoma and 5000 rads postoperative irradiation. Seven years later, an osteoblastic osteosarcoma occurred in the frontotemporal region. She received total tumor removal and chemotherapy. However, computed tomography subsequently revealed multiple small lesions at the margin of the bone flap. A chest x-ray film demonstrated lung metastasis. Local recurrence and lung metastasis require careful attention in radiation-induced osteosarcoma patients. (author).

  12. Social impacts induced by radiation risk in Fukushima prefecture

    International Nuclear Information System (INIS)

    Murayama, Takehiko

    2011-01-01

    An accident of Fukushima Daiichi nuclear power plant induced by an earthquake of M9.0 and subsequent tsunami gave various kinds of impacts around the plant. After reviewing arguments of local governments for low dose radiation risk, this paper analyzed social impacts by the risk in terms of a gap of emergency response between national and local governments, corruption of communities in various levels induced by plural statements for risk levels in low level radiation, and economic impacts for agricultural crops made in Fukushima prefecture. Afterwards, clues for improving the situation were discussed, which include understanding of characteristics of public perception, attitudes of experts and interactive risk communication. (author)

  13. Radiation-induced void swelling in metals and alloys

    International Nuclear Information System (INIS)

    Zelinskij, V.F.; Neklyudov, I.M.; Ozhigov, L.S.; Reznichenko, Eh.A.; Rozhkov, V.V.; Chernyaeva, T.T.

    1979-01-01

    Main regularities in the development of radiation-induced void swelling are considered. Special attention is paid to consideration of a possibility to obtain information on material behaviour under conditions of reactor irradiation proceeding from the data of simulation experiments and to methods of rate control, for the processes which occur in material during irradiation and further annealing by the way of rationalized alloying, of thermomechanical treatment and programmed change of irradiation conditions under operation. Problems of initiation and growth of voids in irradiated materials are discussed as well as the ways to decrease the rate of radiation-induced void swelling

  14. The radiation induced degradation of polymers

    International Nuclear Information System (INIS)

    Wilski, H.

    1987-01-01

    A compilation was made of all data about the radiation stability of thermoplastic polymeric materials, published in the literature up to the end of 1985. From those experiments in which the irradiation was carried out in air half value doses (elongation) (= hvd) as a measure of radiation stability were extracted and compared on the basis of the chemical structure of the polymers, the chemical composition of the materials under test and the dose rate, respectively. The first result is that our knowledge of the radiation stability of polymers, if irradiated in air, is still very incomplete. On the other hand enough data were found for some polymers, to see that there is a region at low dose rates where the half value dose Dsub(e) increases with the dose rate (dD/dt) according to the equation Dsub(e)=Dsub(el).(dD/dt)sup(n). This seems to be the normal behavior. Values for the hvd at 1 Gy/h (in air) were found to lie between 1 and 500 kGy (with PTFE and PS at the respective ends of the scale), whereas n varied only between 0.1 and 0.4. The range of validity of the equation and the magnitude of the coefficients strongly depend on the chemical nature of the polymer and also on the kind and amount of the additives used. At dose rates in the neighborhood of 10 5 Gy/h the influence of the dose rate (and the atmosphere) disappears. (author)

  15. 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

  16. 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.

  17. Radiation induced effects in the developing central nervous system

    International Nuclear Information System (INIS)

    Gisone, P.; Dubner, D.; Michelin, S.C.; Perez, M.R. Del

    1997-01-01

    The embryo and the human foetus are particularly sensitive to ionizing radiation and this sensitivity presents various qualitative and quantitative functional changes during intra-uterine development. Apart from radiation induced carcinogenesis, the most serious consequence of prenatal exposure in human beings is severe mental retardation. The principal data on radiation effects on human beings in the development of the central nervous system come form epidemiological studies carried out in individuals exposed in utero during the atomic explosion at Hiroshima and Nagasaki. These observations demonstrate the existence of a time of maximum radiosensitivity between the weeks 8 and 15 of the gestational period, a period in which the proliferation and neuronal migration takes place. Determination of the characteristics of dose-response relationship and the possible existence of a threshold dose of radiation effects on the development of the central nervous system is relevant to radiation protection against low dose radiation and the establishment of dose limits for occupational exposure and the public. Studies were conducted on the generation of nitrous-oxide and its relation with the production of active species of oxygen in brains of exposed rats in utero exposed to doses of up to 1 Gy during their maximum radiosensitivity. The possible role of the mechanism of radiation induced damage in the development of the central nervous system is discussed

  18. The effects of cysteamine on the radiation-induced apoptosis

    International Nuclear Information System (INIS)

    Choi, Young Min; Cho, Heung Lae; Park, Chang Gyo; Lee, Hyung Sik; Hur, Won Joo

    2000-01-01

    To investigate the pathways of radiation induced apoptosis and the effect of cysteamine (β-mercaptoethylamine), as a radioprotector, on it. HL-60 cells were assigned to control, irradiated, and cysteamine (1 mM, 10 mM) pretreated groups. Irradiation was given in a single fraction of 10 Gy (6 MV x-ray) and cysteamine was administered 1 hour before irradiation. The activities of caspase-8 were measured in control and irradiated group to evaiuate its relation to the radiation induced apoptosis. To evaluate the role of cysteamine in radiation induced apoptosis, the number of viable cells, the expression and activity or caspase-3, and the expression of poly (ADP-ribose) polymerase (PARP) were measured and compared after irradiating the HL cells with cysteamine pretreatment or not. The intracellular caspase-8 activity, known to be related to the death receptor induced apoptosis, was not affected by irradiation( p>0.05). The number of viable cells began to decrease from 6 hours after irradiation (p>0.05), but the number of viable cells in 1 mM cysteamine pretreated group was not decreased after irradiation and was similar to those in the control group. In caspase-3 analyses, known as apoptosis executioner, its expression was not different but its activity was increased by irradialion(p>0.05). However, this increase of activity was suppressed by the pretreatment of 1 mM cysteamine. The cleavage of PARP, thought to be resulted from caspase-3 activation, occurred, after irradiation, which was attenuated by the pretreatment of 1 mM cysteamine. These results show that radiation induced apoptotic process is somewhat different from death receptor induced one and the pretreatment of 1 mM cysteamine has a tendency to decrease the radiation-induced apoptosis in HL-60 cells

  19. Radiation-induced anorexia in Syrian hamsters

    International Nuclear Information System (INIS)

    Kindt, A.; Sattler, E.L.; Schraub, A.

    1980-01-01

    The recovery of Syrian hamsters after split dose application (interval 11 days) was studied on the basis of the weight response and of food uptake. Two periods of weight loss and anorexia can be distinguished, an early one immediately after irradiation and a secondary one 6-10 days later. The secondary response is a function of the radiation dose and allows to distinguish survivors from non-survivors, since it is much more pronounced and longerlasting in the latter than in the former. The first response appears not to be influenced by a previous conditioning irradiation. (orig.) [de

  20. Radiation-induced corrosion of stellite-6

    International Nuclear Information System (INIS)

    Behazin, M.; Wren, J.C.

    2012-09-01

    Stellite-6 is a Co-based (58%) alloy that is used for components that require high wear-resistance, such as valve facings and ball bearings in nuclear reactors. In the reactor core, stable 59 Co can be neutron activated by absorption of a neutron to become the radioactive isotope, 60 Co. The 60 Co that is created constitutes a safety hazard for plant workers who have to perform maintenance on the reactor. One of the operational and safety issues in a nuclear reactor is the potential corrosion of Co-based alloys and the introduction of dissolved Co ions into the reactor core. While the corrosion of Stellite-6 has been studied its corrosion behaviour with ionizing radiation present has not been well established. Corrosion kinetics depend on both the aqueous redox conditions and the physical and chemical nature of the alloy surface. The high radiation fields present in a reactor core will cause water to decompose to a range of redox-active species (both highly oxidizing (e.g., ·OH, H 2 O 2 ) and highly reducing (e.g., ·eaq - , ·O 2 - )). These species can significantly influence corrosion kinetics. The effect of γ-radiation on the corrosion of Stellite-6 at pH 10.6 was investigated at temperatures ≤ 150 deg. C. Since the corrosion rate depends strongly on the type of oxide that is present on the material surface, the focus of this corrosion study was to establish the mechanism by which radiolysis affects the nature of the oxide that is present on Stellite-6. The results show that γ-radiation (at a dose rate of 5.5 kGy.h -1 ) increases the corrosion potential on Stellite-6 from -0.7 VSCE to 0.12 VSCE . The corrosion potential without irradiation present is in a potential range where oxidation is limited to the formation of a Co (OH) 2 and CoCr 2 O 4 outer oxide layer on a pre-existing Cr 2 O 3 film. The corrosion potential with irradiation is in a potential range where further oxidation of Co (OH) 2 to CoOOH also occurs. However, since CoOOH is less soluble than

  1. Radiation-induced anorexia in Syrian hamsters

    Energy Technology Data Exchange (ETDEWEB)

    Kindt, A.; Sattler, E.L.; Schraub, A.

    1980-10-01

    The recovery of Syrian hamsters after split dose application (interval 11 days) was studied on the basis of the weight response and of food uptake. Two periods of weight loss and anorexia can be distinguished, an early one immediately after irradiation and a secondary one 6-10 days later. The secondary response is a function of the radiation dose and allows to distinguish survivors from non-survivors, since it is much more pronounced and longerlasting in the latter than in the former. The first response appears not to be influenced by a previous conditioning irradiation.

  2. Radiation induced oxidation for water remediation

    International Nuclear Information System (INIS)

    Gehringer, P.

    1997-01-01

    The action of ionizing radiation on halogenated hydrocarbons, in the presence and absence of ozone, was studied in water and wastewater. The combined ozone/electron-beam irradiation process was found especially suited for remediation of low-level contaminated groundwater. This combined treatment was often more effective than irradiation alone for wastewater decontamination. It reduced the COD without a simultaneous increase of BOD. Introduction of gaseous ozone directly into the irradiation chamber improved the water-flow turbulence, allowing treatment in layers thicker than the penetration range of the electrons, with increased decontamination efficiency. (author)

  3. Contribution of radiation-induced, nitric oxide-mediated bystander effect to radiation-induced adaptive response.

    Science.gov (United States)

    Matsumoto, H.; Ohnishi, T.

    There has been a recent upsurge of interest in radiation-induced adaptive response and bystander effect which are specific modes in stress response to low-dose low-dose rate radiation Recently we found that the accumulation of inducible nitric oxide NO synthase iNOS in wt p53 cells was induced by chronic irradiation with gamma rays followed by acute irradiation with X-rays but not by each one resulting in an increase in nitrite concentrations of medium It is suggested that the accumulation of iNOS may be due to the depression of acute irradiation-induced p53 functions by pre-chronic irradiation In addition we found that the radiosensitivity of wt p53 cells against acute irradiation with X-rays was reduced after chronic irradiation with gamma rays This reduction of radiosensitivity of wt p53 cells was nearly completely suppressed by the addition of NO scavenger carboxy-PTIO to the medium This reduction of radiosensitivity of wt p53 cells is just radiation-induced adaptive response suggesting that NO-mediated bystander effect may considerably contribute to adaptive response induced by radiation

  4. Radiation-Induced Esophagitis is Mitigated by Soy Isoflavones

    Directory of Open Access Journals (Sweden)

    Matthew D Fountain

    2016-11-01

    Full Text Available Introduction: Lung cancer patients receiving radiotherapy present with acute esophagitis and chronic fibrosis, as a result of radiation injury to esophageal tissues. We have shown that soy isoflavones alleviate pneumonitis and fibrosis caused by radiation toxicity to normal lung. The effect of soy isoflavones on esophagitis histopathological changes induced by radiation was investigated. Methods: C57BL/6 mice were treated with 10 Gy or 25 Gy single thoracic irradiation and soy isoflavones for up to 16 weeks. Damage to esophageal tissues was assessed by H&E, Masson’s Trichrome and Ki-67 staining at 1, 4, 10, 16 weeks after radiation. The effects on smooth muscle cells and leukocyte infiltration were determined by immunohistochemistry using anti-αSMA and anti-CD45 respectively. Results: Radiation caused thickening of esophageal tissue layers that was significantly reduced by soy isoflavones. Major radiation alterations included hypertrophy of basal cells in mucosal epithelium and damage to smooth muscle cells in muscularis mucosae as well as disruption of collagen fibers in lamina propria connective tissue with leukocyte infiltration. These effects were observed as early as one week after radiation and were more pronounced with a higher dose of 25 Gy. Soy isoflavones limited the extent of tissue damage induced by radiation both at 10 and 25 Gy.Conclusions: Soy isoflavones have a radioprotective effect on the esophagus, mitigating the early and late effects of radiation injury in several esophagus tissue layers. Soy could be administered with radiotherapy to decrease the incidence and severity of esophagitis in lung cancer patients receiving thoracic radiation therapy.

  5. Effect of salidroside on radiation-induced bone marrow adipogenesis

    International Nuclear Information System (INIS)

    Zhu Jincan; Chen Xiaoyu; Liu Chengcheng; Zhu Aizhen; Liu Shantao; Liu Gexiu

    2014-01-01

    Objective: To investigate the potential and underlying molecular mechanism of salidroside in ameliorating radiation-induced bone marrow adipogenesis and stimulating hematopoiesis. Methods: The female BALB/c mice aged 6-7 weeks were randomly divided into normal control group, radiation group and salidroside group. The radiation group and salidroside group were irradiated with 6.0 Gy of "6"0Co γ-rays. The salidroside group was intraperitoneally injected with 30 mg·kg"-"1·d"-"1 salidroside at 12 h and then every day until 8th d after radiation. The normal control group and radiation group were treated with equal volume of saline as control of salidroside. At 14 d after radiation, the mice weight, peripheral blood count, femur bone marrow histology, and the proportion of adipocyte area were measured, and the expressions of PPAR-γ and FABP4 were detected by q-PCR. Results: After irradiation, the numbers of white blood cells, hemoglobin and platelet in peripheral blood were reduced obviously, and the percentage of adipocyte area was increased significantly. Compared with mice in the radiation group, salidroside inhibited adipogenesis and reduced the proportion of adipocyte area (t = 13.31, P < 0.05) by reducing the expressions of PPAR-γ and FABP4 (t = 8.64, 13.19, P < 0.05). The number of white blood cells was partly recovered at 7 d after irradiation (t = 5.80, P < 0.05). Both white blood cells and hemoglobinin in peripheral blood of the salidroside group were higher than those in the radiation group at 14 d after irradiation. Conclusions: Salidroside could inhibit radiation-induced bone marrow adipogenesis and regulate bone marrow microenvironment, thereby promotes hematopoietic recovery in mice after radiation injury. (authors)

  6. Radiation-induced apoptosis in F9 teratocarcinoma cells

    International Nuclear Information System (INIS)

    Langley, R.E.; Palayoor, S.T.; Coleman, C.N.; Bump, E.A.

