WorldWideScience

Sample records for bystander effect-induced mutagenicity

  1. Bystander effect-induced mutagenicity in HPRT locus of CHO cells following BNCT neutron irradiation: Characteristics of point mutations by sequence analysis

    Energy Technology Data Exchange (ETDEWEB)

    Kinashi, Yuko [Research Reactor Institute, Kyoto University, Kumatori-cho, Sennan-gun, Osaka (Japan)], E-mail: kinashi@rri.kyoto-u.ac.jp; Suzuki, Minoru; Masunaga, Shinichiro; Ono, Koji [Research Reactor Institute, Kyoto University, Kumatori-cho, Sennan-gun, Osaka (Japan)

    2009-07-15

    To investigate bystander mutagenic effects induced by alpha particles during boron neutron capture therapy (BNCT), we mixed cells that were electroporated with borocaptate sodium (BSH), which led to the accumulation of {sup 10}B inside the cells, with cells that did not contain the boron compound. BSH-containing cells were irradiated with {alpha} particles produced by the {sup 10}B(n,{alpha}){sup 7}Li reaction, whereas cells without boron were only affected by the {sup 1}H(n,{gamma}){sup 2}H and {sup 14}N(n,{rho}){sup 14}C reactions. The frequency of mutations induced in the hypoxanthine-guanine phosphoribosyltransferase (HPRT) locus was examined in Chinese hamster ovary (CHO) cells irradiated with neutrons (Kyoto University Research Reactor: 5 MW). Neutron irradiation of 1:1 mixtures of cells with and without BSH resulted in a survival fraction of 0.1, and the cells that did not contain BSH made up 99.4% of the surviving cell population. Using multiplex polymerase chain reactions (PCRs), molecular structural analysis indicated that most of the mutations induced by the bystander effect were point mutations and that the frequencies of total and partial deletions induced by the bystander effect were lower than those resulting from the {alpha} particles produced by the {sup 10}B(n,{alpha}){sup 7}Li reaction or the neutron beam from the {sup 1}H(n,{gamma}){sup 2}H and {sup 14}N(n,{rho}){sup 14}C reactions. The types of point mutations induced by the BNCT bystander effect were analyzed by cloning and sequencing methods. These mutations were comprised of 65.5% base substitutions, 27.5% deletions, and 7.0% insertions. Sequence analysis of base substitutions showed that transversions and transitions occurred in 64.7% and 35.3% of cases, respectively. G:C{yields}T:A transversion induced by 8-oxo-guanine in DNA occurred in 5.9% of base substitution mutants in the BNCT bystander group. The characteristic mutations seen in this group, induced by BNCT {alpha} particles

  2. Bystander effect of alpha-particle irradiation on mutagenicity and its associated mechanism

    International Nuclear Information System (INIS)

    Lu Ying; Yang Zhihua; Cao Zhenshan; Fan Feiyue; Zhu Maoxiang

    2004-01-01

    The work is to investigate α-particle irradiation-induced bystander effects on the mutagenicity in human chromosome 11 in the human-hamster hybrid (A L cells) and its possible mechanism. A L cells were used for assaying mutation rates of human chromosome 11 through screening mutants in the presence of anti-CD59 surface antigen antibody (S1) and complement. A grid was interposed between α-particle source and the cells being irradiated, so as to fix proportion of the irradiated cells (15%) and the bystander effects on the mutagenicity were detected. Free radical scavenger DMSO and intercellular communication inhibitor Lindane were selected to investigate the potential mechanism of α-particle induced bystander effect. There was clear dose-dependent relationship between mutation rate and the dose of alpha particle radiation. However, the mutant fractions of cell population shielded by the grid in α-particle irradiation system were much higher than the expected levels of irradiated cells. Lindane, but not DMSO, could obviously decrease this bystander effect induced by α-particle irradiation. Alpha-particle irradiation can induce bystander effect on the mutagenicity, in which intercellular communication may play important roles

  3. 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)

  4. Involvement of MAPK proteins in bystander effects induced by chemicals and ionizing radiation

    International Nuclear Information System (INIS)

    Asur, Rajalakshmi; Balasubramaniam, Mamtha; Marples, Brian; Thomas, Robert A.; Tucker, James D.

    2010-01-01

    Many studies have examined bystander effects induced by ionizing radiation, however few have evaluated the ability of chemicals to induce similar effects. We previously reported the ability of two chemicals, mitomycin C (MMC) and phleomycin (PHL) to induce bystander effects in normal human lymphoblastoid cell lines. The focus of the current study was to determine the involvement of the MAPK proteins in bystander effects induced by physical and chemical DNA damaging agents and to evaluate the effects of MAPK inhibition on bystander-induced caspase 3/7 activation. The phosphorylation levels of the MAPK proteins ERK1/2, JNK, and p38, were measured from 1 to 24 h following direct or bystander exposure to MMC, PHL or radiation. We observed transient phosphorylation, at early time points, of all 3 proteins in bystander cells. We also evaluated the effect of MAPK inhibition on bystander-induced caspase 3/7 activity to determine the role of MAPK proteins in bystander-induced apoptosis. We observed bystander-induced activation of caspase 3/7 in bystander cells. Inhibition of MAPK proteins resulted in a decrease in caspase 3/7 activity at the early time points, and the caspase activity increased (in the case of ERK inhibition) or returned to basal levels (in the case of JNK or p38 inhibition) between 12 and 24 h. PHL is considered to be a radiomimetic agent, however in the present study PHL behaved more like a chemical and not like radiation in terms of MAPK phosphorylation. These results point to the involvement of MAPK proteins in the bystander effect induced by radiation and chemicals and provide additional evidence that this response is not limited to radiation but is a generalized stress response in cells.

  5. 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

  6. Radiation and chemotherapy bystander effects induce early genomic instability events: telomere shortening and bridge formation coupled with mitochondrial dysfunction.

    LENUS (Irish Health Repository)

    Gorman, Sheeona

    2012-02-01

    The bridge breakage fusion cycle is a chromosomal instability mechanism responsible for genomic changes. Radiation bystander effects induce genomic instability; however, the mechanism driving this instability is unknown. We examined if radiation and chemotherapy bystander effects induce early genomic instability events such as telomere shortening and bridge formation using a human colon cancer explant model. We assessed telomere lengths, bridge formations, mitochondrial membrane potential and levels of reactive oxygen species in bystander cells exposed to medium from irradiated and chemotherapy-treated explant tissues. Bystander cells exposed to media from 2Gy, 5Gy, FOLFOX treated tumor and matching normal tissue showed a significant reduction in telomere lengths (all p values <0.018) and an increase in bridge formations (all p values <0.017) compared to bystander cells treated with media from unirradiated tissue (0Gy) at 24h. There was no significant difference between 2Gy and 5Gy treatments, or between effects elicited by tumor versus matched normal tissue. Bystander cells exposed to media from 2Gy irradiated tumor tissue showed significant depolarisation of the mitochondrial membrane potential (p=0.012) and an increase in reactive oxygen species levels. We also used bystander cells overexpressing a mitochondrial antioxidant manganese superoxide dismutase (MnSOD) to examine if this antioxidant could rescue the mitochondrial changes and subsequently influence nuclear instability events. In MnSOD cells, ROS levels were reduced (p=0.02) and mitochondrial membrane potential increased (p=0.04). These events were coupled with a decrease in percentage of cells with anaphase bridges and a decrease in the number of cells undergoing telomere length shortening (p values 0.01 and 0.028 respectively). We demonstrate that radiation and chemotherapy bystander responses induce early genomic instability coupled with defects in mitochondrial function. Restoring mitochondrial

  7. Elevated sodium chloride concentrations enhance the bystander effects induced by low dose alpha-particle irradiation

    International Nuclear Information System (INIS)

    Han Wei; Zhu Lingyan; Jiang Erkang; Wang Jun; Chen Shaopeng; Bao Linzhi; Zhao Ye; Xu An; Yu Zengliang; Wu Lijun

    2007-01-01

    Previous studies have shown that high NaCl can be genotoxic, either alone or combined with irradiation. However, little is known about the relationship between environmental NaCl at elevated conditions and radiation-induced bystander effects (RIBE). RIBE, which has been considered as non-targeted bystander responses, has been demonstrated to occur widely in various cell lines. In the present study, RIBE under the elevated NaCl culture condition was assessed in AG 1522 cells by both the induction of γ-H2AX, a reliable marker of DNA double-strand break (DSB) for the early process ( G -methyl-L-arginine, an inhibitor of nitric oxide synthase, the induced fraction of foci-positive cells was effectively inhibited both in 0.2 cGy α-particle irradiated and adjacent non-irradiated regions under either normal or elevated NaCl conditions. These results suggested that the cultures with elevated NaCl medium magnified the damage effects induced by the low dose α-particle irradiation and nitric oxide generated by irradiation was also very important in this process

  8. Elevated sodium chloride concentrations enhance the bystander effects induced by low dose alpha-particle irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Han Wei; Zhu Lingyan; Jiang Erkang; Wang Jun; Chen Shaopeng; Bao Linzhi; Zhao Ye; Xu An; Yu Zengliang [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Wu Lijun [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China)], E-mail: ljw@ipp.ac.cn

    2007-11-01

    Previous studies have shown that high NaCl can be genotoxic, either alone or combined with irradiation. However, little is known about the relationship between environmental NaCl at elevated conditions and radiation-induced bystander effects (RIBE). RIBE, which has been considered as non-targeted bystander responses, has been demonstrated to occur widely in various cell lines. In the present study, RIBE under the elevated NaCl culture condition was assessed in AG 1522 cells by both the induction of {gamma}-H2AX, a reliable marker of DNA double-strand break (DSB) for the early process (<1 h post irradiation), and the generation of micronuclei (MN), a sensitive marker for relative long process of RIBE. Our results showed that in the absence of irradiation, NaCl at elevated concentration such as 8.0, 9.0 and 10.0 g/L did not significantly increase the frequency of {gamma}-H2AX foci-positive cells and the number of foci per positive cell comparing with that NaCl at a normal concentration (6.8 g/L). However, with 0.2 cGy {alpha}-particle irradiation, the induced fraction of {gamma}-H2AX foci-positive cells and the number of induced {gamma}-H2AX foci per positive cell were significantly increased in both irradiated and adjacent non-irradiated regions. Similarly, the induction of MN by 0.2 cGy {alpha}-particle irradiation also increased with the elevated NaCl concentrations. With N{sup G}-methyl-L-arginine, an inhibitor of nitric oxide synthase, the induced fraction of foci-positive cells was effectively inhibited both in 0.2 cGy {alpha}-particle irradiated and adjacent non-irradiated regions under either normal or elevated NaCl conditions. These results suggested that the cultures with elevated NaCl medium magnified the damage effects induced by the low dose {alpha}-particle irradiation and nitric oxide generated by irradiation was also very important in this process.

  9. 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. 

  10. Influence of Magnolol on the bystander effect induced by alpha-particle irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Wong, T.P.W.; Law, Y.L. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Tse, A.K.W.; Fong, W.F. [Research and Development Division, School of Chinese Medicine, Hong Kong Baptist University, Baptist University Road, Kowloon Tong (Hong Kong); Yu, K.N. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong)], E-mail: peter.yu@cityu.edu.hk

    2010-04-15

    In this work, the influence of Magnolol on the bystander effect in alpha-particle irradiated Chinese hamster ovary (CHO) cells was examined. The bystander effect was studied through medium transfer experiments. Cytokinesis-block micronucleus (CBMN) assay was performed to quantify the chromosome damage induced by alpha-particle irradiation. Our results showed that the alpha-particle induced micronuclei (MN) frequencies were suppressed with the presence of Magnolol.

  11. Relationship between P53 and bystander effect induced by radiated hepatoma cells

    International Nuclear Information System (INIS)

    Zhao Meijia; Shen Bo; Yuan Dexiao; Cheng Honghong; Shao Chunlin

    2009-01-01

    The role of p53 in bystander responses on normal liver cells were investigated by co-culturing irradiated hepatoma cells with non-irradiated bystander Chang liver cells. It was found that radiosensitivity of the hepatoma cells was relative to p53. HepG2 cells with wtp53 had the highest radiosensitivity followed by PLC/PRF/5 cells with mtp53 and Hep3B cells with null-p53. The induction of bystander micronucleus(MN) was observed only in the Chang liver cells that had been co-cultured with HepG2 cells but not co-cultured with PLC/PRF/5 or Hep3B. Also, this bystander MN was relative to the irradiation dose and the cell co-culture rime. When the hepatoma cells were treated with pifithrin-α, a p53 inhibitor, their radiosensitivities were reduced, and the bystander effect was diminished. The results indicate that p53 could regulate not only the radiosensitivity but also the bystander response. (authors)

  12. Probability of bystander effect induced by alpha-particles emitted by radon progeny using the analytical model of tracheobronchial tree

    International Nuclear Information System (INIS)

    Jovanovic, B.; Nikezic, D.

    2010-01-01

    Radiation-induced biological bystander effects have become a phenomenon associated with the interaction of radiation with cells. There is a need to include the influence of biological effects in the dosimetry of the human lung. With this aim, the purpose of this work is to calculate the probability of bystander effect induced by alpha-particle radiation on sensitive cells of the human lung. Probability was calculated by applying the analytical model cylinder bifurcation, which was created to simulate the geometry of the human lung with the geometric distribution of cell nuclei in the airway wall of the tracheobronchial tree. This analytical model of the human tracheobronchial tree represents the extension of the ICRP 66 model, and follows it as much as possible. Reported probabilities are calculated for various targets and alpha-particle energies. Probability of bystander effect has been calculated for alpha particles with 6 and 7.69 MeV energies, which are emitted in the 222 Rn chain. The application of these results may enhance current dose risk estimation approaches in the sense of the inclusion of the influence of the biological effects. (authors)

  13. Antitumor bystander effect induced by radiation-inducible target gene therapy combined with α particle irradiation

    International Nuclear Information System (INIS)

    Liu Hui; Jin Chufeng; Wu Yican; Ge Shenfang; Wu Lijun; FDS Team

    2012-01-01

    In this work, we investigated the bystander effect of the tumor and normal cells surrounding the target region caused by radiation-inducible target gene therapy combined with α-particle irradiation. The receptor tumor cell A549 and normal cell MRC-5 were co-cultured with the donor cells irradiated to 0.5 Gy or the non-irradiated donor cells, and their survival and apoptosis fractions were evaluated. The results showed that the combined treatment of Ad-ET and particle irradiation could induce synergistic antitumor effect on A549 tumor cell, and the survival fraction of receptor cells co-cultured with the irradiated cells decreased by 6%, compared with receptor cells co-cultured with non-irradiated cells, and the apoptosis fraction increased in the same circumstance, but no difference was observed with the normal cells. This study demonstrates that Ad-ET combined with α-particle irradiation can significantly cause the bystander effect on neighboring tumor cells by inhibiting cell growth and inducing apoptosis, without obvious toxicity to normal cells. This suggests that combining radiation-inducible TRAIL gene therapy and irradiation may improve tumor treatment efficacy by specifically targeting tumor cells and even involving the neighboring tumor cells. (authors)

  14. Preliminary study on bystander effect induced by ionizing radiation in vivo

    International Nuclear Information System (INIS)

    Chen Feng; Tu Yu

    2010-01-01

    In order to investigate the effect of γ-rays on neuro development of fetal brain tissue as bystander effect organ, pregnant Kunming mice were randomly divided into blank control group, 0.5 Gy whole-body exposed group, 0.5 Gy head exposed group, 1.0 Gy whole-body exposed group, 1.0 Gy head exposed group, 2.0 Gy whole-body exposed group and 2.0 Gy head exposed group. The exposed mice were exposed with a vertical single acute dose using 60 Co therapy apparatus on 9th day of pregnancy, and cesarean operation were performed to gain fetal mice on 18th day of pregnancy. Then the levels of AchE and Ach were detected using ELISA kit. Compared with the blank control group, the levels of Ach in 0.5 Gy and 1.0 Gy head exposed groups were decreased (p<0.05); the levels of AchE and Ach decreased in 2.0 Gy whole-body and head exposed groups(p<0.05); the level of Ach in 0.5 Gy whole-body exposed group increased (p<0.05). And bystander effect in fetal brain tissue was induced by ionizing radiation in head exposed groups, which was similar with that in the whole-body exposed groups. (authors)

  15. Characterisation of a bystander effect induced in human tissue explant cultures by low LET radiation

    International Nuclear Information System (INIS)

    Motersill, C.; O'Malley, K.; Seymour, C.B.

    2002-01-01

    The existence of a bystander effect following both alpha and gamma irradiation of many cell lines is not now in dispute. The significance of this effect for cancer risk assessment and radiotherapy treatment planning requires demonstration of its relevance in vivo. The problem in demonstrating the existence of the effect in vivo is that other systemic effects may mask or confound the effect being investigated and it is practically impossible to attribute an effect in a particular cell to a signal produced in another irradiated cell. To approach this problem, an assay has been developed where fragments of human tissue can be irradiated ex vivo and the media harvested and added to unirradiated, clonogenic cells which have a well characterised and stable response to the bystander signal. The variation in the production of a signal from patient to patient can thus be assessed. The results of a study using tissue from over 100 patients attending Beaumont and St Vincent's Hospitals in Dublin for investigation of urological disorders including follow-up after treatment for transitional cell carcinoma (TCC) and resection of suspect prostatic lesions, are now available. Blood samples from the prostate group were also obtained. The results show that there is variation in the effect of the signal produced by irradiated tissue from different patients. This holds for bladder, prostate and blood. Gender, smoking status and the existence of a malignancy influence the expression of the signal by normal tissue. Male gender, smoking and a pre-existing malignancy all reduce the amount or effect of the signal produced into medium when the tissue is exposed. The effects of exposure to medium containing the signal are transmitted to distant progeny of the exposed cell population. The results may be important not only for understanding radiation risk mechanisms for protection but also for radiotherapy treatment planning where they may open new avenues for development of drugs for combined

  16. Bystander effect induced by radiotherapeutic doses in breast carcinoma cell line

    International Nuclear Information System (INIS)

    Zubiria, M.G.; Martinez, M.; Dodat, D.; Sanchez, G.; Casas, O.; Guerci, A.

    2008-01-01

    Full text: Bystander effect (BSE) refers to observed effects in cells that have not been directly crossed by radiation and which are near the radiated cells. It is suggested that different communication and signaling cellular pathways, such as gap junctions and the release of diverse clastogenics factors (reactive oxygen species and cytokines), take place in this phenomenon. Delayed Genomic Instability (GI) could be explained by means of BSE and it could be showed by the decrease of cloning efficiency, the increase of apoptosis, point mutations, and micronuclei frequency. The relevance of this phenomenon is discussed in the carcinogenic process. Besides, BSE is also important because of its impact on the present paradigm of the ionizing effect of radiation, essentially based on the Theory of the Target. The importance of this research in radiotherapy could be the optimization of the therapeutic effects of radiation. In the present study was evaluated the BSE in breast carcinoma cell line MCF-7 by the application of both techniques: Comet Assay (alkaline version) and Clonogenic Assay. Conclusions: ROS involvement in BSE was corroborated by Comet Assay in this cell line; ICM treatment decreased cloning efficiency, checked by Clonogenic Assay. This results are very important for the reconsideration of the current paradigm of Target Theory and its application in radiobiology. (author)

  17. Analysis of mutagenic effects induced by carbon beams at different LET in a red yeast strain

    International Nuclear Information System (INIS)

    Sun Haining; Wang Jufang; Ma Shuang; Lu Dong; Wu Xin; Li Wenjian

    2011-01-01

    To evaluate inactive and mutagenic effects of carbon beam at different LET, the inactivation cross section and mutation cross section induced by carbon beams of different LET values were investigated in a red yeast strain Rhodotorula glutinis AY 91015. It was found that the maximum inactivation cross section of 4.37μm 2 , which was very close to the average nucleus cross section, was at LET of 120.0 keV/μm. The maximum mutation cross section was at LET of 96.0 keV/μm. Meanwhile, the highest mutagenicity of carbon ion was found around 58.2 keV/μm. It implied that the most efficient LET to induce mutation in survival yeasts was 58.2 keV/μm, which corresponded to energy of 35 MeV/u carbon beam. The most effective carbon beam to induce inactivation and mutation located at different energy region. (authors)

  18. Bystander Effect Induced by Electroporation is Possibly Mediated by Microvesicles and Dependent on Pulse Amplitude, Repetition Frequency and Cell Type.

    Science.gov (United States)

    Prevc, Ajda; Bedina Zavec, Apolonija; Cemazar, Maja; Kloboves-Prevodnik, Veronika; Stimac, Monika; Todorovic, Vesna; Strojan, Primoz; Sersa, Gregor

    2016-10-01

    Bystander effect, a known phenomenon in radiation biology, where irradiated cells release signals which cause damage to nearby, unirradiated cells, has not been explored in electroporated cells yet. Therefore, our aim was to determine whether bystander effect is present in electroporated melanoma cells in vitro, by determining viability of non-electroporated cells exposed to medium from electroporated cells and by the release of microvesicles as potential indicators of the bystander effect. Here, we demonstrated that electroporation of cells induces bystander effect: Cells exposed to electric pulses mediated their damage to the non-electroporated cells, thus decreasing cell viability. We have shown that shedding microvesicles may be one of the ways used by the cells to mediate the death signals to the neighboring cells. The murine melanoma B16F1 cell line was found to be more electrosensitive and thus more prone to bystander effect than the canine melanoma CMeC-1 cell line. In B16F1 cell line, bystander effect was present above the level of electropermeabilization of the cells, with the threshold at 800 V/cm. Furthermore, with increasing electric field intensities and the number of pulses, the bystander effect also increased. In conclusion, electroporation can induce bystander effect which may be mediated by microvesicles, and depends on pulse amplitude, repetition frequency and cell type.

  19. Application of microbeam in bio-science and life science. Biological effects induced in bystander cells by particle microbeams

    International Nuclear Information System (INIS)

    Suzuki, Masao

    2006-01-01

    Biological events occurring in cells directly hit by radiation appear in bystander cells nearby not hit directly, which is called the bystander effect. This review describes the events and mechanisms of biological bystander effect yielded by the low-dose radiation including the microbeam. Bystander effects, particularly by charged particle beams, have been studied by two representative approaches by α-ray from plutonium (stochastic irradiation) and by particle microbeams (targeted irradiation), where a bystander effect like chromosome aberrations is shown to occur by communication between irradiated and non-irradiated cells through gap junction. Bystander effects that do not require the cell contact also occur in the irradiated cell-conditioned medium (ICCM), where, not only the short-life radicals like reactive oxygen species and NO, but also more long-life factors participate. Authors have shown the presence of such bystander-inducing factors in ICCM, producing the aberrations even 48 hr after irradiation of either low or high linear energy transfer (LET) radiation. Bystander effects can be important from the aspect of risk assessments of radiation in the terrestrial/spatial environment involving aircraft as well as in cancer therapy by low-dose heavy particle beams. (T.I)

  20. Mutagenic effects induced by accumulating rare earths nuclides with different ionic radius in fission fragments

    International Nuclear Information System (INIS)

    Zhu Shoupeng; Wang Liuyi; Cao Genfa; Sun Baofu

    1991-05-01

    The purpose of the present study was to ascertain the correlation between the different ionic radius of rare earths nuclides such as 170 Tm, 152 Eu, 147 Pm and its accumulation peculiarity as well as induction of mutagenic effect on bone marrow cells. The study showed that the accumulation peculiarity of rare earths nuclides will vary with the ionic radius. The results indicated that large ionic radius of 147 Pm was selectively localized in liver in early stage, while small ionic radius of 170 Tm and 152 Eu were deposited in bone predominantly. There was a positive relationship between the incidence of chromosome aberration rates and the absorption dose in skeleton by 170 Tm, 152 Eu, or 147 Pm. Studies indicated that the chromosome aberration rates were elevated when the absorption dose in skeleton was increased. Among the type of chromosome aberrations induced by rare earths nuclides with different ionic radius, chromatid breakage was predominant, accompanied with a few chromosome breakage and translocation. At the same time mitosis index of metaphase cells was depressed. Internal contamination of 170 Tm, 152 Eu, or 147 Pm can be induced by some aberrations in one cell. This phenomenon might be due in part to nonuniform irradiation of bone marrow cell with local deposition of these rare earths nuclides with different ionic radius

  1. Protective and detrimental bystander effects induced by x-irradiation in the limb bud cell cultures of fetal mice

    International Nuclear Information System (INIS)

    Wang, B.; Ohyama, H.; Shang, Y.; Yukawa, O.; Aizawa, S.; Hayata, I.

    2003-01-01

    Full text: Radioadaptive response and bystander effect represent important phenomena in radiobiology with an impact on the novel bioresponse mechanisms and risk estimates. The micromass cultures of limb bud cells (LBCs) provide an in vitro cellular maturation system, in which progress of cellular proliferation and differentiation is comparably paralleled to that of in vivo. This paper reports for the first time the evidential correlation and interaction, which simultaneously exist in the micromass culture system, between radioadaptive response and bystander effect. A radioadaptive response was induced in LBCs of embryonic day 11 (E11) ICR mice. Conditioning irradiation of the E11 cells with 30 cGy resulted in a significant protective effect against the occurrence of apoptosis, inhibition of cellular proliferation and differentiation induced by a challenging dose of 5 Gy given next day. Both protective and detrimental bystander effects were observed, namely, irradiating 50% of the E11 cells with 30 cGy led to a successful induction of radioadaptive response, and irradiating 70% of the E12 cells with 5 Gy produced comparably the detrimental effect to that of when all the cells were irradiated. Further, the bystander effects were markedly vanished by pretreatment of the cells with inhibitors to block the gap junction-mediated intracellular communication. These results indicated that the bystander effect played an important role in both the induction of a protective effect by the conditioning dose and the detrimental effect by the challenging irradiation. Concerning the underlying mechanism, the gap junction-mediated intracellular communication was suggested being involved in the induction of the bystander effects

  2. Studying the synergistic damage effects induced by 1.8 GHz radiofrequency field radiation (RFR) with four chemical mutagens on human lymphocyte DNA using comet assay in vitro

    International Nuclear Information System (INIS)

    Wang Baohong; He Jiliang; Jin Lifen; Lu Deqiang; Zheng Wei; Lou Jianlin; Deng Hongping

    2005-01-01

    The aim of this investigation was to study the synergistic DNA damage effects in human lymphocytes induced by 1.8 GHz radiofrequency field radiation (RFR, SAR of 3 W/kg) with four chemical mutagens, i.e. mitomycin C (MMC, DNA crosslinker), bleomycin (BLM, radiomimetic agent), methyl methanesulfonate (MMS, alkylating agent), and 4-nitroquinoline-1-oxide (4NQO, UV-mimetic agent). The DNA damage of lymphocytes exposed to RFR and/or with chemical mutagens was detected at two incubation time (0 or 21 h) after treatment with comet assay in vitro. Three combinative exposure ways were used. Cells were exposed to RFR and chemical mutagens for 2 and 3 h, respectively. Tail length (TL) and tail moment (TM) were utilized as DNA damage indexes. The results showed no difference of DNA damage indexes between RFR group and control group at 0 and 21 h incubation after exposure (P > 0.05). There were significant difference of DNA damage indexes between MMC group and RFR + MMC co-exposure group at 0 and 21 h incubation after treatment (P 0.05). The experimental results indicated 1.8 GHz RFR (SAR, 3 W/kg) for 2 h did not induce the human lymphocyte DNA damage effects in vitro, but could enhance the human lymphocyte DNA damage effects induced by MMC and 4NQO. The synergistic DNA damage effects of 1.8 GHz RFR with BLM or MMS were not obvious

  3. Experimental verification for in vitro technique confirmation of bystander effect induced by gamma radiation in CHO-K1 cell line

    International Nuclear Information System (INIS)

    Viana, P.H.L.; Goes, A.M.; Gomes, D.A.

    2013-01-01

    The bystander effect refers to biological responses detected in cells not directly irradiated but influenced, somehow, by signals transmitted from neighboring irradiated cells. These biological responses include sister chromatid exchange, mutations, micronucleus formation, chromosomal aberrations, carcinogenesis, apoptosis and necrosis. Although its existence is unquestionable, the mechanisms involved on triggering the bystander effect are not yet completely elucidated. Previous studies have shown that the bystander effect depends on a large variety of parameters including the radiation dose, the dose rate, the type of radiation and type of cells or tissue. This study aims to confirm the technique previously used in the literature in human cell lines for the bystander effect verification. The results suggest that the working conditions adopted by the group show technical efficiency and enables the reproduction of the bystander effect. (author)

  4. Inactive and mutagenic effects induced by carbon beams of different LET values in a red yeast strain

    International Nuclear Information System (INIS)

    Wang Jufang; Lu Dong; Wu Xin; Sun Haining; Ma Shuang; Li Renmin; Li Wenjian

    2010-01-01

    To evaluate biological action of microorganism exposed to charged particles during the long distance space exploration, induction of inactivation and mutation in a red yeast strain Rhodotorula glutinis AY 91015 by carbon beams of different LET values (14.9-120.0 keV μm -1 ) was investigated. It was found that survival curves were exponential, and mutation curves were linear for all LET values. The dependence of inactivation cross section on LET approached saturation near 120.0 keV μm -1 . The mutation cross section saturated when LET was higher than 58.2 keV μm -1 . Meanwhile, the highest RBE i for inactivation located at 120.0 keV μm -1 and the highest RBE m for mutation was at 58.2 keV μm -1 . The experiments imply that the most efficient mutagenic part of the depth dose profile of carbon ion is at the plateau region with intermediate LET value in which energy deposited is high enough to induce mutagenic lesions but too low to induce over kill effect in the yeast cells.

  5. Inactive and mutagenic effects induced by carbon beams of different LET values in a red yeast strain

    Science.gov (United States)

    Wang, Jufang; Lu, Dong; Wu, Xin; Sun, Haining; Ma, Shuang; Li, Renmin; Li, Wenjian

    2010-09-01

    To evaluate biological action of microorganism exposed to charged particles during the long distance space exploration, induction of inactivation and mutation in a red yeast strain Rhodotorula glutinis AY 91015 by carbon beams of different LET values (14.9-120.0 keV μm -1) was investigated. It was found that survival curves were exponential, and mutation curves were linear for all LET values. The dependence of inactivation cross section on LET approached saturation near 120.0 keV μm -1. The mutation cross section saturated when LET was higher than 58.2 keV μm -1. Meanwhile, the highest RBE i for inactivation located at 120.0 keV μm -1 and the highest RBE m for mutation was at 58.2 keV μm -1. The experiments imply that the most efficient mutagenic part of the depth dose profile of carbon ion is at the plateau region with intermediate LET value in which energy deposited is high enough to induce mutagenic lesions but too low to induce over kill effect in the yeast cells.

  6. Inactive and mutagenic effects induced by carbon beams of different LET values in a red yeast strain

    Energy Technology Data Exchange (ETDEWEB)

    Wang Jufang, E-mail: jufangwang@impcas.ac.c [Institute of Modern Physics, Chinese Academy of Sciences, Nanchang Road No. 509, Lanzhou 730000 (China); Lu Dong; Wu Xin; Sun Haining; Ma Shuang; Li Renmin; Li Wenjian [Institute of Modern Physics, Chinese Academy of Sciences, Nanchang Road No. 509, Lanzhou 730000 (China)

    2010-09-15

    To evaluate biological action of microorganism exposed to charged particles during the long distance space exploration, induction of inactivation and mutation in a red yeast strain Rhodotorula glutinis AY 91015 by carbon beams of different LET values (14.9-120.0 keV {mu}m{sup -1}) was investigated. It was found that survival curves were exponential, and mutation curves were linear for all LET values. The dependence of inactivation cross section on LET approached saturation near 120.0 keV {mu}m{sup -1}. The mutation cross section saturated when LET was higher than 58.2 keV {mu}m{sup -1}. Meanwhile, the highest RBE{sub i} for inactivation located at 120.0 keV {mu}m{sup -1} and the highest RBE{sub m} for mutation was at 58.2 keV {mu}m{sup -1}. The experiments imply that the most efficient mutagenic part of the depth dose profile of carbon ion is at the plateau region with intermediate LET value in which energy deposited is high enough to induce mutagenic lesions but too low to induce over kill effect in the yeast cells.

  7. Vincristine-induced bystander effect in human lymphocytes

    Energy Technology Data Exchange (ETDEWEB)

    Testi, Serena; Azzarà, Alessia; Giovannini, Caterina; Lombardi, Sara [Unità di Genetica, Dipartimento di Biologia, Pisa University, Via Derna 1, 56126 Pisa (Italy); Piaggi, Simona [Dipartimento di Ricerca Traslazionale e delle Nuove Tecnologie in Medicina e Chirurgia, Pisa University, Via Savi 10, 56126 Pisa (Italy); Facioni, Maria Sole [Unità di Genetica, Dipartimento di Biologia, Pisa University, Via Derna 1, 56126 Pisa (Italy); Scarpato, Roberto, E-mail: roberto.scarpato@unipi.it [Unità di Genetica, Dipartimento di Biologia, Pisa University, Via Derna 1, 56126 Pisa (Italy); Research Center of Nutraceuticals and Food for Health, University of Pisa, Pisa (Italy)

    2016-07-15

    Highlights: • We studied whether or not vincristine induced a bystander response in human lymphocytes. • Vincristine significantly increased MN frequencies in mononucleated recipient cells. • ROS or soluble proteins (IL-32 and TGF-β) may account for the observed response. - Abstract: Bystander effect is a known radiobiological effect, widely described using ionizing radiations and which, more recently, has also been related to chemical mutagens. In this study, we aimed to assess whether or not a bystander response can be induced in cultured human peripheral lymphocytes by vincristine, a chemotherapeutic mutagen acting as spindle poison, and by mitomycin-C, an alkylating agent already known to induce this response in human lymphoblastoid cells. Designing a modified ad hoc protocol for the cytokinesis blocked micronucleus (MN) assay, we detected the presence of a dose-dependent bystander response in untreated cultures receiving the conditioned medium (CM) from mitomycin-C (MMC) or vincristine (VCR) treated cultures. In the case of MMC, MN frequencies, expressed as micronucleated binucleates, were: 13.5 ± 1.41 at 6 μM, 22 ± 2.12 at 12 μM or 28.25 ± 5.13 at 15 μM vs. a control value of 4.75 ± 1.59. MN levels for VCR, expressed as micronucleated mononucleates were: 2.75 ± 0.88 at 0.0 μM, 27.25 ± 2.30 at 0.4 μM, 46.25 ± 1.94 at 0.8 μM, 98.25 ± 7.25 at 1.6 μM. To verify that no mutagen residual was transferred to recipient cultures together with the CM, we evaluated MN levels in cultures receiving the medium immediately after three washings following the chemical treatment (unconditioned medium). We further confirmed these results using a cell-mixing approach where untreated lymphocytes were co-cultured with donor cells treated with an effect-inducing dose of MMC or VCR. A distinct production pattern of both reactive oxygen species and soluble mediator proteins by treated cells may account for the differences observed in the manifestation of the

  8. Vincristine-induced bystander effect in human lymphocytes

    International Nuclear Information System (INIS)

    Testi, Serena; Azzarà, Alessia; Giovannini, Caterina; Lombardi, Sara; Piaggi, Simona; Facioni, Maria Sole; Scarpato, Roberto

    2016-01-01

    Highlights: • We studied whether or not vincristine induced a bystander response in human lymphocytes. • Vincristine significantly increased MN frequencies in mononucleated recipient cells. • ROS or soluble proteins (IL-32 and TGF-β) may account for the observed response. - Abstract: Bystander effect is a known radiobiological effect, widely described using ionizing radiations and which, more recently, has also been related to chemical mutagens. In this study, we aimed to assess whether or not a bystander response can be induced in cultured human peripheral lymphocytes by vincristine, a chemotherapeutic mutagen acting as spindle poison, and by mitomycin-C, an alkylating agent already known to induce this response in human lymphoblastoid cells. Designing a modified ad hoc protocol for the cytokinesis blocked micronucleus (MN) assay, we detected the presence of a dose-dependent bystander response in untreated cultures receiving the conditioned medium (CM) from mitomycin-C (MMC) or vincristine (VCR) treated cultures. In the case of MMC, MN frequencies, expressed as micronucleated binucleates, were: 13.5 ± 1.41 at 6 μM, 22 ± 2.12 at 12 μM or 28.25 ± 5.13 at 15 μM vs. a control value of 4.75 ± 1.59. MN levels for VCR, expressed as micronucleated mononucleates were: 2.75 ± 0.88 at 0.0 μM, 27.25 ± 2.30 at 0.4 μM, 46.25 ± 1.94 at 0.8 μM, 98.25 ± 7.25 at 1.6 μM. To verify that no mutagen residual was transferred to recipient cultures together with the CM, we evaluated MN levels in cultures receiving the medium immediately after three washings following the chemical treatment (unconditioned medium). We further confirmed these results using a cell-mixing approach where untreated lymphocytes were co-cultured with donor cells treated with an effect-inducing dose of MMC or VCR. A distinct production pattern of both reactive oxygen species and soluble mediator proteins by treated cells may account for the differences observed in the manifestation of the

  9. Bystander Effects Induced by Continuous Low-Dose-Rate 125I Seeds Potentiate the Killing Action of Irradiation on Human Lung Cancer Cells In Vitro

    International Nuclear Information System (INIS)

    Chen, H.H.; Jia, R.F.; Yu, L.; Zhao, M.J.; Shao, C.L.; Cheng, W.Y.

    2008-01-01

    Purpose: To investigate bystander effects of low-dose-rate (LDR) 125 I seed irradiation on human lung cancer cells in vitro. Methods and Materials: A549 and NCI-H446 cell lines of differing radiosensitivity were directly exposed to LDR 125 I seeds irradiation for 2 or 4 Gy and then cocultured with nonirradiated cells for 24 hours. Induction of micronucleus (MN), γH2AX foci, and apoptosis were assayed. Results: After 2 and 4 Gy irradiation, micronucleus formation rate (MFR) and apoptotic rate of A549 and NCI-H446 cells were increased, and the MFR and apoptotic rate of NCI-H446 cells was 2.1-2.8 times higher than that of A549 cells. After coculturing nonirradiated bystander cells with 125 I seed irradiated cells for 24 hours, MFR and the mean number of γH2AX foci/cells of bystander A549 and NCI-H446 cells were similar and significantly higher than those of control (p 125 I seeds could induce bystander effects, which potentiate the killing action on tumor cells and compensate for the influence of nonuniform distribution of radiation dosage on therapeutic outcomes

  10. The bystander effect-induced formation of micronucleated cells is inhibited by antioxidants, but the parallel induction of apoptosis and loss of viability are not affected

    International Nuclear Information System (INIS)

    Konopacka, Maria; Rzeszowska-Wolny, Joanna

    2006-01-01

    X-rays induce various DNA damages including strand breaks that lead to formation of micronuclei and chromosomal aberrations as well as increased number of apoptotic cells. Similar effects appear when non-irradiated cells are treated with medium collected from cultures of irradiated cells (irradiation conditioned medium - ICM). This phenomenon was termed 'bystander effect'. A number of studies suggest that bystander effect appears to be associated with up-regulation of oxidative metabolism. We thus compared the effects of antioxidant Vitamins C and E on the frequency of micronuclei and apoptotic cells in both directly irradiated cell cultures and in cultures exposed to ICM. Addition of Vitamins C or E (1-40 μg/ml) to culture medium after exposure to radiation or ICM reduced the frequency of micronuclei in a concentration-dependent manner. These vitamins had no effect on cell viability, clonogenic survival or the frequency of apoptotic cells under both conditions tested. These results show that the bystander effect causes micronucleation in addition to other known effects and suggest that the factors causing micronucleation by X-irradiation, oxidative DNA damage and incomplete repair, are regulated by apoptosis-independent pathways

  11. Bystander deixis

    DEFF Research Database (Denmark)

    Rijkhoff, Jan

    1998-01-01

    The purpose of this contribution is to discuss non-standard speech forms of Romani and other languages in the larger context of bystander deixis, a subcategory of social deixis. First I will propose a three-way classification of instances of bystander deixis and illustrate them with examples from...... Romani and several other languages across the globe. The second part is concerned with the contextual factors that must have a place in a discourse model that wants to be able to handle linguistic manifestations of bystander deixis. Due the fact that Romani has typically been used for in......-group communication, this language presents a particularly rich source of information in the area of secret languages and other forms of bystander deixis. Moreover, as is also made abundantly clear in this volume, many jargons, trade varieties, secret languages and other more or less non-standard speech varieties...

  12. Interferon-β lipofection II. Mechanisms involved in cell death and bystander effect induced by cationic lipid-mediated interferon-β gene transfer to human tumor cells.

    Science.gov (United States)

    Villaverde, M S; Gil-Cardeza, M L; Glikin, G C; Finocchiaro, L M E

    2012-06-01

    We evaluated the cytotoxic effects (apoptosis, necrosis and early senescence) of human interferon-β (hIFNβ) gene lipofection. The cytotoxicity of hIFNβ gene lipofection resulted equivalent to that of the corresponding addition of the recombinant protein (rhIFNβ) on human tumor cell lines derived from Ewing's sarcoma (EW7 and COH) and colon (HT-29) carcinomas. However, it was stronger than rhIFNβ on melanoma (M8) and breast adenocarcinoma (MCF7). To reveal the mechanisms involved in these differences, we compared the effects of hIFNβ gene and rhIFNβ protein on EW7 and M8 (sensitive and resistant to rhIFNβ protein, respectively). Lipofection with hIFNβ gene caused a mitochondrial potential decrease simultaneous with an increase of oxidative stress in both cell lines. However, rhIFNβ protein displayed the same pattern of response only in EW7-sensitive cell line. The great bystander effect of the hIFNβ gene lipofection, involving the production of reactive oxygen species, would be among the main causes of its success. In EW7, this effect killed >60% of EW7 cell population, even though only 1% of cells were expressing the transgene. As hIFNβ gene was effective even in the rhIFNβ protein-resistant M8 cell line and in a way not limited by low lipofection efficiency, these results strongly support the clinical potential of this approach.

  13. Bystander effect: Biological endpoints and microarray analysis

    Energy Technology Data Exchange (ETDEWEB)

    Chaudhry, M. Ahmad [Department of Medical Laboratory and Radiation Sciences, College of Nursing and Health Sciences, University of Vermont, 302 Rowell Building, Burlington, VT 05405 (United States) and DNA Microarray Facility, University of Vermont, Burlington, VT 05405 (United States)]. E-mail: mchaudhr@uvm.edu

    2006-05-11

    In cell populations exposed to ionizing radiation, the biological effects occur in a much larger proportion of cells than are estimated to be traversed by radiation. It has been suggested that irradiated cells are capable of providing signals to the neighboring unirradiated cells resulting in damage to these cells. This phenomenon is termed the bystander effect. The bystander effect induces persistent, long-term, transmissible changes that result in delayed death and neoplastic transformation. Because the bystander effect is relevant to carcinogenesis, it could have significant implications for risk estimation for radiation exposure. The nature of the bystander effect signal and how it impacts the unirradiated cells remains to be elucidated. Examination of the changes in gene expression could provide clues to understanding the bystander effect and could define the signaling pathways involved in sustaining damage to these cells. The microarray technology serves as a tool to gain insight into the molecular pathways leading to bystander effect. Using medium from irradiated normal human diploid lung fibroblasts as a model system we examined gene expression alterations in bystander cells. The microarray data revealed that the radiation-induced gene expression profile in irradiated cells is different from unirradiated bystander cells suggesting that the pathways leading to biological effects in the bystander cells are different from the directly irradiated cells. The genes known to be responsive to ionizing radiation were observed in irradiated cells. Several genes were upregulated in cells receiving media from irradiated cells. Surprisingly no genes were found to be downregulated in these cells. A number of genes belonging to extracellular signaling, growth factors and several receptors were identified in bystander cells. Interestingly 15 genes involved in the cell communication processes were found to be upregulated. The induction of receptors and the cell

  14. Bystander effect: Biological endpoints and microarray analysis

    International Nuclear Information System (INIS)

    Chaudhry, M. Ahmad

    2006-01-01

    In cell populations exposed to ionizing radiation, the biological effects occur in a much larger proportion of cells than are estimated to be traversed by radiation. It has been suggested that irradiated cells are capable of providing signals to the neighboring unirradiated cells resulting in damage to these cells. This phenomenon is termed the bystander effect. The bystander effect induces persistent, long-term, transmissible changes that result in delayed death and neoplastic transformation. Because the bystander effect is relevant to carcinogenesis, it could have significant implications for risk estimation for radiation exposure. The nature of the bystander effect signal and how it impacts the unirradiated cells remains to be elucidated. Examination of the changes in gene expression could provide clues to understanding the bystander effect and could define the signaling pathways involved in sustaining damage to these cells. The microarray technology serves as a tool to gain insight into the molecular pathways leading to bystander effect. Using medium from irradiated normal human diploid lung fibroblasts as a model system we examined gene expression alterations in bystander cells. The microarray data revealed that the radiation-induced gene expression profile in irradiated cells is different from unirradiated bystander cells suggesting that the pathways leading to biological effects in the bystander cells are different from the directly irradiated cells. The genes known to be responsive to ionizing radiation were observed in irradiated cells. Several genes were upregulated in cells receiving media from irradiated cells. Surprisingly no genes were found to be downregulated in these cells. A number of genes belonging to extracellular signaling, growth factors and several receptors were identified in bystander cells. Interestingly 15 genes involved in the cell communication processes were found to be upregulated. The induction of receptors and the cell

  15. Experimental verification for in vitro technique confirmation of bystander effect induced by gamma radiation in CHO-K1 cell line; Verificacao experimental para confirmacao da tecnica in vitro do efeito bystander induzido por radiacao gama na linhagem celular CHO-K1

    Energy Technology Data Exchange (ETDEWEB)

    Viana, P.H.L.; Goes, A.M.; Gomes, D.A., E-mail: pedroleroybio@hotmail.com [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento Bioquimica e Imunologia. Lab. de Imunologia Celular e Molecular; Grynberg, S.E., E-mail: seg@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2013-08-15

    The bystander effect refers to biological responses detected in cells not directly irradiated but influenced, somehow, by signals transmitted from neighboring irradiated cells. These biological responses include sister chromatid exchange, mutations, micronucleus formation, chromosomal aberrations, carcinogenesis, apoptosis and necrosis. Although its existence is unquestionable, the mechanisms involved on triggering the bystander effect are not yet completely elucidated. Previous studies have shown that the bystander effect depends on a large variety of parameters including the radiation dose, the dose rate, the type of radiation and type of cells or tissue. This study aims to confirm the technique previously used in the literature in human cell lines for the bystander effect verification. The results suggest that the working conditions adopted by the group show technical efficiency and enables the reproduction of the bystander effect. (author)

  16. Bystander effects of radiation

    International Nuclear Information System (INIS)

    Umar, Neethu Fathima; Daniel, Nittu

    2013-01-01

    The Radiation-Induced Bystander Effect is the phenomenon in which unirradiated cells show irradiated effects due to the signals received from nearby irradiated cells. Evidence suggests that targeted cytoplasmic irradiation results in mutation in the nucleus of the hit cells. Cells that are not directly hit by an alpha particle, but are in the vicinity of one that is hit, also contribute to the genotoxic response of the cell population. When cells are irradiated, and the medium is transferred to unirradiated cells, these unirradiated cells show bystander responses when assayed for clonogenic survival and oncogenic transformation. The demonstration of a bystander effect in human tissues and, more recently, in whole organisms have clear implication of the potential relevance of the non-targeted response to human health. This effect may also contribute to the final biological consequences of exposure to low doses of radiation. The radiation-induced bystander effect represents a paradigm shift in our understanding of the radiobiological effects of ionizing radiation, in that extranuclear and extracellular events may also contribute to the final biological consequences of exposure to low doses of radiation. Multiple pathways are involved in the bystander phenomenon, and different cell types respond differently to bystander signalling. Using cDNA microarrays, a number of cellular signalling genes, including cyclooxygenase-2 (CQX-2), have been shown to be casually linked to the bystander phenomenon. The observation that inhibition of the phosphorylation of extracellular signal-related kinase (ERK) suppressed the bystander response further confirmed the important role of the mitogen-activated protein kinase (MAPK) signalling cascade in the bystander process. The cells deficient in mitochondrial DNA showed a significantly reduced response to bystander signalling, suggesting a functional role of mitochondria in the signalling process. (author)

  17. Bystander effects and radiotherapy.

    Science.gov (United States)

    Marín, Alicia; Martín, Margarita; Liñán, Olga; Alvarenga, Felipe; López, Mario; Fernández, Laura; Büchser, David; Cerezo, Laura

    2015-01-01

    Radiation-induced bystander effects are defined as biological effects expressed after irradiation by cells whose nuclei have not been directly irradiated. These effects include DNA damage, chromosomal instability, mutation, and apoptosis. There is considerable evidence that ionizing radiation affects cells located near the site of irradiation, which respond individually and collectively as part of a large interconnected web. These bystander signals can alter the dynamic equilibrium between proliferation, apoptosis, quiescence or differentiation. The aim of this review is to examine the most important biological effects of this phenomenon with regard to areas of major interest in radiotherapy. Such aspects include radiation-induced bystander effects during the cell cycle under hypoxic conditions when administering fractionated modalities or combined radio-chemotherapy. Other relevant aspects include individual variation and genetics in toxicity of bystander factors and normal tissue collateral damage. In advanced radiotherapy techniques, such as intensity-modulated radiation therapy (IMRT), the high degree of dose conformity to the target volume reduces the dose and, therefore, the risk of complications, to normal tissues. However, significant doses can accumulate out-of-field due to photon scattering and this may impact cellular response in these regions. Protons may offer a solution to reduce out-of-field doses. The bystander effect has numerous associated phenomena, including adaptive response, genomic instability, and abscopal effects. Also, the bystander effect can influence radiation protection and oxidative stress. It is essential that we understand the mechanisms underlying the bystander effect in order to more accurately assess radiation risk and to evaluate protocols for cancer radiotherapy.

  18. Radiation Bystander Effects Mechanism

    Directory of Open Access Journals (Sweden)

    Shokohzaman Soleymanifard

    2009-06-01

    Full Text Available Introduction: Radiation Induced Bystander Effect (RIBE which cause radiation effects in non-irradiated cells, has challenged the principle according to which radiation traversal through the nucleus of a cell is necessary for producing biological responses. What is the mechanism of this phenomenon? To have a better understanding of this rather ambiguous concept substantial number of original and reviewed article were carefully examined. Results: Irradiated cells release molecules which can propagate in cell environment and/or transmit through gap junction intercellular communication. These molecules can reach to non-irradiated cells and transmit bystander signals. In many investigations, it has been confirmed that these molecules are growth factors, cytokines, nitric oxide and free radicals like reactive oxygen species (ROS. Transmission of by stander signal to neighboring cells persuades them to produce secondary growth factors which in their turn cause further cell injuries. Some investigators suggest, organelles other than nucleus (mitochondria and cell membrane are the origin of these signals.  There is another opinion which suggests double strand breaks (DSB are not directly generated in bystander cells, rather they are due to smaller damage like single strand breaks which accumulate and end up to DSB. Although bystander mechanisms have not been exactly known, it can be confirmed that multiple mechanisms and various pathways are responsible for this effect. Cell type, radiation type, experimental conditions and end points identify the dominant mechanism. Conclusion: Molecules and pathways which are responsible for RIBE, also cause systemic responses to other non-irradiation stresses. So RIBE is a kind of systemic stress or innate immune responses, which are performed by cell microenvironment. Irradiated cells and their signals are components of microenvironment for creating bystander effects.

  19. Nitric oxide mediated bystander responses induced by microbeam targeted cells

    International Nuclear Information System (INIS)

    Shao, C.; Prise, K.M.; Folkard, M.; Michael, B.D.

    2003-01-01

    Considerable evidence has recently been accumulated in support of the existence of a 'bystander effect', which cells having received no irradiation show biological consequences from their vicinal irradiated cells. The application of microbeams is providing new insights into the radiation-induced bystander effect. The present study found that when a fraction of radioresistant human glioblastoma cells were individually targeted with a precise number of helium ions generated from the Gray Cancer Institute Charged Particle Microbeam, micronucleus (MN) induction significantly exceeded the expected value that was calculated from the number of MN observed when all of the cells were targeted assuming no bystander effect occurring. Even when only a single cell within a population was hit by one helium ion, the MN induction in the population could be increased by 16%. These results provide direct evidence of radiation-induced bystander effect. Moreover, MN was effectively induced in the unirradiated primary human fibroblasts and glioblastoma cells either co-cultured with irradiated cells or treated with the medium harvested from irradiated cells, indicating a signal molecule was produced from the irradiated cells. However, when c-PTIO, a nitric oxide (NO)-specific scavenger, was present in the medium during and after irradiation until MN analysis, the production of MN in all of the above cases was reduced to low levels. Consequently, NO plays an important role in the radiation-induced bystander effect

  20. Susceptibility to bystander DNA damage is influenced by replication and transcriptional activity

    Science.gov (United States)

    Dickey, Jennifer S.; Baird, Brandon J.; Redon, Christophe E.; Avdoshina, Valeriya; Palchik, Guillermo; Wu, Junfang; Kondratyev, Alexei; Bonner, William M.; Martin, Olga A.

    2012-01-01

    Direct cellular DNA damage may lead to genome destabilization in unexposed, bystander, cells sharing the same milieu with directly damaged cells by means of the bystander effect. One proposed mechanism involves double strand break (DSB) formation in S phase cells at sites of single strand lesions in the DNA of replication complexes, which has a more open structure compared with neighboring DNA. The DNA in transcription complexes also has a more open structure, and hence may be susceptible to bystander DSB formation from single strand lesions. To examine whether transcription predisposes non-replicating cells to bystander effect-induced DNA DSBs, we examined two types of primary cells that exhibit high levels of transcription in the absence of replication, rat neurons and human lymphocytes. We found that non-replicating bystander cells with high transcription rates exhibited substantial levels of DNA DSBs, as monitored by γ-H2AX foci formation. Additionally, as reported in proliferating cells, TGF-β and NO were found to mimic bystander effects in cell populations lacking DNA synthesis. These results indicate that cell vulnerability to bystander DSB damage may result from transcription as well as replication. The findings offer insights into which tissues may be vulnerable to bystander genomic destabilization in vivo. PMID:22941641

  1. Bystanders Are the Key to Stopping Bullying

    Science.gov (United States)

    Padgett, Sharon; Notar, Charles E.

    2013-01-01

    Bullying is the dominance over another. Bullying occurs when there is an audience. Peer bystanders provide an audience 85% of instances of bullying. If you remove the audience bullying should stop. The article is a review of literature (2002-2013) on the role of bystanders; importance of bystanders; why bystanders behave as they do; resources to…

  2. MRC5 and QU-DB bystander cells can produce bystander factors and induce radiation bystander effect

    Directory of Open Access Journals (Sweden)

    Mohammad Taghi Bahreyni Toossi

    2014-01-01

    Full Text Available Radiation damages initiated by radiation-induced bystander effect (RIBE are not limited to the first or immediate neighbors of the irradiated cells, but the effects have been observed in the cells far from the irradiation site. It has been postulated that bystander cells, by producing bystander factors, are actively involved in the propagation of bystander effect in the regions beyond the initial irradiated site. Current study was planned to test the hypothesis. MRC5 and QU-DB cell lines were irradiated, and successive medium transfer technique was performed to induce bystander effects in two bystander cell groups. Conditioned medium extracted from the target cells was transferred to the bystander cells (first bystander cells. After one hour, conditioned medium was substituted by fresh medium. Two hours later, the fresh medium was transferred to a second group of non-irradiated cells (second bystander cells. Micronucleated cells (MC were counted to quantify damages induced in the first and second bystander cell groups. Radiation effect was observed in the second bystander cells as well as in the first ones. Statistical analyses revealed that the number of MC in second bystander subgroups was significantly more than the corresponding value observed in control groups, but in most cases it was equal to the number of MC observed in the first bystander cells. MRC5 and QU-DB bystander cells can produce and release bystander signals in the culture medium and affect non-irradiated cells. Therefore, they may contribute to the RIBE propagation.

  3. Genotoxic damage in non-irradiated cells: contribution from the bystander effect

    International Nuclear Information System (INIS)

    Zhou, H.; Randers-Pherson, G.; Suzuki, M.; Waldren, C.A.; Hei, T.K.

    2002-01-01

    It has always been accepted dogma that the deleterious effects of ionising radiation such as mutagenesis and carcinogenesis are due mainly to direct damage to DNA. Using the Columbia University charged-particle microbeam and the highly sensitive A L cell mutagenic assay, it is shown here that non-irradiated cells acquire the mutagenic phenotype through direct contact with cells whose nuclei are traversed with 2 alpha particles each. Pre-treatment of cells with lindane, a gap junction inhibitor, significantly decreased the mutant yield. Furthermore, when irradiated cells were mixed with control cells in a similar ration as the in situ studies, no enhancement in bystander mutagenesis was detected. Our studies provide clear evidence that genotoxic damage can be induced in non-irradiated cells, and that gap junction mediated cell-cell communication plays a critical role in the bystander phenomenon. (author)

  4. Bystander or No Bystander for Gene Directed Enzyme Prodrug Therapy

    Directory of Open Access Journals (Sweden)

    Adam V. Patterson

    2009-11-01

    Full Text Available Gene directed enzyme prodrug therapy (GDEPT of cancer aims to improve the selectivity of chemotherapy by gene transfer, thus enabling target cells to convert nontoxic prodrugs to cytotoxic drugs. A zone of cell kill around gene-modified cells due to transfer of toxic metabolites, known as the bystander effect, leads to tumour regression. Here we discuss the implications of either striving for a strong bystander effect to overcome poor gene transfer, or avoiding the bystander effect to reduce potential systemic effects, with the aid of three successful GDEPT systems. This review concentrates on bystander effects and drug development with regard to these enzyme prodrug combinations, namely herpes simplex virus thymidine kinase (HSV-TK with ganciclovir (GCV, cytosine deaminase (CD from bacteria or yeast with 5-fluorocytodine (5-FC, and bacterial nitroreductase (NfsB with 5-(azaridin-1-yl-2,4-dinitrobenzamide (CB1954, and their respective derivatives.

  5. Bystander effects of exposure to low-dose-rate 125I seeds on human lung cancers cells in vitro

    International Nuclear Information System (INIS)

    Jia Rongfei; Chen Honghong; Yu Lei; Zhao Meijia; Shao Chunlin; Cheng Wenying

    2007-01-01

    The bystander effects induced by continuous low-dose-rate (LDR) 125 I seeds radiation on damage of human lung cancer cells were investigated. Human adenocarcinoma cell line A549 and human small cell lung cancer cell line NCI-H446, which have different sensitivities to high-dose rate (HDR) external irradiation, were exposed directly to 125 I seeds in vitro and co-cultured with unirradiated cells for 24 h. Using cytokinesis-blocking micronucleus method and γ H2AX fluorescence immunoassay, bystander effects induced by 2Gy and 4Gy 125 I seed irradiation on micronucleus formation and DNA double-strand breaks (DSBs) of human lung cancer cells were detected and evaluated. The results showed that irradiation with 125 I seeds can induce medium-mediated bystander effects in A549 cells and NCI-H446 cells, exhibiting that both micronuclei formation and γ H2AX focus formation in bystander cells were increased significantly compared with non-irradiated cells. The extent of DNA damage induced by bystander effects was correlated with accumulated radiation dose and radiosensitive of tumor cells. NCI-H446 cells that were sensitive to HDR γ irradiation were more sensitive to continuous LDR irradiation and bystander effects than A549. However, a comparison between the bystander effects and direct effects elicits the intensity of bystander responses of A549 cells was higher than that of NCI-H446 cells. A dose-related reduction in bystander responses was observed both in A549 cells and NCI-H446 cells, suggesting that the signaling factors involved in the bystander signaling pathways may decrease with the increase of cell damages. (authors)

  6. On the Actual Risk of Bystander Intervention

    DEFF Research Database (Denmark)

    Liebst, Lasse Suonperä; Heinskou, Marie Bruvik; Ejbye-Ernst, Peter

    2018-01-01

    Objectives: Bystander studies have rarely considered the victimization risk associated with intervention into violent, dangerous emergencies. To address this gap, we aim to identify factors that influence bystanders’ risk of being physically victimized. Methods: We observed bystander behavior fro...

  7. Bystander signaling via oxidative metabolism

    Directory of Open Access Journals (Sweden)

    Sawal HA

    2017-08-01

    Full Text Available Humaira Aziz Sawal,1 Kashif Asghar,2 Matthias Bureik,3 Nasir Jalal4 1Healthcare Biotechnology Department, Atta-ur-Rahman School of Applied Biosciences, National University of Sciences and Technology, Islamabad, 2Basic Sciences Research, Shaukat Khanum Memorial Cancer Hospital and Research Centre, Lahore, Pakistan; 3Health Science Platform, School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, China; 4Health Science Platform, Department of Molecular and Cellular Pharmacology, Tianjin University, Tianjin, China Abstract: The radiation-induced bystander effect (RIBE is the initiation of biological end points in cells (bystander cells that are not directly traversed by an incident-radiation track, but are in close proximity to cells that are receiving the radiation. RIBE has been indicted of causing DNA damage via oxidative stress, besides causing direct damage, inducing tumorigenesis, producing micronuclei, and causing apoptosis. RIBE is regulated by signaling proteins that are either endogenous or secreted by cells as a means of communication between cells, and can activate intracellular or intercellular oxidative metabolism that can further trigger signaling pathways of inflammation. Bystander signals can pass through gap junctions in attached cell lines, while the suspended cell lines transmit these signals via hormones and soluble proteins. This review provides the background information on how reactive oxygen species (ROS act as bystander signals. Although ROS have a very short half-life and have a nanometer-scale sphere of influence, the wide variety of ROS produced via various sources can exert a cumulative effect, not only in forming DNA adducts but also setting up signaling pathways of inflammation, apoptosis, cell-cycle arrest, aging, and even tumorigenesis. This review outlines the sources of the bystander effect linked to ROS in a cell, and provides methods of investigation for researchers who would like to

  8. Bystander signaling via oxidative metabolism.

    Science.gov (United States)

    Sawal, Humaira Aziz; Asghar, Kashif; Bureik, Matthias; Jalal, Nasir

    2017-01-01

    The radiation-induced bystander effect (RIBE) is the initiation of biological end points in cells (bystander cells) that are not directly traversed by an incident-radiation track, but are in close proximity to cells that are receiving the radiation. RIBE has been indicted of causing DNA damage via oxidative stress, besides causing direct damage, inducing tumorigenesis, producing micronuclei, and causing apoptosis. RIBE is regulated by signaling proteins that are either endogenous or secreted by cells as a means of communication between cells, and can activate intracellular or intercellular oxidative metabolism that can further trigger signaling pathways of inflammation. Bystander signals can pass through gap junctions in attached cell lines, while the suspended cell lines transmit these signals via hormones and soluble proteins. This review provides the background information on how reactive oxygen species (ROS) act as bystander signals. Although ROS have a very short half-life and have a nanometer-scale sphere of influence, the wide variety of ROS produced via various sources can exert a cumulative effect, not only in forming DNA adducts but also setting up signaling pathways of inflammation, apoptosis, cell-cycle arrest, aging, and even tumorigenesis. This review outlines the sources of the bystander effect linked to ROS in a cell, and provides methods of investigation for researchers who would like to pursue this field of science.

  9. Moral Disengagement Among Bystanders to School Bullying

    DEFF Research Database (Denmark)

    Obermann, Marie-Louise

    2011-01-01

    This study examined the use of moral disengagement among children indirectly involved in bullying (bystanders). A sample of Danish adolescents (N = 660, M age 12.6 years) were divided into four groups depending on their bystander status: (a) outsiders, who did not experience bullying among...... their peers; (b) defenders, who were likely to help the victims in bullying episodes; (c) guilty bystanders, who did nothing to help bullied peers but felt guilty about it; and (d) unconcerned bystanders, who witnessed peers being bullied, without feeling responsible. Results indicated that, besides from...... active personal involvement in bullying others, being an unconcerned bystander to bullying also associates with moral disengagement. Unconcerned bystanders had significantly higher moral disengagement than guilty bystanders and defenders. Outsiders also showed significant higher disengagement than...

  10. Bystander Effects of Ionizing Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Little, John B. [Harvard T.H. Chan School of Public Health, Boston, MA (United States). Dept. of Genetics and Complex Diseases

    2017-01-17

    The objectives of this grant renewal are to provide administrative support and travel funds to allow the continued participation of the principal investigator (Dr. John B. Little) as an advisor to research initiated by several research fellows from his laboratory. The actual research will be carried out under the direction of Dr. Hatsumi Nagasawa with the collaboration of Dr. Joel Bedford at the Colorado State University, and by Drs. Edouard Azzam and Sonia de Toledo at the University of Medicine and Dentistry of New Jersey. Dr. Little will advise on the planning of experiments and development of experimental protocols, the analysis of data, and the preparation of manuscripts for publication. The Specific Aims for several of the planned experiments include: 1) to extend studies of the role of recombinational repair in the bystander effect by examining other genes in this pathway and cell lines deficient in excision repair; 2) to continue studies to determine the nature of the damage signal transmitted to bystander cells including the expression of several connexins in the bystander response, and the extent to which the enhanced oxidative metabolism observed in bystander cells may relate to the nature of the transmitted bystander signal; 3) to utilize a genome-wide approach to examine the genetic basis for the hypersensitivity to ionization we have observed in unaffected parents of patients with hereditary retinoblastoma, as well as from a group of apparently normal individuals that show similar radiosensitivity; 4) to complete studies concerning the induction of high frequencies of cells with massive chromosome damage in clonal derivatives of p53 and p21 knockout mouse cell lines; in particular to examine the role of telomere changes in this phenomenon. Overall, the results of these studies should enhance our understanding of the risk of low-dose exposures to ionizing radiation, including human populations to residential radon as well as occupational exposures.

  11. Mechanisms of the Bystander Effect

    International Nuclear Information System (INIS)

    Hall, Eric J.

    2008-01-01

    Generations of students in radiation biology have been taught that heritable biological damage requires direct damage to DNA. We now know that this is not true. The Bystander Effect is the name given to the phenomenon whereby biological effects are observed in cells that are not themselves traversed by a charged particle, but are in close proximity to cells that are. Several research groups have convincingly demonstrated a bystander effect for alpha particle, which are heavy and high LET, because charged particles can be focused into a tiny beam that can be directed onto individual cells. The biological effects seen in adjacent non-hit cells clearly represents a bystander effect. It is not so easy to demonstrate a similar effect for x-rays or for the electrons set in motion by the absorption of x-rays. In this project we used two types of cell that could be recognized one from the other. One cell type was fed radioactive tritiated thymidine, which is incorporated into the DNA, . The tritium emits electrons which have a very short range so that they do not even get out of the cell. These cells were then mixed with a different type of cell which are routinely used to assess mutations. The mixed cells formed a cluster, where the two types of cells were in close contact, and left for some hours. Subsequently, the two types of cells were separated and studied. A substantial fraction of the cells that had incorporated the tritiated thymidine were killed by the radiation. The interesting finding is that the cells that had not incorporated tritiated thymidine, but had been in close contact with cells that had, exhibited a significant incidence of mutations. These experiments clearly demonstrated a bystander effect for low LET electrons. In further experiments, it was possible to show that the bystander effect was greatest when the two cell types were in gap junction communication.

  12. Bystander Effects of Ionizing Radiation

    International Nuclear Information System (INIS)

    Little, John B.

    2017-01-01

    The objectives of this grant renewal are to provide administrative support and travel funds to allow the continued participation of the principal investigator (Dr. John B. Little) as an advisor to research initiated by several research fellows from his laboratory. The actual research will be carried out under the direction of Dr. Hatsumi Nagasawa with the collaboration of Dr. Joel Bedford at the Colorado State University, and by Drs. Edouard Azzam and Sonia de Toledo at the University of Medicine and Dentistry of New Jersey. Dr. Little will advise on the planning of experiments and development of experimental protocols, the analysis of data, and the preparation of manuscripts for publication. The Specific Aims for several of the planned experiments include: 1) to extend studies of the role of recombinational repair in the bystander effect by examining other genes in this pathway and cell lines deficient in excision repair; 2) to continue studies to determine the nature of the damage signal transmitted to bystander cells including the expression of several connexins in the bystander response, and the extent to which the enhanced oxidative metabolism observed in bystander cells may relate to the nature of the transmitted bystander signal; 3) to utilize a genome-wide approach to examine the genetic basis for the hypersensitivity to ionization we have observed in unaffected parents of patients with hereditary retinoblastoma, as well as from a group of apparently normal individuals that show similar radiosensitivity; 4) to complete studies concerning the induction of high frequencies of cells with massive chromosome damage in clonal derivatives of p53 and p21 knockout mouse cell lines; in particular to examine the role of telomere changes in this phenomenon. Overall, the results of these studies should enhance our understanding of the risk of low-dose exposures to ionizing radiation, including human populations to residential radon as well as occupational exposures.

  13. Genomic instability induced in distant progeny of bystander cells depends on the connexins expressed in the irradiated cells.

    Science.gov (United States)

    de Toledo, Sonia M; Buonanno, Manuela; Harris, Andrew L; Azzam, Edouard I

    2017-10-01

    To examine the time window during which intercellular signaling though gap junctions mediates non-targeted (bystander) effects induced by moderate doses of ionizing radiation; and to investigate the impact of gap junction communication on genomic instability in distant progeny of bystander cells. A layered cell culture system was developed to investigate the propagation of harmful effects from irradiated normal or tumor cells that express specific connexins to contiguous bystander normal human fibroblasts. Irradiated cells were exposed to moderate mean absorbed doses from 3.7 MeV α particle, 1000 MeV/u iron ions, 600 MeV/u silicon ions, or 137 Cs γ rays. Following 5 h of co-culture, pure populations of bystander cells, unexposed to secondary radiation, were isolated and DNA damage and oxidative stress was assessed in them and in their distant progeny (20-25 population doublings). Increased frequency of micronucleus formation and enhanced oxidative changes were observed in bystander cells co-cultured with confluent cells exposed to either sparsely ionizing ( 137 Cs γ rays) or densely ionizing (α particles, energetic iron or silicon ions) radiations. The irradiated cells propagated signals leading to biological changes in bystander cells within 1 h of irradiation, and the effect required cellular coupling by gap junctions. Notably, the distant progeny of isolated bystander cells also exhibited increased levels of spontaneous micronuclei. This effect was dependent on the type of junctional channels that coupled the irradiated donor cells with the bystander cells. Previous work showed that gap junctions composed of connexin26 (Cx26) or connexin43 (Cx43) mediate toxic bystander effects within 5 h of co-culture, whereas gap junctions composed of connexin32 (Cx32) mediate protective effects. In contrast, the long-term progeny of bystander cells expressing Cx26 or Cx43 did not display elevated DNA damage, whereas those coupled by Cx32 had enhanced DNA

  14. Spatially Fractionated Radiation Induces Cytotoxicity and Changes in Gene Expression in Bystander and Radiation Adjacent Murine Carcinoma Cells

    Science.gov (United States)

    Asur, Rajalakshmi S.; Sharma, Sunil; Chang, Ching-Wei; Penagaricano, Jose; Kommuru, Indira M.; Moros, Eduardo G.; Corry, Peter M.; Griffin, Robert J.