    1994-01-01

    We have found that F9 murine teratocarcinoma cells undergo morphological changes and internucleosomal DNA fragmentation characteristic of apoptosis after exposure to ionizing radiation. We studied the time course, radiation dose-response, and the effects of protein and RNA synthesis inhibitors on this process. The response is dose dependent in the range 2-12 Gy. Internucleosomal DNA fragmentation can be detected as early as 6 h postirradiation and is maximal by 48 h. Cycloheximide, a protein synthesis inhibitor, and 5,6-dichloro-1-β-D-ribofuranosylbenzimidazole, an RNA synthesis inhibitor, both induced internucleosomal DNA fragmentation in the unirradiated cells and enhanced radiation-induced DNA fragmentation. F9 cells can be induced to differentiate into cells resembling endoderm with retinoic acid. After irradiation, differentiated F9 cells exhibit less DNA fragmentation than stem cells. This indicates that ionizing radiation can induce apoptosis in non-lymphoid tumours. We suggest that embryonic tumour cells may be particularly susceptible to agents that induce apoptosis. (Author)

  7. Radiation-induced apoptosis in F9 teratocarcinoma cells

    Energy Technology Data Exchange (ETDEWEB)

    Langley, R E; Palayoor, S T; Coleman, C N; Bump, E A [Joint Center for Radiation Therapy and Dana Farber Cancer Inst., Boston (United States)

    1994-05-01

    We have found that F9 murine teratocarcinoma cells undergo morphological changes and internucleosomal DNA fragmentation characteristic of apoptosis after exposure to ionizing radiation. We studied the time course, radiation dose-response, and the effects of protein and RNA synthesis inhibitors on this process. The response is dose dependent in the range 2-12 Gy. Internucleosomal DNA fragmentation can be detected as early as 6 h postirradiation and is maximal by 48 h. Cycloheximide, a protein synthesis inhibitor, and 5,6-dichloro-1-[beta]-D-ribofuranosylbenzimidazole, an RNA synthesis inhibitor, both induced internucleosomal DNA fragmentation in the unirradiated cells and enhanced radiation-induced DNA fragmentation. F9 cells can be induced to differentiate into cells resembling endoderm with retinoic acid. After irradiation, differentiated F9 cells exhibit less DNA fragmentation than stem cells. This indicates that ionizing radiation can induce apoptosis in non-lymphoid tumours. We suggest that embryonic tumour cells may be particularly susceptible to agents that induce apoptosis. (Author).

  8. Molecular analysis of radiation-induced experimental tumors in mice

    International Nuclear Information System (INIS)

    Niwa, O.; Muto, M.; Suzuki, F.

    1992-01-01

    Molecular analysis was made on mouse tumors induced by radiation and chemicals. Expression of oncogenes was studied in 12 types of 178 mouse tumors. Southern blotting was done on tumors in which overexpression of oncogenes was noted. Amplification of the myc oncogene was found in chemically induced sarcomas, but not those induced by radiations. Radiogenic thymomas were studied in detail. These thymomas were induced in two different ways. The first was thymomas induced by direct irradiation of F1 mice between C57BL/6NxC3H/He. Southern analysis of DNA revealed deletion of specific minisatellite bands in these tumors. DNA from directly induced thymomas induced focus formation when transfected into normal Golden hamster cells. The mouse K-ras oncogene was detected in these transformants. The second type of thymomas was induced by X-irradiation of thymectomized B10.thy1.2 mice in which normal thymus from congenic B10,thy1.1. mice was grafted. Thymomas of the donor origin was analysed by transfection and the transformants by DNA from those indirectly induced thymomas did not contain activated ras oncogenes. (author)

  9. Radiation-induced endometriosis in Macaca mulatta

    International Nuclear Information System (INIS)

    Fanton, J.W.; Golden, J.G.

    1991-01-01

    Female rhesus monkeys received whole-body doses of ionizing radiation in the form of single-energy protons, mixed-energy protons, X rays, and electrons. Endometriosis developed in 53% of the monkeys during a 17-year period after exposure. Incidence rates for endometriosis related to radiation type were: single-energy protons, 54%; mixed-energy protons, 73%; X rays, 71%; and electrons, 57%. The incidence of endometriosis in nonirradiated control monkeys was 26%. Monkeys exposed to single-energy protons, mixed-energy protons, and X rays developed endometriosis at a significantly higher rate than control monkeys (chi 2, P less than 0.05). Severity of endometriosis was staged as massive, moderate, and minimal. The incidence of these stages were 65, 16, and 19%, respectively. Observations of clinical disease included weight loss in 43% of the monkeys, anorexia in 35%, space-occupying masses detected by abdominal palpation in 55%, abnormal ovarian/uterine anatomy on rectal examination in 89%, and radiographic evidence of abdominal masses in 38%. Pathological lesions were endometrial cyst formation in 69% of the monkeys, adhesions of the colon in 66%, urinary bladder in 50%, ovaries in 86%, and ureters in 44%, focal nodules of endometrial tissue throughout the omentum in 59%, and metastasis in 9%. Clinical management of endometriosis consisted of debulking surgery and bilateral salpingo-oophorectomy combined in some cases with total abdominal hysterectomy. Postoperative survival rates at 1 and 5 years for monkeys recovering from surgery were 48 and 36%, respectively

  10. Radiation-induced malignant tumours: a specific cytogenetic profile?

    International Nuclear Information System (INIS)

    Chauveinc, L.; Gaboriaux, G.; Dutrillaux, A. M.; Dutrillaux, B.; Chauveinc, L.; Ricoul, M.; Sabatier, L.; Dutrillaux, B.

    1997-01-01

    To date, there is no criterion enabling to determine the spontaneous or radio-induced origin of malignant tumour occurring in a previously irradiated patient. Biological studies are rare. The cytogenetic data which could be found in the literature for eleven radio-induced tumours suggest that aneuploidies and polyclonality are frequent events. We studied, by R-Banding cytogenetic technique, five patients with short-term cultures (3 cases), short and long-term cultures (1 case) and xeno-grafting on nude pattern a high rate of balanced translocations, numerous random break points and a polyclonal evolution (10 clones). All other tumours, including the xeno-grafting sarcoma, had a monoclonal profile with complex karyotypes, hypo-diploid formulas and many deletions. These results show that the mechanism of radiation-induced tumours frequently involves chromosomes losses and deletions. The most likely explanation is that these alterations unmask radiation induced recessive mutations of tumour suppressor genes. (authors)

  11. Radiation induced degradation of DNA in photodynamic therapy of cancer

    International Nuclear Information System (INIS)

    Ion, Rodica; Scarlat, F.; Niculescu, V.I.R.; Scarlat, Fl.; Gunaydin, Keriman

    2001-01-01

    DNA is a critical cellular target for oxidative processes induced by physical and chemical stresses. It is known that the direct effect of ionizing radiation on DNA results mainly in base ionization and may lead to mutation, carcinogenesis and cell death. The degradation of DNA induced by laser and ionizing radiation (electron and photon beam) is analyzed in this paper. The ionizing radiation degradation of DNA is a radical process. A series of lesions among the major base degradation product has been measured in isolated DNA exposed to gamma radiation in aerated aqueous solution. Degradation can be accounted for by the formation of hydroxyl radicals upon radiolysis of water (indirect effect). The production of DNA damage by ionizing radiation involves two mechanisms, direct and indirect effects. Direct effect leads to ionization and excitation of DNA molecules, while indirect effect is due to the interaction of reactive species, in particular of OH radicals produced by water radiolysis, with targets in DNA. The relative contribution of the two mechanisms in damaging DNA depends on the type of radiation. Single strand breaks and base damage seem to be mainly produced by the attack of hydroxyl radicals on DNA, whereas double strand breaks result predominantly of direct energy deposition. The four bases are degraded in high yield. Direct effect has been mimicked by photo-induced electron abstraction from the bases producing their radical cation. The base damage may also occur from the formation of radical cation of purine and pyrimidine components. When DNA is irradiated in solution, single strand breaks are mainly due to the abstraction of an H atom from the 4 ' position of 2 ' -deoxyribose by the attack of OH radicals produced by water radiolysis. Quantification of the modified bases showed the guanine is the preferential target. Ionizing radiation induces several types of DNA modifications, including chain breaks, DNA-protein cross-links, oxidized DNA bases

  12. Study of radiation induced structural changes in nitrile rubber

    International Nuclear Information System (INIS)

    Cardona, F.; Hill, D.J.T.; Pomery, P.J.; Whittaker, A.K.

    1996-01-01

    Full text: Copolymers of butadiene (BD) and acrylonitrile (AN) (NBR rubber), have become important commercial material. NBR rubbers are part of a larger classification of products often referred to as special-purpose rubbers. Oil resistance is the most important property of nitrile rubbers, and refer to the ability of the vulcanised product to retain its original physical properties such as modulus, tensile strength, abrasion resistance and dimensions, while in contact with oils and fuels. Despite these reported advantages very few studies have been conducted on the radiation yields and structural changes in nitrile rubbers during exposure to high energy radiation. In this study we are investigating the stability against gamma and UV radiation, to different doses in vacuum, of butadiene, acrylonitrile and NBR copolymers with different composition ratio BD/AN. The mechanism of radiation induced structural changes is being investigated using experimental techniques such as ESR, NMR (Solid-state), FT-IR, RAMAN and UV spectroscopy. Also is being investigated the effect of irradiation on the mechanical properties of stressed and unstressed samples by TGA, DSC, DMA, Instron and Creep Test measurements. So far the main effect have been a marked radiation-induced loss of unsaturation in the butadiene units, cis to trans isomerization and formation of crosslink structures (intermolecular and intramolecular). One of the main challenges in the studies of NBR polymers is to observe directly the crosslinks produces by the radiation induced chemical reactions. IR spectroscopy is unsuitable because of the low molar absorbity of the peaks related to intermolecular crosslinking and the overlapping of the peaks (1630-1670 cm-1) related to intramolecular crosslinking (cyclization), with conjugated and nonconjugated (-C=C-; -C=N-) double bonds. A. K. Whittaker has shown that crosslink structures in PBD can be detected and measured directly using solid-state 13 C NMR. This technique

  13. [The occupational radiation-induced cataract in five industrial radiographers].

    Science.gov (United States)

    Benzarti Mezni, A; Loukil, I; Hriz, N; Kallel, K; Mlaiki, N; Ben Jemaâ, A

    2012-04-01

    The industrial uses of ionizing radiation in Tunisia are expanding, especially in industry and most particularly in the nondestructive testing of welds. Thus workers operating in the non-destructive testing of welds may develop a radiation-induced cataract varying in time to onset depending on the dose. To describe the characteristics of the radiation-induced cataract in patients exposed to ionizing radiation, determine the risk factors of radiation-induced cataracts. This was an anamnestic, clinical, and environmental study of five cases of radiation-induced cataract in workers employed in non-destructive testing of welds. This series of five cases had a mean age of 30.2 years and 5.53 years of work experience, ranging from 14 months to 15 years. All the patients were male and industrial radiographers specialized in nondestructive testing of welds. The average duration of exposure to ionizing radiation was 5.53 years. None of the patients had worn protective gear such as eye goggles. The ophthalmic check-up for the five special industrial radiographers showed punctuate opacities in three cases, punctiform opacities in one eye in one case, and phacosclerosis with bilateral lens multiple crystalline stromal opacities in a case of micro-lens opacities in both eyes with opalescence of both eyes in one case. These cataracts had been declared as occupational diseases. The value of a specialized ophthalmologic surveillance among these workers and the early diagnosis of lens opacities must be emphasized. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

  14. Radiation-induced genetic effects in germ cells of mammals

    International Nuclear Information System (INIS)

    Van Buul, P.P.W.

    1993-01-01

    The aim of the project is to gain information on the effects of ionizing radiation on germ cells of rodents and primates as measured by induced chromosomal translocations. Different aspects of the very significant interspecies differences between the mouse and the rhesus monkey (Macaca mulatta) for translocation induction in spermatogonial stem cells were studied. In addition, possible mechanisms for the well established reduced transmission of induced mouse translocations were investigated. (R.P.) 6 refs

  15. Radiation-induced cancers of the head and neck, (3)

    International Nuclear Information System (INIS)

    Umatani, Katsunori; Satoh, Takeo; Yoshino, Kunitoshi; Takagi, Tadashi; Fujii, Takashi; Hatta, Chihiro; Maetani, Chikahide; Lu, Bo

    1989-01-01

    This paper discusses twenty patients with radiation-induced cancers of the head and neck treated in the Department of Otorhinolaryngology, the Center for Adult Diseases, Osaka, from January 1979 to December 1985. The most common site of radiation-induced cancers was the hypopharynx and cervical esophagus (70%). We found synchronous double cancers in 2 out of the 20 patients (10%). One patient had hypopharyngeal cancer and thyroid cancer, and the other had oropharyngeal cancer and thyroid cancer. All of the laryngeal cancers were in the supraglottic area. Cancer of the hypopharynx and cervical esophagus occurred more frequently in females (1:3.7 males-females ratio). Half of the patients (10/20) had received irradiation for tuberculous cervical adenitis and 8 patients had been irradiated for malignant tumors. The averaged latent period in the patients who had irradiated for benign conditions was 37.4 years, and that for malignant diseases was 16.0 years. Therefore the latent period of the former was 2.3 times as long as that of the latter. The incidence of radiation-induced cancers in all the patients who had the cancer of the hypopharynx and cervical esophagus was 9% and that of the laryngeal cancer was 0.7%. The incidence of radiation-induced cancers in the hypopharynx and cervical esophagus remarkably differed from that in the larynx. However, it was suggested that the larynx was as resistant to radiation induction as the hypopharynx. Six of the 20 patients (30%) had radiation-induced thyroid tumors. Among them, the incidence of cancers was 33%. (author)

  16. Mechanisms of radiation induced creep and growth

    International Nuclear Information System (INIS)

    Bullough, R.; Wood, M.H.

    1980-01-01

    Irradiation creep occurs primarily because the applied stress causes the evolving microstructure to respond in an anisotropic fashion to the interstitial and vacancy fluxes. On the other hand, irradiation growth requires the response to be naturally anisotropic in the absence of applied stress. Four fundamental mechanisms of irradiation creep have been conjectured: stress induced preferred absorption (SIPA) of the point defects on the dislocations, stress induced preferred nucleation (SIPN) of point defects in planar aggregates (edge dislocation loops), stress induced climb and glide (SICG) of the dislocation network and stress induced gas driven interstitial deposition (SIGD). These mechanisms will be briefly outlined and commented upon. The contributions made by these mechanisms to the total strain are not, in general, mutually separable and also depend on the prevailing (and changing) microstructure during irradiation. The fundamental mechanism of irradiation growth will be discussed: it is believed to arise by the preferred condensation of point defects and climb of dislocation loops and network on certain crystallographic planes. The preferred absorption and nucleation is thus a consequence of natural crystallographic anisotropy and not due to any external stresses. Again the effectiveness of this mechanism depends on the prevailing microstructure in the material. In this connection will be particularly drawn to the significance of solute trapping, segregation at grain boundaries, dislocation bias for interstitials and transport parameters for an understanding of irradiation growth in materials like zirconium and its alloys; the relevance of recent simulation studies of growth in such materials using electrons to the growth under neutron irradiation will be discussed in detail and a consistent model of growth in these materials will be presented. (orig.)