    2012-01-01

    Radiation-induced bystander effects have been extensively studied at low doses, since evidence of bystander induced cell killing and other effects on unirradiated cells were found to be predominant at doses up to 0.5 Gy. Therefore, few studies have examined bystander effects induced by exposure to higher doses of radiation, such as spatially fractionated radiation (GRID) treatment. In the present study, we evaluate the ability of GRID treatment to induce changes in GRID adjacent (bystander) regions, in two different murine carcinoma cell lines following exposure to a single irradiation dose of 10 Gy. Murine SCK mammary carcinoma cells and SCCVII squamous carcinoma cells were irradiated using a brass collimator to create a GRID pattern of nine circular fields 12 mm in diameter with a center-to-center distance of 18 mm. Similar to the typical clinical implementation of GRID, this is approximately a 50:50 ratio of direct and bystander exposure. We also performed experiments by irradiating separate cultures and transferring the medium to unirradiated bystander cultures. Clonogenic survival was evaluated in both cell lines to determine the occurrence of radiation-induced bystander effects. For the purpose of our study, we have defined bystander cells as GRID adjacent cells that received approximately 1 Gy scatter dose or unirradiated cells receiving conditioned medium from irradiated cells. We observed significant bystander killing of cells adjacent to the GRID irradiated regions compared to sham treated controls. We also observed bystander killing of SCK and SCCVII cells cultured in conditioned medium obtained from cells irradiated with 10 Gy. Therefore, our results confirm the occurrence of bystander effects following exposure to a high-dose of radiation and suggest that cell-to-cell contact is not required for these effects. In addition, the gene expression profile for DNA damage and cellular stress response signaling in SCCVII cells after GRID exposure was studied

  15. Differential effects of p53 on bystander phenotypes induced by gamma ray and high LET heavy ion radiation

    Science.gov (United States)

    He, Mingyuan; Dong, Chen; Konishi, Teruaki; Tu, Wenzhi; Liu, Weili; Shiomi, Naoko; Kobayashi, Alisa; Uchihori, Yukio; Furusawa, Yoshiya; Hei, Tom K.; Dang, Bingrong; Shao, Chunlin

    2014-04-01

    High LET particle irradiation has several potential advantages over γ-rays such as p53-independent response. The purpose of this work is to disclose the effect of p53 on the bystander effect induced by different LET irradiations and underlying mechanism. Lymphocyte cells of TK6 (wild type p53) and HMy2.CIR (mutated p53) were exposed to either low or high LET irradiation, then their mitochondrial dysfunction and ROS generation were detected. The micronuclei (MN) induction in HL-7702 hepatocytes co-cultured with irradiated lymphocytes was also measured. It was found that the mitochondrial dysfunction, p66Shc activation, and intracellular ROS were enhanced in TK6 but not in HMy2.CIR cells after γ-ray irradiation, but all of them were increased in both cell lines after carbon and iron irradiation. Consistently, the bystander effect of MN formation in HL-7702 cells was only triggered by γ-irradiated TK6 cells but not by γ-irradiated HMy2.CIR cells. But this bystander effect was induced by both lymphocyte cell lines after heavy ion irradiation. PFT-μ, an inhibitor of p53, only partly inhibited ROS generation and bystander effect induced by 30 keV/μm carbon-irradiated TK6 cells but failed to suppress the bystander effect induced by the TK6 cells irradiated with either 70 keV/μm carbon or 180 keV/μm iron. The mitochondrial inhibitors of rotenone and oligomycin eliminated heavy ion induced ROS generation in TK6 and HMy2.CIR cells and hence diminished the bystander effect on HL-7702 cells. These results clearly demonstrate that the bystander effect is p53-dependent for low LET irradiation, but it is p53-independent for high LET irradiation which may be because of p53-independent ROS generation due to mitochondrial dysfunction.

  16. The key role of miR-21-regulated SOD2 in the medium-mediated bystander responses in human fibroblasts induced by α-irradiated keratinocytes

    International Nuclear Information System (INIS)

    Tian, Wenqian; Yin, Xiaoming; Wang, Longxiao; Wang, Jingdong; Zhu, Wei; Cao, Jianping; Yang, Hongying

    2015-01-01

    , overexpression of SOD2 abolished the bystander oxidative stress and DNA damage, indicating that SOD2 was critical to the induction of RIBEs. Moreover, we found that miR-21 regulated SOD2, suggesting that miR-21 might mediate bystander responses through its regulation on SOD2. In conclusion, this study revealed a profound role of miR-21-regulated SOD2 of unirradiated WS1 cells in bystander effects induced by α-irradiated HaCaT keratinocytes.

  17. The key role of miR-21-regulated SOD2 in the medium-mediated bystander responses in human fibroblasts induced by α-irradiated keratinocytes

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Wenqian; Yin, Xiaoming; Wang, Longxiao; Wang, Jingdong; Zhu, Wei; Cao, Jianping [School of Radiation Medicine and Protection, Medical College of Soochow University/Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, 199 Renai Road, Suzhou Industrial Park, Suzhou, Jiangsu Province 215123 (China); Yang, Hongying, E-mail: yanghongying@suda.edu.cn [School of Radiation Medicine and Protection, Medical College of Soochow University/Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, 199 Renai Road, Suzhou Industrial Park, Suzhou, Jiangsu Province 215123 (China); Institute of Radiotherapy & Oncology, Soochow University (China)

    2015-10-15

    , overexpression of SOD2 abolished the bystander oxidative stress and DNA damage, indicating that SOD2 was critical to the induction of RIBEs. Moreover, we found that miR-21 regulated SOD2, suggesting that miR-21 might mediate bystander responses through its regulation on SOD2. In conclusion, this study revealed a profound role of miR-21-regulated SOD2 of unirradiated WS1 cells in bystander effects induced by α-irradiated HaCaT keratinocytes.

  18. Mutagenicity of complex mixtures

    International Nuclear Information System (INIS)

    Pelroy, R.A.

    1985-01-01

    The effect of coal-derived complex chemical mixtures on the mutagenicity of 6-aminochrysene (6-AC) was determined with Salmonella typhimurium TA98. Previous results suggested that the mutagenic potency of 6-AC for TA98 in the standard microsomal activation (Ames) assay increased if it was presented to the cells mixed with high-boiling coal liquids (CL) from the solvent refined coal (SRC) process. In this year's work, the apparent mutational synergism of CL and 6-AC was independently verified in a fluctuation bioassay which allowed quantitation of mutational frequencies and cell viability. The results of this assay system were similar to those in the Ames assay. Moreover, the fluctation assay revealed that mutagenesis and cellular toxicity induced by 6-AC were both strongly enhanced if 6-AC was presented to the cells mixed in a high-boiling CL. 4 figures

  19. Bystander effects in unicellular organisms

    International Nuclear Information System (INIS)

    DeVeaux, Linda C.; Durtschi, Lynn S.; Case, Jonathan G.; Wells, Douglas P.

    2006-01-01

    Radiation-induced bystander effects have been seen in mammalian cells from diverse origins. These effects can be transmitted through the medium to cells not present at the time of irradiation. We have developed an assay for detecting bystander effects in the unicellular eukaryote, the fission yeast Schizosaccharomyces pombe. This assay allows maximal exposure of unirradiated cells to cells that have received electron beam irradiation. S. pombe cells were irradiated with 16-18 MeV electrons from a pulsed electron LINAC. When survival of the irradiated cells decreased to approximately 50%, forward-mutation to 2-deoxy-D-glucose resistance increased in the unirradiated bystander cells. Further increase in dose had no additional effect on this increase. In order to detect this response, it was necessary for the irradiated cell/unirradiated cell ratio to be high. Other cellular stresses, such as heat treatment, UV irradiation, and bleomycin exposure, also caused a detectable response in untreated cells grown with the treated cells. We discuss evolutionary implications of these results

  20. Bystander effects in unicellular organisms

    Energy Technology Data Exchange (ETDEWEB)

    DeVeaux, Linda C. [Idaho Accelerator Center, Campus Box 8263, Idaho State University, Pocatello, ID 83209 (United States) and Department of Biological Sciences, Campus Box 8007, Idaho State University, Pocatello, ID 83209 (United States)]. E-mail: develind@isu.edu; Durtschi, Lynn S. [Department of Biological Sciences, Campus Box 8007, Idaho State University, Pocatello, ID 83209 (United States); Case, Jonathan G. [Department of Physics, Campus Box 8106, Idaho State University, Pocatello, ID 83209 (United States); Wells, Douglas P. [Department of Physics, Campus Box 8106, Idaho State University, Pocatello, ID 83209 (United States)

    2006-05-11

    Radiation-induced bystander effects have been seen in mammalian cells from diverse origins. These effects can be transmitted through the medium to cells not present at the time of irradiation. We have developed an assay for detecting bystander effects in the unicellular eukaryote, the fission yeast Schizosaccharomyces pombe. This assay allows maximal exposure of unirradiated cells to cells that have received electron beam irradiation. S. pombe cells were irradiated with 16-18 MeV electrons from a pulsed electron LINAC. When survival of the irradiated cells decreased to approximately 50%, forward-mutation to 2-deoxy-D-glucose resistance increased in the unirradiated bystander cells. Further increase in dose had no additional effect on this increase. In order to detect this response, it was necessary for the irradiated cell/unirradiated cell ratio to be high. Other cellular stresses, such as heat treatment, UV irradiation, and bleomycin exposure, also caused a detectable response in untreated cells grown with the treated cells. We discuss evolutionary implications of these results.

  1. Bystander effects in unicellular organisms.

    Science.gov (United States)

    DeVeaux, Linda C; Durtschi, Lynn S; Case, Jonathan G; Wells, Douglas P

    2006-05-11

    Radiation-induced bystander effects have been seen in mammalian cells from diverse origins. These effects can be transmitted through the medium to cells not present at the time of irradiation. We have developed an assay for detecting bystander effects in the unicellular eukaryote, the fission yeast Schizosaccharomyces pombe. This assay allows maximal exposure of unirradiated cells to cells that have received electron beam irradiation. S. pombe cells were irradiated with 16-18 MeV electrons from a pulsed electron LINAC. When survival of the irradiated cells decreased to approximately 50%, forward-mutation to 2-deoxy-d-glucose resistance increased in the unirradiated bystander cells. Further increase in dose had no additional effect on this increase. In order to detect this response, it was necessary for the irradiated cell/unirradiated cell ratio to be high. Other cellular stresses, such as heat treatment, UV irradiation, and bleomycin exposure, also caused a detectable response in untreated cells grown with the treated cells. We discuss evolutionary implications of these results.

  2. A correlation of long term effects and radiation quality in the progeny of bystander cells after microbeam radiations: The experimental study of radiotherapy for cancer risk mitigation

    Science.gov (United States)

    Autsavapromporn, N.; Konishi, T.; Liu, C.; Plante, I.; Funayama, T.; Usami, N.; Azzam, EI; Suzuki, M.

    2017-06-01

    The goal of this study is to investigate the role of radiation quality and gap junction intercellular communication (GJIC) in the propagation of delayed stressful effects in the progeny of bystander human skin fibroblasts cultures (NB1RGB). Briefly, confluent NB1RGB cells in the presence and absence of gap junction inhibitor (AGA) were exposed to ionizing radiation (IR) with a different linear energy transfer (LET) either 5.35 keV X rays (LET ∼6 keV/μm) or 18.3 MeV/u carbon (LET ∼103 keV/μm) microbeam radiations. Following 20 populations post-irradiation, the progeny of bystander NB1RGB cells were harvested and assayed for several of biological endpoints. Our results showed that expression of stressful effects in the progeny of bystander cells is dependent on LET. The progeny of bystander cells exposed to low-LET X rays showed the persistence of oxidative stress and it was correlated with the increased mutant fraction. Such effect were not observed after high-LET carbon ions. Interestingly, inhibition of GJIC mitigated the toxic effects in the progeny of bystander cells. Together, the results contribute to the understanding of the fundamental radiation biology relating to the high-LET carbon ions to mitigate cancer risk after radiotherapy. Furthermore, GJIC be considered as a critical mediator in the bystander mutagenic effect.

  3. A Bully's Bystanders Are Never Innocent

    Science.gov (United States)

    Coloroso, Barbara

    2005-01-01

    Though they play the least active role, bystanders are a critical element in bullying. With peers looking on and providing at least tacit support, the bully is no longer acting alone. The bystanders have become allies to the point of magnifying the supposed negative attributes of the target. If the bullying cycle is to be broken, the role of the…

  4. Bystander effects of ionizing radiation can be modulated by signaling amines

    International Nuclear Information System (INIS)

    Poon, R.C.C.; Agnihotri, N.; Seymour, C.; Mothersill, C.

    2007-01-01

    Actual risk and risk management of exposure to ionizing radiation are among the most controversial areas in environmental health protection. Recent developments in radiobiology especially characterization of bystander effects have called into question established dogmas and are thought to cast doubt on the scientific basis of the risk assessment framework, leading to uncertainty for regulators and concern among affected populations. In this paper we test the hypothesis that small signaling molecules widely used throughout the animal kingdom for signaling stress or environmental change, such as 5-Hydroxytryptamine (5-HT, serotonin), L-DOPA, glycine or nicotine are involved in bystander signaling processes following ionizing radiation exposure. We report data which suggest that nano to micromolar concentrations of these agents can modulate bystander-induced cell death. Depletion of 5-HT present in tissue culture medium, occurred following irradiation of cells. This suggested that 5-HT might be bound by membrane receptors after irradiation. Expression of 5-HT type 3 receptors which are Ca 2+ ion channels was confirmed in the cells using immunocytochemistry and receptor expression could be increased using radiation or 5-HT exposure. Zofran and Kitryl, inhibitors of 5-HT type 3 receptors, and reserpine a generic serotonin antagonist block the bystander effect induced by radiation or by serotonin. The results may be important for the mechanistic understanding of how low doses of radiation interact with cells to produce biological effects

  5. Genotoxicity in the eyes of bystander cells

    International Nuclear Information System (INIS)

    Hei, Tom K.; Persaud, Rudranath; Zhou, Hongning; Suzuki, Masao

    2004-01-01

    The controversial use of a linear, no threshold extrapolation model for low dose risk assessment has become even more so in light of the recent reports on the bystander phenomenon. The answer to the question as to which of the two phenomena, bystander versus adaptive response, is more important has practical implication in terms of low dose radiation risk assessment. In this review, genotoxicity is used as an endpoint to introduce the two phenomena, provide some insight into the mechanisms of bystander effect and to bridge the two low dose phenomena which operate in opposite directions: the bystander effect tends to exaggerate the effect at low doses, by communicating damage from hit to non-hit cells whereas the adaptive response confers resistance to a subsequent challenging dose by an initial low priming dose

  6. Handbook of mutagenicity test procedures

    International Nuclear Information System (INIS)

    Kilbey, B.J.; Legatov, M.

    1977-01-01

    27 articles are presented on particular techniques of mutagen testing. Background information is given in materials, experimental design, pitfalls and difficults, to enable the reader to perform these tests with minimal additional help. Also included is the use of data from population records, the handling and safety aspects of mutagens and carcinogens and some of the basic statistical concepts to be borne in mind when mutation experiments are designed. (C.F.)

  7. Are Victims Truly Worse Off in the Presence of Bystanders? Revisiting the Bystander Effect

    NARCIS (Netherlands)

    Fromell, Hanna; Nosenzo, Daniele; Owens, Trudy; Tufano, Fabio

    2017-01-01

    Previous studies have shown that individuals are less likely to help a person in need when there are “bystanders” present who can also offer help. We designed an experiment to re-examine this “bystander effect” using modified dictator games. We find lower giving rates in the presence of bystanders,

  8. Leverage Between the Buffering Effect and the Bystander Effect in Social Networking.

    Science.gov (United States)

    Chiu, Yu-Ping; Chang, Shu-Chen

    2015-08-01

    This study examined encouraged and inhibited social feedback behaviors based on the theories of the buffering effect and the bystander effect. A system program was used to collect personal data and social feedback from a Facebook data set to test the research model. The results revealed that the buffering effect induced a positive relationship between social network size and feedback gained from friends when people's social network size was under a certain cognitive constraint. For people with a social network size that exceeds this cognitive constraint, the bystander effect may occur, in which having more friends may inhibit social feedback. In this study, two social psychological theories were applied to explain social feedback behavior on Facebook, and it was determined that social network size and social feedback exhibited no consistent linear relationship.

  9. The key role of miR-21-regulated SOD2 in the medium-mediated bystander responses in human fibroblasts induced by α-irradiated keratinocytes.

    Science.gov (United States)

    Tian, Wenqian; Yin, Xiaoming; Wang, Longxiao; Wang, Jingdong; Zhu, Wei; Cao, Jianping; Yang, Hongying

    2015-10-01

    cells in bystander effects induced by α-irradiated HaCaT keratinocytes. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Mutagenic azide metabolite is azidoalanine

    International Nuclear Information System (INIS)

    Owais, W.M.; Rosichan, J.L.; Ronald, R.C.; Kleinhofs, A.; Nilan, R.A.

    1981-01-01

    Sodium axide produces high mutation rates in a number of species. Azide mutagenicity is mediated through a metabolite in barley and bacteria. Many studies showed that azide affects the L-cysteine biosynthesis pathway. Cell-free extracts of Salmonella typhimurium convert azide and O-acetylserine to the mutagenic metabolite. O-acetylserine sulfhydrylase was identified as the enzyme responsible for the metabolite biosynthesis. To confirm the conclusion that the azide metabolite is formed through the β-substitution pathway of L-cysteine, we radioactively labeled the azide metabolite using 14 C-labeled precursors. Moreover, the mutagenic azide metabolite was purified and identified as azidoalanine based on mass spectroscopy and elemental analysis. 26 refs., 3 figs., 1 tab

  11. Bystander Programs: Accommodating or Derailing Sexism?

    Directory of Open Access Journals (Sweden)

    Adam Reid

    2017-09-01

    Full Text Available Bystander programs implemented to meet federal requirements to reduce sexual assaults on college campuses in the United States must include primary prevention. Survey data (n = 280 and interview data (n = 20 presented in this paper explore students’ hypothetical and actual willingness to intervene as bystanders. Although most students surveyed (57% claim they would be very likely to intervene, fewer than half would be very suspicious of someone leading away an intoxicated individual at a party (45% of women and 28% of men: p < 0.01. Interview data reveal how students perceive risk factors at college parties and what types of bystander measures they attempt, including “distractions”, a nonconfrontational tactic in which bystanders avoid more direct but socially risky interventions. Subsumed in many current bystander programs is an invisible element of valorizing harmony. Condoning bystanders’ unwillingness to directly confront seemingly predatory individuals could make change seem out of reach and could also embolden offenders whose behavior is observed and only temporarily thwarted.

  12. Radiation-induced bystander effects enhanced by elevated sodium chloride through sensitizing cells to bystander factors

    International Nuclear Information System (INIS)

    Zhu Lingyan; Han Wei; Chen Shaopeng; Zhao Ye; Jiang Erkang; Bao Lingzhi; Pei Bei; Yang Gen; Zhao Guoping; Wang Jun; Xu An; Wu Lijun

    2008-01-01

    Radiation-induced bystander effects (RIBE) have been demonstrated to occur widely in various cell lines. However, very little data is available on the genotoxic effects of RIBE combined with other factor(s). We reported previously that with a low dose of α-particle irradiation, the fraction of γ-H2AX foci-positive cells in non-irradiated bystander cells was significantly increased under elevated NaCl culture conditions. In this study, we further investigated the functional role of NaCl in the enhancement of RIBE using a specially designed co-culture system and micronucleus (MN) test. It was shown that the MN frequency was not increased significantly by elevated NaCl (9.0 g/L) alone or by medium exposure. However, with 1.0 cGy α-particle irradiation, the induced MN frequency increased significantly in both irradiated and non-irradiated bystander regions. Additional studies showed that elevated NaCl made the non-irradiated bystander cells more vulnerable to bystander factors. Furthermore, it was found that the induced MN frequency in cells both in irradiated and non-irradiated bystander regions was weakened when the hypertonic medium was changed to normotonic medium for 2 h before irradiation. Such observations were quite similar to the co-effect of NaCl and hydrogen peroxide (H 2 O 2 ), indicating that elevated NaCl might sensitize non-irradiated cells to bystander factors-induced oxidative stress

  13. Mutagenicity of cooked foods. Kuumennuskaesiteltyjen elintarvikkeiden mutageenisuus

    Energy Technology Data Exchange (ETDEWEB)

    Tikkanen, L. (Valtion teknillinen tutkimuskeskus, Espoo (Finland). Elintarvikelaboratorio)

    1989-09-01

    In this study the mutagenic activity in different kinds of ordinary Finnish foods was determined using mainly the Ames Salmonella bacterial assay. The purpose of this study was also to acquire the technical capability to study cooked food mutagens and to get basic informavtion about the mutagenic activity of foods under different cooking conditions. The samples tested were different kinds of ready-to-eat foods. Products were industrially heat-processed by frying and roasting, sterilization, smoking, deep-frying, spray-drying and UHT-treatment. According to the results, the majority of the fried and roasted food samples containing meat or fish were clearly or strongly mutagenic. Some of the products processed by sterilization and deep-frying were marginally mutagenic. The effect of the frying temperature on the mutagenicity in the Ames test was studied with minced meat. The mutagenic activity of the fried meat clearly correlated with the frying temperature. There were conspicuous differences in mutagenic activity between different fried and roasted products. Charcoal-grilled fish and the surface layers of the grilled meat and chicken were strongly mutagenic. Meat and fish hamburgers were in most cases only slightly mutagenic. The mutagenic activity was stronger in the surface layers of the products than in the inside. Also reheating by frying increased the mutagenicity of meat patties clearly. Differences in mutagenic activity between equivalent products of different manufacturers were evident in many cases. Variation of the mutagenicity was most conspicuous in the grilled products. This variation indicates that the industrial processing of food has a marked effect on the mutagenic activity of the final product, which thus might be reduced by modifying the process. The solvent extraction method used in this study was more effective than the Blue-Cotton method for the isolation of mutagenic compounds.

  14. The bystander effect of cancer gene therapy

    International Nuclear Information System (INIS)

    Lumniczky, K.; Safrany, G.

    2008-01-01

    Cancer gene therapy is a new, promising therapeutic agent. In the clinic, it should be used in combination with existing modalities, such as tumour irradiation. First, we summarise the most important fields of cancer gene therapy: gene directed enzyme pro-drug therapy; the activation of an anti-tumour immune attack; restoration of the wild type p53 status; the application of new, replication competent and oncolytic viral vectors; tumour specific, as well as radiation- and hypoxia-induced gene expression. Special emphasizes are put on the combined effect of these modalities with local tumour irradiation. Using the available vector systems, only a small portion of the cancer cells will contain the therapeutic genes under therapeutic situations. Bystander cell killing might contribute to the success of various gene therapy protocols. We summarise the evidences that lethal bystander effects may occur during cancer gene therapy. Bystander effects are especially important in the gene directed enzyme pro-drug therapy. There, bystander cell killing might have different routes: cell communication through gap junction intercellular contacts; release of toxic metabolites into the neighbourhood or to larger distances; phagocytosis of apoptotic bodies; and the activation of the immune system. Bystander cell killing can be enhanced by the introduction of gap junction proteins into the cells, by further activating the immune system with immune-stimulatory molecules, or by introducing genes into the cells that help the transfer of cytotoxic genes and / or metabolites into the bystander cells. In conclusion, there should be additional improvements in cancer gene therapy for the more efficient clinical application. (orig.)

  15. Mutagenic DNA repair in enterobacteria

    International Nuclear Information System (INIS)

    Sedgwick, S.G.; Chao Ho; Woodgate, R.

    1991-01-01

    Sixteen species of enterobacteria have been screened for mutagenic DNA repair activity. In Escherichia coli, mutagenic DNA repair is encoded by the umuDC operon. Synthesis of UmuD and UmuC proteins is induced as part of the SOS response to DNA damage, and after induction, the UmuD protein undergoes an autocatalytic cleavage to produce the carboxy-terminal UmuD' fragment needed for induced mutagenesis. The presence of a similar system in other species was examined by using a combined approach of inducible-mutagenesis assays, cross-reactivity to E. coli UmuD and UmuD' antibodies to test for induction and cleavage of UmuD-like proteins, and hybridization with E. coli and Salmonella typhimurium u mu DNA probes to map umu-like genes. The results indicate a more widespread distribution of mutagenic DNA repair in other species than was previously thought. They also show that umu loci can be more complex in other species than in E. coli. Differences in UV-induced mutability of more than 200-fold were seen between different species of enteric bacteria and even between multiple natural isolates of E. coli, and yet some of the species which display a poorly mutable phenotype still have umu-like genes and proteins. It is suggested that umuDC genes can be curtailed in their mutagenic activities but that they may still participate in some other, unknown process which provides the continued stimulus for their retention

  16. Rethinking the bystander role in school violence prevention.

    Science.gov (United States)

    Stueve, Ann; Dash, Kimberly; O'Donnell, Lydia; Tehranifar, Parisa; Wilson-Simmons, Renée; Slaby, Ronald G; Link, Bruce G

    2006-01-01

    Public concerns about school shootings and safety draw attention to the role bystanders can play in preventing school violence. Although school violence prevention plans are often required, there is little guidance about whether these should address the roles of bystanders and what actions bystanders should take in different circumstances, from more common instances of bullying and fighting to rare, but potentially lethal, threats and use of weapons. Literature pertaining to bystanders is reviewed and applied to the school setting. The definition of bystander is expanded, including parents, teachers, and other school staff as well as youths and those who have information about potential violence as well as those who witness its occurrence. Barriers preventing bystanders from taking positive actions are discussed. The authors call on health promotion researchers and practitioners to work with school communities to identify norms, attitudes, and outcome expectancies that shape bystander behaviors to inform prevention efforts.

  17. Commensal bacteria drive endogenous transformation and tumour stem cell marker expression through a bystander effect.

    Science.gov (United States)

    Wang, Xingmin; Yang, Yonghong; Huycke, Mark M

    2015-03-01

    Commensal bacteria and innate immunity play a major role in the development of colorectal cancer (CRC). We propose that selected commensals polarise colon macrophages to produce endogenous mutagens that initiate chromosomal instability (CIN), lead to expression of progenitor and tumour stem cell markers, and drive CRC through a bystander effect. Primary murine colon epithelial cells were repetitively exposed to Enterococcus faecalis-infected macrophages, or purified trans-4-hydroxy-2-nonenal (4-HNE)-an endogenous mutagen and spindle poison produced by macrophages. CIN, gene expression, growth as allografts in immunodeficient mice were examined for clones and expression of markers confirmed using interleukin (IL) 10 knockout mice colonised by E. faecalis. Primary colon epithelial cells exposed to polarised macrophages or 4-hydroxy-2-nonenal developed CIN and were transformed after 10 weekly treatments. In immunodeficient mice, 8 of 25 transformed clones grew as poorly differentiated carcinomas with 3 tumours invading skin and/or muscle. All tumours stained for cytokeratins confirming their epithelial cell origin. Gene expression profiling of clones showed alterations in 3 to 7 cancer driver genes per clone. Clones also strongly expressed stem/progenitor cell markers Ly6A and Ly6E. Although not differentially expressed in clones, murine allografts positively stained for the tumour stem cell marker doublecortin-like kinase 1. Doublecortin-like kinase 1 and Ly6A/E were expressed by epithelial cells in colon biopsies for areas of inflamed and dysplastic tissue from E. faecalis-colonised IL-10 knockout mice. These results validate a novel mechanism for CRC that involves endogenous CIN and cellular transformation arising through a microbiome-driven bystander effect. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  18. Bystanders not so innocent after all.

    Science.gov (United States)

    Batten, Marcel; Ghilardi, Nico

    2012-06-29

    Interleukin 27 (IL-27) regulates immune responses, including T helper 17 (Th17) cell activity. In this issue of Immunity, Hirahara et al. (2012) demonstrate that IL-27 suppresses Th17 cells in trans through induction of the inhibitory ligand PD-L1 on bystander T cells. Copyright © 2012 Elsevier Inc. All rights reserved.

  19. Mutagenicity tests on irradiated food

    International Nuclear Information System (INIS)

    Johnston-Arthur, T.

    1979-01-01

    The mutagenicity of ''standard'' food pellets from three different suppliers was tested after radappertization and after sterilization with steam, respectively. The histidine-deficient mutants G-46 and TA-1530 of salmonella typhimurium were used as indicators in a hostmediated assay. The mutant TA-1530 showed a highly sighificant increase of the back-mutation frequency after feeding with pellets irradiated with 3 Mrad gamma radiation. There were, however, large quantitative differences between the products of different suppliers. (G.G.)

  20. Radiation-induced bystander effects enhanced by elevated sodium chloride through sensitizing cells to bystander factors

    Energy Technology Data Exchange (ETDEWEB)

    Zhu Lingyan; Han Wei; Chen Shaopeng; Zhao Ye; Jiang Erkang; Bao Lingzhi; Pei Bei; Yang Gen; Zhao Guoping; Wang Jun; Xu An [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei 230031, Anhui (China); Wu Lijun [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei 230031, Anhui (China)], E-mail: ljw@ipp.ac.cn

    2008-09-26

    Radiation-induced bystander effects (RIBE) have been demonstrated to occur widely in various cell lines. However, very little data is available on the genotoxic effects of RIBE combined with other factor(s). We reported previously that with a low dose of {alpha}-particle irradiation, the fraction of {gamma}-H2AX foci-positive cells in non-irradiated bystander cells was significantly increased under elevated NaCl culture conditions. In this study, we further investigated the functional role of NaCl in the enhancement of RIBE using a specially designed co-culture system and micronucleus (MN) test. It was shown that the MN frequency was not increased significantly by elevated NaCl (9.0 g/L) alone or by medium exposure. However, with 1.0 cGy {alpha}-particle irradiation, the induced MN frequency increased significantly in both irradiated and non-irradiated bystander regions. Additional studies showed that elevated NaCl made the non-irradiated bystander cells more vulnerable to bystander factors. Furthermore, it was found that the induced MN frequency in cells both in irradiated and non-irradiated bystander regions was weakened when the hypertonic medium was changed to normotonic medium for 2 h before irradiation. Such observations were quite similar to the co-effect of NaCl and hydrogen peroxide (H{sub 2}O{sub 2}), indicating that elevated NaCl might sensitize non-irradiated cells to bystander factors-induced oxidative stress.

  1. Human somatic, germinal and heritable mutagenicity

    International Nuclear Information System (INIS)

    Mendelsohn, M.L.

    1987-05-01

    This report deals with the general process of variant formation rather than with the consequences of a specific variant being present. It focusses on mutational mechanisms, mutagens, and the method for detecting de novo mutants and estimating mutation rate. It is to human genetics much like disease causation and prevention medicine are to medicine as a whole. The word ''mutagenicity'' is used in the title and throughout the text to connote the causation of all classes of genetic damage. Mutagenicity and the corresponding words mutation, mutagen and mutagenesis can have multiple meaning, sometimes relating to gene mutation, sometimes to heritable mutation, and somtimes to all types of genetic damage. 38 refs., 1 tab

  2. Bystander Tactics: Life on Turf in Karachi

    Directory of Open Access Journals (Sweden)

    Tania Ahmad

    2012-03-01

    Full Text Available This article posits an analytic of the bystander, as a supplement to studies of perpetrators and victims, in relation to political affiliation, mobilization and violence in Karachi. In particular, I use ethnographic findings to elucidate the tactics of anticipation used by Karachi residents of neighborhoods widely considered the turf of the Muttahida Qaumi Movement (MQM. The examples of students’ and teachers’ reactions to a college rumble between rival groups, parents’ attempts to keep their sons from being recruited into party politics, and young people confident in their ability to navigate an economy of affiliation demonstrate a range of bystander tactics, in which subjection and subversion are aligned. Although metanarratives of democratization frequently elide the everyday activity of standing by, it constitutes a pervasive mode of participation in Karachi’s political landscape.

  3. Modulation of mutagen-induced biological effects by inhibitors of DNA repair

    International Nuclear Information System (INIS)

    Natarajan, A.T.; Mullenders, L.F.H.; Zwanenburg, T.S.B.

    1986-01-01

    When lesions are induced in the DNA by mutagenic agents, they are subjected to cellular repair. Unrepaired and misrepaired lesions lead to biological effects, such as cell killing, point mutations and chromosomal alterations (aberrations and sister chromatid exchanges - SCEs). It is very difficult to directly correlate any particular type of lesion to a specific biological effect. However, in specific cases, this has been done. For example, short wave UV induced biological effects (cell killing, chromosomal alterations) result predominantly from induced cyclobutane dimers and by photoreactivation experiments, one can demonstrate that with the removal of dimers all types biological effects are diminished. In cases where many types of lesions are considered responsible for the observed biological effects other strategies have been employed to identify the possible lesion. The frequencies of induced chromosomal alterations and point mutations increase with the dose of the mutagen employed and an inhibition of DNA repair following treatment with the mutagen. Prevention of the cells from dividing following mutagen treatment allows them to repair premutational damage, thus reducing the biological effects induced. By comprehensive studies involving quantification of primary DNA lesions, their repair and biological effects will enable us to understand to some extent the complex processes involved in the manifestation of specific biological effects that follow the treatment of cells with mutagenic carcinogens

  4. Neutron induced bystander effect among zebrafish embryos

    Science.gov (United States)

    Ng, C. Y. P.; Kong, E. Y.; Kobayashi, A.; Suya, N.; Uchihori, Y.; Cheng, S. H.; Konishi, T.; Yu, K. N.

    2015-12-01

    The present paper reported the first-ever observation of neutron induced bystander effect (NIBE) using zebrafish (Danio rerio) embryos as the in vivo model. The neutron exposure in the present work was provided by the Neutron exposure Accelerator System for Biological Effect Experiments (NASBEE) facility at the National Institute of Radiological Sciences (NIRS), Chiba, Japan. Two different strategies were employed to induce NIBE, namely, through directly partnering and through medium transfer. Both results agreed with a neutron-dose window (20-50 mGy) which could induce NIBE. The lower dose limit corresponded to the threshold amount of neutron-induced damages to trigger significant bystander signals, while the upper limit corresponded to the onset of gamma-ray hormesis which could mitigate the neutron-induced damages and thereby suppress the bystander signals. Failures to observe NIBE in previous studies were due to using neutron doses outside the dose-window. Strategies to enhance the chance of observing NIBE included (1) use of a mono-energetic high-energy (e.g., between 100 keV and 2 MeV) neutron source, and (2) use of a neutron source with a small gamma-ray contamination. It appeared that the NASBEE facility used in the present study fulfilled both conditions, and was thus ideal for triggering NIBE.

  5. Carcinogenicity and mutagenicity of chromium.

    Science.gov (United States)

    Léonard, A; Lauwerys, R R

    1980-11-01

    Occupational exposure represents the main source of human contamination by chromium. For non-occupationally exposed people the major environmental exposure to chromium occurs as a consequence of its presence in food. Chromium must be considered as an essential element. Its deficiency impairs glucose metabolism. Trivalent chromium salts are poorly absorbed through the gastro-intestinal and respiratory tracts because they do not cross membranes easily. Hexavalent chromium can be absorbed by the oral and pulmonary routes and probably also through the skin. After its absorption, hexavalent chromium is rapidly reduced to the trivalent form which is probably the only form to be found in biological material. Epidemiological studies have shown that some chromium salts (mainly the slightly soluble hexavalent salts) are carcinogens. Lung cancers have, indeed, often been reported among workers in chromate-producing industry and, to a lesser extent, in workers from the chrome-pigment industry. The first attempts to produce cancers in experimental animals by inhalation or parenteral introduction gave negative or equivocal results but, from 1960, positive results have been obtained with various chromium compounds. As for the carcinogenic activity, the mutagenicity of chromium has mainly been found with hexavalent salts. In the majority of assay systems used, trivalent chromium appears inactive. It can be considered as evident, however, that the ultimate mutagen which binds to the genetic material is the trivalent form produced intracellularly from hexavalent chromium, the apparent lack of activity of the trivalent form being due to its poor cellular uptake.

  6. Mutagenicity of vinyl chloride after metabolic activation

    Energy Technology Data Exchange (ETDEWEB)

    Rannug, U; Johansson, A; Ramel, C; Wachtmeister, C A

    1974-01-01

    Vinyl chloride has recently been shown to cause a malignant liver tumor disease in man after occupational exposure in PVC plants. This actualizes the problem of whether such hazards could be avoided or at least diminished in the future by a screening for mutagenicity of chemicals used in industries. The basis for such a screening procedure is the close correlation between carcinogenic and mutagenic effects of chemicals. Experiments with Salmonella bacteria showed that the carcinogenic hazard of vinyl chloride could have been traced by means of mutagenicity tests. The data indicate that vinyl chloride is not mutagenic per se but becomes mutagenic after a metabolic activation in the liver. 24 references, 1 figure, 4 tables.

  7. Bystander-witnessed cardiac arrest is associated with reported agonal breathing and leads to less frequent bystander CPR.