  17. Radiation-induced camptocormia and dropped head syndrome. Review and case report of radiation-induced movement disorders

    Energy Technology Data Exchange (ETDEWEB)

    Seidel, Clemens; Kuhnt, Thomas; Kortmann, Rolf-Dieter; Hering, Kathrin [Leipzig University, Department of Radiotherapy and Radiation Oncology, Leipzig (Germany)

    2015-10-15

    In recent years, camptocormia and dropped head syndrome (DHS) have gained attention as particular forms of movement disorders. Camptocormia presents with involuntary forward flexion of the thoracolumbar spine that typically increases during walking or standing and may severely impede walking ability. DHS is characterized by weakness of the neck extensors and a consecutive inability to extend the neck; in severe cases the head is fixed in a ''chin to chest position.'' Many diseases may underlie these conditions, and there have been some reports about radiation-induced camptocormia and DHS. A PubMed search with the keywords ''camptocormia,'' ''dropped head syndrome,'' ''radiation-induced myopathy,'' ''radiation-induced neuropathy,'' and ''radiation-induced movement disorder'' was carried out to better characterize radiation-induced movement disorders and the radiation techniques involved. In addition, the case of a patient developing camptocormia 23 years after radiation therapy of a non-Hodgkin's lymphoma of the abdomen is described. In total, nine case series of radiation-induced DHS (n = 45 patients) and - including our case - three case reports (n = 3 patients) about radiogenic camptocormia were retrieved. Most cases (40/45 patients) occurred less than 15 years after radiotherapy involving extended fields for Hodgkin's disease. The use of wide radiation fields including many spinal segments with paraspinal muscles may lead to radiation-induced movement disorders. If paraspinal muscles and the thoracolumbar spine are involved, the clinical presentation can be that of camptocormia. DHS may result if there is involvement of the cervical spine. To prevent these disorders, sparing of the spine and paraspinal muscles is desirable. (orig.) [German] In den letzten Jahren haben Bewegungsstoerungen von Wirbelsaeule und paraspinaler Muskulatur in

  18. Radiation-induced aftertreatment of textiles

    International Nuclear Information System (INIS)

    Okada, Toshio

    1978-01-01

    Techniques to improve the properties of textiles by graft polymerization of acrylic acid, metacrylic acid, etc. on natural and synthetic fibers by irradiation of electron beam or γ ray were developed and put into practical use. Such graft polymerization by irradiation is effective technique to give synthetic fibers hydrophilic property, heat-shrinkage resistance, dye affinity, static electricity prevention, combustion resistance, etc.. Irradiation is also applied for adhesion of nonwoven fabric, coating processing of textiles, and printing processing of fabrics. Thus, the processing of textiles by radiation, especially electron beam, is effective to give new properties to textiles, but its importance has been also recognized as energy saving and public nuisance-avoiding processes. A great deal of energy reduction can be expected by electron beam irradiation method. (Kobatake, H.)

  19. Degradation of polycarbonate induced by gamma radiation

    International Nuclear Information System (INIS)

    Araujo, E.S. de; Guedes, S.M.L.

    1992-01-01

    Polycarbonate (PC) DUROLON amorphous, of molecular weight 22000 g/mol is used in medical supplies and may be sterilized by gamma radiation. The main chain scission and polymer degradation occur when this polymer is irradiated. The value G = 1.54 to DUROLON was obtained by equation: 10 6 /M v = 10 6 /M v' + 0.054 G R. The degradation without crosslinking it is not general rule to all types of polycarbonates; an comparison was realized. The infrared (FT-IR) spectra of irradiated PC by gamma rays with different doses showed the main chain scissions in carbonyl groups. The mechanism of polymeric degradation to DUROLON, observed by NMR spectra, is a recombination of phenoxy and phenyl radicals. (author)

  20. Radiation induced processes in moss cells

    International Nuclear Information System (INIS)

    Doehren, R. v.

    1975-01-01

    The moss F.h. shows apical growth in the protonema cells which spread radially from the spor. Every apical daughter cell during the state of 'Caulonema' and just before in the state of 'Caulonema Primanen' initiates cell division as soon as more than twice the length of the mother cell is reached. All this allows to follow radiation effects in single cells conveniently. UV irradiation on the range of 254 nm and 280 nm delivered at different parts of the cell area delays cell division markedly may suppress it, and is able to stop the process of growing in relation to the delivered dose and to the irradiated area as well. In case of irradiation of the area next to where the membrane is just being formed - that is to say next to the phragmoplast - the new membrane will be wrongly oriented. In particular giant cells are occurring in the case of nucleus irradiation during early prophase. (orig./GSE) [de

  1. Radiation-induced degassing of cryopumps

    International Nuclear Information System (INIS)

    Graham, W.G.; Ruby, L.

    1978-06-01

    The pressure-gauge response of the system to the TRIGA pulses is shown. With an unloaded cryopump, an apparent pressure pulse is produced which is only slightly longer than the reactor pulse itself. In separate experiments, it was found that a similarly appearing pulse is produced by a completely sealed-off vacuum gauge. With a deuterium-loaded cryopump, a very much larger pressure pulse was produced, which had a long exponential tail, characteristic of a re-pumpdown of the system. The pumping speed, as computed from the exponential, is about half that observed previously when the cryopump was subjected to D 2 -gas pulses, in the absense of radiation. Additional experiments were run with the core of the reactor retracted somewhat into the pool, in order to change the mix of gamma rays, thermal neutrons, and fast neutrons so as to preferentially depress the latter

  2. Radiation-induced polymerization of hydrogen cyanide

    International Nuclear Information System (INIS)

    Mozhaev, P.S.; Kichigina, G.A.; Kiryukhin, D.P.

    1995-01-01

    The chain reaction of HCN polymerization in a γ-radiation field does not occur at 77 K. When irradiated HCN is warmed up to ambient temperature, a polymer is formed. The heat of polymerization of HCN is 44.0±6.0 kJ/mol and the polymer yield reaches 2.5% for a dose of 725 kGy. Amorphous polymer products (with yields increasing up to 33.5%) and needle crystals (presumably HCN tetramer) are formed upon storage of irradiated HCN at room temperature. The polymer is stable below 700 K, has a conductivity of 3x10 -5 Ω -1 cm -f1 , and displays an EPR spectrum typical of polyconjugated systems. A radical mechanism of the formation of conjugated chain -C=N-C=N- is suggested. The tetramer is produced by a combination of aminocyanocarbene biradicals

  3. 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

  4. Stimulation of respiration in rat thymocytes induced by ionizing radiation

    International Nuclear Information System (INIS)

    Gudz, T.I.; Pandelova, I.G.; Novgorodov, S.A.

    1994-01-01

    The effect of X irradiation on the respiration of rat thymocytes was studied. An increase in the rate of O 2 uptake was observed 1 h after cells were irradiated with doses of 6-10 Gy. The radiation-induced increase in respiration could be blocked by oligomycin, an inhibitor of mitochondrial ATP synthase, suggesting control by increased cytoplasmic ATP turnover. The stimulation of respiration was not associated with changes in the activity of mitochondrial electron transfer enzymes or permeability of the inner membrane. Several inhibitors of processes which used ATP were screened for their effects on the basal respiration rate and on the radiation response. In irradiated thymocytes, an enhancement of inhibition of respiration by ouabain, La 3+ and cycloheximide was observed. These results indicate that the radiation-induced stimulation of respiration is due to changes in ion homeostasis and protein synthesis. The effect of X irradiation was shown to be independent of the redox status of nonprotein thiols and was not associated with detectable changes in some products of lipid peroxidation. The radiation-induced decrease in activity of superoxide dismutase suggests free radical involvement in deleterious effects of radiation. 43 refs., 2 figs., 3 tabs

  5. Radiation induced chlorophyll mutations in rice

    International Nuclear Information System (INIS)

    Bari, G.; Mustafa, G.; Soomro, A.M.; Baloch, A.W.

    1985-01-01

    Air dried grains of four local varieties of rice were treated with gamma-rays and fast neutrons for determining their mutagenic effectiveness through the occurence of chlorophyll mutations. Fast neutrons were more effective in inducing chlorophyll mutations and the rice variety Basmati 370 produced maximum number of mutations followed by varieties Sonahri Sugdasi, Jajai 77 and Sada Gulab. The highest frequency of chlorophyll mutations was that of albina types followed by striata types. The xantha, viridis and tigrina types of mutations were less frequent. (authors)

  6. Radiation induced lipid oxidation in fish

    International Nuclear Information System (INIS)

    Snauwaert, F.; Tobback, P.; Maes, E.; Thyssen, J.

    1977-01-01

    Oxidative rancidity in herring and redfish was studied as a function of the applied irradiation dose, the storage time and storage temperature and the packaging conditions. - Measurements of the TBA (thiobarbituric acid) value and the peroxide value were used to evaluate the degree of oxidation of lipids, and were related with sensory scores. - Especially for the fatty fish species (herring) irradiation accelerated lipid oxidation and induced oxidative rancidity. Irradiation of vacuum-packed herring fillets and subsequent storage at +2 C seems to be an interesting process. For the experiments conducted on a semi-fatty fish (redfish), oxidative rancidity was never the limiting factor for organoleptic acceptability. (orig.) [de

  7. Radiation-Induced Bystander Response: Mechanism and Clinical Implications

    Science.gov (United States)

    Suzuki, Keiji; Yamashita, Shunichi

    2014-01-01

    Significance: Absorption of energy from ionizing radiation (IR) to the genetic material in the cell gives rise to damage to DNA in a dose-dependent manner. There are two types of DNA damage; by a high dose (causing acute or deterministic effects) and by a low dose (related to chronic or stochastic effects), both of which induce different health effects. Among radiation effects, acute cutaneous radiation syndrome results from cell killing as a consequence of high-dose exposure. Recent advances: Recent advances in radiation biology and oncology have demonstrated that bystander effects, which are emerged in cells that have never been exposed, but neighboring irradiated cells, are also involved in radiation effects. Bystander effects are now recognized as an indispensable component of tissue response related to deleterious effects of IR. Critical issues: Evidence has indicated that nonapoptotic premature senescence is commonly observed in various tissues and organs. Senesced cells were found to secrete various proteins, including cytokines, chemokines, and growth factors, most of which are equivalent to those identified as bystander factors. Secreted factors could trigger cell proliferation, angiogenesis, cell migration, inflammatory response, etc., which provide a tissue microenvironment assisting tissue repair and remodeling. Future directions: Understandings of the mechanisms and physiological relevance of radiation-induced bystander effects are quite essential for the beneficial control of wound healing and care. Further studies should extend our knowledge of the mechanisms of bystander effects and mode of cell death in response to IR. PMID:24761341

  8. Neurolysis and myocutaneous flap for radiation induced brachial plexus neuropathy

    International Nuclear Information System (INIS)

    Hirachi, Kazuhiko; Minami, Akio; Kato, Hiroyuki; Nishio, Yasuhiko; Ohnishi, Nobuki

    1998-01-01

    Surgical treatment for radiation induced brachial plexus neuropathy is difficult. We followed 9 patients of radiation induced brachial plexus neuropathy who were surgically treated with neurolysis and myocutaneous flap coverage. Their ages ranged from 29 to 72 years old. Their diagnoses were breast cancer in 6 patients, lingual cancer in 1, thyroid cancer in 1 and malignant lymphoma in 1. Total dose of radiation ranged from 44 to 240 Gy. Interval from radiation therapy to our surgery ranged from 1 to 18 years (mean 6.7 years). Chief complaints were dysesthesia in 9 patients, motor weakness in 7 patients and dullach in scar formation of radiated skin in 7 patients. Preoperative neural functions were slight palsy in 1, moderate palsy in 5 and complete palsy in 3. In surgical treatment, neurolysis of the brachial plexus was done and it was covered by latissimus dorsi myocutaneous flap. We evaluated about dysesthesia and motor recovery after treatment for neuropathy. Follow up periods ranged from 1 to 11 years (average in 5 years). Dysesthesia improved in 6 patients and got worse in 3 patients. Motor weakness recovered in only 2 patients and got worse in 7 patients. From our results, intolerable dysesthesia which was first complaint of these patients improved. But motor function had not recovered. Our treatment was thought to be effective for extraneural factor like an compression neuropathy by scar formation and poor vascularity. But it was not effective for intraneural damage by radiation therapy. (author)

  9. Study on DNA damages induced by UV radiation

    International Nuclear Information System (INIS)

    Doan Hong Van; Dinh Ba Tuan; Tran Tuan Anh; Nguyen Thuy Ngan; Ta Bich Thuan; Vo Thi Thuong Lan; Tran Minh Quynh; Nguyen Thi Thom

    2015-01-01

    DNA damages in Escherichia coli (E. coli) exposed to UV radiation have been investigated. After 30 min of exposure to UV radiation of 5 mJ/cm"2, the growth of E. coli in LB broth medium was about only 10% in compared with non-irradiated one. This results suggested that the UV radiation caused the damages for E. coli genome resulted in reduction in its growth and survival, and those lesions can be somewhat recovered. For both solutions of plasmid DNAs and E. coli cells containing plasmid DNA, this dose also caused the breakage on single and double strands of DNA, shifted the morphology of DNA plasmid from supercoiled to circular and linear forms. The formation of pyrimidine dimers upon UV radiation significantly reduced when the DNA was irradiated in the presence of Ganoderma lucidum extract. Thus, studies on UV-induced DNA damage at molecular level are very essential to determine the UV radiation doses corresponding to the DNA damages, especially for creation and selection of useful radiation-induced mutants, as well as elucidation the protective effects of the specific compounds against UV light. (author)

  10. Poor outcome in radiation-induced constrictive pericarditis

    International Nuclear Information System (INIS)

    Karram, T.; Rinkevitch, D.; Markiewicz, W.

    1993-01-01

    The purpose was to compare the outcome of patients with radiation-induced constrictive pericarditis versus patients with constiction due to another etiology. Twenty patients with constrictive pericarditis were seen during 1975-1986 at a single medical center. Six had radiation-induced constrictive pericarditis (Group A). The etiology was idiopathic in ten subjects and secondary to carcinomatous encasement, chronic renal failure, purulent infection and tuberculosis in one patient each (Group B, N = 14). Meang age was 53.4 ± 15.5 years. Extensive pericardiectomy was performed in 3/6 Group A and 13/14 Group B patients. All Group A patients died, 4 weeks - 11 years post-diagnosis (median = 10 months). Two Group A patients died suddenly, one died post-operatively of respiratory failure, another of pneumonia and two of recurrent carcinoma. Thirteen Group B patients are alive (median follow-up = 72 months). The only death in this group was due to metastatic cancer. The poor outcome with radiation-induced constriction is probably multi-factorial. Poor surgical outcome is to be expected in patients with evidence of recurrent tumor, high-dose irradiation, pulmonary fibrosis or associated radiation-induced myocardinal, valvular or coronary damage

  11. Homoeologous chromatin exchange in a radiation-induced gene transfer

    International Nuclear Information System (INIS)

    Dvorak, J.; Knott, D.R.

    1977-01-01

    Some of the ionizing-radiation-induced translocations between alien and wheat chromosomes show no deleterious effects and are transmitted normally through the pollen. Translocations of this type will be called ''compensating''. In one such compensating translocation, designated T4, it was found that chromatin in the long arm of wheat chromosome 7D was replaced with homoeologous chromatin of the Agropyron chromosome

  12. Radiation-induced vascular lesions of the skin: an overview

    NARCIS (Netherlands)

    Flucke, U.E.; Requena, L.; Mentzel, T.

    2013-01-01

    Radiation-induced cutaneous vascular neoplasms occur infrequently and comprise benign, so-called atypical vascular lesions (AVL) and angiosarcomas (AS), often being high-grade malignant tumors. Both arise most frequently within previously irradiated skin in breast-conserving-treated mammary cancer

  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. A radiation-induced compact type Granny Smith apple mutation

    International Nuclear Information System (INIS)

    Hurter, N.; Van Tonder, M.J.

    1982-01-01

    More successful compact mutant clones of Granny Smith apple are being sought, for those that have so far arisen naturally have undesirable tree and fruit charateristics. For this purpose, gamma rays from a Cobalt-60 radiation unit were used to induce mutant types artificially. One compact mutation of Granny Smith was produced via re-irradiation

  15. Kinetics of radiation-induced segregation in ternary alloys

    International Nuclear Information System (INIS)

    Lam, N.O.; Kumar, A.; Wiedersich, H.

    1982-01-01

    Model calculations of radiation-induced segregation in ternary alloys have been performed, using a simple theory. The theoretical model describes the coupling between the fluxes of radiation-induced defects and alloying elements in an alloy A-B-C by partitioning the defect fluxes into those occurring via A-, B-, and C-atoms, and the atom fluxes into those taking place via vacancies and interstitials. The defect and atom fluxes can be expressed in terms of concentrations and concentration gradients of all the species present. With reasonable simplifications, the radiation-induced segregation problem can be cast into a system of four coupled partial-differential equations, which can be solved numerically for appropriate initial and boundary conditions. Model calculations have been performed for ternary solid solutions intended to be representative of Fe-Cr-Ni and Ni-Al-Si alloys under various irradiation conditions. The dependence of segregation on both the alloy properties and the irradiation variables, e.g., temperature and displacement rate, was calculated. The sample calculations are in good qualitative agreement with the general trends of radiation-induced segregation observed experimentally

  16. Electronic-excitation induced radiation damage in glasses

    Energy Technology Data Exchange (ETDEWEB)

    Vigouroux, J P

    1985-01-01

    In order to understand the microscopic nature of radiation induced defects in insulators, we have studied localization of negative and positive charges in amorphous and monocrystalline SiO2. The behaviour of these charges is linked to creation of point defects by electronic excitation. The role of intense electric fields under irradiation is pointed out.