    Science.gov (United States)

    Brinkrolf, P; Metelmann, B; Scharte, C; Zarbock, A; Hahnenkamp, K; Bohn, A

    2018-04-18

    Although the importance of bystander cardiopulmonary resuscitation has been shown in multiple studies, the rate of bystander cardiopulmonary resuscitation is still relatively low in many countries. Little is known on bystanders' perceptions influencing the decision to start cardiopulmonary resuscitation. Our study aims to determine such factors. Semi-structured telephone interviews with bystanders of out-of-hospital cardiac arrests between December 2014 and April 2016 were performed in a prospective manner. This single-center survey was conducted in the city of Münster, Germany. The bystander's sex and age, the perception of the victim's breathing and initial condition were correlated with the share of bystander cardiopulmonary resuscitation in the corresponding group. 101 telephone interviews were performed with 57 male and 44 female participants showing a mean age of 52.7 (SD ± 16.3). In case of apnoea 38 out of 46 bystanders (82.6%) started cardiopulmonary resuscitation; while in case of descriptions indicating agonal breathing 19 out of 35 bystanders (54.3%) started cardiopulmonary resuscitation (p = .007). If the patient was found unconscious 47 out of 63 bystanders (74.7%) performed cardiopulmonary resuscitation, while in cases of witnessed cardiac arrest 19 out of 38 bystanders (50%) attempted cardiopulmonary resuscitation (p = .012). Witnessed change of consciousness is an independent factor significantly lowering the probability of starting cardiopulmonary resuscitation (regression coefficient -1.489, p bystander-CPR was started. These data reinforce the importance of teaching the recognition of early cardiac arrest. Copyright © 2018 Elsevier B.V. All rights reserved.

  8. Measuring Bystander Attitudes and Behavior to Prevent Sexual Violence

    Science.gov (United States)

    McMahon, Sarah; Allen, Christopher T.; Postmus, Judy L.; McMahon, Sheila M.; Peterson, N. Andrew; Lowe Hoffman, Melanie

    2014-01-01

    Objective: The purpose of this study is to further investigate the factor structure and strength of the Bystander Attitude Scale-Revised and Bystander Behavior Scale-Revised (BAS-R and BBS-R). Participants: First-year students (N = 4,054) at a large public university in the Northeast completed a survey in 2010 as part of a larger longitudinal…

  9. Lipids, atherosclerosis and CVD risk: is CRP an innocent bystander?

    DEFF Research Database (Denmark)

    Nordestgaard, B G; Zacho, J

    2009-01-01

    AIM: To evaluate recent human studies with respect to the interpretation of whether elevated plasma levels of C-reactive protein (CRP) cause cardiovascular disease (CVD), or whether elevated CRP levels more likely is an innocent bystander. DATA SYNTHESIS: Elevated CRP concentrations...... and vulnerability of atherosclerotic plaques, and thus simply an innocent bystander in CVD....

  10. The Bystander in Commercial Life : Obliged by Beneficence or Rescue

    NARCIS (Netherlands)

    Dubbink, Wim

    2016-01-01

    Liberalist thinking argues that moral agents have a right (or duty) to pursue an ordinary life. It also insists that moral agent can be bystanders. A bystander is involved with morally bad states of affairs in the sense that they are bound by moral duty, but for a non-blameworthy reason. A common

  11. Rape Myth Beliefs and Bystander Attitudes among Incoming College Students

    Science.gov (United States)

    McMahon, Sarah

    2010-01-01

    Objective: The bystander approach to rape prevention is gaining popularity on college campuses, although research is limited. This study explored bystander attitudes and their relationship with rape myths in a sample of college students. Participants: Surveys from 2,338 incoming undergraduate students at a large, northeastern university were…

  12. Bystander cells enhance NK cytotoxic efficiency by reducing search time.

    Science.gov (United States)

    Zhou, Xiao; Zhao, Renping; Schwarz, Karsten; Mangeat, Matthieu; Schwarz, Eva C; Hamed, Mohamed; Bogeski, Ivan; Helms, Volkhard; Rieger, Heiko; Qu, Bin

    2017-03-13

    Natural killer (NK) cells play a central role during innate immune responses by eliminating pathogen-infected or tumorigenic cells. In the microenvironment, NK cells encounter not only target cells but also other cell types including non-target bystander cells. The impact of bystander cells on NK killing efficiency is, however, still elusive. In this study we show that the presence of bystander cells, such as P815, monocytes or HUVEC, enhances NK killing efficiency. With bystander cells present, the velocity and persistence of NK cells were increased, whereas the degranulation of lytic granules remained unchanged. Bystander cell-derived H 2 O 2 was found to mediate the acceleration of NK cell migration. Using mathematical diffusion models, we confirm that local acceleration of NK cells in the vicinity of bystander cells reduces their search time to locate target cells. In addition, we found that integrin β chains (β1, β2 and β7) on NK cells are required for bystander-enhanced NK migration persistence. In conclusion, we show that acceleration of NK cell migration in the vicinity of H 2 O 2 -producing bystander cells reduces target cell search time and enhances NK killing efficiency.

  13. The bystander effect in an N-person dictator game

    NARCIS (Netherlands)

    Panchanathan, K.; Frankenhuis, W.E.; Silk, J.B.

    2013-01-01

    Dozens of studies show that bystanders are less likely to help victims as bystander number increases. However, these studies model one particular situation, in which victims need only one helper. Using a multi-player dictator game, we study a different but common situation, in which a recipient’s

  14. Bystander Approaches: Empowering Students to Model Ethical Sexual Behavior

    Science.gov (United States)

    Lynch, Annette; Fleming, Wm. Michael

    2005-01-01

    Sexual violence on college campuses is well documented. Prevention education has emerged as an alternative to victim-- and perpetrator--oriented approaches used in the past. One sexual violence prevention education approach focuses on educating and empowering the bystander to become a point of ethical intervention. In this model, bystanders to…

  15. When bystanders become bothersome : The negative consequences of bystander conflict and the moderating role of resilience

    NARCIS (Netherlands)

    van Erp, Kim J.P.M.; Rispens, Sonja; Gevers, Josette M.P.; Demerouti, Evangelia

    2015-01-01

    Bystander conflict is a situation in which employees are hindered in their work by parties not involved in the primary process. Public service employees and emergency care workers, such as ambulance employees and firefighters, often encounter this kind of conflict with potentially far-reaching

  16. When bystanders become bothersome : the negative consequences of bystander conflict and the moderating role of resilience

    NARCIS (Netherlands)

    van Erp, Kim; Rispens, Sonja; Gevers, Josette M.P.; Demerouti, Evangelia

    2014-01-01

    Bystander conflict is a situation in which employees are hindered in their work by parties not involved in the primary process. Public service employees and emergency care workers, such as ambulance employees and firefighters, often encounter this kind of conflict with potentially far-reaching

  17. The lonely bystander: ostracism leads to less helping in virtual bystander situations

    NARCIS (Netherlands)

    van Bommel, Marco; van Prooijen, Jan-Willem; Elffers, Henk; van Lange, Paul A.M.

    2016-01-01

    People are less likely to help when they have been ostracized, or when they are in the presence of bystanders. In the current manuscript we test both these influences simultaneously. We postulated two opposing hypotheses: first, helping decreases after ostracism, even when intervention is already

  18. The bystander effect: is reactive oxygen species the driver?

    International Nuclear Information System (INIS)

    Szumiel, I.

    2003-01-01

    The paper reviews selected examples of the bystander effect, such as clonogenic survival decrease, chromosomal aberrations and mutations. The similarities and differences between the biological effects in directly targeted and bystander cells are briefly discussed. Also reviewed are the experimental data which support the role of reactive oxygen species (ROS), especially *O 2 - , as mediators of the bystander effect. Endogenously generated ROS, due to activation of NAD(P)H oxidases, play a kay role in the introduction of DNA damage in bystander cells. All the observed effects in bystander cells, such as alteration in gene expression patterns, chromosomal aberrations, sister chromatid exchanges, mutations, genome instability and neoplastic transformation are the consequence of DNA damage. (author)

  19. The Bystander-Effect: A Meta-Analytic Review on Bystander Intervention in Dangerous and Non-Dangerous Emergencies

    Science.gov (United States)

    Fischer, Peter; Krueger, Joachim I.; Greitemeyer, Tobias; Vogrincic, Claudia; Kastenmuller, Andreas; Frey, Dieter; Heene, Moritz; Wicher, Magdalena; Kainbacher, Martina

    2011-01-01

    Research on bystander intervention has produced a great number of studies showing that the presence of other people in a critical situation reduces the likelihood that an individual will help. As the last systematic review of bystander research was published in 1981 and was not a quantitative meta-analysis in the modern sense, the present…

  20. 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).

  1. Alkaline azide mutagenicity in cowpea

    Energy Technology Data Exchange (ETDEWEB)

    Mahna, S K; Bhargava, Anubha; Mohan, Lalit [Cytogenetics and Mycology Laboratory, Department of Botany, Government College, Ajmer (India)

    1990-07-01

    Sodium azide is known as a potent mutagen in cereals and legumes. It is very effective in acidic medium in barley. Here an attempt is made to measure the effectiveness of sodium azide in alkaline medium (pH 7.4) on cowpea (Vigna unguiculata (L.) Walp., variety FS-68). Seeds pre-soaked in distilled water for 5 hours were treated with different concentrations (10{sup -6}, 10{sup -5}, 10{sup -4} and 10{sup -3}M) of sodium azide (NaN{sub 3}) for 4 hours at 28{+-} 2 deg. C. Bottles were intermittently shaken, then the seeds were thoroughly washed in running tap water and subsequently planted in pots. The treatment caused significant biological damage such as reduction in seed germination, length of root and shoot, number of nodules and pods per plant and morphological leaf variations. Morphological, as well as chlorophyll mutants, were detected in M{sub 2}.

  2. Alkaline azide mutagenicity in cowpea

    International Nuclear Information System (INIS)

    Mahna, S.K.; Bhargava, Anubha; Mohan, Lalit

    1990-01-01

    Sodium azide is known as a potent mutagen in cereals and legumes. It is very effective in acidic medium in barley. Here an attempt is made to measure the effectiveness of sodium azide in alkaline medium (pH 7.4) on cowpea (Vigna unguiculata (L.) Walp., variety FS-68). Seeds pre-soaked in distilled water for 5 hours were treated with different concentrations (10 -6 , 10 -5 , 10 -4 and 10 -3 M) of sodium azide (NaN 3 ) for 4 hours at 28± 2 deg. C. Bottles were intermittently shaken, then the seeds were thoroughly washed in running tap water and subsequently planted in pots. The treatment caused significant biological damage such as reduction in seed germination, length of root and shoot, number of nodules and pods per plant and morphological leaf variations. Morphological, as well as chlorophyll mutants, were detected in M 2

  3. Enteropathogenic Escherichia coli: foe or innocent bystander?

    Science.gov (United States)

    Hu, Jia; Torres, Alfredo G.

    2015-01-01

    Enteropathogenic Escherichia coli (EPEC) remain one the most important pathogens infecting children and they are one of the main causes of persistent diarrhea worldwide. Historically, typical EPEC (tEPEC), defined as those isolates with the attaching and effacement (A/E) genotype (eae+), which possess bfpA+ and lack the stx- genes are found strongly associated with diarrheal cases. However, occurrence of atypical EPEC (aEPEC; eae+ bfpA- stx-) in diarrheal and asymptomatic hosts has made investigators question the role of these pathogens in human disease. Current epidemiological data is helping answering the question whether EPEC is mainly a foe or an innocent bystander during infection. PMID:25726041

  4. Radiation-induced bystander effects in vivo are sex specific

    International Nuclear Information System (INIS)

    Koturbash, Igor; Kutanzi, Kristy; Hendrickson, Karl; Rodriguez-Juarez, Rocio; Kogosov, Dmitry; Kovalchuk, Olga

    2008-01-01

    Ionizing radiation (IR) effects span beyond the area of direct exposure and can be observed in neighboring and distant naive cells and organs. This phenomenon is termed a 'bystander effect'. IR effects in directly exposed tissue in vivo are epigenetically mediated and distinct in males and females. Yet, IR-induced bystander effects have never been explored in a sex-specificity domain. We used an in vivo mouse model, whereby the bystander effects are studied in spleen of male and female animals subjected to head exposure when the rest of the body is protected by a medical-grade lead shield. We analyzed the induction of DNA damage and alterations in global DNA methylation. Molecular parameters were correlated with cellular proliferation and apoptosis levels. The changes observed in bystander organs are compared to the changes in unexposed animals and animals exposed to predicted and measured scatter doses. We have found the selective induction of DNA damage levels, global DNA methylation, cell proliferation and apoptosis in exposed and bystander spleen tissue of male and female mice. Sex differences were significantly diminished in animals subjected to a surgical removal of gonads. These data constitute the first evidence of sex differences in radiation-induced bystander effects in mouse spleen in vivo. We show the role of sex hormones in spleen bystander responses and discuss implications of the observed changes

  5. Mitochondrial mutagenesis induced by tumor-specific radiation bystander effects.

    LENUS (Irish Health Repository)

    Gorman, Sheeona

    2012-02-01

    The radiation bystander effect is a cellular process whereby cells not directly exposed to radiation display cellular alterations similar to directly irradiated cells. Cellular targets including mitochondria have been postulated to play a significant role in this process. In this study, we utilized the Random Mutation Capture assay to quantify the levels of random mutations and deletions in the mitochondrial genome of bystander cells. A significant increase in the frequency of random mitochondrial mutations was found at 24 h in bystander cells exposed to conditioned media from irradiated tumor explants (p = 0.018). CG:TA mutations were the most abundant lesion induced. A transient increase in the frequency of random mitochondrial deletions was also detected in bystander cells exposed to conditioned media from tumor but not normal tissue at 24 h (p = 0.028). The increase in both point mutations and deletions was transient and not detected at 72 h. To further investigate mitochondrial dysfunction, mitochondrial membrane potential and reactive oxygen species were assessed in these bystander cells. There was a significant reduction in mitochondrial membrane potential and this was positively associated with the frequency of random point mutation and deletions in bystander cells treated with conditioned media from tumor tissue (r = 0.71, p = 0.02). This study has shown that mitochondrial genome alterations are an acute consequence of the radiation bystander effect secondary to mitochondrial dysfunction and suggests that this cannot be solely attributable to changes in ROS levels alone.

  6. Bystander effects and their implications for clinical radiotherapy

    International Nuclear Information System (INIS)

    Munro, Alastair J

    2009-01-01

    Radiation-induced bystander effects are defined as those biological effects expressed, after irradiation, by cells whose nuclei have not been directly irradiated. Radiation oncologists are only gradually beginning to appreciate the clinical relevance of radiation-induced bystander effects and associated phenomena: adaptive responses, genomic instability and abscopal effects. Incorporating bystander effects into the science underpinning clinical radiotherapy will involve moving beyond simple mechanistic models and towards a more systems-based approach. It is, given the protean nature of bystander effects, difficult to devise a coherent research strategy to investigate the clinical impact and relevance of bystander phenomena. Epidemiological approaches will be required, the traditional research models based on randomised controlled trials are unlikely to be adequate for the task. Any consideration of bystander effects challenges not only clinicians' preconceptions concerning the effects of radiation on tumours and normal tissues but also their ingenuity. This review covers, from a clinical perspective, the issues and problems associated with radiation-induced bystander effects.

  7. Radiation-induced bystander effects in vivo are sex specific

    Energy Technology Data Exchange (ETDEWEB)

    Koturbash, Igor; Kutanzi, Kristy; Hendrickson, Karl; Rodriguez-Juarez, Rocio; Kogosov, Dmitry [Department of Biological Sciences, University of Lethbridge, Alberta T1K 3M4 (Canada); Kovalchuk, Olga [Department of Biological Sciences, University of Lethbridge, Alberta T1K 3M4 (Canada)], E-mail: olga.kovalchuk@uleth.ca

    2008-07-03

    Ionizing radiation (IR) effects span beyond the area of direct exposure and can be observed in neighboring and distant naive cells and organs. This phenomenon is termed a 'bystander effect'. IR effects in directly exposed tissue in vivo are epigenetically mediated and distinct in males and females. Yet, IR-induced bystander effects have never been explored in a sex-specificity domain. We used an in vivo mouse model, whereby the bystander effects are studied in spleen of male and female animals subjected to head exposure when the rest of the body is protected by a medical-grade lead shield. We analyzed the induction of DNA damage and alterations in global DNA methylation. Molecular parameters were correlated with cellular proliferation and apoptosis levels. The changes observed in bystander organs are compared to the changes in unexposed animals and animals exposed to predicted and measured scatter doses. We have found the selective induction of DNA damage levels, global DNA methylation, cell proliferation and apoptosis in exposed and bystander spleen tissue of male and female mice. Sex differences were significantly diminished in animals subjected to a surgical removal of gonads. These data constitute the first evidence of sex differences in radiation-induced bystander effects in mouse spleen in vivo. We show the role of sex hormones in spleen bystander responses and discuss implications of the observed changes.

  8. Radiation-induced bystander effects in vivo are sex specific.

    Science.gov (United States)

    Koturbash, Igor; Kutanzi, Kristy; Hendrickson, Karl; Rodriguez-Juarez, Rocio; Kogosov, Dmitry; Kovalchuk, Olga

    2008-07-03

    Ionizing radiation (IR) effects span beyond the area of direct exposure and can be observed in neighboring and distant naïve cells and organs. This phenomenon is termed a 'bystander effect'. IR effects in directly exposed tissue in vivo are epigenetically mediated and distinct in males and females. Yet, IR-induced bystander effects have never been explored in a sex-specificity domain. We used an in vivo mouse model, whereby the bystander effects are studied in spleen of male and female animals subjected to head exposure when the rest of the body is protected by a medical-grade lead shield. We analyzed the induction of DNA damage and alterations in global DNA methylation. Molecular parameters were correlated with cellular proliferation and apoptosis levels. The changes observed in bystander organs are compared to the changes in unexposed animals and animals exposed to predicted and measured scatter doses. We have found the selective induction of DNA damage levels, global DNA methylation, cell proliferation and apoptosis in exposed and bystander spleen tissue of male and female mice. Sex differences were significantly diminished in animals subjected to a surgical removal of gonads. These data constitute the first evidence of sex differences in radiation-induced bystander effects in mouse spleen in vivo. We show the role of sex hormones in spleen bystander responses and discuss implications of the observed changes.

  9. Obstacles to bystander cardiopulmonary resuscitation in Japan.

    Science.gov (United States)

    Shibata, K; Taniguchi, T; Yoshida, M; Yamamoto, K

    2000-05-01

    bystander cardiopulmonary resuscitation (CPR) is performed infrequently in Japan. We conducted this study to identify Japanese attitudes toward the performance of bystander CPR. participants were asked about their willingness to perform CPR with varying scenarios and CPR techniques (mouth-to-mouth ventilation plus chest compression (MMV plus CC) versus chest compression alone (CC)). a total of 1302/1355 individuals completed the questionnaire, including high school students, teachers, emergency medical technicians, medical nurses, and medical students. About 2% of high school students, 3% of teachers, 26% of emergency medical technicians, 3% of medical nurses and 16% of medical students claimed they would 'definitely' perform MMV plus CC on a stranger. However, 21-72% claimed they would prefer the alternative of performing CC alone. Respondents claimed their unwillingness to perform MMV is not due to the fear of contracting a communicable disease, but the lack of confidence in their ability to perform CPR properly. in all categories of respondents, willingness to perform MMV plus CC for a stranger was disappointingly low. Better training in MMV together with teaching awareness that CC alone can be given should be instituted to maximize the number of potential providers of CPR in the community, even in communities where the incidence of HIV is very low.

  10. Genetic Signatures of HIV-1 Envelope-mediated Bystander Apoptosis

    Science.gov (United States)

    Joshi, Anjali; Lee, Raphael T. C.; Mohl, Jonathan; Sedano, Melina; Khong, Wei Xin; Ng, Oon Tek; Maurer-Stroh, Sebastian; Garg, Himanshu

    2014-01-01

    The envelope (Env) glycoprotein of HIV is an important determinant of viral pathogenesis. Several lines of evidence support the role of HIV-1 Env in inducing bystander apoptosis that may be a contributing factor in CD4+ T cell loss. However, most of the studies testing this phenomenon have been conducted with laboratory-adapted HIV-1 isolates. This raises the question of whether primary Envs derived from HIV-infected patients are capable of inducing bystander apoptosis and whether specific Env signatures are associated with this phenomenon. We developed a high throughput assay to determine the bystander apoptosis inducing activity of a panel of primary Envs. We tested 38 different Envs for bystander apoptosis, virion infectivity, neutralizing antibody sensitivity, and putative N-linked glycosylation sites along with a comprehensive sequence analysis to determine if specific sequence signatures within the viral Env are associated with bystander apoptosis. Our studies show that primary Envs vary considerably in their bystander apoptosis-inducing potential, a phenomenon that correlates inversely with putative N-linked glycosylation sites and positively with virion infectivity. By use of a novel phylogenetic analysis that avoids subtype bias coupled with structural considerations, we found specific residues like Arg-476 and Asn-425 that were associated with differences in bystander apoptosis induction. A specific role of these residues was also confirmed experimentally. These data demonstrate for the first time the potential of primary R5 Envs to mediate bystander apoptosis in CD4+ T cells. Furthermore, we identify specific genetic signatures within the Env that may be associated with the bystander apoptosis-inducing phenotype. PMID:24265318

  11. Mutagenicity studies with the mouse spot test

    Energy Technology Data Exchange (ETDEWEB)

    Gocke, E.; Wild, D.; Eckhardt, K.; King, M.T.

    1983-04-01

    The mammalian spot test, which detects somatic gene mutations in mouse embryos, was investigated with selected chemicals to (a) further validate this test system ethylnitrosourea, ethyl methanesulfonate, 2-acetylaminofluorene and colchicine (ENU, EMS, 2AAF), and (b) evaluate the mutagenic potential, in a whole-mammal system, of environmental compounds that had been previously recognized as mutagens in other mammalian or submammalian test systems (1,2-dichloroethane, hydroquinone, nitrofurantoin, o-phenylenediamine, fried sausage extract). Of these substances, ENU, EMS and 2AAF were significantly mutagenic, 1,2-dichloroethane was probably weakly mutagenic. The ENU data were used to estimate the number of pigment precursor cells present at the time of treatment (day 9.25). We also describe in this report the use of a fluorescence microscope for classification of hairs from spots on the coat of C57BL/6JHan X T hybrids.

  12. Mutagenic activities of biochars from pyrolysis.

    Science.gov (United States)

    Piterina, Anna V; Chipman, J Kevin; Pembroke, J Tony; Hayes, Michael H B

    2017-08-15

    Biochar production, from pyrolysis of lignocellulosic feedstocks, agricultural residues, and animal and poultry manures are emerging globally as novel industrial and commercial products. It is important to develop and to validate a series of suitable protocols for the ecological monitoring of the qualities and properties of biochars. The highly sensitive Salmonella mutagenicity assays (the Ames test) are used widely by the toxicology community and, via the rat liver extract (S9), can reflect the potential for mammalian metabolic activation. We examined the Ames test for analyses of the mutagenic activities of dimethylsulphoxide (DMSO) extracts of biochars using two bacterial models (S. typhimurium strains TA98 and TA100) in the presence and in the absence of the metabolic activation with the S9-mix. Tester strain TA98 was most sensitive in detecting mutagenic biochar products, and the contribution of S9 was established. Temperature and times of pyrolysis are important. Biochar pyrolysed at 400°C for 10min, from a lignocellulose precursor was mutagenic, but not when formed at 800°C for 60min, or at 600°C for 30min. Biochars from poultry litter, and manures of calves fed on grass had low mutagenicities. Biochar from pig manure had high mutagenicity; biochars from manures of cows fed on a grass plus cereals, those of calves fed on mother's milk, and biochars from solid industrial waste had intermediate mutagenicities. The methods outlined can indicate the need for further studies for screening and detection of the mutagenic residuals in a variety of biochar products. Copyright © 2017. Published by Elsevier B.V.

  13. Hygiene assessment of irradiated potato mutagenic activity

    International Nuclear Information System (INIS)

    Uralova, M.; Grunt, J.; Patzeltova, N.

    1977-01-01

    Albino rat males were fed on gamma-irradiated potatoes for one month and mated with two intact female rats each. The dominant lethal mutation method was then used for the study of possible mutagenic activity of the irradiated potatoes. No statistically significant differences were observed and no mutagenic activity was found. Thus, the test showed that potatoes irradiated with a dose of 10 krad of gamma radiation does not present genetic hazards for albino rats. (L.O.)

  14. Mutagenic and carcinogenic properties of drinking water

    International Nuclear Information System (INIS)

    Kool, H.J.; van Kreijl, C.F.; Hrubec, J.

    1985-01-01

    In this chapter results of oxidation treatments with chlorine, ozone, chlorine dioxide, and ultraviolet (UV), with respect to their effects on activity (Ames test) in drinking water supplies are reviewed. In addition, the authors present the preliminary results of a pilot plant study on the effects of chlorine and chlorine dioxide on mutagenicity. Furthermore, results of several carcinogenicity studies performed with organic drinking water concentrates are discussed in relation to the results of a Dutch carcinogenicity study with mutagenic drinking water concentrates

  15. Kaempferol, a mutagenic flavonol from Helichrysum simillimum.

    Science.gov (United States)

    Elgorashi, Ee; van Heerden, Fr; van Staden, J

    2008-11-01

    Helichrysum simillimum is native to South Africa. It is used for the treatment of coughs, colds, fever, infections, headache, and menstrual pain. Extracts of this species showed mutagenic effects in the Salmonella/microsome assay. The aim of this study was to isolate and determine the mutagenic constituents of H. simillimum. Bioassay-guided fractionation of 90% aqueous methanol extracts, using Salmonella typhimurium TA98, led to the isolation of the flavonol kaempferol.

  16. Are nonparticipants in prosocial behavior merely innocent bystanders?

    Science.gov (United States)

    Anker, Ashley E; Feeley, Thomas Hugh

    2011-01-01

    Latané and Darley's (1970) bystander intervention theory was used to model individuals' participation in two prosocial behaviors (organ donation, green living). It is argued that nonparticipants in prosocial helping are innocent bystanders who likely fail to notice the need, do not interpret the cause as an emergency, do not accept responsibility for the need to help, and have little knowledge on how to help. Data in study 1 (n = 494) indicate support for the proposed innocent bystander path model (notice event → interpret event as emergency → accept responsibility → knowledge of how to help) in organ donation. Study 2 (n = 519) replicated the model in the context of green living and additionally found a direct path from noticing the event to knowledge of how to help. Implications of framing nonparticipation in prosocial behaviors as innocent bystander effects are discussed in context of campaign communication.

  17. 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)

  18. 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)

  19. ATR-dependent bystander effects in non-targeted cells

    International Nuclear Information System (INIS)

    Burdak-Rothkamm, S.

    2007-01-01

    Complete text of publication follows. Radiation induced non-targeted bystander effects have been reported for a range of endpoints including the induction of γH2AX foci which serve as a marker for DNA double strand breaks. We have recently reported the induction of γH2AX foci in non-targeted bystander cells up to 48 hours after irradiation and the involvement of reactive oxygen species (ROS) and TGF-beta 1 in the induction of γH2AX foci (Oncogene (2007) 26:993-1002). Here, we wanted to determine the role of the PI3-like kinases ATM, ATR and DNA-PK in DNA damage signalling in bystander cells. Conditioned medium from T98G cells irradiated with 2 Gy of X-rays was transferred onto non-irradiated cells that were subsequently analysed for the induction of γH2AX, ATR and 53BP1 foci as well as clonogenic survival. Irradiated T98G glioma cells generated signals that induced γH2AX and 53BP1 foci in cells treated with the conditioned medium from irradiated cells. These foci co-localised with ATR foci. Inhibition of ATM and DNA-PK could not suppress the induction of bystander γH2AX foci whereas the mutation of ATR in Seckel cells abrogated bystander foci induction. A restriction of bystander foci to the S-phase of the cell cycle both in T98G cells and in ATR- proficient fibroblasts was observed. These results identify ATR as a central player within the bystander signalling cascade leading to γH2AX and 53BP1 foci formation, and suggest a mechanism of DNA damage induction in non-targeted cells. Further investigations have shown decreased clonogenic cell survival in bystander T98G and ATR wild-type fibroblasts. ATR mutated Seckel cells and also ATM-/- fibroblasts were resistant to this effect suggesting a role for both ATR and ATM in the bystander signalling cascade with regard to cell survival. Taken together, these observations support a hypothesis of DNA damage-induced accumulation of stalled replication forks in bystander cells which are subsequently processed by

  20. Long-term biological effects induced by ionizing radiation--implications for dose mediated risk.

    Science.gov (United States)

    Miron, S D; Astărăstoae, V

    2014-01-01

    Ionizing radiations are considered to be risk agents that are responsible for the effects on interaction with living matter. The occurring biological effects are due to various factors such as: dose, type of radiation, exposure time, type of biological tissue, health condition and the age of the person exposed. The mechanisms involved in the direct modifications of nuclear DNA and mitochondrial DNA are reviewed. Classical target theory of energy deposition in the nucleus that causes DNA damages, in particular DNA double-strand breaks and that explanation of the biological consequences of ionizing radiation exposure is a paradigm in radiobiology. Recent experimental evidences have demonstrated the existence of a molecular mechanism that explains the non-targeted effects of ionizing radiation exposure. Among these novel data, genomic instability and a variety of bystander effects are discussed here. Those bystander effects of ionizing radiation are fulfilled by cellular communication systems that give rise to non-targeted effects in the neighboring non irradiated cells. This paper provides also a commentary on the synergistic effects induced by the co-exposures to ionizing radiation and various physical agents such as electromagnetic fields and the co-exposures to ionizing radiation and chemical environmental contaminants such as metals. The biological effects of multiple stressors on genomic instability and bystander effects are also discussed. Moreover, a brief presentation of the methods used to characterize cyto- and genotoxic damages is offered.

  1. Significance and nature of bystander responses induced by various agents.

    Science.gov (United States)

    Verma, Neha; Tiku, Ashu Bhan

    2017-07-01

    Bystander effects in a biological system are the responses shown by non-targeted neighbouring cells/tissues/organisms. These responses are triggered by factors released from targeted cells when exposed to a stress inducing agent. The biological response to stress inducing agents is complex, owing to the diversity of mechanisms and pathways activated in directly targeted and bystander cells. These responses are highly variable and can be either beneficial or hazardous depending on the cell lines tested, dose of agent used, experimental end points and time course selected. Recently non-targeted cells have even been reported to rescue the directly exposed cells by releasing protective signals that might be induced by non-targeted bystander responses. The nature of bystander signal/s is not yet clear. However, there are evidences suggesting involvement of ROS, RNS, protein factors and even DNA molecules leading to the activation of a number of signaling pathways. These can act independently or in a cascade, to induce events leading to changes in gene expression patterns that could elicit detrimental or beneficial effects. Many review articles on radiation induced bystander responses have been published. However, to the best of our knowledge, a comprehensive review on bystander responses induced by other genotoxic chemicals and stress inducing agents has not been published so far. Therefore, the aim of the present review is to give an overview of the literature on different aspects of bystander responses: agents that induce these responses, factors that can modulate bystander responses and the mechanisms involved. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Mutagenicity and co-mutagenicity of static magnetic field in SOD-deficient Escherichia coli

    International Nuclear Information System (INIS)

    Yoshie, Sachiko; Ikehata, Masateru; Hayakawa, Toshio; Hirota, Noriyuki; Takemura, Taro; Minowa, Takashi; Hanagata, Nobutaka

    2008-01-01

    The effects of strong static magnetic fields (SMFs) on mutagenesis related to reactive oxygen species were investigated. To estimate mutagenicity of SMFs, superoxide dismutase (SOD)-deficient Escherichia coli QC774 and its parental strain GC4468 were employed. Tester strains were exposed to 5, 10 and 13 T SMFs for 24 hr at 37 C degrees in LB medium. After exposure, mutation frequency on thymine synthesis genes was determined for evaluation of mutagenicity of SMFs exposure. In the result, no statistically significant difference in mutation frequency on thymine synthesis genes was observed between SMF-exposed cells and unexposed cells in all of magnetic flux densities. Furthermore, SMFs up to 13 T did not affect mutagenicity of plumbagine under its presence of 25 μM, respectively. It suggests that SMF did not have either mutagenicity or co-mutagenicity in SOD-deficient and its parental E. coli strains under the condition in this study. (author)

  3. Guidelines for Bystander First Aid 2016.

    Science.gov (United States)

    Pek, Jen Heng

    2017-07-01

    Cardiac life support is a form of first aid for cardiac emergencies. However, research and evidence in this field is lacking compared with other forms of first aid. Having identified the common emergencies that are encountered in the hospital, based on the available evidence, we have put together what could be an evidence-based approach to the first aid management of some of these common emergencies, viz. breathlessness, chest pain, allergies, stroke, heat injury, poisoning, unconsciousness, seizures, and trauma situations such as bleeding, wounds, contusions, head injury, burns and fractures. Educating the public is the key to developing a first responder bystander. These guidelines could become the basis for training of the public. Copyright: © Singapore Medical Association.

  4. Public Knowledge and Attitudes towards Bystander Cardiopulmonary Resuscitation in China

    Directory of Open Access Journals (Sweden)

    Meng Chen

    2017-01-01

    Full Text Available The rate of bystander CPR is much lower in China than in developed countries. This survey was implemented to assess the current status of layperson CPR training, to analyze the willingness of bystanders to perform CPR, and to identify barriers to improving bystander CPR rates. The questionnaire included individual information, current status of bystander CPR training, and individual’s willingness and attitude towards performing CPR. There were 25.6% laypersons who took CPR training. The majority (98.6% of laypersons would perform CPR on their family members, but fewer laypersons (76.3% were willing to perform CPR on strangers. Most respondents (53.2% were worried about legal issues. If laws were implemented to protect bystanders who give aid, the number of laypersons who were not willing to perform CPR on strangers dropped from 23.7% to 2.4%. An increasing number of people in China know CPR compared with the situation in the past. CPR training in China is much less common than in many developed countries. The barriers are that laypersons are not well-trained and they fear being prosecuted for unsuccessful CPR. More accredited CPR training courses are needed in China. The laws should be passed to protect bystanders who provide assistance.

  5. Significance of radiation-induced bystander effects in radiation therapy

    International Nuclear Information System (INIS)

    Suzuki, Masao

    2014-01-01

    Since 1994, a Phase I/II clinical study and radiotherapy have carried out using carbon-ion beams produced with the Heavy Ion Medical Accelerator in Chiba (HIMAC) at National Institute of Radiological Sciences. Now we constructed the new treatment facility for the advanced carbon-ion therapy at HIMAC applying a 3D fast spot scanning system with pencil beams. In the field of fundamental biological studies for high-LET heavy ions, there are some reports regarding bystander effects after exposure to alpha particles derived from 238 Pu or He-ion microbeams. However, only limited sets of studies have examined bystander effects after exposure to different ion species heavier than helium, such as carbon ions. We have been investigating bystander cellular responses in both normal human and human tumor cells irradiated with the HIMAC carbon ions. Bystander cell-killing effect was observed in the cells harboring wild-type P53 gene, but not in the P53-mutated cells. Moreover, observed bystander effect was suppressed by treating with a specific inhibitor of gap-junction mediated cell-cell communication. There is clear evidence that the carbon-ion irradiation enables the enhanced cell killing in cells with wild-type P53 gene via gap-junction mediated bystander effect. (author)

  6. The positive bystander effect: passive bystanders increase helping in situations with high expected negative consequences for the helper.

    Science.gov (United States)

    Fischer, Peter; Greitemeyer, Tobias

    2013-01-01

    The present field study investigated the interplay between the presence of a passive bystander (not present versus present) in a simulated bike theft and expected negative consequences (low versus high) in predicting intervention behavior when no physical victim is present. It was found that an additional bystander increases individual intervention in situations where the expected negative consequences for the helper in case of intervention were high (i.e., when the bike thief looks fierce) compared to situations where the expected negative consequences for the helper were low (i.e., when the bike thief does not look fierce). In contrast, no such effect for high vs. low expected negative consequences was observed when no additional bystander observed the critical situation. The results are discussed in light of previous laboratory findings on expected negative consequences and bystander intervention.

  7. Molecular and genetic mechanisms of environmental mutagens

    International Nuclear Information System (INIS)

    Kubitschek, H.E.; Derstine, P.L.; Griego, V.M.; Matsushita, T.; Peak, J.G.; Peak, M.J.; Reynolds, P.R.; Webb, R.B.; Williams-Hill, D.