  17. Poor outcome in radiation-induced constrictive pericarditis

    Energy Technology Data Exchange (ETDEWEB)

    Karram, T.; Rinkevitch, D.; Markiewicz, W. (Technion Medical School, Haifa (Israel))

    1993-01-15

    The purpose was to compare the outcome of patients with radiation-induced constrictive pericarditis versus patients with constiction due to another etiology. Twenty patients with constrictive pericarditis were seen during 1975-1986 at a single medical center. Six had radiation-induced constrictive pericarditis (Group A). The etiology was idiopathic in ten subjects and secondary to carcinomatous encasement, chronic renal failure, purulent infection and tuberculosis in one patient each (Group B, N = 14). Meang age was 53.4 [+-] 15.5 years. Extensive pericardiectomy was performed in 3/6 Group A and 13/14 Group B patients. All Group A patients died, 4 weeks - 11 years post-diagnosis (median = 10 months). Two Group A patients died suddenly, one died post-operatively of respiratory failure, another of pneumonia and two of recurrent carcinoma. Thirteen Group B patients are alive (median follow-up = 72 months). The only death in this group was due to metastatic cancer. The poor outcome with radiation-induced constriction is probably multi-factorial. Poor surgical outcome is to be expected in patients with evidence of recurrent tumor, high-dose irradiation, pulmonary fibrosis or associated radiation-induced myocardinal, valvular or coronary damage.

  18. Homoeologous chromatin exchange in a radiation-induced gene transfer

    Energy Technology Data Exchange (ETDEWEB)

    Dvorak, J; Knott, D R [Department of Crop Science, University of Saskatchewan, Saskatoon, Saskatchewan, Canada

    1977-03-01

    Some of the ionizing-radiation-induced translocations between alien and wheat chromosomes show no deleterious effects and are transmitted normally through the pollen. Translocations of this type will be called ''compensating''. In one such compensating translocation, designated T4, it was found that chromatin in the long arm of wheat chromosome 7D was replaced with homologous chromatin of the Agropyron chromosome.

  19. Ionizing radiation induces tumor cell lysyl oxidase secretion

    DEFF Research Database (Denmark)

    Shen, Colette J; Sharma, Ashish; Vuong, Dinh-Van

    2014-01-01

    BACKGROUND: Ionizing radiation (IR) is a mainstay of cancer therapy, but irradiation can at times also lead to stress responses, which counteract IR-induced cytotoxicity. IR also triggers cellular secretion of vascular endothelial growth factor, transforming growth factor beta and matrix...

  20. Radiation-induced augmentation of the immune response

    International Nuclear Information System (INIS)

    Anderson, R.E.; Lefkovits, I.; Troup, G.M.

    1980-01-01

    Radiation-induced augmentation of the immune response has been shown to occur both in vivo and in vitro. Evidence is presented to implicate injury to an extremely radiosensitive T cell in the expression of this phenomenon. Experiments are outlined which could be employed to support or reflect this hypothesis

  1. ROS Mediates Radiation-Induced Differentiation in Human Lung Fibroblast

    International Nuclear Information System (INIS)

    Park, Sa Rah; Ahn, Ji Yeon; Kim, Mi Hyeung; Lim, Min Jin; Yun, Yeon Sook; Song, Jie Young

    2009-01-01

    One of the most common tumors worldwide is lung cancer and the number of patients with lung cancer received radiotherapy is increasing rapidly. Although radiotherapy may have lots of advantages, it can also induce serious adverse effects such as acute radiation pneumonitis and pulmonary fibrosis. Pulmonary fibrosis is characterized by excessive production of smooth muscle actin-alpha (a-SMA) and accumulation of extracellular matrix (ECM) such as collagen and fibronectin. There has been a great amount of research about fibrosis but the exact mechanism causing the reaction is not elucidated especially in radiation-induced fibrosis. Until now it has been known that several factors such as transforming growth factor (TGF-b), tumor necrosis factor (TNF), IL-6, platelet-derived growth factor (PDGF) and reactive oxygen species are related to fibrosis. It is also reported that reactive oxygen species (ROS) can be induced by radiation and can act as a second messenger in various signaling pathways. Therefore we focused on the role of ROS in radiation induced fibrosis. Here, we suggest that irradiation generate ROS mainly through NOX4, result in differentiation of lung fibroblast into myofibroblast

  2. Preparation of polymer microspheres by radiation-induced polymerization

    International Nuclear Information System (INIS)

    Naka, Y.; Yamamoto, Y.; Yoshida, Y.; Tagawa, S.

    1995-01-01

    Cross-liking monomer, diethylene glycol dimethacrylate gives microspheres from organic solution by radiation-induced polymerization. /One of the remarkable result is that the number of the microspheres is not changing during the polymerization. Ethyl methacrylate, maleic anhydride, styrene and acrylamide are used as comonomers. These comonomers give the microspheres in the range of 0 to 0.4 as mol fractions. (author)

  3. A case of radiation-induced cancer of the hypopharynx

    International Nuclear Information System (INIS)

    Miyamoto, Kouji; Shimizu, Yukio; Yura, Jirou; Itoh, Yasufumi; Ikeda, Tsuneko; Outsubo, Toshio; Saitou, Hitoshi

    2001-01-01

    We report a case of radiation-induced cancer of the hypopharynx in a 65-year-old woman. The patient had received radiation treatment for Basedow's disease for several years starting at the age of 10 years. On June 26, 1993, she was examined at our hospital because of hoarseness and dysphagia. On July 22, right lobectomy was performed for suspected thyroid cancer. During this operation, endoscopy revealed hypopharyngeal cancer. Twenty-two days after surgery, total pharyngolaryngectomy and total esophagectomy were performed and a pharyngogastrostomy and a permanent tracheostomy were created. Histologic examination revealed moderately differentiated squamous cell cancer. This case was diagnosed as radiation-induced caner according to the diagnostic criteria of Sakai. (author)

  4. Radiation-induced soft-tissue and bone sarcoma

    International Nuclear Information System (INIS)

    Kim, J.H.; Chu, F.C.; Woodard, H.Q.; Melamed, R.; Huvos, A.; Cantin, J.

    1978-01-01

    From the records of Memorial Hospital of the past 50 years, 47 cases with an established diagnosis of radiation-induced sarcoma were identified and divided into two groups: the first included 20 cases of soft-tissue sarcoma arising from irradiated tissues, and the second comprised 27 cases of bone sarcoma arising from normal bones in the irradiated field. Medians for the latent periods from irradiation to diagnosis of bone and soft-tissue sarcoma were 11 and 12, years, respectively. In bone sarcomas, the latent period was longer after larger radiation doses and children appeared to be more susceptible to cancer induction than adults. Criteria for establishing the diagnosis of radiation-induced sarcoma and the magnitude of the risk of bone sarcoma are discussed

  5. Radiation induced mutant crop varieties: accomplishment and societal deployment

    International Nuclear Information System (INIS)

    D'Souza, S.F.

    2009-01-01

    One of the peaceful applications of atomic energy is in the field of agriculture. It finds application in crop improvement, crop nutrition, crop protection and food preservation. Genetic improvement of crop plants is a continuous endeavor. Success of a crop improvement programme depends on the availability of large genetic variability, which a plant breeder can combine to generate new varieties. In nature, occurrence of natural variability in the form of spontaneous mutations is extremely low (roughly 10 -6 ), which can be enhanced to several fold (approximately 10 -3 ) by using ionizing radiations or chemical mutagens. Radiation induced genetic variability in crop plants is a valuable resource from which plant breeder can select and combine different desired characteristics to produce better crop varieties. Crop improvement programmes at Bhabha Atomic Research Centre (BARC) envisage radiation based induced mutagenesis along with recombination breeding in country's important cereals (rice and wheat), oilseeds (groundnut, mustard, soybean and sunflower), grain legumes (blackgram, mungbean, pigeonpea and cowpea), banana and sugarcane

  6. Binding of radiation-induced phenylalanine radicals to DNA

    International Nuclear Information System (INIS)

    Schans, G.P. van der; Rijn, C.J.S. van; Bleichrodt, J.F.

    1975-11-01

    When an aqueous solution of double-stranded DNA of bacteriophage PM2 containing phenylalanine and saturated with N 2 O is irradiated with γ-rays, radiation-induced phenylalanine radicals are bound covalently. Under the conditions used about 25 phenylalanine molecules may be bound per lethal hit. Also for single-stranded PM2 DNA, most of the phenylalanine radicals bound are non-lethal. Evidence is presented that in double-stranded DNA an appreciable fraction of the single-strand breaks is induced by phenylalanine radicals. Radiation products of phenylalanine and the phenylalanine bound to the DNA decrease the sensitivity of the DNA to the induction of single-strand breaks. There are indications that the high efficiency of protection by radiation products of phenylalanine is due to their positive charge, which will result in a relatively high concentration of these compounds in the vicinity of the negatively charged DNA molecules

  7. A case of radiation-induced cancer of the hypopharynx

    Energy Technology Data Exchange (ETDEWEB)

    Miyamoto, Kouji; Shimizu, Yukio; Yura, Jirou; Itoh, Yasufumi; Ikeda, Tsuneko [Matsunami General Hospital, Kasamatsu, Gifu (Japan); Outsubo, Toshio; Saitou, Hitoshi

    2001-06-01

    We report a case of radiation-induced cancer of the hypopharynx in a 65-year-old woman. The patient had received radiation treatment for Basedow's disease for several years starting at the age of 10 years. On June 26, 1993, she was examined at our hospital because of hoarseness and dysphagia. On July 22, right lobectomy was performed for suspected thyroid cancer. During this operation, endoscopy revealed hypopharyngeal cancer. Twenty-two days after surgery, total pharyngolaryngectomy and total esophagectomy were performed and a pharyngogastrostomy and a permanent tracheostomy were created. Histologic examination revealed moderately differentiated squamous cell cancer. This case was diagnosed as radiation-induced caner according to the diagnostic criteria of Sakai. (author)

  8. Radiation-induced mutagenicity and lethality in Salmonella typhimurium

    International Nuclear Information System (INIS)

    Isildar, M.; Bakale, G.

    1983-01-01

    The mutagenic and lethal effects of ionizing radiation on histidine-deficient auxotrophs of Salmonella typhimurium were studied to improve the understanding of radiation damage to DNA. The auxotrophs were divided into two groups - one which is sensitive to base-pair substitutions and another sensitive to frameshifts. These groups were composed of parent-daughter pairs in which the chemical mutagenicity enhancing plasmid, pKM101, is absent in the parent strain and present in the daughter. Co-60 #betta#-radiation and 250 kV x-rays were used to irradiate the bacteria. Irradiation of the frameshift - sensitive strains which carry the pKm101 plasmid doubled the absolute number of induced revertants whereas irradiation of the base-pair substitution sensitive strain which also carries the pKm101 plasmid produced nearly no change in the number of induced revertants. A nearly negligible effect on the mutation rate was observed for all parent strains

  9. A study of radiation-induced cerebral vascular injury in nasopharyngeal carcinoma patients with radiation-induced temporal lobe necrosis.

    Directory of Open Access Journals (Sweden)

    Jianhong Ye

    Full Text Available To investigate radiation-induced carotid and cerebral vascular injury and its relationship with radiation-induced temporal lobe necrosis in nasopharyngeal carcinoma (NPC patients.Fifty eight NPC patients with radiation-induced temporal lobe necrosis (TLN were recruited in the study. Duplex ultrasonography was used to scan bilateral carotid arterials to evaluate the intima-media thickness (IMT and occurrence of plaque formation. Flow velocities of bilateral middle cerebral arteries (MCAs, internal carotid arteries (ICAs and basal artery (BA were estimated through Transcranial Color Doppler (TCD. The results were compared with data from 33 patients who were free from radiation-induced temporal lobe necrosis after radiotherapy and 29 healthy individuals.Significant differences in IMT, occurrence of plaques of ICAs and flow velocities of both MCAs and ICAs were found between patients after radiotherapy and healthy individuals (p<0.05. IMT had positive correlation with post radiation interval (p = 0.049. Compared with results from patients without radiation-induced TLN, the mean IMT was significantly thicker in patients with TLN (p<0.001. Plaques were more common in patients with TLN than patients without TLN (p = 0.038. In addition, flow velocities of MCAs and ICAs in patients with TLN were much faster (p<0.001, p<0.001. Among patients with unilateral TLN, flow velocity of MCAs was significantly different between ipsilateral and contralateral sides to the lesion (p = 0.001.Thickening of IMT, occurrence of plaque formation and hemodynamic abnormality are more common in patients after radiotherapy, especially in those with TLN, compared with healthy individuals.

  10. Radiation-induced attenuation in integrated optical materials

    International Nuclear Information System (INIS)

    Evans, B.D.

    1989-01-01

    This paper reports that three materials commonly employed in opto-electronic integrated circuits evaluated for radiation-induced optical attenuation in the range 300 nm to 3000 nm. These include optically clear epoxy and crystalline lithium niobate after Co-60 exposure and crystalline tellurium dioxide after mixed gamma/fast-neutron exposure. In all these materials, however, induced loss was restricted to shorter wavelengths; attenuation induced at the telecommunications windows near 850, 1300 and 1550 nm was <0.1 dB/cm

  11. 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

  12. Pathogenesis of radiation-induced osteosarcomas

    International Nuclear Information System (INIS)

    Luz, A.

    1980-07-01

    Results backed by experiments are presented here for the osteosarcoma induction in mice after incorporation of radium-224 or thorium-227. The dose-response relationship for osteosarcoma induction by short-lived alpha radiation is very much influenced by the time distribution of the applied activity and is thus influenced by the dose rate in the skeleton. In the total dose range investigated the decrease of the dose rate leads to an increase of the ontogenetic effect to a tumour incidence of nearly 100%. If the internal exposure starts after the period of rapid skeletal growth the osteosarcoma risk is not reduced compared with the young animals and the tumour latency period is even shorter. This reducing of the latency period is dependent on the expected osteosarcoma risk. In the case of a lower exogenic risk the date for the clinical tumour manifestations seems to be determined by the date of the manifestation of spontaneous osteosarcomas whereas, in the case of a great exogenic risk, the agent obviously determines when the tumour appears. A spontaneous osteodysplasia in the skeleton of old female mice certainly cannot be defined as the co-factor of osteosarcomagenesis. The non-neoplastic proliferated cells which are morphologically similar to the osteodysplastia are found to a larger extent in the skeleton of female mice with but also in male mice. It is not clear whether this is a real preneoplasia or a parallel phenomenon of the osteosarcomagenesis. (orig./MG) [de

  13. Electromagnetic radiation induced by mining rock failure

    Energy Technology Data Exchange (ETDEWEB)

    Frid, V. [Geological and Environmental Sciences, Ben Gurion University of the Negev, Beer Sheva (Israel 84105); Vozoff, K. [V& amp; A Geoscience, POB 996 Spit Junction (NSW Australia 2088)

    2005-10-17

    Anticipating roof fall in mine workings has been a problem for centuries. The focus in the search for early warning indicators has been on observing seismic (acoustic) events prior to the fall. These precursors have been studied in great detail at many places, but none has been fully successful. So far, no valid, effective early warning system based on low-frequency seismic precursors has been established. In this paper, we investigated a promising new technique, which is not yet completely understood or been widely tested in mines. The new method is the sensing of the embryonic stages of roof fall by detection of high frequency electromagnetic radiation (EMR) emitted from rock microcracks. Two examples of combined observations of EMR and low frequency acoustic emission prior to roof fall at Moonee Colliery are presented. Anomalously high EMR was detected more than 1 h before roof fall, giving a significant time advantage over the first indicators of low frequency acoustic emission. Analysis of Benioff strain release diagrams of EMR emanating from developing medium scale failure in the mine enabled us to fill the 'gap' between previously known microscale (rock fracture in lab) and macroscale (earthquake) EMR observations, and to conclude that indeed a common fundamental relationship must lie behind this multi-scale phenomenon. (author)

  14. Radiation induced crosslinking of cellulose ethers

    International Nuclear Information System (INIS)

    Wach, A.R.; Mitomo, H.; Yoshii, F.; Kume, T.