    1981-01-01

    This program is primarily concerned with elucidation of the nature of DNA lesions produced by environmental and energy related mutagens, their mechanisms of action, and their repair. The main focus is on actions of chemical mutagens and electromagnetic radiations. Synergistic interactions between mutagens and the mutational processes that lead to synergism are being investigated. Mutagens are chosen for study on the basis of their potential for analysis of mutation (as genetic probes), for development of procedures for reducing mutational damage, for their potential importance to risk assessment, and for development of improved mutagen testing systems. Bacterial cells are used because of the rapidity and clarity of scientific results that can be obtained, the detailed genetic maps, and the many well-defined mutand strains available. The conventional tools of microbial and molecular genetics are used, along with intercomparison of genetically related strains. Advantage is taken of tcollective dose commitment will result in more attention being paid to potential releases of radionuclides at relatively short times after disposal

  8. Mutagens in urine of carbon electrode workers

    Energy Technology Data Exchange (ETDEWEB)

    Pasquini, R; Monarca, S; Sforzolini, G S; Conti, R; Fagioli, F

    1982-01-01

    Following previous work carried out in an Italian factory producing carbon electrodes and evaluating the occupational mutagenic-carcinogenic hazards, the authors studied the presence of mutagen metabolites in the urine of workers in the same factory who were exposed to petroleum coke and pitch and in the urine of a control group of unexposed workers. The urine samples were concentrated by absorption on XAD-2 columns and were tested using the Salmonella/microsome assay (strain TA98, TA100, TA1535, TA1538) with and without the addition of beta-glucuronidase and metabolizing system. The collection of urine samples was carried out twice, with an interval of 2 months; 'before working time', 'after working time', and also during Sunday. The results showed that urine samples collected 'before' occupational exposure (upon waking) or on Sunday revealed no mutagenic activity in either worker groups and that the urine samples collected after or during occupational exposure revealed high mutagenic activity in the exposed workers, with a statistically significant difference between the mean of the revertants/plate values for exposed and unexposed workers. On the basis of the previous and the present research, the authors suggest that application of the Salmonella/microsome test to work environments could offer useful and suitable tool for evaluating the health hazards due to mutagenic/carcinogenic substances from occupational exposure.

  9. Bystander effects and biota: implications of radiation-induced bystander effects for protection of the environment from ionising radiation

    International Nuclear Information System (INIS)

    Mothersill, C.E.; Seymour, C.B.

    2003-01-01

    Bystander effects are now known to be induced by both high and low LET in a variety of cells in culture. They have been proven to occur in vivo in mice following 0.5Gy total body irradiation and in blood from humans being treated for cancer by radiotherapy. Effects have also been detected in fish, crustacea and molluscs. The important questions now are not whether bystander effects occur but why and what implications they have, if any, for radiation protection. Different species and different genetic backgrounds within a species produce different types of bystander effect, different organs also produce different effects. This paper will review the data in this field and will discuss likely implications for protection of man and non-human biota. In particular it will look at the potential long-term outcomes for different organisational levels, from cell to ecosystem, of bystander mechanisms. In view of new concerns about the effects of low level radiation on non-human biota, emphasis will be placed on considering how bystander effects might operate at chronic low doses versus acute accidental low doses. Problems of radiation interaction with chemicals, whether chemicals can also induce 'bystander effects' , and how regulators might handle these situations which occur all the time in real environments, will be presented for discussion. Finally the paper will discuss likely implications of these mechanisms for evolutionary biology

  10. THE GENOTOXICITY OF AMBIENT OUTDOOR AIR, A REVIEW: SALMONELLA MUTAGENICITY

    Science.gov (United States)

    The genotoxicity of ambient outdoor air, a review: Salmonella mutagenicityAbstractMutagens in urban air pollution come from anthropogenic sources (especially combustion sources) and are products of airborne chemical reactions. Bacterial mutation tests have been used ...

  11. Bystander effects: intercellular transmission of radiation damage signals

    Energy Technology Data Exchange (ETDEWEB)

    Little, J.B.; Azzam, E.I.; Toledo, S.M. de; Nagasawa, H

    2002-07-01

    Biological effects were examined in confluent cultures of fibroblasts and epithelial cells exposed to very low mean doses of alpha radiation, doses by which only 1-2% of the cells were actually traversed by an alpha particle. Enhanced frequencies of sister chromatid exchanges and HPRT mutations occurred in the non-irradiation, 'bystander' cells associated with a similar increase in the frequency of micronuclei, indicating the induction of DNA damage in these cells. In order to gain information concerning molecular pathways, changes in gene expression were examined in bystander cells by western analysis and in situ immunofluorescence staining. The expression levels of p53, p21 and MDM2 were significantly modulated in bystander cells: the damage signals leading to these changes were transmitted from irradiated to bystander cells by gap junction mediated intracellular communication. The bystander response was suppressed by incubation with superoxide dismutase as well as an inhibitor of NADPH oxidase, suggesting the effect may be mediated by oxidative stress. To examine other signalling pathways responsive to oxidative stress, the activation of stress-related kinases and their downstream transcription factors were analysed in bystander cells by western blotting and electrophoretic mobility shift assays: a 2-4 fold increase in the phosphorylation levels of JNK, EPK1/2, p90RSK, Elk-1 and ATF2 was observed. These changes were detected by 15 min after irradiation and persisted for at least 1 h. These findings indicate the activation of multiple signal transduction pathways in bystander cells, involving signals arising from the plasma membrane as well as from DNA damage. (author)

  12. 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.

  13. Radioprotection of targeted and bystander cells by methylproamine

    International Nuclear Information System (INIS)

    Burdak-Rothkamm, Susanne; Smith, Andrea; Lobachevsky, Pavel; Martin, Roger; Prise, Kevin M.

    2015-01-01

    Radioprotective agents are of interest for application in radiotherapy for cancer and in public health medicine in the context of accidental radiation exposure. Methylproamine is the lead compound of a class of radioprotectors which act as DNA binding anti-oxidants, enabling the repair of transient radiation-induced oxidative DNA lesions. This study tested methylproamine for the radioprotection of both directly targeted and bystander cells. T98G glioma cells were treated with 15 μM methylproamine and exposed to 137 Cs γ-ray/X-ray irradiation and He 2+ microbeam irradiation. Radioprotection of directly targeted cells and bystander cells was measured by clonogenic survival or γH2AX assay. Radioprotection of directly targeted T98G cells by methylproamine was observed for 137 Cs γ-rays and X-rays but not for He 2+ charged particle irradiation. The effect of methylproamine on the bystander cell population was tested for both X-ray irradiation and He 2+ ion microbeam irradiation. The X-ray bystander experiments were carried out by medium transfer from irradiated to non-irradiated cultures and three experimental designs were tested. Radioprotection was only observed when recipient cells were pretreated with the drug prior to exposure to the conditioned medium. In microbeam bystander experiments targeted and nontargeted cells were co-cultured with continuous methylproamine treatment during irradiation and postradiation incubation; radioprotection of bystander cells was observed. Methylproamine protected targeted cells from DNA damage caused by γ-ray or X-ray radiation but not He 2+ ion radiation. Protection of bystander cells was independent of the type of radiation which the donor population received. (orig.) [de

  14. Up-regulation of ROS by mitochondria-dependent bystander signaling contributes to genotoxicity of bystander effects

    International Nuclear Information System (INIS)

    Chen Shaopeng; Zhao Ye; Zhao Guoping; Han Wei; Bao Lingzhi; Yu, K.N.; Wu Lijun

    2009-01-01

    Genomic instability can be observed in bystander cells. However, the underlying mechanism(s) is still relatively unclear. In a previous study, we found that irradiated cells released mitochondria-dependent intracellular factor(s) which could lead to bystander γ-H2AX induction. In this paper, we used normal (ρ + ) and mtDNA-depleted (ρ 0 ) human-hamster hybrid cells to investigate mitochondrial effects on the genotoxicity in bystander effect through medium transfer experiments. Through the detection of DNA double-strand breaks with γ-H2AX, we found that the fraction of γ-H2AX positive cells changed with time when irradiation conditioned cell medium (ICCM) were harvested. ICCM harvested from irradiated ρ + cells at 10 min post-irradiation (ρ + ICCM 10min ) caused larger increases of bystander γ-H2AX induction comparing to ρ 0 ICCM 10min , which only caused a slight increase of bystander γ-H2AX induction. The ρ + ICCM 10min could also result in the up-regulation of ROS production (increased by 35% at 10 min), while there was no significant increase in cells treated with ρ 0 ICCM 10min . We treated cells with dimethyl sulfoxide (DMSO), the scavenger of ROS, and quenched γ-H2AX induction by ρ + ICCM. Furthermore, after the medium had been transferred and the cells were continuously cultured for 7 days, we found significantly increased CD59 - gene loci mutation (increased by 45.9%) and delayed cell death in the progeny of ρ + ICCM-treated bystander cells. In conclusion, the work presented here suggested that up-regulation of the mitochondria-dependent ROS might be very important in mediating genotoxicity of bystander effects.

  15. Up-regulation of ROS by mitochondria-dependent bystander signaling contributes to genotoxicity of bystander effects

    Energy Technology Data Exchange (ETDEWEB)

    Chen Shaopeng [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Zhao Ye; Zhao Guoping [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Han Wei [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Bao Lingzhi [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Yu, K.N., E-mail: peter.yu@cityu.edu.hk [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Wu Lijun, E-mail: ljw@ipp.ac.cn [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China)

    2009-06-18

    Genomic instability can be observed in bystander cells. However, the underlying mechanism(s) is still relatively unclear. In a previous study, we found that irradiated cells released mitochondria-dependent intracellular factor(s) which could lead to bystander {gamma}-H2AX induction. In this paper, we used normal ({rho}{sup +}) and mtDNA-depleted ({rho}{sup 0}) human-hamster hybrid cells to investigate mitochondrial effects on the genotoxicity in bystander effect through medium transfer experiments. Through the detection of DNA double-strand breaks with {gamma}-H2AX, we found that the fraction of {gamma}-H2AX positive cells changed with time when irradiation conditioned cell medium (ICCM) were harvested. ICCM harvested from irradiated {rho}{sup +} cells at 10 min post-irradiation ({rho}{sup +} ICCM{sub 10min}) caused larger increases of bystander {gamma}-H2AX induction comparing to {rho}{sup 0} ICCM{sub 10min}, which only caused a slight increase of bystander {gamma}-H2AX induction. The {rho}{sup +} ICCM{sub 10min} could also result in the up-regulation of ROS production (increased by 35% at 10 min), while there was no significant increase in cells treated with {rho}{sup 0} ICCM{sub 10min}. We treated cells with dimethyl sulfoxide (DMSO), the scavenger of ROS, and quenched {gamma}-H2AX induction by {rho}{sup +} ICCM. Furthermore, after the medium had been transferred and the cells were continuously cultured for 7 days, we found significantly increased CD59{sup -} gene loci mutation (increased by 45.9%) and delayed cell death in the progeny of {rho}{sup +} ICCM-treated bystander cells. In conclusion, the work presented here suggested that up-regulation of the mitochondria-dependent ROS might be very important in mediating genotoxicity of bystander effects.

  16. Radioprotection of targeted and bystander cells by methylproamine

    Energy Technology Data Exchange (ETDEWEB)

    Burdak-Rothkamm, Susanne [Queen' s University Belfast, Centre for Cancer Research and Cell Biology, Belfast (United Kingdom); Oxford University Hospitals, Cellular Pathology, Oxford (United Kingdom); Smith, Andrea; Lobachevsky, Pavel; Martin, Roger [Peter MacCallum Cancer Centre, Molecular Radiation Biology Laboratory, Melbourne (Australia); University of Melbourne, The Sir Peter MacCallum Department of Oncology, Melbourne (Australia); Prise, Kevin M. [Queen' s University Belfast, Centre for Cancer Research and Cell Biology, Belfast (United Kingdom)

    2014-09-23

    Radioprotective agents are of interest for application in radiotherapy for cancer and in public health medicine in the context of accidental radiation exposure. Methylproamine is the lead compound of a class of radioprotectors which act as DNA binding anti-oxidants, enabling the repair of transient radiation-induced oxidative DNA lesions. This study tested methylproamine for the radioprotection of both directly targeted and bystander cells. T98G glioma cells were treated with 15 μM methylproamine and exposed to {sup 137}Cs γ-ray/X-ray irradiation and He{sup 2+} microbeam irradiation. Radioprotection of directly targeted cells and bystander cells was measured by clonogenic survival or γH2AX assay. Radioprotection of directly targeted T98G cells by methylproamine was observed for {sup 137}Cs γ-rays and X-rays but not for He{sup 2+} charged particle irradiation. The effect of methylproamine on the bystander cell population was tested for both X-ray irradiation and He{sup 2+} ion microbeam irradiation. The X-ray bystander experiments were carried out by medium transfer from irradiated to non-irradiated cultures and three experimental designs were tested. Radioprotection was only observed when recipient cells were pretreated with the drug prior to exposure to the conditioned medium. In microbeam bystander experiments targeted and nontargeted cells were co-cultured with continuous methylproamine treatment during irradiation and postradiation incubation; radioprotection of bystander cells was observed. Methylproamine protected targeted cells from DNA damage caused by γ-ray or X-ray radiation but not He{sup 2+} ion radiation. Protection of bystander cells was independent of the type of radiation which the donor population received. (orig.) [German] Radioprotektive Agenzien sind sowohl in der Strahlentherapie von Krebserkrankungen als auch im Strahlenschutz im Zusammenhang mit akzidenteller Exposition von Bedeutung. Methylproamine ist die Leitsubstanz einer Klasse von

  17. Beyond the Situational Model: Bystander Action Consequences to Intervening in Situations Involving Sexual Violence.

    Science.gov (United States)

    Moschella, Elizabeth A; Bennett, Sidney; Banyard, Victoria L

    2016-03-02

    Sexual violence is a widely reported problem in college communities. To date, research has largely focused on bystander intervention as one way to help prevent this problem. Although perceived consequences of bystander intervention, such as the weighting of costs and benefits, have been examined, little research has explored what happens after a bystander intervenes. The current study investigated what bystanders report as perceived outcomes and actual consequences of their bystander actions in response to risk for sexual assault. Of the 545 surveyed, 150 reported having taking bystander action in the past month and qualitatively described their bystander behavior and the responses of those parties involved. A range of behavioral responses and intervention methods were identified. The most frequent responses reported by participants were victims conveying positive and perpetrators conveying negative responses. Different types of helping were associated with bystanders reporting different types of responses to their actions. Future research should incorporate additional measures of consequences of bystander intervention. Implications for policy and bystander intervention programs are discussed, stressing the need for bystander intervention programs to address a range of bystander behaviors and explain the potential consequences and risks of intervening. © The Author(s) 2016.

  18. A Randomized Controlled Trial of a Multi-Dose Bystander Intervention Program Using Peer Education Theater

    Science.gov (United States)

    McMahon, Sarah; Winter, Samantha C.; Palmer, Jane E.; Postmus, Judy L.; Peterson, N. Andrew; Zucker, Sharon; Koenick, RuthAnne

    2015-01-01

    This article reports findings from a longitudinal, experimental evaluation of a peer education theater program, Students Challenging Realities and Educating Against Myths (SCREAM) Theater. This study examines the impact of SCREAM Theater on a range of bystander-related outcomes (i.e. bystander intentions, bystander efficacy, perception of friend…

  19. Promoting Prosocial Behaviors to Prevent Dating Violence among College Students: Evaluation of a Bystander Intervention

    Science.gov (United States)

    Borsky, Amanda E.

    2014-01-01

    The objective of this dissertation was to evaluate a bystander behavior program at the Jefferson College of Health Sciences (JCHS) in Roanoke, Virginia. Specifically, this dissertation examined the: (1) preliminary measurement properties of a newly developed bystander behavior intention scale; (2) impact of the bystander intervention at JCHS; and…

  20. LGBT Discrimination on Campus and Heterosexual Bystanders: Understanding Intentions to Intervene

    Science.gov (United States)

    Dessel, Adrienne B.; Goodman, Kevin D.; Woodford, Michael R.

    2017-01-01

    Discrimination targeting lesbian, gay, bisexual, and transgender (LGBT) students on college campuses occurs. Bystander intervention is important in supporting targeted students and improving campus climate for LGBT students. Peer-familiarity context (i.e., who the bystander knows in the situation) can play a role in bystander intervention, but…

  1. Adolescent Bystander Behavior in the School and Online Environments and the Implications for Interventions Targeting Cyberbullying

    Science.gov (United States)

    Patterson, Lisa J.; Allan, Alfred; Cross, Donna

    2017-01-01

    The aim of this study was to add to the emerging knowledge about the role of bystanders in cyberbullying. To differentiate online versus offline bystander behaviors, 292 Australian children (mean age = 15.2; female = 54.4%) reviewed hypothetical scenarios experimentally manipulated by bystander sex, relationship to target and perpetrator, and…

  2. 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

  3. Mutagens and carcinogens in foods. Epidemiologic review.

    OpenAIRE

    Hislop, T. G.

    1993-01-01

    Evidence that diet contributes to the development of cancer is strengthening. This paper examines mutagens and carcinogens, such as naturally occurring substances, products of cooking and food processing, intentional and unintentional additives, and contaminants, found in foods. Such substances are present in minute quantities in the diets of average Canadians. Indication of health risk is largely limited to experimental laboratory evidence.

  4. Mutagens and carcinogens in foods. Epidemiologic review.

    Science.gov (United States)

    Hislop, T. G.

    1993-01-01

    Evidence that diet contributes to the development of cancer is strengthening. This paper examines mutagens and carcinogens, such as naturally occurring substances, products of cooking and food processing, intentional and unintentional additives, and contaminants, found in foods. Such substances are present in minute quantities in the diets of average Canadians. Indication of health risk is largely limited to experimental laboratory evidence. PMID:8499796

  5. Simultaneous Determination of Mutagenicity and Toxicity of ...

    African Journals Online (AJOL)

    A demonstration of cytotoxicity is required (measurement of cell number, culture confluency and inhibition of mitotic index) for in vitro cytogenetic assays. The study therefore investigated whether delayed cytotoxicity can be used to simultaneously predict mutagenicity and cytotoxicty. Chinese hamster lung cells were ...

  6. Synthesis and radiolabeling of heterocyclic food mutagens

    International Nuclear Information System (INIS)

    Rapoport, H.; Waterhouse, A.L.; Thompson, C.M.; O'Connell, J.F.

    1986-01-01

    The imidazoquinoline and imidazoquinoxaline food mutagens found in cooked meat are being synthesized by unambiguous methods that allow for the preparation of sufficient quantities of material for biological studies. These methods avoid difficult separations of regioisomeric mixtures of products and are designed to allow incorporation of specific high level tritium labeling

  7. Predictive Models for Carcinogenicity and Mutagenicity ...

    Science.gov (United States)

    Mutagenicity and carcinogenicity are endpoints of major environmental and regulatory concern. These endpoints are also important targets for development of alternative methods for screening and prediction due to the large number of chemicals of potential concern and the tremendous cost (in time, money, animals) of rodent carcinogenicity bioassays. Both mutagenicity and carcinogenicity involve complex, cellular processes that are only partially understood. Advances in technologies and generation of new data will permit a much deeper understanding. In silico methods for predicting mutagenicity and rodent carcinogenicity based on chemical structural features, along with current mutagenicity and carcinogenicity data sets, have performed well for local prediction (i.e., within specific chemical classes), but are less successful for global prediction (i.e., for a broad range of chemicals). The predictivity of in silico methods can be improved by improving the quality of the data base and endpoints used for modelling. In particular, in vitro assays for clastogenicity need to be improved to reduce false positives (relative to rodent carcinogenicity) and to detect compounds that do not interact directly with DNA or have epigenetic activities. New assays emerging to complement or replace some of the standard assays include VitotoxTM, GreenScreenGC, and RadarScreen. The needs of industry and regulators to assess thousands of compounds necessitate the development of high-t

  8. Novel features of radiation-induced bystander signaling in Arabidopsis thaliana demonstrated using root micro-grafting

    Science.gov (United States)

    Wang, Ting; Li, Fanghua; Xu, Wei; Bian, Po; Wu, Yuejin; Wu, Lijun

    2012-01-01

    Radiation-induced bystander effects (RIBE) have been well demonstrated in whole organisms, as well as in single-cell culture models in vitro and multi-cellular tissues models in vitro, however, the underlying mechanisms remain unclear, including the temporal and spatial course of bystander signaling. The RIBE in vivo has been shown to exist in the model plant Arabidopsis thaliana (A. thaliana). Importantly, the unique plant grafting provides a delicate approach for studying the temporal and spatial course of bystander signaling in the context of whole plants. In our previous study, the time course of bystander signaling in plants has been well demonstrated using the root micro-grafting technique. In this study, we further investigated the temporal cooperation pattern of multiple bystander signals, the directionality of bystander signaling, and the effect of bystander tissues on the bystander signaling. The results showed that the bystander response could also be induced efficiently when the asynchronously generated bystander signals reached the bystander tissues in the same period, but not when they entered into the bystander tissues in an inversed sequence. The absence of bystander response in root-inversed grafting indicated that the bystander signaling along roots might be of directionality. The bystander signaling was shown to be independent of the bystander tissues. PMID:23072991

  9. Workplace mobbing: How the victim's coping behavior influences bystander responses.

    Science.gov (United States)

    Mulder, Roelie; Bos, Arjan E R; Pouwelse, Mieneke; van Dam, Karen

    2017-01-01

    Victims of workplace mobbing show diverse coping behavior. We investigated the impact of this behavior on bystander cognitions, emotions, and helping toward the victim, integrating coping literature with attribution theory. Adult part-time university students (N = 161) working at various organizations participated in a study with a 3(Coping: approach/avoidance/neutral) × 2(Gender Victim: male/female) × 2(Gender Bystander: male/female) design. Victims showing approach (vs. avoidance) coping were considered to be more self-reliant and less responsible for the continuation of the mobbing, and they elicited less anger. Continuation responsibility and self-reliance mediated the relationship between the victim's coping behavior and bystanders' helping intentions. Female (vs. male) participants reported more sympathy for the victim and greater willingness to help, and female (vs. male) victims elicited less anger. Theoretical and practical implications of the findings are discussed.

  10. Induced mutations in chickpea (Cicer arietinum L.) I. comparative mutagenic effectiveness and efficiency of physical & chemical mutagens

    International Nuclear Information System (INIS)

    Kharkwal, M.C.

    1998-01-01

    Mutagenic effectiveness usually means the rate of mutation as related to dose. Mutagenic efficiency refers to the mutation rate in relation to damage. Studies on comparative mutagenic effectiveness and efficiency of two physical (gamma rays and fast neutrons) and two chemical mutagens (NMU and EMS) on two desi (G 130 & H 214), one kabuli (C 104) and one green seeded (L 345) chickpea (Cicer arietinum L.) have been reported. The treatments included three doses each of gamma rays (400, 500 and 600 Gy) and fast neutrons (5, 10 and 15 Gy) and two concentrations with two different durations of two chemical mutagens, NMU 0.01% 20h and 0.02% 8h) and EMS (0.1% 20h and 0.2% 8h). Results indicated that chemical mutagens, particularly NMU are not only more effective but also efficient than physical mutagens in inducing mutations in chickpea. Mutagenic effectiveness and efficiency showed differential behaviour depending upon mutagen and varietal type. Chemical mutagens were more efficient than physical in inducing cholorophyll as well as viable and total number of mutations. Among the mutagens NMU was the most potent, while in the physical, gamma rays were more effective. Out of four mutagens, NMU was the most effective and efficient in inducing a high frequency and wide spectrum of chlorophyll mutations in the M2 followed by fast neutrons. While gamma rays showed least effectiveness, EMS was least efficient mutagens. Major differences in the mutagenic response of the four cultivars were observed. The varieties of desi type were more resistant towards mutagenic treatment than kabuli and green seeded type

  11. Chemistry of mutagens and carcinogens in broiled food.

    Science.gov (United States)

    Nishimura, S

    1986-01-01

    From a chemical point of view, the following subjects are important areas in studies on mutagens and carcinogens in broiled foods. In addition to heterocyclic amines which need microsomal activation, the structural elucidation of more labile direct-acting mutagens is necessary. It is known that there are still various unknown minor mutagens in broiled foods. Although the structural characterization of such compounds is more difficult, it is important since they might be hazardous in spite of their low mutagenicity. A more feasible and easier method for quantitative analysis of mutagens, in addition to HPLC and GC/MS methods presently employed, must be developed. The mechanism of formation of mutagens by broiling of food should be studied. An effective chemical method to prevent formation of mutagens or to destroy them, once formed, should be developed. PMID:3757944

  12. Ionizing radiation-induced bystander mutagenesis and adaptation: Quantitative and temporal aspects

    International Nuclear Information System (INIS)

    Zhang Ying; Zhou Junqing; Baldwin, Joseph; Held, Kathryn D.; Prise, Kevin M.; Redmond, Robert W.; Liber, Howard L.

    2009-01-01

    This work explores several quantitative aspects of radiation-induced bystander mutagenesis in WTK1 human lymphoblast cells. Gamma-irradiation of cells was used to generate conditioned medium containing bystander signals, and that medium was transferred onto naive recipient cells. Kinetic studies revealed that it required up to 1 h to generate sufficient signal to induce the maximal level of mutations at the thymidine kinase locus in the bystander cells receiving the conditioned medium. Furthermore, it required at least 1 h of exposure to the signal in the bystander cells to induce mutations. Bystander signal was fairly stable in the medium, requiring 12-24 h to diminish. Medium that contained bystander signal was rendered ineffective by a 4-fold dilution; in contrast a greater than 20-fold decrease in the cell number irradiated to generate a bystander signal was needed to eliminate bystander-induced mutagenesis. This suggested some sort of feedback inhibition by bystander signal that prevented the signaling cells from releasing more signal. Finally, an ionizing radiation-induced adaptive response was shown to be effective in reducing bystander mutagenesis; in addition, low levels of exposure to bystander signal in the transferred medium induced adaptation that was effective in reducing mutations induced by subsequent γ-ray exposures.

  13. Bystander Effects During Synchrotron Imaging Procedures?

    International Nuclear Information System (INIS)

    Schueltke, Elisabeth; Nikkhah, Guido; Bewer, Brian; Wysokinski, Tomasz; Chapman, Dean

    2010-01-01

    Using monochromatic beam and synchrotron phase-contrast technique at the biomedical beamline of the Italian synchrotron facility Elettra (SYRMEP), we have shown in a small animal model of malignant brain tumor that it is possible to obtain high-resolution images of very small tumors when they have developed from implanted tumor cells loaded with colloidal gold nanoparticles (GNP). All previous experiments were conducted in post-mortem samples. We have now designed a cell culture experiment to investigate the effects of synchrotron radiation with an energy and dose profile similar to that expected in our first in vivo imaging studies according to the protocol developed at SYRMEP.Materials and Methods: Culture flasks containing either gold-loaded or naieve C6 glioma cells were exposed to a dose of 0.5 Gy at 24 keV. The irradiated medium was aspirated and replaced with fresh growth medium. Twenty-four hours later this non-irradiated medium exposed to irradiated cells was aspirated, then added to non-irradiated C6 cells in order to investigate whether bystander effects are seen under the conditions of our image acquisition protocol. The irradiated medium was added to a number of other non-irradiated cell cultures. Cell counts were followed until 72 hrs after irradiation. Western blots were conducted with H2AX antibodies. This experiment was one of the first biomedical experiments conducted at BMIT, the new biomedical imaging and therapy beamline of the Canadian Light Source.Results: No significant differences in proliferation were seen between cells that were directly irradiated, exposed to irradiated medium or exposed to the non-irradiated 24-hr-medium from the irradiated cells. However, there was a tendency towards a higher number of double strand breaks in previously irradiated cells when they were exposed to non-irradiated medium that had been in contact with irradiated cells for 24 hrs.

  14. Bystander defibrillation for out-of-hospital cardiac arrest in Public vs Residential Locations

    DEFF Research Database (Denmark)

    Hansen, Steen Møller; Hansen, Carolina Malta; Folke, Fredrik

    2017-01-01

    Importance: Bystander-delivered defibrillation (hereinafter referred to as bystander defibrillation) of patients with out-of-hospital cardiac arrests (OHCAs) remains limited despite the widespread dissemination of automated external defibrillators (AEDs). Objective: To examine calendar changes...... in bystander defibrillation and subsequent survival according to a public or a residential location of the cardiac arrest after nationwide initiatives in Denmark to facilitate bystander-mediated resuscitative efforts, including bystander defibrillation. Design, Setting, and Participants: This nationwide study......, 2016. Exposures: Nationwide initiatives to facilitate bystander resuscitative efforts, including bystander defibrillation, consisted of resuscitation training of Danish citizens, dissemination of on-site AEDs, foundation of an AED registry linked to emergency medical dispatch centers, and dispatcher...

  15. Mechanism of bystander-blaming: defensive attribution, counterfactual thinking, and gender.

    Science.gov (United States)

    Levy, Inna; Ben-David, Sarah

    2015-01-01

    Contemporary victimology recognizes that an understanding of the mechanism of blaming requires a comprehensive approach that includes the victim, the offender, and the bystander. However, most of the existing research on blaming focuses on the victim and the offender, ignoring the issue of bystander-blaming. This study highlights the bystander and investigates bystander-blaming by exploring some theoretical explanations, including counterfactual thinking, defensive attribution, and gender differences. The study included 363 young male and female participants, who read vignettes describing the behavior of the victim and the bystander in a rape scenario and answered questions regarding bystander-blaming. The results show that both counterfactual thinking and defensive attribution play a role in bystander-blaming. This article addresses the theoretical and practical implications of these findings. © The Author(s) 2013.

  16. Predicting Improvement After a Bystander Program for the Prevention of Sexual and Dating Violence.

    Science.gov (United States)

    Hines, Denise A; Palm Reed, Kathleen M

    2015-07-01

    Although evidence suggests that bystander prevention programs are promising interventions for decreasing sexual violence and dating violence on college campuses, there have been no studies to date evaluating moderators of bystander program effectiveness. The current study evaluates whether different demographic characteristics, attitudes, knowledge, and behaviors at pretest predict change over a 6-month follow-up for students who participated in a bystander prevention program. Participants in the three assessments (pretest, posttest, 6-month follow-up) included 296 college students who were mandated to attend a bystander program during their first year orientation. Analyses showed that with few exceptions, the bystander program worked best for students who were most at risk given their pretest demographics and levels of attitudes condoning dating violence and sexual violence, bystander efficacy, and bystander behaviors. Results are discussed in terms of suggestions for future research. © 2014 Society for Public Health Education.

  17. Human Lung Cancer Risks from Radon – Part III - Evidence of Influence of Combined Bystander and Adaptive Response Effects on Radon Case-Control Studies - A Microdose Analysis

    Science.gov (United States)

    Leonard, Bobby E.; Thompson, Richard E.; Beecher, Georgia C.

    2012-01-01

    Since the publication of the BEIR VI (1999) report on health risks from radon, a significant amount of new data has been published showing various mechanisms that may affect the ultimate assessment of radon as a carcinogen, in particular the potentially deleterious Bystander Effect (BE) and the potentially beneficial Adaptive Response radio-protection (AR). The case-control radon lung cancer risk data of the pooled 13 European countries radon study (Darby et al 2005, 2006) and the 8 North American pooled study (Krewski et al 2005, 2006) have been evaluated. The large variation in the odds ratios of lung cancer from radon risk is reconciled, based on the large variation in geological and ecological conditions and variation in the degree of adaptive response radio-protection against the bystander effect induced lung damage. The analysis clearly shows Bystander Effect radon lung cancer induction and Adaptive Response reduction in lung cancer in some geographical regions. It is estimated that for radon levels up to about 400 Bq m−3 there is about a 30% probability that no human lung cancer risk from radon will be experienced and a 20% probability that the risk is below the zero-radon, endogenic spontaneous or perhaps even genetically inheritable lung cancer risk rate. The BEIR VI (1999) and EPA (2003) estimates of human lung cancer deaths from radon are most likely significantly excessive. The assumption of linearity of risk, by the Linear No-Threshold Model, with increasing radon exposure is invalid. PMID:22942874

  18. [Mutagenicity of radon and radon daughters

    International Nuclear Information System (INIS)

    1990-01-01

    The current objective of our research is to investigate the dose-response relationship of the lethal and mutagenic effects of exposure of cells to radon and its decay products. Dose-rate dependence will be studied, as well as the nature of the DNA lesions. The effect of DNA repair on the lethal and mutagenic effects of exposure and on the character of the DNA lesions will be investigated by comparing the response of L5178Y strains which differ in their ability to rejoin X radiation-induced DNA double-strand breaks. This report discusses progress incurred from 4/1/1988--10/1/1990. 5 refs., 9 figs., 6 tabs

  19. AN OVERVIEW OF MUTAGENIC POTENTIAL OF PESTICIDES

    Directory of Open Access Journals (Sweden)

    Aurel Popescu

    2013-12-01

    Full Text Available This paper presents a synthesis of mutagenic potential of a few pesticides. Cytotoxicity tests, using plant test systems in vivo, such as Allium cepa, are validated by the similar results performed in animal testing in vitro. Cytogenetic tests are usefulness for identifying and evaluating the damaging effects of pesticides present in various concentrations under different exposure times on living organisms. Mutagenic potential of different pesticides used can be detected cytologically by cellular inhibition (mitotic index and replication index are used as indicators of adequate cell proliferation, disruption in metaphase, induction of chromosomal aberrations, numerical and structural, ranging from chromosomal fragmentation to the disorganization of the mitotic spindle, and consequently of all subsequent dependent mitotic phases.

  20. Mutagenicity potential of commercial broth cubes at varying concentrations

    International Nuclear Information System (INIS)

    De Torres, Nelson Velasquez; Talain, Augusto Nicolas.

    1997-01-01

    Today, there has been a growing concern on the mutagenicity potential of environmental chemical systems. These environmental chemicals such as pesticides, food additives, synthetic drugs, water and atmospheric pollutants are possible causes of mutagenic activity. Meat products and some meat flavorings, were also reported to exhibit mutagenic activity. And since these products are normal part of the daily human diet, there is a need for extensive studies regarding the possible mutagenic activity associated with these products. This study aimed to evaluate the mutagenicity potential of commercial broth cubes at varying concentration. The researchers sought to answer the following questions: 1. Do beef, pork and chicken broth cubes exhibit mutagenic activity? 2. Are there significant differences in the mutagenic activity among the three samples? 3. Are these significant differences in the mutagenic activity exhibited by each of the samples compared to that of Mitomycin-C (positive control)? 4. Which of the sample of each specific concentration exhibit the greatest mutagenic activity? Three specific concentrations of beef, pork and chicken broth cubes were prepared and their mutagenicity potential was evaluated by using the Micronucleus test. The formation of micro nucleated polychromatic and micro nucleated normo chromatic erythrocytes in bone marrow cells of mice treated with these samples were detected using a Carl-Zeiss photo microscope. The statistical tool used to test the validity of the null hypothesis was analysis of variance using randomized complete block design and independent T- test. (author)

  1. Mutagenicity potential of commercial broth cubes at varying concentrations

    Energy Technology Data Exchange (ETDEWEB)

    De Torres, Nelson Velasquez; Talain, Augusto Nicolas

    1998-12-31

    Today, there has been a growing concern on the mutagenicity potential of environmental chemical systems. These environmental chemicals such as pesticides, food additives, synthetic drugs, water and atmospheric pollutants are possible causes of mutagenic activity. Meat products and some meat flavorings, were also reported to exhibit mutagenic activity. And since these products are normal part of the daily human diet, there is a need for extensive studies regarding the possible mutagenic activity associated with these products. This study aimed to evaluate the mutagenicity potential of commercial broth cubes at varying concentration. The researchers sought to answer the following questions: 1. Do beef, pork and chicken broth cubes exhibit mutagenic activity? 2. Are there significant differences in the mutagenic activity among the three samples? 3. Are these significant differences in the mutagenic activity exhibited by each of the samples compared to that of Mitomycin-C (positive control)? 4. Which of the sample of each specific concentration exhibit the greatest mutagenic activity? Three specific concentrations of beef, pork and chicken broth cubes were prepared and their mutagenicity potential was evaluated by using the Micronucleus test. The formation of micro nucleated polychromatic and micro nucleated normo chromatic erythrocytes in bone marrow cells of mice treated with these samples were detected using a Carl-Zeiss photo microscope. The statistical tool used to test the validity of the null hypothesis was analysis of variance using randomized complete block design and independent T- test. (author). 28 refs., 9 figs., 26 tabs.

  2. Investigations on potential co-mutagenic effects of formaldehyde

    Energy Technology Data Exchange (ETDEWEB)

    Speit, Günter, E-mail: guenter.speit@uni-ulm.de; Linsenmeyer, Regina; Duong, Giang; Bausinger, Julia

    2014-02-15

    Highlights: • A549 cells were exposed to formaldehyde in combination with various mutagens. • Formaldehyde did not affect the induction and removal of DNA damage (comet assay). • Formaldehyde did not affect the induction of micronuclei by the mutagens tested. • The expression of the O{sup 6}-methylguanine-DNA methyltransferase was not affected. - Abstract: The genotoxicity and mutagenicity of formaldehyde (FA) has been well-characterized during the last years. Besides its known direct DNA-damaging and mutagenic activity in sufficiently exposed cells, FA at low concentrations might also enhance the mutagenic and carcinogenic effects of other environmental mutagens by interfering with the repair of DNA lesions induced by these mutagens. To further assess potential co-mutagenic effects of FA, we exposed A549 human lung cells to FA in combination with various mutagens and measured the induction and removal of DNA damage by the comet assay and the production of chromosomal mutations by the cytokinesis-block micronucleus assay (CBMN assay). The mutagens tested were ionizing radiation (IR), (±)-anti-B[a]P-7,8-dihydrodiol-9,10-epoxide (BPDE), N-nitroso-N-methylurea (methyl nitrosourea; MNU) and methyl methanesulfonate (MMS). FA (10–75 μM) did not enhance the genotoxic and mutagenic activity of these mutagens under the test conditions applied. FA alone and in combination with MNU or MMS did not affect the expression (mRNA level) of the gene of the O{sup 6}-methylguanine-DNA methyltransferase (MGMT) in A549 cells. The results of these experiments do not support the assumption that low FA concentrations might interfere with the repair of DNA damage induced by other mutagens.

  3. Space mutagenic effect of Trichoderma reesei

    International Nuclear Information System (INIS)

    Tian Xingshan; Zhou Fengzheng; Huang Xiaoguang; Kuang Zheshi; Pan Mushui; Li Guoli; Guo Yong

    2005-01-01

    The slant mycelia cultured with or without mutagenic agent diethyl sulfate (DS) and spores of Trichoderma reesei were loaded in the 18th returning satellite. Systematical screening showed that the life cycle and morphology of some strains had changed after space flight. After selection and domestication, 3 mutant strains with high cellulose enzyme activity were isolated. The cellulose enzyme productivities of the mutants were significantly increased more than 50%, and the mutant were generically stable. (authors)

  4. Mutagenic DNA repair in Escherichia coli. VII

    International Nuclear Information System (INIS)

    Bridges, B.A.; Mottershead, R.P.

    1978-01-01

    Incubation of E. coli WP2 in the presence of chloramphenicol (CAP) for 90 min before and 60 min after γ-irradiation had no effect on the induction of Trp + mutations. Bacteria that had been treated with CAP for 90 min prior to UV irradiation showed normal or near normal yields of induced mutations to streptomycin or colicin E2 resistance. Most of these mutations lost their photoreversibility (indicating 'fixation') during continued incubation with CAP for a further 60 min after irradiation, during which time neither protein nor DNA synthesis was detectable. It is suggested that CAP-sensitive protein synthesis is not required for mutagenic (error-prone) repair of lesions in pre-existing DNA, arguing against an inducible component in this repair. In contrast the frequency of UV-induced mutations to Trp + (largely at suppressor loci) was drastically reduced by CAP pretreatment, confirming the need for an active replication fork for UV-mutagenesis at these loci. It is known from the work of others that CAP given after UV abolishes mutagenesis at these loci. It is concluded that CAP-sensitive protein synthesis (consistent with a requirement for an inducible function) is necessary for mutagenic repair only in newly-replicated DNA (presumably at daughter strand gaps) and not in pre-existing DNA. The data are consistent with but do not prove the hypothesis that CAP-sensitive and insensitive modes of mutagenesis reflect minor differences in the operation of a single basic mutagenic repair system. (Auth.)

  5. Incoming College Students' Bystander Behaviors to Prevent Sexual Violence

    Science.gov (United States)

    McMahon, Sarah; Banyard, Victoria L.; McMahon, Sheila M.

    2015-01-01

    Evaluations of bystander intervention education programs demonstrate that this approach results in students' increased willingness to intervene in prosocial ways to prevent sexual violence (e.g., Moynihan, Banyard, Arnold, Eckstein, & Stapleton, 2010). These programs often focus on first-year college students, though theories and research on…

  6. A Qualitative Exploration of Cyber-Bystanders and Moral Engagement

    Science.gov (United States)

    Price, Deborah; Green, Deborah; Spears, Barbara; Scrimgeour, Margaret; Barnes, Alan; Geer, Ruth; Johnson, Bruce

    2014-01-01

    Studies have found that moral disengagement plays a significant role in the continuation of bullying situations (Bonanno, 2005); however, the moral stance of cyber-bystanders--those who witness online bullying--is not yet clear. While research into traditional face-to-face bullying reported that peers would probably or certainly intervene to…

  7. Delayed innocent bystander cell death following hypoxia in Caenorhabditis elegans.

    Science.gov (United States)

    Sun, C-L; Kim, E; Crowder, C M

    2014-04-01

    After hypoxia, cells may die immediately or have a protracted course, living or dying depending on an incompletely understood set of cell autonomous and nonautonomous factors. In stroke, for example, some neurons are thought to die from direct hypoxic injury by cell autonomous primary mechanisms, whereas other so called innocent bystander neurons die from factors released from the primarily injured cells. A major limitation in identifying these factors is the inability of current in vivo models to selectively target a set of cells for hypoxic injury so that the primarily injured cells and the innocent bystanders are clearly delineated. In order to develop such a model, we generated transgenic Caenorhabditis elegans strains where 2-3% of somatic cells were made selectively sensitive to hypoxia. This was accomplished by cell type-specific wild-type rescue in either pharyngeal myocytes or GABAergic neurons of a hypoxia resistance-producing translation factor mutation. Surprisingly, hypoxic targeting of these relatively small subsets of non-essential cells produced widespread innocent bystander cell injury, behavioral dysfunction and eventual organismal death. The hypoxic injury phenotypes of the myocyte or neuron sensitized strains were virtually identical. Using this model, we show that the C. elegans insulin receptor/FOXO transcription factor pathway improves survival when activated only after hypoxic injury and blocks innocent bystander death.

  8. Friends, strangers, and bystanders: Informal practices of sexual assault intervention.

    Science.gov (United States)

    Wamboldt, Alexander; Khan, Shamus R; Mellins, Claude Ann; Hirsch, Jennifer S

    2018-05-07

    Sexual assault is a part of many students' experiences in higher education. In U.S. universities, one in four women and one in ten men report being sexually assaulted before graduation. Bystander training programmes have been shown to modestly reduce campus sexual assault. Like all public health interventions, however, they have unintended social consequences; this research examines how undergraduate men on one campus understand bystander interventions and how those understandings shape their actual practices. We draw on ethnographic data collected between August 2015 and January 2017 at Columbia University and Barnard College. Our findings show that university training and an earnest desire to be responsible lead many men to intervene in possible sexual assaults. However, students' gendered methods target more socially vulnerable and socially distant men while protecting popular men and those to whom they are socially connected. Students' actual bystander practices thus reproduce social hierarchies in which low prestige may or may not be connected to actual risks of sexual assault. These results suggest that understanding intragroup dynamics and social hierarchies is essential to assault prevention in universities and that students' actions as bystanders may be effective at preventing assaults in some circumstances but may lead to new risks of sexual assault.

  9. Bystander Obligations at the Domestic and International Level Compared

    NARCIS (Netherlands)

    Spijkers, Otto|info:eu-repo/dai/nl/328454559

    2014-01-01

    This article examines whether States have a legal obligation to assist victims of serious breaches of fundamental obligations owed to the international community as a whole. This so-called ‘bystander State responsibility’ is compared with a similar legal obligation to assist victims at the domestic

  10. Bystander Reaction to Women Fighting: Developing a Theory of Intervention

    Science.gov (United States)

    Lowe, Robert D.; Levine, Mark; Best, Rachel M.; Heim, Derek

    2012-01-01

    This article explores accounts of bystanders to female-on-female public violence. Group interviews with participants in the night-time economy are carried out. Whereas men tend to respond to the discussion topic of female-on-female violence with laughter, this laughter reveals ambivalence and discomfort as much as amusement. Men seem to negotiate…

  11. Bystanders' Supportive and Passive Responses to Cyberaggression

    Science.gov (United States)

    Machackova, Hana; Dedkova, Lenka; Sevcikova, Anna; Cerna, Alena

    2018-01-01

    Bystanders in cyberaggression can support the victim, join the aggressor, or remain passive. We examined how supportive and passive adolescent Czech cyberbystanders (N = 443, ages 12-18) differ in terms of individual characteristics, emotional responses, and contextual factors. The most substantial distinguishing factor between the two groups…

  12. Reactive oxygen species and nitric oxide signaling in bystander cells.

    Science.gov (United States)

    Jella, Kishore Kumar; Moriarty, Roisin; McClean, Brendan; Byrne, Hugh J; Lyng, Fiona M

    2018-01-01

    It is now well accepted that radiation induced bystander effects can occur in cells exposed to media from irradiated cells. The aim of this study was to follow the bystander cells in real time following addition of media from irradiated cells and to determine the effect of inhibiting these signals. A human keratinocyte cell line, HaCaT cells, was irradiated (0.005, 0.05 and 0.5 Gy) with γ irradiation, conditioned medium was harvested after one hour and added to recipient bystander cells. Reactive oxygen species, nitric oxide, Glutathione levels, caspase activation, cytotoxicity and cell viability was measured after the addition of irradiated cell conditioned media to bystander cells. Reactive oxygen species and nitric oxide levels in bystander cells treated with 0.5Gy ICCM were analysed in real time using time lapse fluorescence microscopy. The levels of reactive oxygen species were also measured in real time after the addition of extracellular signal-regulated kinase and c-Jun amino-terminal kinase pathway inhibitors. ROS and glutathione levels were observed to increase after the addition of irradiated cell conditioned media (0.005, 0.05 and 0.5 Gy ICCM). Caspase activation was found to increase 4 hours after irradiated cell conditioned media treatment (0.005, 0.05 and 0.5 Gy ICCM) and this increase was observed up to 8 hours and there after a reduction in caspase activation was observed. A decrease in cell viability was observed but no major change in cytotoxicity was found in HaCaT cells after treatment with irradiated cell conditioned media (0.005, 0.05 and 0.5 Gy ICCM). This study involved the identification of key signaling molecules such as reactive oxygen species, nitric oxide, glutathione and caspases generated in bystander cells. These results suggest a clear connection between reactive oxygen species and cell survival pathways with persistent production of reactive oxygen species and nitric oxide in bystander cells following exposure to irradiated cell

  13. Investigations into the bystander effect: signal versus response

    International Nuclear Information System (INIS)

    Vines, A.M.; Seymour, C.B.; Mothersill, C.E.

    2003-01-01

    The bystander effect is the general term used to describe the effects seen in cells or tissue that have never been directly irradiated, but display similar symptoms to those that have. Some of these symptoms include reduced cell survival, chromosomal aberrations, and increased apoptosis. This investigation aims to explore the signal produced by certain cell and tissue types, and the relationship this has with the subsequent response. The goal is to elucidate whether the reduction in cell survival frequently seen in response to the bystander effect is determined by the signal produced or the response of the cell type. Firstly, a matrix design experiment was set up using 3 cell lines. Each cell line was irradiated to produce ICCM (Irradiated Cell Conditioned Medium), which was in turn used to treat all cell lines in the study. Medium transfer is carried out within cell lines, (ICCM from CHO onto CHO cells) and between cell lines (ICCM from CHO onto HPV-G cells). In the second set of experiments, tissue samples from male Wister rats were used to generate ITCM (Irradiated Tissue Conditioned Medium). This medium was then tested on a cell line with an established response to the bystander effect. As an extension to these two experimental protocols, both ICCM and ITCM were used to investigate if there is calcium flux in the cells as a response to the bystander medium. This has recently been shown to be an early response to the bystander signal. Results indicate that it is the signal produced by the irradiated cells that determine the overall effect of the bystander signal, and not the response of the cells expose to it. CHO-K1 cells treated with autologous ICCM show a 16.2% drop in cell survival. However, when this cell line is treated with HPV-G ICCM, it shows a 36.5% drop in survival. HPV-G cells treated with autologous medium display a similar response to this, with a 41.1% drop in survival, though when treated with CHO-K1 ICCM, the drop in survival is 22.9%. This

  14. Multi-College Bystander Intervention Evaluation for Violence Prevention.

    Science.gov (United States)

    Coker, Ann L; Bush, Heather M; Fisher, Bonnie S; Swan, Suzanne C; Williams, Corrine M; Clear, Emily R; DeGue, Sarah

    2016-03-01

    The 2013 Campus Sexual Violence Elimination Act requires U.S. colleges to provide bystander-based training to reduce sexual violence, but little is known about the efficacy of such programs for preventing violent behavior. This study provides the first multiyear evaluation of a bystander intervention's campus-level impact on reducing interpersonal violence victimization and perpetration behavior on college campuses. First-year students attending three similarly sized public university campuses were randomly selected and invited to complete online surveys in the spring terms of 2010-2013. On one campus, the Green Dot bystander intervention was implemented in 2008 (Intervention, n=2,979) and two comparison campuses had no bystander programming at baseline (Comparison, n=4,132). Data analyses conducted in 2014-2015 compared violence rates by condition over the four survey periods. Multivariable logistic regression was used to estimate violence risk on Intervention relative to Comparison campuses, adjusting for demographic factors and time (2010-2013). Interpersonal violence victimization rates (measured in the past academic year) were 17% lower among students attending the Intervention (46.4%) relative to Comparison (55.7%) campuses (adjusted rate ratio=0.83; 95% CI=0.79, 0.88); a similar pattern held for interpersonal violence perpetration (25.5% in Intervention; 32.2% in Comparison; adjusted rate ratio=0.79; 95% CI=0.71, 0.86). Violence rates were lower on Intervention versus Comparison campuses for unwanted sexual victimization, sexual harassment, stalking, and psychological dating violence victimization and perpetration (pSexual Violence Elimination Act bystander training requirements. Copyright © 2016 American Journal of Preventive Medicine. All rights reserved.

  15. Timely bystander CPR improves outcomes despite longer EMS times.

    Science.gov (United States)

    Park, Gwan Jin; Song, Kyoung Jun; Shin, Sang Do; Lee, Kyung Won; Ahn, Ki Ok; Lee, Eui Jung; Hong, Ki Jeong; Ro, Young Sun

    2017-08-01

    This study aimed to determine the impact of bystander CPR on clinical outcomes in patients with increasing response time from collapse to EMS response. A population-based observational study was conducted in patients with witnessed out-of-hospital cardiac arrest (OHCA) of presumed cardiac etiology from 2012 to 2014. The time interval from collapse to CPR by EMS providers was categorized into quartile groups: fastest group (bystander CPR and the time interval from collapse to CPR by EMS providers. A total of 15,354 OHCAs were analyzed. Bystander CPR was performed in 8591 (56.0%). Survival to hospital discharge occurred in 1632 (10.6%) and favorable neurological outcome in 996 (6.5%). In an interaction model of bystander CPR, compared to the fastest group, adjusted odds ratios (AORs) (95% CIs) for survival to discharge were 0.89 (0.66-1.20) in the fast group, 0.76 (0.57-1.02) in the late group, and 0.52 (0.37-0.73) in the latest group. For favorable neurological outcome, AORs were 1.12 (0.77-1.62) in the fast group, 0.90 (0.62-1.30) in the late group, 0.59 (0.38-0.91) in the latest group. The survival from OHCA decreases as the ambulance response time increases. The increase in mortality and worsening neurologic outcomes appear to be mitigated in those patients who receive bystander CPR. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Preventing Interpersonal Violence on College Campuses: The Effect of One Act Training on Bystander Intervention.

    Science.gov (United States)

    Alegría-Flores, Kei; Raker, Kelli; Pleasants, Robert K; Weaver, Mark A; Weinberger, Morris

    2015-05-22

    Sexual assault, stalking, dating violence, and intimate partner violence, herein collectively termed interpersonal violence (IV), are public health problems affecting 20% to 25% of female college students. Currently, One Act is one of the few IV prevention training programs at universities that teach students bystander skills to intervene in low- and high-risk IV situations. The objectives of this study were 1) to evaluate One Act's effects on date rape attitudes and behaviors, and bystanders' confidence, willingness to help, and behavior, and 2) to compare the effects on bystander skills between One Act and Helping Advocates for Violence Ending Now (HAVEN), an IV response training program with similar participants. Data were collected over 2 years, before and after One Act and HAVEN trainings. We measured outcomes with four scales: College Date Rape Attitudes and Behaviors, Bystander Confidence, Willingness to Help, and Bystander Behavior. The analysis compared within- and between-group mean differences in scale scores pre- and post-trainings using linear mixed models. One Act showed improvements for date rape attitudes and behaviors (p trainings' effects on bystander willingness to help and behavior had similar patterns but were not statistically significant. We found a larger positive impact on bystander confidence among students who participated in the bystander prevention training compared with the response training. Further research is needed to improve the measures for bystander behavior and measure the bystander trainings' larger impact on the community. © The Author(s) 2015.

  17. Predicting High-School Students' Bystander Behavior in Simulated Dating Violence Situations.

    Science.gov (United States)

    Jouriles, Ernest N; Rosenfield, David; Yule, Kristen; Sargent, Kelli S; McDonald, Renee

    2016-03-01

    Dating violence among adolescents is associated with a variety of negative health consequences for victims. Bystander programs are being developed and implemented with the intention of preventing such violence, but determinants of high-school students' responsive bystander behavior remain unclear. The present study examines hypothesized determinants of high-school students' bystander behavior in simulated situations of dating violence. Participants were 80 high-school students who completed self-reports of hypothesized determinants of bystander behavior (responsibility, efficacy, and perceived benefits for intervening) at a baseline assessment. A virtual-reality paradigm was used to observationally assess bystander behavior at 1-week and 6-month assessments after baseline. Efficacy for intervening was positively associated with observed bystander behavior at the 1-week and 6-month assessments. Moreover, efficacy predicted bystander behavior over and above feelings of responsibility and perceived benefits for intervening. Contrary to our predictions, neither responsibility nor perceived benefits for intervening were associated with observed bystander behavior. This research advances our understanding of determinants of bystander behavior for high-school students and can inform prevention programming for adolescents. The study also introduces an innovative way to assess high-school students' bystander behavior. Copyright © 2016 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

  18. 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.

  19. Alpha-particles microbeam irradiation: impact of reactive oxygen species in bystander effect

    International Nuclear Information System (INIS)

    Hanot, M.

    2008-11-01

    Ionizing radiation-induced bystander effects arise in bystander cells that receive signals from directly irradiated cells. To date, free radicals are believed to play an active role in the bystander response, but this is incompletely characterized. To mark temporal and spatial impacts of bystander effect, we employed a precise α-particle microbeam to target a small fraction of sub-confluent osteoblastic cell cultures (MC3T3-E1). We identified the cellular membrane and mitochondria like two distinct places generating reactive oxygen species. The global oxidative stress observed after irradiation was significantly attenuated after filipin treatment, evidencing the pivotal role of membrane in MC3T3-E1 cells bystander response. To determine impact of bystander effect at a cell level, cellular consequences of this membrane-dependant bystander effect were then investigated. A variable fraction of the cell population (10 to 100%) was individually targeted. In this case, mitotic death and micronuclei yield both increased in bystander cells as well as in targeted cells demonstrating a role of bystander signals between irradiated cells in an autocrine or paracrine manner. Our results indicate a complex interaction of direct irradiation and bystander signals that lead to a membrane-dependant amplification of cell responses. (author)

  20. Bystander Interventions for Sexual Assault and Dating Violence on College Campuses: Are We Putting Bystanders in Harm's Way?

    Science.gov (United States)

    Witte, Tricia H.; Casper, Deborah M.; Hackman, Christine L.; Mulla, Mazheruddin M.

    2017-01-01

    Objective: The present study investigated the well-being of bystanders who witness and intervene in sexual assault and dating violence situations on campus. Participants: Participants were 321 young men and women from a large university in the southeastern United States. Methods: Participants completed a survey at the end of the Spring semester of…

  1. Mutagenic activity of phthalate esters in bacterial liquid suspension assays.

    OpenAIRE

    Seed, J L

    1982-01-01

    The mutagenic activities of several phthalate esters have been evaluated in an 8-azaguanine resistance assay in Salmonella typhimurium. Three phthalate esters were found to be mutagenic: dimethyl phthalate, diethyl phthalate and di-n-butyl phthalate. A number of other phthalate esters were not found to be mutagenic, including di(2-ethylhexyl) phthalate, di-n-octyl phthalate, diallyl phthalate, diisobutyl phthalate and diisodecyl phthalate. A metabolite of di(2-ethylhexyl) phthalate, 2-ethylhe...

  2. Past, present, and future of mutagens in cooked foods.

    Science.gov (United States)

    Sugimura, T

    1986-08-01

    Mutation assay with Salmonella typhimurium enabled us to detect various types of mutagens in cooked foods. A series of mutagenic heterocyclic amines has been isolated and identified in broiled fish and meat and in pyrolyzates of amino acids and proteins. Feeding experiments showed these mutagens to be carcinogenic in mice and rats. The mechanism of formation and pathway of metabolic activation of these heterocyclic amines have been elucidated. Their contents in various cooked foods have been determined. The presence of mutagenic nitropyrenes (some of which were confirmed as carcinogens) in grilled chicken was also established. Roasted coffee beans also yield mutagens such as methylglyoxal. The formation of mutagen precursors, including beta-carboline derivatives and tyramine which become mutagens with nitrite treatment, was found during food processing. Oncogene activation in animal tumors induced by some of these food mutagens/carcinogens has been confirmed. The role of mutagens/carcinogens in cooked foods in human cancer development has not yet been exactly evaluated. In order to do this, more information on their carcinogenic potency, human intake, metabolism in the human body, and the effects of combined administration with other initiators, promoters and other modifying factors in food is required.

  3. Self-protective function of post-conflict bystander affiliation in mandrills.

    Directory of Open Access Journals (Sweden)

    Gabriele Schino

    Full Text Available BACKGROUND: Affiliative interactions exchanged between victims of aggression and individuals not involved in the original aggression (bystanders have been observed in various species. Three hypothetical functions have been proposed for these interactions: consolation, self-protection and substitute reconciliation, but data to test them are scanty. METHODOLOGY/PRINCIPAL FINDINGS: We conducted post-conflict and matched control observations on a captive group of mandrills (Mandrillus sphinx. We found that victims often redirected aggression to bystanders, that they received most affiliation from those bystanders that were frequently the target of redirection, and that bystander affiliation reduced the likelihood of redirection. Bystander affiliation did not reduce the victim's distress (as measured by its scratching rates and was not received primarily from kin/friends. Finally, bystander affiliation did not reduce the likelihood of renewed aggression from the original aggressor. CONCLUSIONS/SIGNIFICANCE: These results provide support for the self-protection hypothesis but not for the consolation and substitute reconciliation hypotheses.

  4. Mutagenicity testing of diethylene glycol monobutyl ether.

    Science.gov (United States)

    Thompson, E D; Coppinger, W J; Valencia, R; Iavicoli, J

    1984-01-01

    The mutagenic potential of diethylene glycol monobutyl ether (diEGBE) was examined with a Tier I battery of in vitro assays followed by a Tier II in vivo Drosophila sex-linked recessive lethal assay. The in vitro battery consisted of: the Salmonella mutagenicity test, the L5178Y mouse lymphoma test, a cytogenetics assay using Chinese hamster ovary cells and the unscheduled DNA synthesis (UDS) assay in rat hepatocytes. Results of the Salmonella mutagenicity test, the cytogenetics test, and the rat hepatocyte assay were negative at concentrations up to 20 microL/plate, 7.92 microL/mL, and 4.4 microL/mL, respectively. Toxicity was clearly demonstrated at all high doses. A weak, but dose-related increase in the mutation frequency (4-fold increase over the solvent control at 5.6 microL/mL with 12% survival) was obtained in the L5178Y lymphoma test in the absence of metabolic activation. Results of the mouse lymphoma assay were negative in the presence of the S-9 activation system. The significance of the mouse lymphoma assay were negative in the presence of the S-9 activation system. The significance of the mouse lymphoma assay results were assessed by performing the Tier II sex-linked recessive lethal assay in Drosophila in which the target tissue is maturing germinal cells. Both feeding (11,000 ppm for 3 days) and injection (0.3 microL of approximately 14,000 ppm solution) routes of administration were employed in the Drosophila assay. Approximately 11,000 individual crosses with an equal number of negative controls were performed for each route of administration. diEGBE produced no increase in recessive lethals under these conditions.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:6389113

  5. Analysis of commercial bouillons for trace levels of mutagens.

    Science.gov (United States)

    Stavric, B; Matula, T I; Klassen, R; Downie, R H

    1993-12-01

    A new method, developed specifically for the extraction of heterocyclic aromatic amine (HAA) type mutagens from different food matrices, was applied to various forms of commercially available bouillons. This procedure is based on liquid-liquid extraction of the sample at different pH values. Recovery and reproducibility of the procedure was determined by processing spiked samples using a mutagenicity bioassay technique as an endpoint. The mutagenicity was tested in the Salmonella/microsome assay using strain TA98 with metabolic activation. 22 bouillon samples in liquid, cube or powder forms from seven manufacturers were extracted and tested for potential mutagenicity. The mutagenic activity of these samples varied and ranged from non-detectable to about 1200 induced revertants per gram of solid material, with a median value of approximately 250 revertants/g. The mutagenic response appeared to be dependent on the source rather than the type or form of the product tested. A negative response was obtained from only one chicken bouillon, and the highest positive response was obtained from a beef bouillon in cube form. It appears that the average beef sample, regardless of form, has a higher mutagenic potency than chicken or chicken and turkey samples. Overall, the intake of mutagens from commercial bouillons (obtained as cubes, concentrates or dry mixes) to prepare one serving (as bouillon, soup, casseroles, etc.) is considerably less than that reported in the literature for one serving of fried beef or pork. The extractability and mutagenic characteristics of these samples indicate the presence of HAA-type mutagens. Work is in progress to identify the mutagenic factors in bouillons.

  6. Assessing chemical mutagens: the risk to humans

    International Nuclear Information System (INIS)

    Brewen, J.G.

    1978-01-01

    Some topics discussed are as follows: chromosomal aberrations induced by x radiation, tritiated thymidine, maleic hydrazide, and nitrogen mustard; removal of pyrimidine dimers by photoreactivation in amphibian cells following uv radiation; effects of 4-nitroquinoline-oxide on leukocytes from XP and normal patients; DNA as a target for alkylating agents; sensitivity of spermatogonia to chemical mutagens; chromosomal aberrations induced by 8-ethoxycaffeine, methoxycaffeine, cytosine arabinoside, streptonigrin, bleomycin, and phleomycin; effects of MMS and triethylenemelamine on germ cells; and use of chromosomal aberrations for improving risk estimates for ionizing radiation

  7. Role of ATM in bystander signaling between human monocytes and lung adenocarcinoma cells.

    Science.gov (United States)

    Ghosh, Somnath; Ghosh, Anu; Krishna, Malini

    2015-12-01

    The response of a cell or tissue to ionizing radiation is mediated by direct damage to cellular components and indirect damage mediated by radiolysis of water. Radiation affects both irradiated cells and the surrounding cells and tissues. The radiation-induced bystander effect is defined by the presence of biological effects in cells that were not themselves in the field of irradiation. To establish the contribution of the bystander effect in the survival of the neighboring cells, lung carcinoma A549 cells were exposed to gamma-irradiation, 2Gy. The medium from the irradiated cells was transferred to non-irradiated A549 cells. Irradiated A549 cells as well as non-irradiated A549 cells cultured in the presence of medium from irradiated cells showed decrease in survival and increase in γ-H2AX and p-ATM foci, indicating a bystander effect. Bystander signaling was also observed between different cell types. Phorbol-12-myristate-13-acetate (PMA)-stimulated and gamma-irradiated U937 (human monocyte) cells induced a bystander response in non-irradiated A549 (lung carcinoma) cells as shown by decreased survival and increased γ-H2AX and p-ATM foci. Non-stimulated and/or irradiated U937 cells did not induce such effects in non-irradiated A549 cells. Since ATM protein was activated in irradiated cells as well as bystander cells, it was of interest to understand its role in bystander effect. Suppression of ATM with siRNA in A549 cells completely inhibited bystander effect in bystander A549 cells. On the other hand suppression of ATM with siRNA in PMA stimulated U937 cells caused only a partial inhibition of bystander effect in bystander A549 cells. These results indicate that apart from ATM, some additional factor may be involved in bystander effect between different cell types. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. MiR-21 is involved in radiation-induced bystander effects

    Science.gov (United States)

    Xu, Shuai; Ding, Nan; Pei, Hailong; Hu, Wentao; Wei, Wenjun; Zhang, Xurui; Zhou, Guangming; Wang, Jufang

    2014-01-01

    Radiation-induced bystander effects are well-established phenomena, in which DNA damage responses are induced not only in the directly irradiated cells but also in the non-irradiated bystander cells through intercellular signal transmission. Recent studies hint that bystander effects are possibly mediated via small non-coding RNAs, especially microRNAs. Thus, more details about the roles of microRNA in bystander effects are urgently needed to be elucidated. Here we demonstrated that bystander effects were induced in human fetal lung MRC-5 fibroblasts through medium-mediated way by different types of radiation. We identified a set of differentially expressed microRNAs in the cell culture medium after irradiation, among which the up-regulation of miR-21 was further verified with qRT-PCR. In addition, we found significant upregulation of miR-21 in both directly irradiated cells and bystander cells, which was confirmed by the expression of miR-21 precursor and its target genes. Transfection of miR-21 mimics into non-irradiated MRC-5 cells caused bystander-like effects. Taken together, our data reveals that miR-21 is involved in radiation-induced bystander effects. Elucidation of such a miRNA-mediated bystander effect is of utmost importance in understanding the biological processes related to ionizing radiation and cell-to-cell communication. PMID:25483031

  9. Students as Prosocial Bystanders to Sexual Assault: Demographic Correlates of Intervention Norms, Intentions, and Missed Opportunities.

    Science.gov (United States)

    Hoxmeier, Jill C; Acock, Alan C; Flay, Brian R

    2017-01-01

    Sexual assault is a major public health issue. Bystander engagement programs are becoming widely used to combat sexual assault on college campuses. The purpose of this study was to examine students' intervention norms, intentions, opportunities, and behaviors as bystanders to sexual assault. Undergraduate students ( N = 779) completed the Sexual Assault Bystander Behavior Questionnaire in the fall of 2014. The t tests revealed differences in students' intervention norms, intentions, opportunities, and missed opportunities based on sex, race/ethnicity, athletic participation, and fraternity/sorority membership. The findings support the use of additional measures to assess bystander behavior and to identify student subpopulations that may benefit from programs aimed at increasing prosocial intervention.

  10. Influence of catechins on bystander responses in CHO cells induced by alpha-particle irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Law, Y.L.; Wong, T.P.W. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Yu, K.N. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong)], E-mail: peter.yu@cityu.edu.hk

    2010-04-15

    In this work, we studied alpha-particle induced and medium-mediated bystander effects in Chinese hamster ovary (CHO) cells through micronucleus (MN) assay. We showed that signal transduction from irradiated cells to bystander cells occur within a short time after irradiation. We then studied the effects of ROS (reactive oxygen species)-scavenging catechins in the medium before irradiation. We observed decreases in the percentage of bystander cells with MN formation and thus proved the protection effect of catechins on bystander cells from radiation.

  11. Contribution of bystander effects in radiation induced genotoxicity

    International Nuclear Information System (INIS)

    Zhou, H.; Persaud, R.; Gillispie, J.; Randers-Pehrson, G.; Hei, T.K.; Suzuki, Masao

    2005-01-01

    The controversial use of a linear, no threshold extrapolation model for low dose risk assessment is based on the accepted dogma that the deleterious effects of ionizing radiation such as mutagenesis and carcinogenesis are attributable mainly to direct damage to DNA. However, this extrapolation was challenged by the recent reports on the bystander phenomenon. The bystander effect contributes to this debate by implying that the biological effects of low doses, where not all cells are traversed by a charged particle, are amplified by the transfer of factors to un-irradiated neighbors. This interested phenomenon implies that a linear extrapolation of risks from high to low doses may underestimate rather than over estimate low dose risks. Together with some radiation-induced phenomena such as adaptive response and genomic instability, the radiobiological response at low doses is likely to be a complex interplay among many factors. (author)

  12. Bystander effects on mammalian cells induced by carbon ions

    International Nuclear Information System (INIS)

    Wang Jufang; Zhao Jing; Ma Qiufeng; Chinese Academy of Sciences, Beijing; Li Weijian; Zhou Guangming; Dang Bingrong; Mao Limin; Feng Yan

    2004-01-01

    Bystander effects on unirradiated V79 cells were observed by irradiated conditioned medium (ICM) method and co-cultured with carbon-ion-irradiated V79 cells. The results showed that the colony formation efficiency of unirradiated cells is obviously decreased by ICM. After co-culture with carbon-ion-irradiated cells for some time, the colony formation efficiency of co-cultured cells was lower than expected results assuming no bystander effects. The micronucleus frequency and hprt gene mutation rate was almost the same as expected results. Cytotoxic factor(s), which was effective for cell growth but not for micronucleus and mutation on unirradiated cells, might be released by irradiated cells. (authors)

  13. Studies on mutagenic effectiveness and efficiency in Fenugreek ...

    African Journals Online (AJOL)

    shagufta

    2013-05-01

    May 1, 2013 ... improvement, the basic studies on effectiveness and efficiency of a mutagen in a crop are necessary to recover high frequency of desirable mutations (Kumar and Mani, 1997; Badere and Chaudhary, 2007). Mutagenic effectiveness is an index of the response of a genotype to the increasing doses of the ...

  14. Is Tobacco Smoke a Germ-Cell Mutagen?

    Science.gov (United States)

    Although no international organization exists to declare whether an agent is a germ-cell mutagen, tobacco smoke may be a human germ-cell mutagen. In the mouse, tobacco smoke induces a significant increase in the mutation frequency at an expanded simple tandem repeat (ESTR) locus....

  15. Mutagenicity of quaternary ammonium salts containing carbohydrate moieties

    Energy Technology Data Exchange (ETDEWEB)

    Dmochowska, Barbara [Department of Carbohydrate Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland); Piosik, Jacek; Woziwodzka, Anna [Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Kladki 24, 80-822 Gdansk (Poland); Sikora, Karol; Wisniewski, Andrzej [Department of Carbohydrate Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland); Wegrzyn, Grzegorz, E-mail: wegrzyn@biotech.univ.gda.pl [Department of Molecular Biology, University of Gdansk, Kladki 24, 80-822 Gdansk (Poland)

    2011-10-15

    Highlights: {yields} A series of quaternary ammonium salts containing carbohydrate moieties, with configuration D-galacto, D-gluco and D-manno, was synthesized and characterized. {yields} The quaternary ammonium salts containing carbohydrate moieties revealed potent mutagenic activities, as assessed by using the Vibrio harveyi bioluminescence mutagenicity test. {yields} The N-[2-(D-glycopyranosyloxy)ethyl]-N,N,N-trimethylaminium salts were of the highest activity in the mutagenicity assay. {yields} We suggest that quaternary ammonium salts may be more hazardous than previously supposed. - Abstract: Quaternary ammonium salts are widely used in industrial, agricultural, healthcare and domestic applications. They are believed to be safe compounds, with little or no health hazard to humans. However, in this report, we demonstrate that a series of newly synthesized quaternary ammonium salts containing carbohydrate moieties reveal potent mutagenic activities, as assessed by using the Vibrio harveyi bioluminescence mutagenicity test. D-Gluco- and D-galacto-derivatives were found to have a higher mutagenic potential than D-manno-derivatives. Among the former groups of compounds, the N-[2-(D-glycopyranosyloxy)ethyl]-N,N,N-trimethylaminium salts were of the highest activity in the mutagenicity assay. These results suggest that the safety of quaternary ammonium salts may be lower than previously supposed, indicating a need for testing such compounds for their mutagenicity.