    2002-01-01

    The effects of high-energy radiation on four ethers of cellulose: carboxymethyl (CMC); hydroxypropyl (HPC), hydroxyethyl (HEC) and methylcellulose (MC) were investigated. Polymers are irradiated in solid state and in aqueous solutions at various concentrations. Degree of substitution (DS) of the derivatives, the concentration of their aqueous solutions and irradiation conditions had a significant impact on the obtained products. Irradiation of polymers in solid state and in diluted aqueous solutions resulted in their degradation. However, it was found that for concentrated solutions gel formation occurred. Paste-like form of the initial material, when water plasticizes the bulk of polymer as well as the high dose rate, what prevents oxygen penetration of the polymer during irradiation, have been found favourable for hydrogel formation. Up to 95% of gel fraction was obtained from solutions of CMC with concentration over 50% irradiated by γ-rays or electron beam. It was pointed out that the ability to the formation of the three-dimensional network is related to the DS of anhydroglucose units and a type of chemical group introduced to main chain of cellulose. Produced hydrogels swelled markedly in water. Despite of the crosslinked structure they underwent degradation by the action of cellulase enzyme or microorganisms from compost, and can be included into the group of biodegradable materials. (author)

  15. Relation between four types of radiation damage and induced repair

    International Nuclear Information System (INIS)

    Radar, M.L.

    1977-08-01

    Four strains of Escherichia coli were exposed to uv and gamma radiation. Procedures are described for mutational studies, classification of revertants, inhibition of postirradiation DNA degradation and radioresistance. Comparisons were made of induction of the error-prone repair (epr) system with four mutagens; uv radiation, near uv radiation, gamma radiation, and DNA-protein crosslinks. An increase in the number of mutations was shown in every case. The observation that induction of mutagenesis, induction of inhibition of post-irradiation DNA degradation, and induction of radioresistance are closely parallel phenomena led to the investigation of the possibility that DNA-protein crosslinks which were known mutagens were also inducers of the epr system. The significance of the results is discussed

  16. Factors that modify risks of radiation-induced cancer

    International Nuclear Information System (INIS)

    Fabrikant, J.I.

    1988-11-01

    The collective influence of biologic and physical factors that modify risks of radiation-induced cancer introduces uncertainties sufficient to deny precision of estimates of human cancer risk that can be calculated for low-dose radiation in exposed populations. The important biologic characteristics include the tissue sites and cell types, baseline cancer incidence, minimum latent period, time-to-tumor recognition, and the influence of individual host (age and sex) and competing etiologic influences. Physical factors include radiation dose, dose rate, and radiation quality. Statistical factors include time-response projection models, risk coefficients, and dose-response relationships. Other modifying factors include other carcinogens, and other biological sources (hormonal status, immune status, hereditary factors)

  17. The influence of infrared radiation on short-term ultraviolet-radiation-induced injuries

    International Nuclear Information System (INIS)

    Kaidbey, K.H.; Witkowski, T.A.; Kligman, A.M.

    1982-01-01

    Because heat has been reported to influence adversely short- and long-term ultraviolet (UV)-radiation-induced skin damage in animals, we investigated the short-term effects of infrared radiation on sunburn and on phototoxic reactions to topical methoxsalen and anthracene in human volunteers. Prior heating of the skin caused suppression of the phototoxic response to methoxsalen as evidenced by an increase in the threshold erythema dose. Heat administered either before or after exposure to UV radiation had no detectable influence on sunburn erythema or on phototoxic reactions provoked by anthracene

  18. 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.

  19. Radiation-induced mesotheliomas in rats

    International Nuclear Information System (INIS)

    Hahn, F.F.; Haley, P.J.; Hubbs, A.F.; Hoover, M.D.; Lundgren, D.L.

    1990-01-01

    Mesotheliomas have been reported in rats that inhaled plutonium, but these tumors have not been extensively studied. To investigate a possible role for inhaled radionuclides in the induction of mesotheliomas, four life-span studies conducted at the Inhalation Toxicology Research Institute are reviewed. A total of 3076 F344 rats were exposed by inhalation to aerosols of 239 PuO 2 , mixed uranium-plutonium oxide, or 144 CeO 2 . Results showed that a low incidence of pleural mesotheliomas was induced by either alpha- or beta-emitting radionuclides deposited and retained in the lung. Chronic alpha irradiation was more effective per unit dose in producing mesotheliomas than chronic beta irradiation of the lung by a factor of 15. 7 refs., 1 tab., 7 figs

  20. Radiation-induced mesotheliomas in rats

    Energy Technology Data Exchange (ETDEWEB)

    Hahn, F.F.; Haley, P.J.; Hubbs, A.F.; Hoover, M.D.; Lundgren, D.L.

    1990-01-01

    Mesotheliomas have been reported in rats that inhaled plutonium, but these tumors have not been extensively studied. To investigate a possible role for inhaled radionuclides in the induction of mesotheliomas, four life-span studies conducted at the Inhalation Toxicology Research Institute are reviewed. A total of 3076 F344 rats were exposed by inhalation to aerosols of {sup 239}PuO{sub 2}, mixed uranium-plutonium oxide, or {sup 144}CeO{sub 2}. Results showed that a low incidence of pleural mesotheliomas was induced by either alpha- or beta-emitting radionuclides deposited and retained in the lung. Chronic alpha irradiation was more effective per unit dose in producing mesotheliomas than chronic beta irradiation of the lung by a factor of 15. 7 refs., 1 tab., 7 figs. (MHB)

  1. Regulation of radiation-induced protein kinase Cδ activation in radiation-induced apoptosis differs between radiosensitive and radioresistant mouse thymic lymphoma cell lines

    International Nuclear Information System (INIS)

    Nakajima, Tetsuo; Yukawa, Osami; Tsuji, Hideo; Ohyama, Harumi; Wang, Bing; Tatsumi, Kouichi; Hayata, Isamu; Hama-Inaba, Hiroko

    2006-01-01

    Protein kinase Cδ (PKCδ) has an important role in radiation-induced apoptosis. The expression and function of PKCδ in radiation-induced apoptosis were assessed in a radiation-sensitive mouse thymic lymphoma cell line, 3SBH5, and its radioresistant variant, XR223. Rottlerin, a PKCδ-specific inhibitor, completely abolished radiation-induced apoptosis in 3SBH5. Radiation-induced PKCδ activation correlated with the degradation of PKCδ, indicating that PKCδ activation through degradation is involved in radiation-induced apoptosis in radiosensitive 3SBH5. In radioresistant XR223, radiation-induced PKCδ activation was lower than that in radiosensitive 3SBH5. Cytosol PKCδ levels in 3SBH5 decreased markedly after irradiation, while those in XR223 did not. There was no apparent change after irradiation in the membrane fractions of either cell type. In addition, basal cytosol PKCδ levels in XR223 were higher than those in 3SBH5. These results suggest that the radioresistance in XR223 to radiation-induced apoptosis is due to a difference in the regulation of radiation-induced PKCδ activation compared to that of 3SBH5. On the other hand, Atm -/- mouse thymic lymphoma cells were more radioresistant to radiation-induced apoptosis than wild-type mouse thymic lymphoma cells. Irradiated wild-type cells, but not Atm -/- cells, had decreased PKCδ levels, indicating that the Atm protein is involved in radiation-induced apoptosis through the induction of PKCδ degradation. The decreased Atm protein levels induced by treatment with Atm small interfering RNA had no effect on radiation-induced apoptosis in 3SBH5 cells. These results suggest that the regulation of radiation-induced PKCδ activation, which is distinct from the Atm-mediated cascade, determines radiation sensitivity in radiosensitive 3SBH5 cells

  2. Automated Detection of Binucleated Cell and Micronuclei using CellProfiler 2.0 Software

    Directory of Open Access Journals (Sweden)

    DWI RAMADHANI

    2013-12-01

    Full Text Available Micronucleus assay in human peripheral lymphocytes usually used to assess chromosomal damage. Manual scoring of micronuclei can be time consuming and large numbers of binucleated cells have to be analyzed to obtain statistically relevant data. Automation of the micronuclei analysis using image processing analysis software can provide a faster and more reliable analysis of micronucleus assay. Here the used of CellProfiler an open access cell image analysis software for automatic detection of binucleated cells and micronuclei were reported. We aimed to know whether there was a significant difference in the number of binucleated cells and micronuclei that obtained by manual and CellProfiler counting. Wilcoxon Rank test was used for statistical analysis to test H0 hypothesis that there was no significant difference in the number of binucleated cells and micronuclei that obtained by manual and CellProfiler counting. We analyzed 135 images for both manual and CellProfiler counting. Our results showed that there was no significant difference between manual and CellProfiler counting for binucleated cells (P = 0.851 and for micronuclei (P = 0.917. In conclusion, the binucleated cells and micronuclei counting using CellProfiler were comparable but not better than manual counting.

  3. Chromosomal aberrations and micronuclei frequencies in Bulgarian control population

    International Nuclear Information System (INIS)

    Popova, I.; Hadjidekova, V.; Hristova, R.; Atanasova, P.

    2004-01-01

    The aim of this investigation is to represent the frequency of spontaneous chromosomal damages in peripheral blood lymphocytes of Bulgarian control population. Material and methods: The investigated group includes persons belonging to both sexes and different ages. Each of them is interviewed of their social and health status. Sixteen persons are examined using the chromosomal aberrations analysis and forty-five with micronucleus test. The frequency of chromosomal aberrations varied between 0 - 2.4 % and the mean value is 1.00 %. The frequency of cells with micronuclei varied between 4.5 - 24.5 % and the mean value 12,9 %. Further work on the investigation of spontaneous frequency of chromosomal damages is in progress. (authors)

  4. Induction of Micronuclei in Human Fibroblasts across the Bragg Curve of Energetic Si and Fe Ions

    Science.gov (United States)

    Wu, H.; Rusek, A.; Hada, M.

    2006-01-01

    The space environment consists of a varying field of radiation particles including high-energy ions, with spacecraft shielding material providing the major protection to astronauts from harmful exposure. Unlike low-LET gamma or X-rays, the presence of shielding does not always reduce the radiation risks for energetic charged particle exposure. Since the dose delivered by the charged particle increases sharply as the particle approaches the end of its range, a position known as the Bragg peak, the Bragg curve does not necessarily represent the biological damage along the particle traversal since biological effects are influenced by the track structure of both primary and secondary particles. Therefore, the biological Bragg curve is dependent on the energy and the type of the primary particle, and may vary for different biological endpoints. We studied micronuclei (MN) induction across the Bragg curve of Si and Fe ions at incident energies of 300 MeV/nucleon and 1 GeV/nucleon. A quantitative biological response curve did not reveal an increased yield of MN at the location of the Bragg peak. However, the ratio of mono- to bi-nucleated cells, which indicates inhibition in cell progression, increased at the Bragg peak location. These results confirm the hypothesis that severely damaged cells at the Bragg peak are likely to go through reproduction death.

  5. Low dose/low fluence ionizing radiation-induced biological effects: The role of intercellular communication and oxidative metabolism

    Science.gov (United States)

    Azzam, Edouard

    Mechanistic investigations have been considered critical to understanding the health risks of exposure to ionizing radiation. To gain greater insight in the biological effects of exposure to low dose/low fluence space radiations with different linear energy transfer (LET) properties, we examined short and long-term biological responses to energetic protons and high charge (Z) and high energy (E) ions (HZE particles) in human cells maintained in culture and in targeted and non-targeted tissues of irradiated rodents. Particular focus of the studies has been on mod-ulation of gene expression, proliferative capacity, induction of DNA damage and perturbations in oxidative metabolism. Exposure to mean doses of 1000 MeV/nucleon iron ions, by which a small to moderate proportion of cells in an exposed population is targeted through the nucleus by an HZE particle, induced stressful effects in the irradiated and non-irradiated cells in the population. Direct intercellular communication via gap-junctions was a primary mediator of the propagation of stressful effects from irradiated to non-irradiated cells. Compromised prolif-erative capacity, elevated level of DNA damage and oxidative stress evaluated by measurements of protein carbonylation, lipid peroxidation and activity of metabolic enzymes persisted in the progeny of irradiated and non-irradiated cells. In contrast, progeny of cells exposed to high or low doses from 150-1000 MeV protons retained the ability to form colonies and harbored similar levels of micronuclei, a surrogate form of DNA damage, as control, which correlated with normal reactive oxygen species (ROS) levels. Importantly, a significant increase in the spontaneous neoplastic transformation frequency was observed in progeny of bystander mouse embryo fibroblasts (MEFs) co-cultured with MEFs irradiated with energetic iron ions but not protons. Of particular significance, stressful effects were detected in non-targeted tissues of rats that received partial

  6. Radiation and desiccation response motif mediates radiation induced gene expression in D. radiodurans

    International Nuclear Information System (INIS)

    Anaganti, Narasimha; Basu, Bhakti; Apte, Shree Kumar

    2015-01-01

    Deinococcus radiodurans is an extremophile that withstands lethal doses of several DNA damaging agents such as gamma irradiation, UV rays, desiccation and chemical mutagens. The organism responds to DNA damage by inducing expression of several DNA repair genes. At least 25 radiation inducible gene promoters harbour a 17 bp palindromic sequence known as radiation and desiccation response motif (RDRM) implicated in gamma radiation inducible gene expression. However, mechanistic details of gamma radiation-responsive up-regulation in gene expression remain enigmatic. The promoters of highly radiation induced genes ddrB (DR0070), gyrB (DR0906), gyrA (DR1913), a hypothetical gene (DR1143) and recA (DR2338) from D. radiodurans were cloned in a green fluorescence protein (GFP)-based promoter probe shuttle vector pKG and their promoter activity was assessed in both E. coli as well as in D. radiodurans. The gyrA, gyrB and DR1143 gene promoters were active in E. coli although ddrB and recA promoters showed very weak activity. In D. radiodurans, all the five promoters were induced several fold following 6 kGy gamma irradiation. Highest induction was observed for ddrB promoter (25 fold), followed by DR1143 promoter (15 fold). The induction in the activity of gyrB, gyrA and recA promoters was 5, 3 and 2 fold, respectively. To assess the role of RDRM, the 17 bp palindromic sequence was deleted from these promoters. The promoters devoid of RDRM sequence displayed increase in the basal expression activity, but the radiation-responsive induction in promoter activity was completely lost. The substitution of two conserved bases of RDRM sequence yielded decreased radiation induction of PDR0070 promoter. Deletion of 5 bases from 5'-end of PDR0070 RDRM increased basal promoter activity, but radiation induction was completely abolished. Replacement of RDRM with non specific sequence of PDR0070 resulted in loss of basal expression and radiation induction. The results demonstrate that

  7. Radiation-induced mutations in fish

    International Nuclear Information System (INIS)

    Schroeder, J.H.

    1980-01-01

    X-ray-induced mutations in teleostean fish were studied from the point of social behavior. A significant reduction in male aggression was found in the postirradiated F 1 generation after the irradiation of parental oogonia and spermatogonia, with 2 x 500 R (24 hr apart) of x-rays, but did not alter the aggression of F 1 females. A study on backcross generation of irradiated line fitted with a two-factor model of dominant genetic factors, high- and low-aggressive, which co-acted additively in repressing the male aggression. Social cohesiveness was compared between F 1 convict cichlides (C. nigrofasciatum) exposed by 0, 250, 500, 750, 1000, and 2000 R of x-rays. The best response was observed in males with 500 R and in females with 750 R. While an increase in cohesiveness was observed in F 1 males with 500 R, the cohesiveness of F 1 females decreased with 750 and 200 R, suggesting that the increase in male was associated with a reduction of inter-male aggression. A new ''guppy male courtship activity test'' was carried out in the offsprings of irradiated guppy, maintained in seawater and in freshwater. The mean values of both the frequency and the duration of four behavioral traits of the male guppy increased in postirradiated F 1 generation of the seawater substrain but were unchanged in that of freshwater's. In F 2 generation the mean values of the same behavioral characters decreased in both seawater and freshwater substrains. (Nakanishi, T.)

  8. Radiation induced structural changes in alpha-copper-zinc alloys

    International Nuclear Information System (INIS)

    Schuele, W.; Gieb, M.

    1991-01-01

    During irradiation of alpha-copper-zinc alloys with high energy electrons and protons a decrease of the electrical resistivity due to an increase of the degree of short range order is observed through radiation enhanced diffusion followed by an increase of the electrical resistivity through the formation of radiation induced interstitial clusters. The initial formation rate of interstitial clusters increases about linearly with the displacement rate for electron and proton irradiation. The largest initial formation rate is found between 60 and 130 0 C becoming negligibly small above 158 0 C and decreases drastically below 60 0 C. The dynamic steady state interstitial cluster concentration increases with decreasing irradiation temperature in the investigated temperature range between 158 and 40 0 C. Above 158 0 C the formation rate of interstitial clusters is negligibly small. Thus the transition temperature for radiation induced interstitial cluster formation is 158 0 C, depending mainly on the migration activation energy of vacancies. The radiation induced interstitial clusters are precipitates in those alloys in which the diffusion rate of the undersized component atoms via an interstitialcy diffusion mechanism is larger than that of the other atoms

  9. Radiation-induced optic neuropathy: A magnetic resonance imaging study

    International Nuclear Information System (INIS)

    Guy, J.; Mancuso, A.; Beck, R.; Moster, M.L.; Sedwick, L.A.; Quisling, R.G.; Rhoton, A.L. Jr.; Protzko, E.E.; Schiffman, J.

    1991-01-01

    Optic neuropathy induced by radiation is an infrequent cause of delayed visual loss that may at times be difficult to differentiate from compression of the visual pathways by recurrent neoplasm. The authors describe six patients with this disorder who experienced loss of vision 6 to 36 months after neurological surgery and radiation therapy. Of the six patients in the series, two had a pituitary adenoma and one each had a metastatic melanoma, multiple myeloma, craniopharyngioma, and lymphoepithelioma. Visual acuity in the affected eyes ranged from 20/25 to no light perception. Magnetic resonance (MR) imaging showed sellar and parasellar recurrence of both pituitary adenomas, but the intrinsic lesions of the optic nerves and optic chiasm induced by radiation were enhanced after gadolinium-diethylenetriaminepenta-acetic acid (DTPA) administration and were clearly distinguishable from the suprasellar compression of tumor. Repeated MR imaging showed spontaneous resolution of gadolinium-DTPA enhancement of the optic nerve in a patient who was initially suspected of harboring recurrence of a metastatic malignant melanoma as the cause of visual loss. The authors found the presumptive diagnosis of radiation-induced optic neuropathy facilitated by MR imaging with gadolinium-DTPA. This neuro-imaging procedure may help avert exploratory surgery in some patients with recurrent neoplasm in whom the etiology of visual loss is uncertain

  10. Radiation-induced mucositis pain in laryngeal cancer

    International Nuclear Information System (INIS)

    Takahashi, Atsuhito; Shoji, Kazuhiko; Iki, Takehiro; Mizuta, Masanobu; Matsubara, Mami

    2009-01-01

    Radiation therapy in those with head and neck malignancies often triggers painful mucositis poorly controlled by nonsteroidal antiinflammatory drugs (NSAIDs). To better understand how radiation-induced pain develops over time, we studied the numerical rating scale (NRS 0-5) pain scores from 32 persons undergoing radiation therapy of 60-72 Gy for newly diagnosed laryngeal cancer. The degree of mucositis was evaluated using Common Terminology Criteria for Adverse Events version3.0 (CTCAE v3.0). We divided the 32 into a conventional fractionation (CF) group of 14 and a hyperfractionation (HF) group of 18, and further divided laryngeal cancer into a small-field group of 23 and a large-field group of 9. The mucositis pain course was similar in CF and HF, but mucositis pain was severer in the HF group, which also required more NSAIDs. Those in the large-field group had severer pain and mucositis and required more NSAIDs than those in the small-field group. We therefore concluded that small/large-field radiation therapy, rather fractionation type, was related to the incidence of radiation-induced mucositis pain. (author)

  11. Protection from ionizing radiation induced damages by phytoceuticals and nutraceuticals

    International Nuclear Information System (INIS)

    Nair, C.K.K.

    2012-01-01

    Exposure of living systems to ionizing radiation cause a variety of damages to DNA and membranes due to generation of free radicals and reactive oxygen species. The radiation induced lesions in the cellular DNA are mainly strand breaks, damage to sugar moiety, alterations and elimination of bases, cross links of the intra and inter strand type and cross links to proteins while peroxidation of the lipids and oxidation of proteins constitute the major lesions in the membranes. The radioprotectors elicit their action by various mechanisms such as i) by suppressing the formation of reactive species, ii) detoxification of radiation induced species, iii) target stabilization and iv) enhancing the repair and recovery processes. The radioprotective compounds are of importance in medical, industrial, environmental, military and space science applications. Radiation protection might offer a tactical advantage on the battlefield in the event of a nuclear warfare. Radioprotectors might reduce the cancer risk to populations exposed to radiations directly or indirectly through industrial and military applications. The antioxidant and radioprotective properties a few of these agents under in vitro and in vivo conditions in animal models will be discussed

  12. Radiation-induced-radioresistance: mechanisms and modification radioprotection

    International Nuclear Information System (INIS)

    Bala, Madhu

    2005-01-01

    Full text: The term radiation-induced-radioresistance (RIR) has been chosen to explain a particular class of resistance against lethal doses of radiation, which is transient and is induced by pre-exposure to low doses of radiation. This is a genetically governed phenomenon and is different from adaptation which in one of its several senses, refers to evolutionary transformation into new behavioural patterns. RIR is understood to be an evolutionarily conserved fundamental cellular defense mechanism. Small doses of radiation acting as stress stimuli evoke a concerted action of molecular pathways which help the organism to cope-up with the genotoxic effects of lethal doses of radiation given subsequently. Such molecular pathways are a complex interplay of genetic and biochemical entities and are increasingly becoming the focus of research world over. Most of our information on this subject has been gathered from prokaryotes, simpler eukaryotes, human cells and the epidemiological studies. A number of genes such as GADD 45, CDKN1A, PBP74, DIR1, DDR have been reported by to participate in RIR. However, till date, the mechanism of RIR remain poorly understood. In this deliberation some of our findings on mechanisms of RIR will be presented. Further, modification of RIR by a metabolic modifier, presently under clinical investigations for tumor radiotherapy, will also be presented

  13. Radiation-induced skin carcinomas of the head and neck

    International Nuclear Information System (INIS)

    Ron, E.; Modan, B.; Preston, D.; Alfandary, E.; Stovall, M.; Boice, J.D. Jr.

    1991-01-01

    Radiation exposures to the scalp during childhood for tinea capitis were associated with a fourfold increase in skin cancer, primarily basal cell carcinomas, and a threefold increase in benign skin tumors. Malignant melanoma, however, was not significantly elevated. Overall, 80 neoplasms were identified from an extensive search of the pathology logs of all major hospitals in Israel and computer linkage with the national cancer registry. Radiation dose to the scalp was computed for over 10,000 persons irradiated for ringworm (mean 7 Gy), and incidence rates were contrasted with those observed in 16,000 matched comparison subjects. The relative risk of radiogenic skin cancer did not differ significantly between men or women or by time since exposure; however, risk was greatest following exposures in early childhood. After adjusting for sex, ethnic origin, and attained age, the estimated excess relative risk was 0.7 per Gy and the average excess risk over the current follow-up was 0.31/10(4) PY-Gy. The risk per Gy of radiation-induced skin cancer was intermediate between the high risk found among whites and no risk found among blacks in a similar study conducted in New York City. This finding suggests the role that subsequent exposure to uv radiation likely plays in the expression of a potential radiation-induced skin malignancy

  14. International Activities in Radiation-Induced Carcinogenesis. Survey Paper

    Energy Technology Data Exchange (ETDEWEB)

    Komarov, E. [World Health Organization, Geneva (Switzerland)

    1969-11-15

    During the past 10 years special attention has been paid to the problem of late effects of radiation and in particular to radiation-induced carcinogenesis and leukaemogenesis. In the UNSCEAR report of 1958-1962 this.problem was mentioned as being of considerable importance from the point of view of estimation of risk to the population from environmental radiation. In 1964 a special report was prepared by UNSCEAR on radiation- induced carcinogenesis. In the ICRP publication No. 8, a chapter dealing with assessment of somatic risks discussed the problem of leukaemia and other neoplasms and particularly stressed the problem of thyroid carcinoma-and bone sarcoma. WHO panels of experts discussed the problem in 1960-1966 and made some recommendations for international activity in this field. In spite of the amount of scientific attention that has been given in recent years to experimental radiobiology in animals and lower forms, it has become abundantly clear that information directly applicable to humans is woefully inadequate and that there is a desperate need for carefully collected data from man on which to base public health planning and day to day work in radiation protection. This has long been recognized in the technical program of WHO in the emphasis given to the practical importance of epidemiology in human radiobiology and the degree to which it depends upon international collaboration.

  15. A study of the process of synchronisation and micronucleation in Beta vulgaris and the monitoring of an isolation procedure for micro-nuclei and micro-protoplasts by confocal laser scanning microscopy and flow cytometry

    NARCIS (Netherlands)

    Famelaer, I.; Verhoeven, H.A.; Dijkhuis, P.; Ramulu, K.S.

    2007-01-01

    The process of synchronization and micro-nuclei induction in a suspension culture of Beta vulgaris, was induced by the sequential treatment with the DNA-synthesis inhibitor aphidicolin (30 mu M, 24 h) and the spindle-toxin amiprophos-methyl (32 mu M, 24 h). Mitotic arrest of divisions, spreading of

  16. Radiation induced graft copolymerization of jute fibre

    International Nuclear Information System (INIS)

    Al-Siddique, F.R.; Khan, A.U.; Sheikh, R.A.

    1983-01-01

    Graft copolymerized jute fibres (GCJF) were prepared by γ-ray induced graft copolymerization of various monomers onto bleached and de-waxed jute samples. The effect of γ-ray dose on the tendency of various monomers to form graft co-polymer was studied. It was found that the tendency decreases as follows: methylmethacrylate (MMA)>acrylonitrile (AN)>styrene (STY)>vinylacetate (VA). When the effect of monomer concentration on the formation of graft co-polymer was studied, it was found that a mixture of AN and STY gave a higher amount of grafting than what was observed for STY or AN alone, when used at a comparable concentration. A study on the effect of concentration of methyl alcohol (a swelling agent for jute) on the tendency of the monomers to form graft co-polymer showed that although there is no effect when only AN is used, an appreciable effect is observed if AN is mixed with STY. In the later case the tendency of graft co-polymerization increases with the increase of CH 3 OH concentration. It was further observed that the increase of CH 3 OH also has a positive influence on MMA to form graft co-polymer in the range of 40-90% CH 3 OH. The affinity of GCJF towards moisture has been found to decrease with the increase of polymer loading onto jute. The presence of swelling agents during graft copolymer formation was also found to decrease the affinity of GCJF towards moisture. (author)

  17. Radiation-induced erectile dysfunction: Recent advances and future directions

    Directory of Open Access Journals (Sweden)

    Javed Mahmood, PhD

    2016-07-01

    Full Text Available Prostate cancer is one of the most prevalent cancers and the second leading cause of cancer-related deaths in men in the United States. A large number of patients undergo radiation therapy (RT as a standard care of treatment; however, RT causes erectile dysfunction (radiation-induced erectile dysfunction; RiED because of late side effects after RT that significantly affects quality of life of prostate cancer patients. Within 5 years of RT, approximately 50% of patients could develop RiED. Based on the past and current research findings and number of publications from our group, the precise mechanism of RiED is under exploration in detail. Recent investigations have shown prostate RT induces significant morphologic arterial damage with aberrant alterations in internal pudendal arterial tone. Prostatic RT also reduces motor function in the cavernous nerve which may attribute to axonal degeneration may contributing to RiED. Furthermore, the advances in radiogenomics such as radiation induced somatic mutation identification, copy number variation and genome-wide association studies has significantly facilitated identification of biomarkers that could be used to monitoring radiation-induced late toxicity and damage to the nerves; thus, genomic- and proteomic-based biomarkers could greatly improve treatment and minimize arterial tissue and nerve damage. Further, advanced technologies such as proton beam therapy that precisely target tumor and significantly reduce off-target damage to vital organs and healthy tissues. In this review, we summarize recent advances in RiED research and novel treatment modalities for RiED. We also discuss the possible molecular mechanism involved in the development of RiED in prostate cancer patients. Further, we discuss various readily available methods as well as novel strategies such as stem cell therapies, shockwave therapy, nerve grafting with tissue engineering, and nutritional supplementations might be used to

  18. 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.

  19. Design Methodologies and to Combat Radiation Induced Corruption in FPGAs and SoCs, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Traditional radiation hardened by process (RHBP) and radiation hardened by design (RHBD) techniques have seen success in mitigating the effects of radiation induced...

  20. Apoptosis induced by high- and low-LET radiations

    International Nuclear Information System (INIS)

    Hendry, J.H.; Potten, C.S.; Merritt, A.

    1995-01-01

    Cell death after irradiation occurs by apoptosis in certain cell populations in tissues. The phenomenon also occurs after high linear energy transfer (LET) irradiation, and the relative biological effectiveness (RBE) is 3 to 4 (with respect to low-LET radiation and apoptosis in intestinal crypts) for neutrons with energies of 14 MeV and up to 600 MeV. It is thought that p53 plays a role in the phenomenon, as radiation-induced apoptosis is not observed in p53-null animals. (orig.)

  1. The effect of caffeine on radiation-induced division delay

    International Nuclear Information System (INIS)

    Snyder, M.H.; Kimler, B.F.; Leeper, D.B.

    1977-01-01

    Caffeine (100 μg/ml) was added to monolayer cultures of Chinese hamster ovary cells coincident with 60 Co γ-irradiation (75 to 300 rad). The results indicated that caffeine (at concentrations that did not perturb cell-cycle progression as monitored by the mitotic selection technique) exerted a protective effect against radiation-induced division delay. This protection consisted of an increase in the number of cells that were refractory to the radiation insult, as well as a decrease in the average time that non-refractory cells were delayed before they recovered their ability to progress through the cell cycle. (U.K.)

  2. Bystander effect induced by ionizing radiation and its application

    International Nuclear Information System (INIS)

    Chen Feng; Tu Yu

    2009-01-01

    An indirect effect induced by ionizing radiation called bystander effect is being highly concentrated. Many domestic and foreign researchers have verified the existence of bystander effect and have got more understanding of the mechanism with advanced detection techniques and methods. So far, the research about it has expanded from a single cell to multiple cells, from the in vitro to the whole, and has extended to in vivo from in vitro, which provides powerful evidence to explain how bystander effects happen and the regulation mechanism and especially gives scientific evidence to clinical radiation oncology application in the future. (authors)

  3. Radiation-induced volatile hydrocarbon production in platelets

    International Nuclear Information System (INIS)

    Radha, E.; Vaishnav, Y.N.; Kumar, K.S.; Weiss, J.F.