  16. QSAR ligand dataset for modelling mutagenicity, genotoxicity, and rodent carcinogenicity

    Directory of Open Access Journals (Sweden)

    Davy Guan

    2018-04-01

    Full Text Available Five datasets were constructed from ligand and bioassay result data from the literature. These datasets include bioassay results from the Ames mutagenicity assay, Greenscreen GADD-45a-GFP assay, Syrian Hamster Embryo (SHE assay, and 2 year rat carcinogenicity assay results. These datasets provide information about chemical mutagenicity, genotoxicity and carcinogenicity.

  17. Mutagenicity of quaternary ammonium salts containing carbohydrate moieties

    International Nuclear Information System (INIS)

    Dmochowska, Barbara; Piosik, Jacek; Woziwodzka, Anna; Sikora, Karol; Wisniewski, Andrzej; Wegrzyn, Grzegorz

    2011-01-01

    Highlights: → A series of quaternary ammonium salts containing carbohydrate moieties, with configuration D-galacto, D-gluco and D-manno, was synthesized and characterized. → The quaternary ammonium salts containing carbohydrate moieties revealed potent mutagenic activities, as assessed by using the Vibrio harveyi bioluminescence mutagenicity test. → The N-[2-(D-glycopyranosyloxy)ethyl]-N,N,N-trimethylaminium salts were of the highest activity in the mutagenicity assay. → We suggest that quaternary ammonium salts may be more hazardous than previously supposed. - Abstract: Quaternary ammonium salts are widely used in industrial, agricultural, healthcare and domestic applications. They are believed to be safe compounds, with little or no health hazard to humans. However, in this report, we demonstrate that a series of newly synthesized quaternary ammonium salts containing carbohydrate moieties reveal potent mutagenic activities, as assessed by using the Vibrio harveyi bioluminescence mutagenicity test. D-Gluco- and D-galacto-derivatives were found to have a higher mutagenic potential than D-manno-derivatives. Among the former groups of compounds, the N-[2-(D-glycopyranosyloxy)ethyl]-N,N,N-trimethylaminium salts were of the highest activity in the mutagenicity assay. These results suggest that the safety of quaternary ammonium salts may be lower than previously supposed, indicating a need for testing such compounds for their mutagenicity.

  18. Attitudes toward the performance of bystander cardiopulmonary resuscitation in Japan.

    Science.gov (United States)

    Taniguchi, Takumi; Omi, Wataru; Inaba, Hideo

    2007-10-01

    Early initiation of bystander cardiopulmonary resuscitation (CPR) improves the chances of successful resuscitation and survival. The importance of bystander CPR is attracting more interest, and there has been an increase in attendance at CPR training courses in Japan. However, there have been few reports regarding Japanese attitudes toward the performance of bystander CPR. The present study was performed to identify current Japanese attitudes toward bystander CPR compared to our previous study performed in 1998. Between February and March 2006, participants were asked about their willingness to perform CPR in five varying scenarios, i.e., performing CPR on a stranger, a trauma patient, a child, an elderly person, and a relative, and CPR techniques consisting of chest compression plus mouth-to-mouth ventilation (CC plus MMV) versus chest compression only (CC only). A total of 4223 individuals (male 50%) completed the questionnaire, including high school students, teachers, emergency medical technicians (EMTs), medical nurses, and medical students. About 70% of the subjects had experienced CPR training more than once. Only 10-30% of high school students, teachers, and health care providers reported willingness to perform CC plus MMV, especially on a stranger or trauma victim. In contrast, 70-100% of these subjects reported willingness to perform CC only, which was the same as in our previous study. The reasons for the unwillingness among laypeople to perform CC plus MMV were inadequate knowledge and/or doubt regarding whether they could perform the techniques effectively, while health care providers reported a fear contracting of a disease. Most laypeople and health care providers are unlikely to perform CC plus MMV, especially on a stranger or trauma victim, but are more likely to perform CC only, as also found in our previous study in 1998. These findings suggest that MMV training should be de-emphasised and the awareness of CC alone should be emphasised because

  19. Cytokines shape chemotherapy-induced and 'bystander' senescence

    Czech Academy of Sciences Publication Activity Database

    Hodný, Zdeněk; Hubáčková, Soňa; Bartek, Jiří

    2010-01-01

    Roč. 2, č. 2 (2010), s. 375-376 ISSN 1945-4589 R&D Projects: GA ČR GA204/08/1418; GA ČR GA301/08/0353 Institutional research plan: CEZ:AV0Z50520514 Keywords : bystander cellular senescence * cytokines * PML Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.964, year: 2010

  20. Bystander Helping Behavior in Response to Workplace Bullying

    OpenAIRE

    Hellemans, Catherine; Dal Cason, Davide; Casini, Annalisa

    2017-01-01

    This research examines the role of colleagues in workplace bullying. While colleagues could often intervene to support the victim or stop the situation, passive behaviors and non-intervention are more frequent. The bystander effect highlighted by Latané and Darley (1970) has been studied in the context of school bullying and sexual harassment, but only rarely in the context of workplace bullying. We tested the impact of the belief in a just world for others, self-efficacy, perceived severity,...

  1. Mutagenic activities of metal compounds in bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Nishioka, H

    1975-01-01

    Environmental contaminations by certain metal compounds are bringing about serious problems to human health, including genetic hazards. It has been reported that some compounds of iron, manganese and mercury induce point mutations in microorganisms. Also it has been observed that those of aluminum, antimony, arsenic, cadmium, lead and tellurium cause chromosome aberrations in plants, insects and cultured human cells. The mechanism of mutation induction by these metals remains, however, still obscure. For screening of chemical mutagens, Kada et al, recently developed a simple and efficient method named rec-assay by observing differential growth sensitivities to drugs in wild and recombination-deficient strains of Bacillus subtilis. When a chemical is more inhibitory for Rec/sup -/ than for Rec/sup +/ cells, it is reasonable to suspect mutagenicity based on its DNA-damaging capacity. In the present report, 56 metal compounds were tested by the rec-assay. Compounds showing positive results in the assay such as potassium dichromate (K/sub 2/Cr/sub 2/O/sub 7/), ammonium molybdate ((NH/sub 4/)/sub 6/Mo/sub 7/O/sub 24/) and sodium arsenite (NaAsO/sub 2/) were then examined as to their capacities to induce reversions in E. coli Trp/sup -/ strains possessing different DNA repair pathways. 11 references, 3 tables.

  2. Changes in mutagenicity of protein pyrolyzates by reaction with nitrite.

    Science.gov (United States)

    Yoshida, D; Matsumoto, T

    1978-09-01

    Pyrolyzates of protein and related materials were treated with nitrite under acidic conditions, and the mutagenic activity toward Salmonella tester strains was determined. After treatment with nitrite in acidic solution, casein pyrolyzate, an extract of roasted chicken meat, tobacco-smoke condensate and some aromatic amines showed appreciable decreases in their mutagenic activities toward Salmonella typhimurium TA 98. Aromatic amines in the pyrolyzates may be changed by nitrite treatment to other forms having no or lower mutagenic activity toward Salmonella typhimurium TA 98. The contribution by aromatic amines to the total mutagenic activity of the pyrolyzates was as high as 80% in both casein pyrolyzate and extract of roasted chicken meat and 50% in tobacco-smoke condensate. Pyrolyzates of protein and related materials did not show a decrease in the mutagenic activity toward Salmonella typhimurium TA 100 with the same treatment.

  3. Host and Viral Factors in HIV-Mediated Bystander Apoptosis

    Science.gov (United States)

    Garg, Himanshu; Joshi, Anjali

    2017-01-01

    Human immunodeficiency virus (HIV) infections lead to a progressive loss of CD4 T cells primarily via the process of apoptosis. With a limited number of infected cells and vastly disproportionate apoptosis in HIV infected patients, it is believed that apoptosis of uninfected bystander cells plays a significant role in this process. Disease progression in HIV infected individuals is highly variable suggesting that both host and viral factors may influence HIV mediated apoptosis. Amongst the viral factors, the role of Envelope (Env) glycoprotein in bystander apoptosis is well documented. Recent evidence on the variability in apoptosis induction by primary patient derived Envs underscores the role of Env glycoprotein in HIV disease. Amongst the host factors, the role of C-C Chemokine Receptor type 5 (CCR5), a coreceptor for HIV Env, is also becoming increasingly evident. Polymorphisms in the CCR5 gene and promoter affect CCR5 cell surface expression and correlate with both apoptosis and CD4 loss. Finally, chronic immune activation in HIV infections induces multiple defects in the immune system and has recently been shown to accelerate HIV Env mediated CD4 apoptosis. Consequently, those factors that affect CCR5 expression and/or immune activation in turn indirectly regulate HIV mediated apoptosis making this phenomenon both complex and multifactorial. This review explores the complex role of various host and viral factors in determining HIV mediated bystander apoptosis. PMID:28829402

  4. Identifiable images of bystanders extracted from corneal reflections.

    Directory of Open Access Journals (Sweden)

    Rob Jenkins

    Full Text Available Criminal investigations often use photographic evidence to identify suspects. Here we combined robust face perception and high-resolution photography to mine face photographs for hidden information. By zooming in on high-resolution face photographs, we were able to recover images of unseen bystanders from reflections in the subjects' eyes. To establish whether these bystanders could be identified from the reflection images, we presented them as stimuli in a face matching task (Experiment 1. Accuracy in the face matching task was well above chance (50%, despite the unpromising source of the stimuli. Participants who were unfamiliar with the bystanders' faces (n = 16 performed at 71% accuracy [t(15 = 7.64, p<.0001, d = 1.91], and participants who were familiar with the faces (n = 16 performed at 84% accuracy [t(15 = 11.15, p<.0001, d = 2.79]. In a test of spontaneous recognition (Experiment 2, observers could reliably name a familiar face from an eye reflection image. For crimes in which the victims are photographed (e.g., hostage taking, child sex abuse, reflections in the eyes of the photographic subject could help to identify perpetrators.

  5. An investigation of bystander effects in Schizosaccharomyces pombe

    International Nuclear Information System (INIS)

    DeVeaux, L.C.; Wells, D.P.; Durtschi, L.S.; Reda, M.; Frujinoiu, C.; Harmon, F.

    2003-01-01

    Full text: 'Bystander' effects have been documented in various mammalian cell types and appear to act by two distinct mechanisms. One response requires a functional gap-junction. A non gap-junction-mediated response has also been observed in human cell lines, indicating release of a signaling factor. No analogous response has been investigated in unicellular organisms. Given that DNA damage signaling pathways are present in simple eukaryotes, we investigated bystander signaling effects using a single-celled organism, the fission yeast Schizosaccharomyces pombe. This organism may provide a much simpler model system than higher eukaryotic cells for studying these effects. We measured survival and mutation rate in an unirradiated culture after exposure to an irradiated culture. These two cultures were mixed immediately after irradiation, and any signaling factor that was produced had direct and continuous access to the unirradiated cells during subsequent cell divisions. The irradiated culture was from a multiply auxotrophic strain, whereas the unirradiated culture was from a prototrophic strain. Surviving colonies of the unirradiated culture were thus easily distinguished from those arising from irradiated cells. Mutation rates were measured as forward mutation to 2-deoxyglucose resistance. We have investigated bystander effects with electron and gamma dose from 6 to 20 MeV electron linacs. We varied electron beam energies, dose rates and temporal distributions of dose. The importance of this research stems from the fundamental evolutionary significance of cell signaling of any kind in unicellular systems, representing a major step toward the evolution of multi-cellular states

  6. Mutagenicity screening: General principles and minimal criteria. Report of a committee of the European Environmental Mutagen Society

    NARCIS (Netherlands)

    Kilbey, B.J.; Igali, S.; Lohman, P.H.M.

    1978-01-01

    A statement of general principles and minimal criteria for the screening of chemicals for potential mutagenicity in man that may be used as guidelines for regulatory agencies and industrial organisations. To make clear the potentialities and current limitations of short-term mutagenicity testing for

  7. Bystander Defibrillation for Out-of-Hospital Cardiac Arrest in Public vs Residential Locations.

    Science.gov (United States)

    Hansen, Steen Møller; Hansen, Carolina Malta; Folke, Fredrik; Rajan, Shahzleen; Kragholm, Kristian; Ejlskov, Linda; Gislason, Gunnar; Køber, Lars; Gerds, Thomas A; Hjortshøj, Søren; Lippert, Freddy; Torp-Pedersen, Christian; Wissenberg, Mads

    2017-05-01

    Bystander-delivered defibrillation (hereinafter referred to as bystander defibrillation) of patients with out-of-hospital cardiac arrests (OHCAs) remains limited despite the widespread dissemination of automated external defibrillators (AEDs). To examine calendar changes in bystander defibrillation and subsequent survival according to a public or a residential location of the cardiac arrest after nationwide initiatives in Denmark to facilitate bystander-mediated resuscitative efforts, including bystander defibrillation. This nationwide study identified 18 688 patients in Denmark with first-time OHCA from June 1, 2001, to December 31, 2012, using the Danish Cardiac Arrest Registry. Patients had a presumed cardiac cause of arrest that was not witnessed by emergency medical services personnel. Data were analyzed from April 1, 2015, to December 10, 2016. Nationwide initiatives to facilitate bystander resuscitative efforts, including bystander defibrillation, consisted of resuscitation training of Danish citizens, dissemination of on-site AEDs, foundation of an AED registry linked to emergency medical dispatch centers, and dispatcher-assisted guidance of bystander resuscitation efforts. The proportion of patients who received bystander defibrillation according to the location of the cardiac arrest and their subsequent 30-day survival. Of the 18 688 patients with OHCAs (67.8% men and 32.2% women; median [interquartile range] age, 72 [62-80] years), 4783 (25.6%) had a cardiac arrest in a public location and 13 905 (74.4%) in a residential location. The number of registered AEDs increased from 141 in 2007 to 7800 in 2012. The distribution of AED location was consistently skewed in favor of public locations. Bystander defibrillation increased in public locations from 3 of 245 (1.2%; 95% CI, 0.4%-3.5%) in 2001 to 78 of 510 (15.3%; 95% CI, 12.4%-18.7%) in 2012 (P bystander defibrillation increased in public locations from 8.3% (95% CI, 1.5%-35.4%) in 2001/2002 to 57

  8. Expression profiles are different in carbon ion-irradiated normal human fibroblasts and their bystander cells

    International Nuclear Information System (INIS)

    Iwakawa, Mayumi; Hamada, Nobuyuki; Imadome, Kaori; Funayama, Tomoo; Sakashita, Testuya; Kobayashi, Yasuhiko; Imai, Takashi

    2008-01-01

    Evidence has accumulated that ionizing radiation induces biological effects in non-irradiated bystander cells having received signals from directly irradiated cells; however, energetic heavy ion-induced bystander response is incompletely characterized. Here we performed microarray analysis of irradiated and bystander fibroblasts in confluent cultures. To see the effects in bystander cells, each of 1, 5 and 25 sites was targeted with 10 particles of carbon ions (18.3 MeV/u, 103 keV/μm) using microbeams, where particles traversed 0.00026, 0.0013 and 0.0066% of cells, respectively. diated cells, cultures were exposed to 10% survival dose (D), 0.1D and 0.01D of corresponding broadbeams (108 keV/μm). Irrespective of the target numbers (1, 5 or 25 sites) and the time (2 or 6 h postirradiation), similar expression changes were observed in bystander cells. Among 874 probes that showed more than 1.5-fold changes in bystander cells, 25% were upregulated and the remainder downregulated. These included genes related to cell communication (PIK3C2A, GNA13, FN1, ANXA1 and IL1RAP), stress response (RAD23B, ATF4 and EIF2AK4) and cell cycle (MYCN, RBBP4 and NEUROG1). Pathway analysis revealed serial bystander activation of G protein/PI-3 kinase pathways. Instead, genes related to cell cycle or death (CDKN1A, GADD45A, NOTCH1 and BCL2L1), and cell communication (IL1B, TCF7 and ID1) were upregulated in irradiated cells, but not in bystander cells. Our results indicate different expression profiles in irradiated and bystander cells, and imply that intercellular signaling between irradiated and bystander cells activate intracellular signaling, leading to the transcriptional stress response in bystander cells

  9. Radiation-induced bystander effects in cultured human stem cells.

    Directory of Open Access Journals (Sweden)

    Mykyta V Sokolov

    2010-12-01

    Full Text Available The radiation-induced "bystander effect" (RIBE was shown to occur in a number of experimental systems both in vitro and in vivo as a result of exposure to ionizing radiation (IR. RIBE manifests itself by intercellular communication from irradiated cells to non-irradiated cells which may cause DNA damage and eventual death in these bystander cells. It is known that human stem cells (hSC are ultimately involved in numerous crucial biological processes such as embryologic development; maintenance of normal homeostasis; aging; and aging-related pathologies such as cancerogenesis and other diseases. However, very little is known about radiation-induced bystander effect in hSC. To mechanistically interrogate RIBE responses and to gain novel insights into RIBE specifically in hSC compartment, both medium transfer and cell co-culture bystander protocols were employed.Human bone-marrow mesenchymal stem cells (hMSC and embryonic stem cells (hESC were irradiated with doses 0.2 Gy, 2 Gy and 10 Gy of X-rays, allowed to recover either for 1 hr or 24 hr. Then conditioned medium was collected and transferred to non-irradiated hSC for time course studies. In addition, irradiated hMSC were labeled with a vital CMRA dye and co-cultured with non-irradiated bystander hMSC. The medium transfer data showed no evidence for RIBE either in hMSC and hESC by the criteria of induction of DNA damage and for apoptotic cell death compared to non-irradiated cells (p>0.05. A lack of robust RIBE was also demonstrated in hMSC co-cultured with irradiated cells (p>0.05.These data indicate that hSC might not be susceptible to damaging effects of RIBE signaling compared to differentiated adult human somatic cells as shown previously. This finding could have profound implications in a field of radiation biology/oncology, in evaluating radiation risk of IR exposures, and for the safety and efficacy of hSC regenerative-based therapies.

  10. Do Sexual Assault Bystander Interventions Change Men's Intentions? Applying the Theory of Normative Social Behavior to Predicting Bystander Outcomes.

    Science.gov (United States)

    Mabry, Amanda; Turner, Monique Mitchell

    2016-01-01

    The high prevalence of sexual assault on college campuses has led to the implementation of health communication programs to prevent sexual assault. A few novel programs focus on primary prevention by targeting social norms related to gender and masculinity among men through bystander intervention. Guided by the theory of normative social behavior, this study sought to examine the relative effect of campaigns communicating positive versus negative injunctive norms and the interaction between exposure to such campaign messages and perceived descriptive norms and relevant cognitive moderators (e.g., outcome expectations, injunctive norms, group identity, ego involvement) among men. A 2 (high/low descriptive norms) × 2 (high/low moderator) × 3 (public service announcement) independent groups quasi-experimental design (N = 332) was used. Results indicated that messages communicating positive injunctive norms were most effective among men who were least likely to engage in bystander intervention. Furthermore, descriptive norms played a significant role in behavioral intentions, such that those with stronger norms were more likely to report intentions to engage in bystander behaviors in the future. Similarly, the moderators of aspiration, injunctive norms, social approval, and ego involvement had a significant positive effect on behavioral intentions. These findings have important implications for future message design strategy and audience segmentation.

  11. Application of mammalian cytogenetics to mutagenicity studies

    International Nuclear Information System (INIS)

    Brewen, J.G.

    1977-01-01

    Studies on induction of chromosome damage in germ cells by triethylene melamine (TEM) included determination of frequencies of chromosomal aberrations observed in human leukocytes after treating different stages of the cell cycle with TEM, frequencies of chromatid aberrations in metaphase I oocytes and the female pronuclear chromosomes following treatment of female mice with TEM, and frequencies of labeled diplotene-diakinesis figures and chromosome abberations at various intervals after treatment of primary spermatocytes with TEM and 3 H-thymidine. Studies on effects of low linear energy transfer radiation on mouse oocytes showed that the frequency of aberrations increased as a function of time and remained constant 8 to 9 days post-exposure. It was concluded that cytogenetic procedures were adequate to evaluate certain mutagenic end points

  12. Mutagenic effects of ion implantation on stevia

    International Nuclear Information System (INIS)

    Wang Cailian; Shen Mei; Chen Qiufang; Lu Ting; Shu Shizhen

    1998-01-01

    Dry seeds of Stevia were implanted by 75 keV nitrogen and carbon ions with various doses. The biological effects in M 1 and mutation in M 2 were studied. The results showed that ion beam was able to induce variation on chromosome structure in root tip cells. The rate of cells with chromosome aberration was increased with ion beam dose. The rate of cells with chromosomal aberration was lower than that induced with γ-rays. Frequency of the mutation induced by implantation of N + and C + ions were higher than those induced by γ-rays. The rate of cell with chromosome aberration and in M 2 useful mutation induced by implantation of C + ion was higher than those induced by implantation of N + ion. Mutagenic effects Feng 1 x Riyuan and Riyuan x Feng 2 by implantation of N + and C + were higher than that of Jining and Feng 2

  13. Conceptualizing the Engaging Bystander Approach to Sexual Violence Prevention on College Campuses

    Science.gov (United States)

    McMahon, Sarah; Postmus, Judy L.; Koenick, Ruth Anne

    2011-01-01

    Bystander intervention offers promise as a sexual violence prevention tool for student affairs administrators on college campuses, but the conceptualization and definition of the approach is in its infancy and needs further development. In an effort to emphasize the potential role of bystanders in the primary prevention of sexual violence, we put…

  14. Sorority Women's and Fraternity Men's Rape Myth Acceptance and Bystander Intervention Attitudes

    Science.gov (United States)

    Bannon, R. Sean; Brosi, Matthew W.; Foubert, John D.

    2013-01-01

    Sorority women and fraternity men are more likely than other students to be survivors and perpetrators of sexual assault, respectively. The present study examined sorority and fraternity members' rape myth acceptance, bystander efficacy, and bystander willingness to help in potential sexual assault situations. Sorority women were more rejecting of…

  15. Effects of a Rape Awareness Program on College Women: Increasing Bystander Efficacy and Willingness to Intervene

    Science.gov (United States)

    Foubert, John D.; Langhinrichsen-Rohling, Jennifer; Brasfield, Hope; Hill, Brent

    2010-01-01

    An experimental study evaluated the efficacy of a sexual assault risk-reduction program on 279 college women that focused on learning characteristics of male perpetrators and teaching bystander intervention techniques. After seeing The Women's Program, participants reported significantly greater bystander efficacy and significantly greater…

  16. Role of iNOS in Bystander Signaling Between Macrophages and Lymphoma Cells

    International Nuclear Information System (INIS)

    Ghosh, Somnath; Maurya, Dharmendra Kumar; Krishna, Malini

    2008-01-01

    Purpose: The present report describes the bystander effects of radiation between similar and dissimilar cells and the role of iNOS in such communication. Materials and Methods: EL-4 and RAW 264.7 cells were exposed to 5 Gy γ-irradiation. The medium from irradiated cells was transferred to unirradiated cells. Results: Irradiated EL-4 cells as well as those cultured in the presence of medium from γ-irradiated EL-4 cells showed an upregulation of NF-κB, iNOS, p53, and p21/waf1 genes. The directly irradiated and the bystander EL-4 cells showed an increase in DNA damage, apoptosis, and NO production. Bystander signaling was also found to exist between RAW 264.7 (macrophage) and EL-4 (lymphoma) cells. Unstimulated or irradiated RAW 264.7 cells did not induce bystander effect in unirradiated EL-4 cells, but LPS stimulated and irradiated RAW 264.7 cells induced an upregulation of NF-κB and iNOS genes and increased the DNA damage in bystander EL-4 cells. Treatment of EL-4 or RAW 264.7 cells with L-NAME significantly reduced the induction of gene expression and DNA damage in the bystander EL-4 cells, whereas treatment with cPTIO only partially reduced the induction of gene expression and DNA damage in the bystander EL-4 cells. Conclusions: It was concluded that active iNOS in the irradiated cells was essential for bystander response

  17. Engaging Upstanders: Class-Wide Approach to Promoting Positive Bystander Behavior

    Science.gov (United States)

    Wood, Laura; Smith, Jennifer; Varjas, Kris; Meyers, Joel

    2016-01-01

    Positive and supportive bystander behaviors have been associated with decreases in the frequency and negative impact of bullying. This article addresses the design, implementation, evaluation, and continuation of a classroom-based intervention that promotes positive bystander behaviors. The Engaging Upstanders curriculum was piloted with two…

  18. Effective suppression of bystander effects by DMSO treatment of irradiated CHO cells

    International Nuclear Information System (INIS)

    Kashino, Genro; Prise, K.M.; Suzuki, Keiji

    2007-01-01

    Evidence is accumulating that irradiated cells produce some signals which interact with non-exposed cells in the same population via a bystander effect. Here, we examined whether dimethyl sulfoxide (DMSO) is effective in suppressing radiation induced bystander effects in Chinese hamster ovary (CHO) and repair deficient xrs5 cells. When 1 Gy-irradiated CHO cells were treated with 0.5% DMSO for 1 hr before irradiation, the induction of micronuclei in irradiated cells was suppressed to 80% of that in non-treated irradiated cells. The suppressive effect of DMSO on the formation of bystander signals was examined and the results demonstrated that 0.5% DMSO treatment of irradiated cells completely suppressed the induction of micronuclei by the bystander effect in non-irradiated cells. It is suggested that irradiated cells ceased signal formation for bystander effects by the action of DMSO. To determine the involvement of reactive oxygen species on the formation of bystander signals, we examined oxidative stress levels using the 2',7'-dichlorofluorescein (DCFH) staining method in irradiated populations. The results showed that the treatment of irradiated cells with 0.5% DMSO did not suppress oxidative stress levels. These results suggest that the prevention of oxidative stress is independent of the suppressive effect of DMSO on the formation of the bystander signal in irradiated cells. It is suggested that increased reactive oxygen species (ROS) in irradiated cells is not a substantial trigger of a bystander signal. (author)

  19. Individual Motivations and Characteristics Associated with Bystander Intervention during Bullying Episodes among Children and Youth

    Science.gov (United States)

    Cappadocia, M. Catherine; Pepler, Debra; Cummings, Joanne G.; Craig, Wendy

    2012-01-01

    The aim of the current study was to explore bystander experiences during bullying episodes among children and youth attending a residential summer camp by investigating rates of witnessing and intervention, as well as individual motivations and characteristics associated with bystander intervention. The majority of children had witnessed bullying…

  20. What Would You Do? Strategies for Bystander Intervention to Prevent Sexual Violence by College Students

    Science.gov (United States)

    McMahon, Sarah; Hoffman, Melanie Lowe; McMahon, Sheila M.; Zucker, Sharon; Koenick, Ruth Anne

    2013-01-01

    Bystander education is an increasingly utilized strategy for addressing sexual assault prevention and intervention on U.S. college campuses. Given the paramount importance of peers among college students, what types of pro-social bystander interventions do students themselves deem feasible in the campus context? Drawing on self-reports from…

  1. Action Research Evaluation of Bystander Intervention Training Created by Munche, Stern, and O'Brien

    Science.gov (United States)

    Shiflet, Jacqueline H.

    2013-01-01

    This qualitative, appreciative inquiry study was an examination of bystander intervention as related to sexual assault in the military. The purpose of the study was to examine how military personnel and Department of Defense civilian employees reflecting diverse backgrounds perceived the effectiveness of bystander intervention training and sexual…

  2. Roles of Fatalism and Parental Support in the Relationship between Bullying Victimization and Bystander Behaviors

    Science.gov (United States)

    Li, Yiqiong; Chen, Peter Y.; Chen, Fu-Li; Wu, Wen-Chi

    2015-01-01

    This article examines how past bullied victims engage two types of bystander behaviors (defender and outsider) when they witness bullying situations.We also investigate if fatalism mediates the relationship between past victimization and two bystander behaviors. Finally, we test if parental support moderates the relationship between fatalism and…

  3. Booze, Bars, and Bystander Behavior: People Who Consumed Alcohol Help Faster in the Presence of Others

    NARCIS (Netherlands)

    van Bommel, Marco; van Prooijen, Jan-Willem; Elffers, Henk; van Lange, Paul A.M.

    2016-01-01

    People help each other less often and less quickly when bystanders are present. In this paper, we propose that alcohol consumption could attenuate or reverse this so-called bystander effect. Alcohol impairs people cognitively and perceptually, leading them to think less about the presence of others

  4. Quality of bystander cardiopulmonary resuscitation during real-life out-of-hospital cardiac arrest

    DEFF Research Database (Denmark)

    Gyllenborg, Tore; Granfeldt, Asger; Lippert, Freddy

    2017-01-01

    BACKGROUND: Cardiopulmonary resuscitation (CPR) can increase survival in out-of-hospital cardiac arrest (OHCA). However, little is known about bystander CPR quality in real-life OHCA. AIM: To describe bystander CPR quality based on automated external defibrillator (AED) CPR process data during OH...

  5. On Standby? A Comparison of Online and Offline Witnesses to Bullying and Their Bystander Behaviour

    Science.gov (United States)

    Quirk, Roslynn; Campbell, Marilyn

    2015-01-01

    Given their ubiquitous presence as witnesses to school-yard bullying, the role of the "bystander" has been studied extensively. The prevalence and behaviour of bystanders to "cyberbullying," however, is less understood. In an anonymous, school-based questionnaire, 716 secondary school students from South-East Queensland…

  6. Debriefing bystanders of out-of-hospital cardiac arrest is valuable.

    Science.gov (United States)

    Møller, Thea Palsgaard; Hansen, Carolina Malta; Fjordholt, Martin; Pedersen, Birgitte Dahl; Østergaard, Doris; Lippert, Freddy K

    2014-11-01

    To explore the concept of debriefing bystanders after participating in an out-of-hospital cardiac arrest resuscitation attempt including (1) bystanders' most commonly addressed reactions after participating in a resuscitation attempt when receiving debriefing from medical dispatchers; (2) their perception of effects of receiving debriefing and (3) bystanders' recommendations for a systematic debriefing concept. Qualitative study based on telephone debriefing to bystanders and interviews with bystanders who received debriefing. Data was analyzed using the phenomenological approach. Six themes emerged from analysis of debriefing audio files: (1) identification of OHCA; (2) emotional and perceptual experience with OHCA; (3) collaboration with healthcare professionals; (4) patients outcome; (5) coping with the experience and (6) general reflections. When evaluating the concept, bystanders expressed positive short term effect of receiving debriefing and a retention of this effect after two months. Recommendations for a future debriefing concept were given. Debriefing by emergency medical dispatchers to OHCA bystanders stimulates reflection, positively influencing the ability to cope with the emotional reactions and the cognitive perception of own performance and motivates improvement of CPR skills. Importantly, it increases confidence to provide CPR in the future. Implementation of telephone debriefing to bystanders at Emergency Medical Dispatch Centres is a low complexity and a low cost intervention though the logistic challenges have to be considered. Copyright © 2014 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

  7. Metabolic aspects of pyrolysis mutagens in food

    International Nuclear Information System (INIS)

    Sato, S.; Negishi, C.; Umemoto, A.; Sugimura, T.

    1986-01-01

    The first step in metabolic activation of mutagenic and carcinogenic heterocyclic amines has been elucidated to be N-hydroxylation by cytochrome P-448. N-Hydroxyamino compounds are further activated to form N-O-acyl derivatives that readily react with DNA. The adducts between the metabolites of Trp-P-2 and Glu-P-1 and DNA were shown to have a C 8 -guanylamino structure. In the case of Glu-P-1, modification of guanine in GC clusters occurred preferentially. Glutathione transferases and myeloperoxidase were shown to inactivate some heterocyclic amines or their active metabolites. Hemin and fatty acids bind to and inactivate them. Fibers and other factors from vegetables also work to inactivate heterocyclic amines. Nitrite at low pH also degraded some heterocyclic amines, but those with an imidazole moiety were resistant. Glu-P-1 induced intestinal tumors in a high incidence when fed orally to rats. When 14 C-Glu-P-1 was administered by gavage into rats about 50% and 35% were excreted into feces and urine, respectively, within 24 hr. When the bile was collected, around 60% of radioactivity was excreted into it within 24 hr. In the bile, N-acetyl-Glu-P-1 was identified as one of the metabolites of Glu-P-1. It showed a mutagenic activity of about one fourth that of Glu-P-1 with S9 mix. Some radioactivity was also detected in the blood. At 24 hr after administration, most of the radioactivity was found to be bound to erythrocyte β-globins and serum proteins including albumin

  8. Induction of Abasic Sites by the Drinking-Water Mutagen MX in Salmonella TA100

    Science.gov (United States)

    Mutagen X (MX) is a chlorinated furanone that accounts for more of the mutagenic activity of drinking water than any other disinfection by-product. It is one of the most potent base-substitution mutagens in the Salmonella (Ames) mutagenicity assay, producing primarily GC to TA mu...

  9. Mutagenicity of anthraquinone and hydroxylated anthraquinones in the Ames/Salmonella microsome system.

    Science.gov (United States)

    Liberman, D F; Fink, R C; Schaefer, F L; Mulcahy, R J; Stark, A A

    1982-01-01

    The mutagenicity of anthracene, anthraquinone, and four structurally similar compounds of each was evaluated in the Ames/Salmonella microsome assay. Anthraquinone was shown to be mutagenic for strains TA1537, TA1538, and TA98 in the absence of rat liver homogenate. The four anthraquinone derivatives tested were mutagenic for TA1537 exclusively. None of the anthracenes exhibited mutagenic activity. PMID:7103489

  10. Mutagenicity of anthraquinone and hydroxylated anthraquinones in the Ames/Salmonella microsome system.

    OpenAIRE

    Liberman, D F; Fink, R C; Schaefer, F L; Mulcahy, R J; Stark, A A

    1982-01-01

    The mutagenicity of anthracene, anthraquinone, and four structurally similar compounds of each was evaluated in the Ames/Salmonella microsome assay. Anthraquinone was shown to be mutagenic for strains TA1537, TA1538, and TA98 in the absence of rat liver homogenate. The four anthraquinone derivatives tested were mutagenic for TA1537 exclusively. None of the anthracenes exhibited mutagenic activity.

  11. [Smoked sausages and food additives: evaluation of total mutagenic activity].

    Science.gov (United States)

    Dugan, A M; Tkacheva, D L

    2011-01-01

    The paper deals with the evaluation of the total mutagenic activity of samples of the inorganic and organic fractions of three technology smoked sausages (boiled-smoked, semi-smoked, and raw-smoked) and some food additives used to manufacture the above sausages. Their mild and moderate mutagenic effects were recorded in a Salmonella typhimurium bacterial test system with a metabolic activation system. Physicochemical analysis of the fractions of the smoked sausages has shown that their study samples are substantially contaminated with heavy metals and representatives of polycyclic aromatic hydrocarbons, partially causing the mutagenic effects observed.

  12. Mutagenicity in drug development: interpretation and significance of test results.

    Science.gov (United States)

    Clive, D

    1985-03-01

    The use of mutagenicity data has been proposed and widely accepted as a relatively fast and inexpensive means of predicting long-term risk to man (i.e., cancer in somatic cells, heritable mutations in germ cells). This view is based on the universal nature of the genetic material, the somatic mutation model of carcinogenesis, and a number of studies showing correlations between mutagenicity and carcinogenicity. An uncritical acceptance of this approach by some regulatory and industrial concerns is over-conservative, naive, and scientifically unjustifiable on a number of grounds: Human cancers are largely life-style related (e.g., cigarettes, diet, tanning). Mutagens (both natural and man-made) are far more prevalent in the environment than was originally assumed (e.g., the natural bases and nucleosides, protein pyrolysates, fluorescent lights, typewriter ribbon, red wine, diesel fuel exhausts, viruses, our own leukocytes). "False-positive" (relative to carcinogenicity) and "false-negative" mutagenicity results occur, often with rational explanations (e.g., high threshold, inappropriate metabolism, inadequate genetic endpoint), and thereby confound any straightforward interpretation of mutagenicity test results. Test battery composition affects both the proper identification of mutagens and, in many instances, the ability to make preliminary risk assessments. In vitro mutagenicity assays ignore whole animal protective mechanisms, may provide unphysiological metabolism, and may be either too sensitive (e.g., testing at orders-of-magnitude higher doses than can be ingested) or not sensitive enough (e.g., short-term treatments inadequately model chronic exposure in bioassay). Bacterial systems, particularly the Ames assay, cannot in principle detect chromosomal events which are involved in both carcinogenesis and germ line mutations in man. Some compounds induce only chromosomal events and little or no detectable single-gene events (e.g., acyclovir, caffeine

  13. A contribution to the study on the mutagenicity of atmospheres

    International Nuclear Information System (INIS)

    Blaise, Philipp

    1986-01-01

    Following a review of the literature, the genotoxic hazards of atmospheric pollutants at various locations (rural sites, motorway tolls, paint shops...) were evaluated by in vitro mutagenicity assays (Ames' test and SOS chromo-test) and analytical methods (gas chromatography and mass spectrometry). Instrumentation and procedures were developed for the sampling of volatile organic pollutants: adsorption on XAD 2 followed by acetone extraction of the compounds trapped. A comparative study allowed to assess the relative mutagenic action of the volatile organic compounds and to establish a mutagenicity scale. (author) [fr

  14. Liver irradiation causes distal bystander effects in the rat brain and affects animal behaviour.

    Science.gov (United States)

    Kovalchuk, Anna; Mychasiuk, Richelle; Muhammad, Arif; Hossain, Shakhawat; Ilnytskyy, Slava; Ghose, Abhijit; Kirkby, Charles; Ghasroddashti, Esmaeel; Kovalchuk, Olga; Kolb, Bryan

    2016-01-26

    Radiation therapy can not only produce effects on targeted organs, but can also influence shielded bystander organs, such as the brain in targeted liver irradiation. The brain is sensitive to radiation exposure, and irradiation causes significant neuro-cognitive deficits, including deficits in attention, concentration, memory, and executive and visuospatial functions. The mechanisms of their occurrence are not understood, although they may be related to the bystander effects.We analyzed the induction, mechanisms, and behavioural repercussions of bystander effects in the brain upon liver irradiation in a well-established rat model.Here, we show for the first time that bystander effects occur in the prefrontal cortex and hippocampus regions upon liver irradiation, where they manifest as altered gene expression and somewhat increased levels of γH2AX. We also report that bystander effects in the brain are associated with neuroanatomical and behavioural changes, and are more pronounced in females than in males.