    1989-01-01

    Generation of volatile hydrocarbons (ethane, pentane) as a measure of lipid peroxidation was followed in preparations from platelet-rich plasma irradiated in vitro. The hydrocarbons in the headspace of sealed vials containing irradiated and nonirradiated washed platelets, platelet-rich plasma, or platelet-poor plasma increased with time. The major hydrocarbon, pentane, increased linearly and significantly with increasing log radiation dose, suggesting that reactive oxygen species induced by ionizing radiation result in lipid peroxidation. Measurements of lipid peroxidation products may give an indication of suboptimal quality of stored and/or irradiated platelets

  4. Effect of electrodes in the radiation induced conductivity for polymers

    International Nuclear Information System (INIS)

    Gregorio Filho, R.; Gross, B.

    1988-01-01

    Samples of PET with 23 μm thickness were exposed to continuous X-rays and the radiation-induced conductivity (RIC) as a function of time were measured, using electrodes of evaporated aluminum and gold. The results showed that the use of higher atomic number metal electrodes increase the received dose rate by sample, without almost modifying the time evolution of the RIC or its dependence with the applied electric field intensity. It is also showed that this increase is caused by the electrode placed in the face of the sample where the radiation strikes, as well as by the one placed in the oposite face. (author) [pt

  5. Delayed radiation-induced necrosis of the brain stem

    International Nuclear Information System (INIS)

    Yukawa, Osamu; Kodama, Yasunori; Kyoda, Jun; Yuki, Kiyoshi; Taniguchi, Eiji; Katayama, Shoichi; Hiroi, Tadashi; Uozumi, Toru.

    1993-01-01

    A 46-year-old man had surgery for a mixed glioma of the frontotemporal lobe. Postoperatively he received 50 Gy of irradiation. Sixteen months later he developed left hemiparesis and left facial palsy. MRI revealed lesion brain stem and basal ganglia. Despite chemotherapy and an additional 50 Gy dose, the patient deteriorated. Autopsy revealed a wide spread radiation-induced necrosis in the right cerebral hemisphere, midbrain and pons. In radiation therapy, great care must be taken to protect the normal brain tissue. (author)

  6. The induced radioactivity danger parameter for gamma radiation

    International Nuclear Information System (INIS)

    Perry, D.R.

    1985-07-01

    Dosimetric and practical aspects of the induced radioactivity danger parameter, as used for calculating the gamma radiation dose rate near to objects that have been exposed to high energy radiation, are examined. A simplified and more generally applicable method of calculation is proposed, based on energy balance in homogeneous media. The problems of applying this in practice are discussed, and it is shown that corrections are generally small enough to be neglected in many practical applications. Examples of calculations by previous and proposed methods are given. (author)

  7. Radiation-induced invagination of the nuclear envelope

    International Nuclear Information System (INIS)

    Szekely, J.G.; Copps, T.P.; Morash, B.D.

    1980-01-01

    Using electron microscopy, we have measured radiation-induced invagination of the nuclear envelope of Chinese hamster V-79 and mouse L cells to produce a quantifiable radiation endpoint on a membrane system. In the dose ranges measured (800 to 3000 rad in L cells and 1270 to 5700 rad in V-79 cells), the amount of invagination increased with dose and continued to develop in intact cells for up to 72 hr after the original population was irradiated. Small vacuoles, which sometimes appeared in the nuclei of L cells, were also more numerous in irradiated cells and increased with dose and incubation time in a similar fashion to invagination development

  8. 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

  9. Water mutagenic potential assessment on a semiarid aquatic ecosystem under influence of heavy metals and natural radioactivity using micronuclei test.

    Science.gov (United States)

    Chaves, Luiz Cláudio Cardozo; Navoni, Julio Alejandro; de Morais Ferreira, Douglisnilson; Batistuzzo de Medeiros, Silvia; Ferreira da Costa, Thomas; Petta, Reinaldo Antônio; Souza do Amaral, Viviane

    2016-04-01

    The contamination of water bodies by heavy metals and ionizing radiation is a critical environmental issue, which can affect water quality and, thus, human health. This study aimed to evaluate the water quality of the Boqueirão de Parelhas Dam in the Brazilian semiarid region. A 1-year study (2013-2014) was performed through the assessment of physicochemical parameters, heavy metal content, and radioactivity along with the mutagenicity potential of water using micronuclei test in Orechromis niloticus (in vivo) and the cytokinesis-block micronucleus (CBMN) assay in human lymphocytes (in vitro). A deterioration of water organoleptics characteristics by the presence of high levels of sulfate and total solids was observed. High concentrations of aluminum, nickel, silver, and lead along with the alpha particle content were higher than the limits suggested by the World Health Organization and Brazilian legislation for drinking water. An increase in the frequency of micronuclei and nuclear abnormalities was observed in both experimental models. The results obtained confirmed the mutagenic potential present in water samples. This study highlights that geogenic agents affect water quality becoming a human health concern to be taken into account due to the relevance that this water reservoir has in the region.

  10. Contribution to the study of radiation induced bone tissue cancer

    International Nuclear Information System (INIS)

    Bouet, Monique.

    1975-01-01

    In this work four original observations of more or less long-delayed cancers induced by ionizing radiations are compared with 34 other cases in the literature, after which an attempt is made to establish a general and prognostic synthesis of the results; the indications to emerge are as follows: - Ionizing radiation-induced cancers are very rare, especially when compared with the extensive therapeutic use made of X-rays; - The probability of radio-cancer formation, though no figures are given in the many papers consulted, seems nevertheless to be higher in cases of benign lesion irradiation; - Induced cancers have been observed after treatments with all types of radiation, whether or not the lesion is tumoral or cancerous, whatever the patient's age at the time of irradiations; - As a general rule these neoplasms appear after a variable latency period but usually from the 6th post-radiotherapy year onwards, with a greater frequency range between 6 and 12 years; - These induced cancers are generally epitheliomas or sarcomas, the latter being noticeably more predominant than in the case of spontaneous cancers. Leukoses may also be observed [fr

  11. The process and promotion of radiation-induced cell death

    International Nuclear Information System (INIS)

    Sasaki, Hiroshi

    1998-01-01

    Radiation-induced cell death is divided into reproductive and interphase death, whose process can be revealed by time-lapse observations. Pedigree analyses of progenies derived from a surviving progenitor cell have shown that moribund cells appear in clusters among cells which are apparently undamaged (lethal sectoring). Sister cell fusion, which likely results from chromosome bridge, is the most frequently observed cell abnormality leading to reproductive death. While interphase death does not occur unless the dose exceeds 10 Gy for low LET radiation such as X-rays, high-LET radiation is very effective at inducing interphase death (RBE: ≅3 at 230 keV/μm). Expression or fixation of potentially lethal damage (PLD) is closely associated with cell cycle events and enhanced by inducing premature chromosome condensation (PCC) at a nonpermissive temperature in tsBN2 cells with a ts-defect in RCC1 protein (a regulator of chromatin condensation) which monitors the completion of DNA replication. Furthermore, higher-order structural changes in nuclear matrix such as induced by leptomycin B, an inhibitor of CRM1 (chromosome region maintenance) protein, also play an important role in the fixation of PLD. (author)

  12. Caffeine ameliorates radiation-induced skin reactions in mice but does not influence tumour radiation response

    Energy Technology Data Exchange (ETDEWEB)

    Hebbar, S.A.; Mitra, A.K.; George, K.C.; Verma, N.C. [Radiation Biology Division, Bhabha Atomic Research Centre, Trombay, Mumbai (India)]. E-mail: ncverma@apsara.barc.ernet.in

    2002-03-01

    Intramuscular administration of caffeine at a dose of 80 mg kg{sup -1} body weight to the gastrocnemius muscles of Swiss mice 5 min prior to local irradiation (35 Gy) of the leg delayed the progression of radiation-induced skin reactions in such animals. While 90% epilation with reddening of the skin was noted in animals treated with radiation alone, animals pretreated with caffeine suffered only partial hair loss with slight reddening of the skin on the 16th and 20th days post-irradiation. Beyond the 28th day, damage scores in irradiated feet for both the groups were similar (score 3) and remained unchanged until the 32nd day and then decreased and disappeared completely in both treatment groups by the 40th day after irradiation. In addition, the effect of caffeine on the radiation response of a mouse fibrosarcoma was investigated. Results showed that intratumoral administration of caffeine at a dose of 80 mg kg{sup -1} body weight 5 min prior to local exposure of tumours to 10 Gy of {sup 60}Co {gamma}-rays did not influence the response of tumours to radiation. The present study thus showed that although caffeine ameliorated radiation-induced skin reactions in the mouse leg, it did not affect the tumour radiation response, indicating its potential application in cancer radiotherapy. (author)

  13. Ionizing radiation induced genomic instability and its relation to radiation carcinogenesis

    International Nuclear Information System (INIS)

    Wang Zhongwen

    2000-01-01

    There are widespread testimonies that the genomic instability induced by ionizing irradiation exits in mammal and its vitro cells. Genomic instability can enhance the frequency of genetic changes among the progeny of the original irradiated cells. In the radiation-leukemogenesis, there is no significant difference between controls and CBA/H mouses of PPI (preconception patent irradiation), but the offsprings of the PPI recipients show a different character (shorter latent period and higher incidence) after an extra γ-radiation. The radiation-induced genomic instability may get the genome on the verge of mutation and lead to carcinogens following mutation of some critical genes. The genomic instability, as the early event of initiation of carcinomas, may be play a specific or unique role

  14. A juvenile case of radiation-induced meningioma two years after radiation for craniopharyngioma

    International Nuclear Information System (INIS)

    Kano, Tomoaki; Zama, Akira; Ono, Nobuo; Nakamura, Tadashi; Tamura, Masaru; Ohe, Tihiro; Nakazato, Yoichi

    1994-01-01

    The patient was a 7-years-old boy who received radiation therapy of 50 Gy after total gross removal of a craniopharyngioma. After two years a follow up CT scan showed a new enhanced lesion in the right temporal tip within the previous irradiation field. Total removal of the tumor was performed and its histological examination showed it to be an atypical meningioma. This atypical meningioma satisfied Cahan's criteria. So we diagnosed this atypical meningioma as radiation-induced meningioma. Immunohistochemically this meningioma stained for Vimentin. An electron microscopical examination showed neither desmosome nor interdigitation. The score of Ki-67 and BrdU-L. I was very small. Compared with previously reported juvenile radiation-induced meningioma, the latency was very short. The patient received growth hormone (GH) replacement therapy. We suspected relation between GH replacement therapy and short latency. He was discharged without any new neurological deficits and we haven't detected tumor recurrence for two years. (author)

  15. Radiation induced defect flux behaviors at zirconium based component

    International Nuclear Information System (INIS)

    Choi, Sang Il; Kim, Ji Hyun; Kwon, Jun Hyun; Lee, Gyeong Geun

    2013-01-01

    In commercial reactor core, structure materials are located in high temperature and high pressure environment. Therefore, main concern of structure materials is corrosion and mechanical properties change than radiation effects on materials. However, radiation effects on materials become more important phenomena because research reactor condition is different from commercial reactor. The temperature is lower than 100 .deg. C and radiation dose is much higher than that of commercial reactor. Among the radiation effect on zirconium based metal, radiation induced growth (RIG), known as volume conservative distortion, is one of the most important phenomena. Recently, theoretical RIG modeling based on radiation damage theory (RDT) and balance equation are developed. However, these growth modeling have limited framework of single crystal and high temperature. To model theoretical RIG in research reactor, qualitative mechanism must be set up. Therefore, this paper intent is establishing defect flux mechanism of zirconium base metal in research reactor for RIG modeling. After than theoretical RIG work will be expanded to research reactor condition

  16. 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.

  17. Countermeasures for Space Radiation Induced Malignancies and Acute Biological Effects

    Science.gov (United States)

    Kennedy, Ann

    The hypothesis being evaluated in this research program is that control of radiation induced oxidative stress will reduce the risk of radiation induced adverse biological effects occurring as a result of exposure to the types of radiation encountered during space travel. As part of this grant work, we have evaluated the protective effects of several antioxidants and dietary supplements and observed that a mixture of antioxidants (AOX), containing L-selenomethionine, N-acetyl cysteine (NAC), ascorbic acid, vitamin E succinate, and alpha-lipoic acid, is highly effective at reducing space radiation induced oxidative stress in both in vivo and in vitro systems, space radiation induced cytotoxicity and malignant transformation in vitro [1-7]. In studies designed to determine whether the AOX formulation could affect radiation induced mortality [8], it was observed that the AOX dietary supplement increased the 30-day survival of ICR male mice following exposure to a potentially lethal dose (8 Gy) of X-rays when given prior to or after animal irradiation. Pretreatment of animals with antioxidants resulted in significantly higher total white blood cell and neutrophil counts in peripheral blood at 4 and 24 hours following exposure to doses of 1 Gy and 8 Gy. Antioxidant treatment also resulted in increased bone marrow cell counts following irradiation, and prevented peripheral lymphopenia following 1 Gy irradiation. Supplementation with antioxidants in irradiated animals resulted in several gene expression changes: the antioxidant treatment was associated with increased Bcl-2, and decreased Bax, caspase-9 and TGF-β1 mRNA expression in the bone marrow following irradiation. These results suggest that modulation of apoptosis may be mechanistically involved in hematopoietic system radioprotection by antioxidants. Maintenance of the antioxidant diet was associated with improved recovery of the bone marrow following sub-lethal or potentially lethal irradiation. Taken together

  18. The use of unstable chromosome aberrations and micronuclei in the individual biomonitoring: a comparative study; Emprego das aberracoes cromossomicas instaveis e micronucleos no biomonitoramento individual: estudo comparativo

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes, Thiago de Salazar e

    2005-02-15

    Biodosimetry is based on the investigation of radioinduced biological effects in order to correlate them with the absorbed dose. The quantification of unstable chromosome aberrations and micronuclei, in peripheral blood lymphocytes, are two methods commonly used in biodosimetry. In this context, the aim of this research was to compare these methods in the biomonitoring of health care professionals occupationally exposed to ionizing radiation. In parallel, the technique of C-banding was evaluated for quality control of unstable chromosome aberrations analyses. Thus, samples of peripheral blood from health care professionals of three hospitals from Recife (Brazil) were collected, and the lymphocytes cultures were carried out based on the cytogenetic classical technique. It was pointed out that analysis of micronuclei is faster than the unstable chromosome aberrations ones, which suggests the use of the former in preliminary evaluation in cases of suspected accidental exposure. C-banding technique was efficient, as confirmatory test, in the identification of dicentrics and rings during the analyses of unstable chromosome aberrations, being able to be applied in the quality control in biodosimetry. The comparison between the individual work conditions with the frequencies of unstable aberrations and micronuclei obtained from cytogenetic analysis, resulted in the change of behavior of the professionals involved in this research, with a better observance of the radioprotection standards. (author)

  19. Structure and radiation induced swelling of steels and alloys

    International Nuclear Information System (INIS)

    Parshin, A.M.

    1983-01-01

    Regularities of vacancy void formation and radiation induced swelling of austenitic chromium-nickel steels and alloyse ferritic steels as well as titanium α-alloys under radiation by light and heavy ions and neutrons are considered. Possible methods for preparation of alloys with increased resistance to radiation swelling are described. Accounting for investigations into ferritic steels and α-alloys of titanium the basic way of weakening vacancy smelling is development of continuous homogeneous decomposition of solid solution using alloying with vividly expressed incubation period at a certain volumetric dilatation as well as decompositions of the type of ordering, K-state, lamination of solid solutions, etc. Additional alloying of solid solutions is also shown to be necessary for increasing recrystallization temperature of cold-deformed steel

  20. Radiation-induced degradation of chlorophenols in aqueous solution

    International Nuclear Information System (INIS)

    Hu Jun; Wang Jianlong

    2005-01-01

    Radiation processing is a promising technology for applications in environmental protection, which includes wastewater treatment, micro-polluted drinking water treatment and the treatment of industrial wastewater containing various toxic and nonbiodegradable pollutants, municipal sewage and sludge disinfection, and flue gas desulfuration, etc. The paper reviews manly the recent progresses in radiolysis of chlorinated phenols in aqueous solution. Advantages and existing problems of the method in this particular application ar discussed. Mechanisms of radiation-induced degradation of chlorophenols, and the factors affecting the degradation efficiency, are discussed, too. It is concluded that combined approaches, such ozone oxidation and other methods, are of great help to the radiation processing application, in terms of lowering down the dose and increasing the efficient of pollutant removal. (authors)

  1. Radiation-induced bilateral common carotid artery stenosis

    International Nuclear Information System (INIS)

    Kobayashi, Nobuaki; Nakagawa, Yoku; Tashiro, Kunio; Abe, Hiroshi

    1986-01-01

    A case of radiation-induced bilateral common carotid artery stenosis is reported. This 60 years old housewife was hospitalized in 1982 because of sudden onset of mild left hemiparesis. Twenty-five years ago, she underwent radiation therapy of approximately 5,000 rads to the anterior cervical region because of thyroid cancer. Angiograms in 1982 revealed bilateral common carotid artery stenosis, especially in the right common carotid artery, the legion of which were included within the field of radiation performed in 1952. Right thromboendarterectomy was performed in 1983. At operation, slight periarterial fibrosis with calcified arteriosclerotic change was found, and dissection between the thickened intima and the media was not so difficult. Histological change of resected thromboendarterium was similar to the one observed in the pure arteriosclerotic disease. (author)

  2. Radiation-induced phase transformation in ferromagnetic perovskite

    Energy Technology Data Exchange (ETDEWEB)

    Podsekin, A K; Dem' yanov, V V; Ivanova, V V; Venevtsev, Yu N [Nauchno-Issledovatel' skij Fiziko-Khimicheskij Inst., Moscow (USSR)

    1976-12-01

    An effect of neutron irradiation inducing a phase transition in ferromagnetic perovskite, Sr/sub 0.3/La/sub 0.7/MnO/sub 3/, has been discovered and studied. It is shown that a change in the Curie temperature is proportional to the dose of reactor irradiation. A decrease in the temperature of the phase transition with the concentration of radiation defects is accompanied by an increase in the electrical specific resistance and a change in the initial lattice parameters. It is shown that the radiation shift is due to at least two causes, viz. to an increase in the parameters of the elementary cell and the growth of the electrical specific resistance as a result of bounded electron states' forming on the radiation defects.

  3. 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

  4. Probabilistic methodology for estimating radiation-induced cancer risk

    International Nuclear Information System (INIS)

    Dunning, D.E. Jr.; Leggett, R.W.; Williams, L.R.

    1981-01-01

    The RICRAC computer code was developed at Oak Ridge National Laboratory to provide a versatile and convenient methodology for radiation risk assessment. The code allows as input essentially any dose pattern commonly encountered in risk assessments for either acute or chronic exposures, and it includes consideration of the age structure of the exposed population. Results produced by the analysis include the probability of one or more radiation-induced cancer deaths in a specified population, expected numbers of deaths, and expected years of life lost as a result of premature fatalities. These calculatons include consideration of competing risks of death from all other causes. The program also generates a probability frequency distribution of the expected number of cancers in any specified cohort resulting from a given radiation dose. The methods may be applied to any specified population and dose scenario

  5. Radiation-Induced Prompt Photocurrents in Microelectronics Physics

    CERN Document Server

    Dodd, P E; Buller, D L; Doyle, B L; Vizkelethy, G; Walsh, D S

    2003-01-01

    The effects of photocurrents in nuclear weapons induced by proximal nuclear detonations are well known and remain a serious hostile environment threat for the US stockpile. This report describes the final results of an LDRD study of the physical phenomena underlying prompt photocurrents in microelectronic devices and circuits. The goals of this project were to obtain an improved understanding of these phenomena, and to incorporate improved models of photocurrent effects into simulation codes to assist designers in meeting hostile radiation requirements with minimum build and test cycles. We have also developed a new capability on the ion microbeam accelerator in Sandia's Ion Beam Materials Research Laboratory (the Transient Radiation Microscope, or TRM) to supply ionizing radiation in selected micro-regions of a device. The dose rates achieved in this new facility approach those possible with conventional large-scale dose-rate sources at Sandia such as HERMES III and Saturn. It is now possible to test the phy...

  6. Radiation - induced changes in the optical properties of hemoglobin molecule

    International Nuclear Information System (INIS)

    Selim, N.S; El-Marakby, S.M.

    2009-01-01

    Adult male albino rats were exposed to different doses of gamma radiation from Cs-137 source. Hemoglobin samples were analyzed 24 hrs after irradiation. The UV-visible spectrum of hemoglobin molecule was measured in the range 200 to 700 nm. The overall spectrum of the hemoglobin molecule showed hypochromicity that increased with dose increase. To investigate the effect of radiation on the hemoglobin molecule, different parameters of the spectrum were calculated: molar absorption coefficient, absorption cross section, transition dipole moment , dipole length, the optical energy gap and activation energy for each characteristic peak. The obtained results revealed that the radiation effect can induce rearrangement of the transition dipole moments and change molecular energy levels of the hemoglobin molecule

  7. Vanguards of paradigm shift in radiation biology. Radiation-induced adaptive and bystander responses

    International Nuclear Information System (INIS)

    Matsumoto, Hideki; Hamada, Nobuyuki; Kobayashi, Yasuhiko; Takahashi, Akihisa; Ohnishi, Takeo

    2007-01-01

    The risks of exposure to low dose ionizing radiation (below 100 mSv) are estimated by extrapolating from data obtained after exposure to high dose radiation, using a linear no-threshold model (LNT model). However, the validity of using this dose-response model is controversial because evidence accumulated over the past decade has indicated that living organisms, including humans, respond differently to low dose/low dose-rate radiation than they do to high dose/high dose-rate radiation. In other words, there are accumulated findings which cannot be explained by the classical ''target theory'' of radiation biology. The radioadaptive response, radiation-induced bystander effects, low-dose radio-hypersensitivity, and genomic instability are specifically observed in response to low dose/low dose-rate radiation, and the mechanisms underlying these responses often involve biochemical/molecular signals that respond to targeted and non-targeted events. Recently, correlations between the radioadaptive and bystander responses have been increasingly reported. The present review focuses on the latter two phenomena by summarizing observations supporting their existence, and discussing the linkage between them from the aspect of production of reactive oxygen and nitrogen species. (author)

  8. 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.

  9. Depleted uranium and radiation - induced lung cancer and leukaemia

    International Nuclear Information System (INIS)

    Mould, R.F.

    2002-01-01

    Reports of leukaemias and other cancers among servicemen who took part in the 1991 Gulf war or in the more recent operations in the Balkans are of continuing interest, as is the possibility, however slight, that depleted uranium (DU) is one of the causative factors. This commentary includes the results of a UK epidemiological study on the mortality of Gulf war veterans and , although not containing information on DU exposure, gives data on overall levels of mortality and therefore carries more weight than anecdotal reports. Also included are brief summaries on radiation-induced lung cancer in uranium workers as well as radiation-induced leukaemia in Japanese atomic bomb survivors and patients ankylosing spondylitis treated using x-rays. This commentary concludes with a critique of Iraqi cancer statistics as well as giving information on environmental contamination in Kosovo and the use of DU ammunition. (author)

  10. Caffeine Markedly Enhanced Radiation-Induced Bystander Effects

    International Nuclear Information System (INIS)

    Jiang Erkang; Wu Lijun

    2009-01-01

    In this paper it is shown that incubation with 2 mM caffeine enhanced significantly the MN (micronucleus) formation in both the 1 cGy α-particle irradiated and non-irradiated bystander regions. Moreover, caffeine treatment made the non-irradiated bystander cells more sensitive to damage signals. Treated by c-PTIO(2-(4-carboxy-phenyl)- 4,4,5,5-tetramethyl-imidazoline-1-oxyl-3-oxide), a nitric oxide (NO) scavenger, the MN frequencies were effectively inhibited, showing that nitric oxide might be very important in mediating the enhanced damage. These results indicated that caffeine enhanced the low dose α-particle radiation-induced damage in irradiated and non-irradiated bystander regions, and therefore it is important to investigate the relationship between the radiosensitizer and radiation-induced bystander effects (RIBE). (ion beam bioengineering)

  11. Promotion of initiated cells by radiation-induced cell inactivation.

    Science.gov (United States)

    Heidenreich, W F; Paretzke, H G

    2008-11-01

    Cells on the way to carcinogenesis can have a growth advantage relative to normal cells. It has been hypothesized that a radiation-induced growth advantage of these initiated cells might be induced by an increased cell replacement probability of initiated cells after inactivation of neighboring cells by radiation. Here Monte Carlo simulations extend this hypothesis for larger clones: The effective clonal expansion rate decreases with clone size. This effect is stronger for the two-dimensional than for the three-dimensional situation. The clones are irregular, far from a circular shape. An exposure-rate dependence of the effective clonal expansion rate could come in part from a minimal recovery time of the initiated cells for symmetric cell division.

  12. Radiation-induced tritium labelling and product analysis

    Energy Technology Data Exchange (ETDEWEB)

    Peng, C.T. (California Univ., San Francisco, CA (United States). Dept. of Pharmaceutical Chemistry)

    1993-05-01

    By-products formed in radiation-induced tritium labelling are identified by co-chromatography with authentic samples or by structure prediction using a quantitative structure-retention index relationship. The by-products, formed from labelling of steroids, polynuclear aromatic hydrocarbons, 7-membered heterocyclic ring structures, 1,4-benzodiazepines, 1-haloalkanes, etc. with activated tritium and adsorbed tritium, are shown to be specifically labelled and anticipated products from known chemical reactions. From analyses of the by-products, one can conclude that the hydrogen abstraction by tritium atoms and the substitution by tritium ions are the mechanisms of labelling. Classification of the tritium labelling methods, on the basis of the type of tritium reagent, clearly shows the active role played by tritium atoms and ions in radiation-induced methods. (author).

  13. Radiation induced graft copolymerization of acrylamide onto poly (3-hydroxybutyrate)

    International Nuclear Information System (INIS)

    Gonzalez Torres, Maykel; Rapado Paneque, Manuel; Paredes Zaldivar, Mayte; Altanes Valentin, Sonia; Barrera Gonzalez, Gisela

    2008-01-01

    The graft copolymer poly (3-hydroxybutyrate)-g- polyacrylamide [P (HB-g-AAm)] was synthesized by radiation induced graft copolymerization of acrylamide onto poly (3-hydroxybutyrate). The study was conducted by the simultaneous irradiation method. The structure of [P (HB-g-AAm)] was identified by Fourier Transform Infrared (FTIR) spectroscopy. Thermal behavior of the graft copolymer was also studied by Thermal Gravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC). From the results it was found that FTIR studies showed new signals (stretching -N-H) as strong evidence of grafting. The grafting degree was found to be 10 % and the thermodynamic parameter obtained from the DSC thermogram of plain PHB and the graft copolymer varied showing decrease in the material crystallinity and increase in the glass transition temperature. These results demonstrate that the radiation induced graft copolymerization reaction of acrylamide onto PHB was successively achieved. (Author)

  14. Non-radiation induced signals in TL dosimetry

    International Nuclear Information System (INIS)

    German, U.; Weinstein, M.

    2002-01-01

    One source of background signals, which are non-radiation related, is the reader system and it includes dark current, external contaminants and electronic spikes. These factors can induce signals equivalent to several hundredths of mSv. Mostly, the effects are minimised by proper design of the TLD reader, but some effects are dependent on proper operation of the system. The other main group of background signals originate in the TL crystal and is due to tribothermoluminescence, dirt, chemical reactions and stimulation by visible or UV light. These factors can have a significant contribution, equivalent to over several mSv, depending on whether the crystal is bare or protected by PTFE. Working in clean environments, monitoring continuously the glow curve and performing glow curve deconvolution are suggested to minimise non-radiation induced spurious signals. (author)

  15. Radiation-induced transient absorption in single mode optical fibers

    International Nuclear Information System (INIS)

    Looney, L.D.; Lyons, P.B.

    1988-01-01

    This paper reviews the measurements conducted by the Los Alamos National Laboratory in support of these NATO efforts wherein radiation-induced transient absorption was measured over time ranges from a few ns to several μs for two single mode fibers. Experimental conditions were varied to provide data for future development of standarized test conditions for single mode fibers. 8 refs., 11 figs

  16. Radiation-induced squamous carcinoma arising within a seborrhoeic keratosis

    Energy Technology Data Exchange (ETDEWEB)

    Suvarna, S.K.; Bagary, M.; Glazer, G. (Saint Mary' s Hospital, London (United Kingdom))

    1993-04-01

    Seborrhoeic keratoses (SK) are common skin tumours. They are benign, and present little difficulty in management. However, rare malignant transformation is recognized. The authors report a case of a squamous cell carcinoma arising from dysplastic changes within a long-standing SK on the chest wall of a 75-year-old retired radiologist, and consider the role of radiation in inducing malignant change within SKs. (author).

  17. Radiation-induced squamous carcinoma arising within a seborrhoeic keratosis

    International Nuclear Information System (INIS)

    Suvarna, S.K.; Bagary, M.; Glazer, G.

    1993-01-01

    Seborrhoeic keratoses (SK) are common skin tumours. They are benign, and present little difficulty in management. However, rare malignant transformation is recognized. The authors report a case of a squamous cell carcinoma arising from dysplastic changes within a long-standing SK on the chest wall of a 75-year-old retired radiologist, and consider the role of radiation in inducing malignant change within SKs. (author)

  18. Silicon radiation detector analysis using back electron beam induced current

    International Nuclear Information System (INIS)

    Guye, R.

    1987-01-01

    A new technique for the observation and analysis of defects in silicon radiation detectors is described. This method uses an electron beam from a scanning electron microscope (SEM) impinging on the rear side of the p + n junction of the silicon detector, which itself is active and detects the electron beam induced current (EBIC). It is shown that this current is a sensitive probe of localized trapping centers, either at the junction surface or somewhere in the volume of the silicon crystal. (orig.)

  19. Role of Neurotensin in Radiation-Induced Hypothermia in Rats

    Science.gov (United States)

    1991-01-01

    radiation-in- appears to mediate neurotensin-induced hylothemnia becaus duced hypothermia and to elucidate the mechanisms in- th mas cell stabilizer...of neurotensin an- tibody alone had no effect on body temperature. An ICV administration of the mast cell stabilizer disodium cromo- 30 3 120glycate...David Kopf Instruments. No. 320) A single cannula was in- pear to be centrally mediated (4. 5). H- stamine has been serteil aseptically into the

  20. Radiation pressure induced difference-sideband generation beyond linearized description

    OpenAIRE

    Xiong, Hao; Fan, Y. W.; Yang, X.; Wu, Y.

    2016-01-01

    We investigate radiation-pressure induced generation of the frequency components at the difference-sideband in an optomechanical system, which beyond the conventional linearized description of optomechanical interactions between cavity fields and the mechanical oscillation. We analytically calculate amplitudes of these signals, and identify a simple square-root law for both the upper and lower difference-sideband generation which can describe the dependence of the intensities of these signals...