  15. Getting angry matters: Going beyond perspective taking and empathic concern to understand bystanders' behavior in bullying.

    Science.gov (United States)

    Pozzoli, Tiziana; Gini, Gianluca; Thornberg, Robert

    2017-12-01

    The present study examined the relations between different empathic dimensions and bystanders' behavior in bullying. Specifically, the indirect effects of empathic concern and perspective taking via empathic anger on defending and passive bystanding were tested in a sample of Italian young adolescents (N = 398; M age  = 12 years, 3 months, 47.2% girls). Path analysis confirmed the direct and indirect effects, via empathic anger, of empathic concern and perspective taking on bystanders' behavior, with the exception of the direct association between perspective taking and passive bystanding that was not significant. Our findings suggest that considering empathic anger together with empathic concern and perspective taking could help researchers to better understand the links between empathic dispositions and bystanders' behavior in bullying. Copyright © 2017. Published by Elsevier Ltd.

  16. Mutagenic effectiveness and efficiency of gamma rays and ethyl methanesulhonate in Indian mustard

    International Nuclear Information System (INIS)

    Prasad, Rajendra; Singh, Basudeo

    1986-01-01

    Mutagenic effectiveness is a measure of the frequency of mutations induced by unit dose of a mutagen while mutagenic efficiency gives the proportion of mutations in relation to other associated undesirable biological effects such as gross chromosomal aberrations, lethality and sterility induced by the mutagen in question (Konzak, et al., 1965). The usefulness of any mutagen in plant breeding depends not only on its mutagenic effectiveness but also on its mutagenic efficiency. The efficiency and effectiveness of ethyl methanesulphonate (EMS) in relation to gamma rays in Indian mustard [Brassica juncea (L.) Czern and Coss] was studied. (author)

  17. Temporally distinct response of irradiated normal human fibroblasts and their bystander cells to energetic heavy ions

    International Nuclear Information System (INIS)

    Hamada, Nobuyuki; Ni, Meinan; Funayama, Tomoo; Sakashita, Tetsuya; Kobayashi, Yasuhiko

    2008-01-01

    Ionizing radiation-induced bystander effects have been documented for a multitude of endpoints such as mutations, chromosome aberrations and cell death, which arise in nonirradiated bystander cells having received signals from directly irradiated cells; however, energetic heavy ion-induced bystander response is incompletely characterized. To address this, we employed precise microbeams of carbon and neon ions for targeting only a very small fraction of cells in confluent fibroblast cultures. Conventional broadfield irradiation was conducted in parallel to see the effects in irradiated cells. Exposure of 0.00026% of cells led to nearly 10% reductions in the clonogenic survival and twofold rises in the apoptotic incidence regardless of ion species. Whilst apoptotic frequency increased with time up to 72 h postirradiation in irradiated cells, its frequency escalated up to 24 h postirradiation but declined at 48 h postirradiation in bystander cells, indicating that bystander cells exhibit transient commitment to apoptosis. Carbon- and neon-ion microbeam irradiation similarly caused almost twofold increments in the levels of serine 15-phosphorylated p53 proteins, irrespective of whether 0.00026, 0.0013 or 0.0066% of cells were targeted. Whereas the levels of phosphorylated p53 were elevated and remained unchanged at 2 h and 6 h postirradiation in irradiated cells, its levels rose at 6 h postirradiation but not at 2 h postirradiation in bystander cells, suggesting that bystander cells manifest delayed p53 phosphorylation. Collectively, our results indicate that heavy ions inactivate clonogenic potential of bystander cells, and that the time course of the response to heavy ions differs between irradiated and bystander cells. These induced bystander responses could be a defensive mechanism that minimizes further expansion of aberrant cells

  18. A Role for Bioelectric Effects in the Induction of Bystander Signals by Ionizing Radiation?

    Science.gov (United States)

    Mothersill, C.; Moran, G.; McNeill, F.; Gow, M.D.; Denbeigh, J.; Prestwich, W.; Seymour, C.B.

    2007-01-01

    The induction of “bystander effects” i.e. effects in cells which have not received an ionizing radiation track, is now accepted but the mechanisms are not completely clear. Bystander effects following high and low LET radiation exposure are accepted but mechanisms are still not understood. There is some evidence for a physical component to the signal. This paper tests the hypothesis that bioelectric or biomagnetic phenomena are involved. Human immortalized skin keratinocytes and primary explants of mouse bladder and fish skin, were exposed directly to ionizing radiation or treated in a variety of bystander protocols. Exposure of cells was conducted by shielding one group of flasks using lead, to reduce the dose below the threshold of 2mGy 60Cobalt gamma rays established for the bystander effect. The endpoint for the bystander effect in the reporter system used was reduction in cloning efficiency (RCE). The magnitude of the RCE was similar in shielded and unshielded flasks. When cells were placed in a Faraday cage the magnitude of the RCE was less but not eliminated. The results suggest that liquid media or cell-cell contact transmission of bystander factors may be only part of the bystander mechanism. Bioelectric or bio magnetic fields may have a role to play. To test this further, cells were placed in a Magnetic Resonance Imaging (MRI) machine for 10min using a typical head scan protocol. This treatment also induced a bystander response. Apart from the obvious clinical relevance, the MRI results further suggest that bystander effects may be produced by non-ionizing exposures. It is concluded that bioelectric or magnetic effects may be involved in producing bystander signaling cascades commonly seen following ionizing radiation exposure. PMID:18648606

  19. Lay Bystanders' Perspectives on What Facilitates Cardiopulmonary Resuscitation and Use of Automated External Defibrillators in Real Cardiac Arrests

    DEFF Research Database (Denmark)

    Malta Hansen, Carolina; Rosenkranz, Simone Mørk; Folke, Fredrik

    2017-01-01

    factors encourage lay bystanders to initiate CPR and AED use in a cohort of bystanders previously trained in CPR techniques who were present at an out-of-hospital cardiac arrest. METHODS AND RESULTS: One-hundred and twenty-eight semistructured qualitative interviews with CPR-trained lay bystanders...... obligation to act. CONCLUSIONS: Several factors other than previous hands-on CPR training facilitate lay bystander instigation of CPR and AED use. The recognition and modification of these factors may increase lay bystander CPR rates and patient survival following an out-of-hospital cardiac arrest....

  20. Mechanism of protection of bystander cells by exogenous carbon monoxide: Impaired response to damage signal of radiation-induced bystander effect

    International Nuclear Information System (INIS)

    Han, W.; Yu, K.N.; Wu, L.J.; Wu, Y.C.; Wang, H.Z.

    2011-01-01

    A protective effect of exogenous carbon monoxide (CO), generated by CO releasing molecule ticarbonyldichlororuthenium (II) dimer (CORM-2), on the bystander cells from the toxicity of radiation-induced bystander effect (RIBE) was revealed in our previous study. In the present work, a possible mechanism of this CO effect was investigated. The results from medium transfer experiments showed that α-particle irradiated Chinese hamster ovary (CHO) cells would release nitric oxide (NO), which was detected with specific NO fluorescence probe, to induce p53 binding protein 1 (BP1) formation in the cell population receiving the medium, and the release peak was found to be at 1 h post irradiation. Treating the irradiated or bystander cells separately with CO (CORM-2) demonstrated that CO was effective in the bystander cells but not the irradiated cells. Measurements of NO production and release with a specific NO fluorescence probe also showed that CO treatment did not affect the production and release of NO by irradiated cells. Protection of CO on cells to peroxynitrite, an oxidizing free radical from NO, suggested that CO might protect bystander cells via impaired response of bystander cells to NO, a RIBE signal in our research system.

  1. Mechanism of protection of bystander cells by exogenous carbon monoxide: Impaired response to damage signal of radiation-induced bystander effect

    Energy Technology Data Exchange (ETDEWEB)

    Han, W. [Department of Physics and Materials Science, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon Tong, Kowloon (Hong Kong); Center of Medical Physics and Technology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031 (China); Yu, K.N., E-mail: peter.yu@cityu.edu.hk [Department of Physics and Materials Science, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon Tong, Kowloon (Hong Kong); Wu, L.J. [Center of Medical Physics and Technology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031 (China); Wu, Y.C. [Center of Medical Physics and Technology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031 (China); School of Nuclear Science and Technology, University of Science and Technology of China, Hefei 230029 (China); Wang, H.Z. [Center of Medical Physics and Technology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031 (China)

    2011-05-10

    A protective effect of exogenous carbon monoxide (CO), generated by CO releasing molecule ticarbonyldichlororuthenium (II) dimer (CORM-2), on the bystander cells from the toxicity of radiation-induced bystander effect (RIBE) was revealed in our previous study. In the present work, a possible mechanism of this CO effect was investigated. The results from medium transfer experiments showed that {alpha}-particle irradiated Chinese hamster ovary (CHO) cells would release nitric oxide (NO), which was detected with specific NO fluorescence probe, to induce p53 binding protein 1 (BP1) formation in the cell population receiving the medium, and the release peak was found to be at 1 h post irradiation. Treating the irradiated or bystander cells separately with CO (CORM-2) demonstrated that CO was effective in the bystander cells but not the irradiated cells. Measurements of NO production and release with a specific NO fluorescence probe also showed that CO treatment did not affect the production and release of NO by irradiated cells. Protection of CO on cells to peroxynitrite, an oxidizing free radical from NO, suggested that CO might protect bystander cells via impaired response of bystander cells to NO, a RIBE signal in our research system.

  2. Nonmutagenicity of betel leaf and its antimutagenic action against environmental mutagens.

    Science.gov (United States)

    Nagabhushan, M; Amonkar, A J; D'Souza, A V; Bhide, S V

    1987-01-01

    Betel leaf (Piper betel) water and acetone extract are nonmutagenic in S. typhimurium strains with and without S9 mix. Both the extracts suppress the mutagenicity of betel quid mutagens in a dose dependent manner. Moreover both the extracts of betel leaf reduce the mutagenicity of benzo(a)pyrene and dimethylbenzanthracene. Acetone extract is more potent than water extract in inhibiting mutagenicity of environmental mutagens.

  3. Mutagenicity of pan residues and gravy from fried meat.

    Science.gov (United States)

    Overvik, E; Nilsson, L; Fredholm, L; Levin, O; Nord, C E; Gustafsson, J A

    1987-02-01

    Lean pork meat was fried with or without the addition of frying-fat at 200 or 250 degrees C. The pan residues were collected by washing the hot pan with boiling water. When producing thickened gravy the water was substituted by a mixture of water and flour, milk and flour or cream and flour. The basic extracts were tested for mutagenicity in Ames' Salmonella test on strain TA98 with the addition of S9 mix. High amounts of mutagenicity were found in all samples. The amounts of mutagenicity in the pan residues were at a comparable level of the amounts found in the meat crusts. Thickening of the gravy caused only small changes in the mutagenicity.

  4. Effectiveness and efficiency of certain mutagens in Linum usitatissimum L

    International Nuclear Information System (INIS)

    Lateef, M.A.; Nizam, J.

    1985-01-01

    The effectiveness and efficiency of gamma rays, hydrazine, hydroxylamine, ethylmethane sulphonate and mitomycin-C. mutagens were studied on the basis of chlorophyll mutations in Linum usitatissimum L. (author)

  5. Expert advice in case of exposure to mutagens or teratogens

    International Nuclear Information System (INIS)

    Steuber, E.D.

    1982-01-01

    To answer the question of any induced hazards in progeny by an exogeneous factor it is necessary to differentiate between mutagenic and teratogenic action. Mutations can be caused by ionisizing radiations and chemicals, e.g. cytostatic drugs. After exposure to mutagenic agents a conception should be prevented for a time of 3 months to avoid a fertilization of a germ cell that has been effected during a very sensible phase. In case of conception during mutagenic exposure it is possible to detect chromosome aberrations by prenatal diagnosis after amniocentesis. The spectrum of possible teratogens is extensive and less specific than that of mutagenic agents. Factors established as embryotoxic in man are for instance radiation, several drugs and some virus infections. They have been known to cause malformations in the fetus, if these events take place during a certain critical period of organogenesis. (orig.) [de

  6. Cytological effects of some new mutagens on rice

    International Nuclear Information System (INIS)

    Wang Cailian; Chen Qiufang; Jin Wei

    2002-01-01

    Air-dried seeds of five rice varieties were carried by recoverable satellite (RS) for space mutation and were irradiated by synchronous irradiation (soft X-rays), protons and nitrogen ions. The cytological effects were compared with that of γ-irradiation. The results indicated that all the mutagens were able to induce variation on chromosome structure in root tip cells. The space environment had a stimulating mitotic effect on root tip cells. Other mutagens had inhibiting mitotic actions. The rates of micronuclei induced by synchronous irradiation and other mutagens were higher than that by γ-rays; and the rates of chromosomal bridge were lower. Furthermore, the radiosensitivity of five varieties varied with different mutagens

  7. How stable are the mutagenic tautomers of DNA bases?

    Directory of Open Access Journals (Sweden)

    Brovarets’ O. O.

    2010-02-01

    Full Text Available Aim. To determine the lifetime of the mutagenic tautomers of DNA base pairs through the investigation of the physicochemical mechanisms of their intramolecular proton transfer. Methods. Non-empirical quantum chemistry, the analysis of the electron density by means of Bader’s atom in molecules (AIM theory and physicochemical kinetics were used. Results. Physicochemical character of the transition state of the intramolecular tautomerisation of DNA bases was investigated, the lifetime of mutagenic tautomers was calculated. Conclusions. The lifetime of the DNA bases mutagenic tautomers by 3–10 orders exceeds typical time of DNA replication in the cell (~103 s. This fact confirms that the postulate, on which the Watson-Crick tautomeric hypothesis of spontaneous transitions grounds, is adequate. The absence of intramolecular H-bonds in the canonical and mutagenic tautomeric forms determine their high stability

  8. Study of Salmonella typhimurium mutagenicity assay of (E ...

    African Journals Online (AJOL)

    Study of Salmonella typhimurium mutagenicity assay of (E)-piplartine by the Ames test. AA Morandim-Giannetti, F Cotinguiba, LO Regasini, MC Frigieri, EA Varanda, A Coqueiro, MJ Kato, VS Bolzani, M Furlan ...

  9. Effect of mutagen combined action on Chlamydomonas Reinhardtii cells. I

    International Nuclear Information System (INIS)

    Vlcek, D.; Podstavkova, S.; Dubovsky, J.

    1978-01-01

    The effect was investigated of single and combined actions of alkylnitrosourea derivatives (N-methyl-N-nitrosourea and N-ethyl-N-nitrosourea) and UV-radiation on the survival of cells of Chlamydomonas reinhardtii algae in dependence on the sequence of application of mutagens and on the given conditions of cultivation following mutagen activity. In particular, the single phases were investigated of the total lethal effect, i.e., the death of cells before division and their death after division. The most pronounced changes in dependence on the sequence of application of mutagens and on the given conditions of cultivation were noted in cell death before division. In dependence on the sequence of application of mutagens, the effect of the combined action on the survival of cells changed from an additive (alkylnitrosourea + UV-radiation) to a protective effect (UV-radiation + alkylnitrosourea). (author)

  10. In vitro evaluation of mutagenicity and genotoxicity of sitagliptin ...

    African Journals Online (AJOL)

    Keywords: Sitagliptin, Artificial sweeteners, Comet assay, DNA damage, Ames assay, Genotoxicity,. Mutagenicity. Tropical Journal of Pharmaceutical Research is indexed by Science Citation Index (SciSearch), Scopus,. International Pharmaceutical Abstract, Chemical Abstracts, Embase, Index Copernicus, EBSCO, African.

  11. Response to Commentaries on Bystander Training as Leadership Training.

    Science.gov (United States)

    Katz, Jackson

    2018-03-01

    In this article, the author responds to three commentaries about his article "Bystander Training as Leadership Training: Notes on the Origins, Philosophy, and Pedagogy of the Mentors in Violence Prevention Model," published in this volume. Topics covered in the commentaries and response include questions about evaluation and evidence for program effectiveness; the necessity for gender violence prevention education to be gender transformative and part of a comprehensive, multilevel prevention approach, especially for adolescents; and the degree to which Mentors in Violence Prevention (MVP), as a "social justice"-oriented program, incorporates intersectional and anti-oppression frameworks and perspectives.

  12. Helminthiasis, bystander diseases and vaccines: analysis of interaction.

    Science.gov (United States)

    Markus, Miles B; Fincham, John E

    2007-11-01

    Helminthiasis has assumed a new medical and veterinary significance following the recognition of its immunomodulatory consequences for the severity of bystander conditions and the efficacy of immunization against non-helminthic diseases of humans and livestock. Recent papers by Jackson et al. and Turner et al. have an important bearing on research in these areas. One of the implications of their work is that the parasitological criterion of egg-positivity versus egg-negativity is too simplistic to use in co-infection and related studies unless accompanied by immunological analysis.

  13. The effect of Aspergillus niger mutagenization on citric acid biosynthesis

    Directory of Open Access Journals (Sweden)

    Stanisław Walisch

    2014-08-01

    Full Text Available The industrial A. niger strain producing citric acid was mutagenized with the use of new chemical mutagens: free nitroxyl radicals. Strains of higher citric acid production yield were obtained. Citric acid was produced in a shorter time compared to the initial strain. During 6-12 months of storage most of the strains preserved their positive features which proves that mutants with profitable biotechnological properties were obtained. These mutants are used in industrial process.

  14. Mutagenicity of Flavonoids Assayed by Bacterial Reverse Mutation (Ames Test

    Directory of Open Access Journals (Sweden)

    Eliana Aparecida Varanda

    2012-05-01

    Full Text Available The mutagenicity of ten flavonoids was assayed by the Ames test, in Salmonella typhimurium strains TA98, TA100 and TA102, with the aim of establishing hydroxylation pattern-mutagenicity relationship profiles. The compounds assessed were: quercetin, kaempferol, luteolin, fisetin, chrysin, galangin, flavone, 3-hydroxyflavone, 5-hydroxyflavone and 7-hydroxyflavone. In the Ames assay, quercetin acted directly and its mutagenicity increased with metabolic activation. In the presence of S9 mix, kaempferol and galangin were mutagenic in the TA98 strain and kaempferol showed signs of mutagenicity in the other strains. The absence of hydroxyl groups, as in flavone, only signs of mutagenicity were shown in strain TA102, after metabolization and, among monohydroxylated flavones (3-hydroxyflavone, 5-hydroxyflavone and 7-hydroxyflavone, the presence of hydroxyl groups only resulted in minor changes. Luteolin and fisetin also showed signs of mutagenicity in strain TA102. Finally, chrysin, which has only two hydroxy groups, at the 5-OH and 7-OH positions, also did not induce mutagenic activity in any of the bacterial strains used, under either activation condition. All the flavonoids were tested at concentrations varying from 2.6 to 30.7 nmol/plate for galangin and 12.1 to 225.0 nmol/plate for other flavonoids. In light of the above, it is necessary to clarify the conditions and the mechanisms that mediate the biological effects of flavonoids before treating them as therapeutical agents, since some compounds can be biotransformed into more genotoxic products; as is the case for galangin, kaempferol and quercetin.

  15. Mutagenicity of comfrey (Symphytum Officinale) in rat liver

    OpenAIRE

    Mei, N; Guo, L; Fu, P P; Heflich, R H; Chen, T

    2005-01-01

    Comfrey is a rat liver toxin and carcinogen that has been used as a vegetable and herbal remedy by humans. In order to evaluate the mechanisms underlying its carcinogenicity, we examined the mutagenicity of comfrey in the transgenic Big Blue rat model. Our results indicate that comfrey is mutagenic in rat liver and the types of mutations induced by comfrey suggest that its tumorigenicity results from the genotoxicity of pyrrolizidine alkaloids in the plant.

  16. Mutagenicity of comfrey (Symphytum Officinale) in rat liver.

    Science.gov (United States)

    Mei, N; Guo, L; Fu, P P; Heflich, R H; Chen, T

    2005-03-14

    Comfrey is a rat liver toxin and carcinogen that has been used as a vegetable and herbal remedy by humans. In order to evaluate the mechanisms underlying its carcinogenicity, we examined the mutagenicity of comfrey in the transgenic Big Blue rat model. Our results indicate that comfrey is mutagenic in rat liver and the types of mutations induced by comfrey suggest that its tumorigenicity results from the genotoxicity of pyrrolizidine alkaloids in the plant.

  17. Study of anti mutagenic and mutagenic effect of different chemicals on clinically isolated strains of pseudomonas aeruginosa

    International Nuclear Information System (INIS)

    Qureshi, A.M.; Durrani, F.; Janjua, M.

    1994-01-01

    This project was undertaken to study the effect of twelve different compounds to test their anti mutagenic and mutagenic activity against clinically isolated strains of Pseudomonas aeruginosa. The effect of these compounds was estimated by counting the number of rifampicin resistant colonies growing in a particular time in a compound. The results were interpreted by plotting graphs between 10g N/NO (Rif R Colonies/ ml) and time to estimate the forward mutation rat. The results revealed that acridine, Basic fuchsin, Caffeine, cycloheximide, Ethidium bromide and Histidine probably have an anti mutagenic effect, while Cysteine, folic acid, Ethyl methane, suplphonate, Manganous Chloride and N-nitrosodietylamine acted as mutagen. Ecoli was used as control through out the study. (author)

  18. What role for DNA damage and repair in the bystander response?

    International Nuclear Information System (INIS)

    Prise, Kevin M.; Folkard, Melvyn; Kuosaite, Virginija; Tartier, Laurence; Zyuzikov, Nikolai; Shao, Chunlin

    2006-01-01

    The radiation-induced bystander effect challenges the accepted paradigm of direct DNA damage in response to energy deposition driving the biological consequences of radiation exposure. With the bystander response, cells which have not been directly exposed to radiation respond to their neighbours being targeted. In our own studies we have used novel targeted microbeam approaches to specifically irradiate parts of individual cells within a population to quantify the bystander response and obtain mechanistic information. Using this approach it has become clear that energy deposited by radiation in nuclear DNA is not required to trigger the effect, with cytoplasmic irradiation required. Irradiated cells also trigger a bystander response regardless of whether they themselves live or die, suggesting that the phenotype of the targeted cell is not a determining factor. Despite this however, a range of evidence has shown that repair status is important for dealing with the consequences of a bystander signal. Importantly, repair processes involved in the processing of dsb appear to be involved suggesting that the bystander response involves the delayed or indirect production of dsb-type lesions in bystander cells. Whether these are infact true dsb or complexes of oxidised bases in combination with strand breaks and the mechanisms for their formation, remains to be elucidated

  19. The development of bystander intentions and social-moral reasoning about intergroup verbal aggression.

    Science.gov (United States)

    Palmer, Sally B; Rutland, Adam; Cameron, Lindsey

    2015-11-01

    A developmental intergroup approach was taken to examine the development of prosocial bystander intentions among children and adolescents. Participants as bystanders (N = 260) aged 8-10 and 13-15 years were presented with scenarios of direct aggression between individuals from different social groups (i.e., intergroup verbal aggression). These situations involved either an ingroup aggressor and an outgroup victim or an outgroup aggressor and an ingroup victim. This study focussed on the role of intergroup factors (group membership, ingroup identification, group norms, and social-moral reasoning) in the development of prosocial bystander intentions. Findings showed that prosocial bystander intentions declined with age. This effect was partially mediated by the ingroup norm to intervene and perceived severity of the verbal aggression. However, a moderated mediation analysis showed that only when the victim was an ingroup member and the aggressor an outgroup member did participants become more likely with age to report prosocial bystander intentions due to increased ingroup identification. Results also showed that younger children focussed on moral concerns and adolescents focussed more on psychological concerns when reasoning about their bystander intention. These novel findings help explain the developmental decline in prosocial bystander intentions from middle childhood into early adolescence when observing direct intergroup aggression. © 2015 The British Psychological Society.

  20. Exosome-mediated microRNA transfer plays a role in radiation-induced bystander effect.

    Science.gov (United States)

    Xu, Shuai; Wang, Jufang; Ding, Nan; Hu, Wentao; Zhang, Xurui; Wang, Bing; Hua, Junrui; Wei, Wenjun; Zhu, Qiyun

    2015-01-01

    Bystander effects can be induced through cellular communication between irradiated cells and non-irradiated cells. The signals that mediate this cellular communication, such as cytokines, reactive oxygen species, nitric oxide and even microRNAs, can be transferred between cells via gap junctions or extracellular medium. We have previously reported that miR-21, a well described DDR (DNA damage response) microRNA, is involved in radiation-induced bystander effects through a medium-mediated way. However, the mechanisms of the microRNA transfer have not been elucidated in details. In the present study, it was found that exosomes isolated from irradiated conditioned medium could induce bystander effects. Furthermore, we demonstrated plenty of evidences that miR-21, which is up-regulated as a result of mimic transfection or irradiation, can be transferred from donor or irradiated cells into extracellular medium and subsequently get access to the recipient or bystander cells through exosomes to induce bystander effects. Inhibiting the miR-21 expression in advance can offset the bystander effects to some extent. From all of these results, it can be concluded that the exosome-mediated microRNA transfer plays an important role in the radiation-induced bystander effects. These findings provide new insights into the functions of microRNAs and the cellular communication between the directly irradiated cells and the non-irradiated cells.

  1. New aspects of studies on stress response. Radiation-induced bystander effect

    International Nuclear Information System (INIS)

    Matsumoto, Hideki; Hayashi, Sachiko; Jin, Zhao-Hui; Hatashita, Masanori; Kano, Eiichi

    2001-01-01

    This review describes the bystander effect which is the secondary stress response induced by the primary target affected by radiation and other environmental factors. The bystander effect can be exerted from the primary target cells through the gap junction, through interaction between ligands and receptors, through interaction between secreted bystander factors and receptors and through secreted bystander factors. Through the first, the typical one firstly shown in AG1521 cells is that, despite the pass of only 2% of irradiated α-particles through the target cell nucleus, much more cells respond to express p53 and p21/WAF1. Through the second, the Fas/Fas ligand in the target induce apoptosis of the non-target cells. As for the third, participation of cytokines and growth factors is suggested. Many investigations concern the fourth of bystander effects by the bystander factors: e.g., authors have studied the effects of X-ray, carbon beam or hyperthermia on nitric oxide synthase induction in A-172 cells. Studies of bystander effects possibly extend the concept of radiation biology. (K.H.)

  2. TakeCARE, a Video to Promote Bystander Behavior on College Campuses: Replication and Extension.

    Science.gov (United States)

    Jouriles, Ernest N; Sargent, Kelli S; Salis, Katie Lee; Caiozzo, Christina; Rosenfield, David; Cascardi, Michele; Grych, John H; O'Leary, K Daniel; McDonald, Renee

    2017-08-01

    Previous research has demonstrated that college students who view TakeCARE, a video bystander program designed to encourage students to take action to prevent sexual and relationship violence (i.e., bystander behavior), display more bystander behavior relative to students who view a control video. The current study aimed to replicate and extend these findings by testing two different methods of administering TakeCARE and examining moderators of TakeCARE's effects on bystander behavior. Students at four universities ( n = 557) were randomly assigned to one of three conditions: (a) view TakeCARE in a monitored computer lab, (b) view TakeCARE at their own convenience after receiving an email link to the video, or (c) view a video about study skills (control group). Participants completed measures of bystander behavior at baseline and at a 1-month follow-up. Participants in both TakeCARE conditions reported more bystander behavior at follow-up assessments, compared with participants in the control condition. The beneficial effect of TakeCARE did not differ significantly across administration methods. However, the effects of TakeCARE on bystander behavior were moderated by students' perceptions of campus responsiveness to sexual violence, with more potent effects when students perceived their institution as responsive to reports of sexual violence.

  3. The effect of melanin on the bystander effect in human keratinocytes

    Energy Technology Data Exchange (ETDEWEB)

    Mosse, I. [Institute of Genetics and Cytology of the National Academy of Sciences, Academicheskaya Str. 27, Minsk (Belarus)]. E-mail: i.mosse@igc.bas-net.by; Marozik, P. [Institute of Genetics and Cytology of the National Academy of Sciences, Academicheskaya Str. 27, Minsk (Belarus); Radiation and Environmental Science Centre, DIT, Dublin 8 (Ireland); Seymour, C. [Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, Ont. (Canada); Mothersill, C. [Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, Ont. (Canada)

    2006-05-11

    The influence of melanin on radiation-induced bystander effects has been studied. Melanin is known to be a natural substance with proved radioprotective properties in different organisms and cell lines. It is non-toxic and is effective against acute and chronic irradiation. The lower the radiation dose, the higher the relative impact of melanin protection. In this study influence of melanin on human keratinocytes (HPV-G cells) has been studied using the colony-forming assay. We have shown that bystander donor medium from 0.5 Gy irradiated cells when transferred to unirradiated cells, caused almost the same effect as direct irradiation. Melanin increased the colony-forming ability of bystander recipient cells when it was added into culture medium before irradiation. The effect of melanin added after irradiation was to produce less protection in both the directly irradiated and bystander medium treated groups. The absorption spectrum of the filtered medium is identical to one of the intact culture medium showing that melanin was not present in filtered medium. Thus, it cannot protect recipient cells but reduces the amount of the bystander effect. It is concluded that melanin added before irradiation effectively decreased the radiation dose. The reduction of the impact of the bystander signal on recipient cells when melanin was added to the donor medium after harvest but before filtration, may mean that the bystander signal has a physical component as melanin can absorb all types of physical energy.

  4. Intercellular and intracellular signaling pathways mediating ionizing radiation-induced bystander effects

    International Nuclear Information System (INIS)

    Hamada, Nobuyuki; Hara, Takamitsu; Kobayashi, Yasuhiko; Matsumoto, Hideki

    2007-01-01

    A rapidly growing body of experimental evidence indicates that ionizing radiation induces biological effects in non-irradiated bystander cells that have received signals from adjacent or distant irradiated cells. This phenomenon, which has been termed the ionizing radiation-induced bystander effect, challenges the long-standing paradigm that radiation traversal through the nucleus of a cell is a prerequisite to elicit genetic damage or a biological response. Bystander effects have been observed in a number of experimental systems, and cells whose nucleus or cytoplasm is irradiated exert bystander responses. Bystander cells manifest a multitude of biological consequences, such as genetic and epigenetic changes, alterations in gene expression, activation of signal transduction pathways, and delayed effects in their progeny. Several mediating mechanisms have been proposed. These involve gap junction-mediated intercellular communication, secreted soluble factors, oxidative metabolism, plasma membrane-bound lipid rafts, and calcium fluxes. This paper reviews briefly the current knowledge of the bystander effect with a focus on proposed mechanisms. The potential benefit of bystander effects to cancer radiotherapy will also be discussed. (author)

  5. The effect of melanin on the bystander effect in human keratinocytes

    International Nuclear Information System (INIS)

    Mosse, I.; Marozik, P.; Seymour, C.; Mothersill, C.

    2006-01-01

    The influence of melanin on radiation-induced bystander effects has been studied. Melanin is known to be a natural substance with proved radioprotective properties in different organisms and cell lines. It is non-toxic and is effective against acute and chronic irradiation. The lower the radiation dose, the higher the relative impact of melanin protection. In this study influence of melanin on human keratinocytes (HPV-G cells) has been studied using the colony-forming assay. We have shown that bystander donor medium from 0.5 Gy irradiated cells when transferred to unirradiated cells, caused almost the same effect as direct irradiation. Melanin increased the colony-forming ability of bystander recipient cells when it was added into culture medium before irradiation. The effect of melanin added after irradiation was to produce less protection in both the directly irradiated and bystander medium treated groups. The absorption spectrum of the filtered medium is identical to one of the intact culture medium showing that melanin was not present in filtered medium. Thus, it cannot protect recipient cells but reduces the amount of the bystander effect. It is concluded that melanin added before irradiation effectively decreased the radiation dose. The reduction of the impact of the bystander signal on recipient cells when melanin was added to the donor medium after harvest but before filtration, may mean that the bystander signal has a physical component as melanin can absorb all types of physical energy

  6. Bystanders intervene to impede grooming in Western chimpanzees and sooty mangabeys

    Science.gov (United States)

    Samuni, Liran; Preis, Anna; Wittig, Roman M.

    2017-01-01

    Grooming interactions benefit groomers, but may have negative consequences for bystanders. Grooming limits bystanders' grooming access and ensuing alliances could threaten the bystander's hierarchy rank or their previous investment in the groomers. To gain a competitive advantage, bystanders could intervene into a grooming bout to increase their own grooming access or to prevent the negative impact of others' grooming. We tested the impact of dominance rank and social relationships on grooming intervention likelihood and outcome in two sympatric primate species, Western chimpanzees (Pan troglodytes verus) and sooty mangabeys (Cercocebus atys atys). In both species, rather than increasing their own access to preferred partners, bystanders intervened mainly when an alliance between groomers could have a negative impact on them: when the lower-ranking groomer was close to the bystander in rank, when either groomer was an affiliation partner whose services they could lose, or the groomers were not yet strongly affiliated with each other. Thus, bystanders in both species appear to monitor grooming interactions and intervene based on their own dominance rank and social relationships, as well as triadic awareness of the relationship between groomers. While the motivation to intervene did not differ between species, mangabeys appeared to be more constrained by dominance rank than chimpanzees. PMID:29291114

  7. Human mutagens: evidence from paternal exposure

    International Nuclear Information System (INIS)

    Narod, S.A.; Douglas, G.R.; Nestmann, E.R.; Blakey, D.H.

    1988-01-01

    The importance of inherited mutations as a cause of human disease has been established clearly through examples of well-defined genetic anomalies, such as Down syndrome and retinoblastoma. Furthermore, it is suspected that environmental contaminants induce mutations resulting in increased risk for such defects in subsequent generations of persons exposed. The present lack of direct evidence for induced inherited genetic disorders in human beings hampers the development of risk estimation techniques for extrapolation from animal models. The most extensive prospective epidemiologic studies of inherited genetic effects have involved survivors of atomic bomb detonations and patients treated with cancer chemotherapy. In neither case has a significant elevation in inherited genetic effects or cancer been detected in the offspring of exposed individuals. Epidemiologic studies of subjects receiving chronic exposure may be confounded by the effect of maternal exposure during pregnancy. Consideration of only paternal exposure can minimize the confounding influence of teratogenicity, enhancing the resolving power of studies for inherited effects. Using this approach, retrospective (case-control) studies of childhood cancer patients have provided limited but suggestive evidence for inheritance of induced effects. Endpoints, such as congenital malformations and spontaneous abortion following paternal exposure, can also be considered as indicators of heritable mutagenic effects. For example, there is limited evidence suggesting that paternal exposure to anaesthetic gases may cause miscarriage and congenital abnormalities as a result of induced male germ cell mutations. 104 references

  8. Association of Bystander Interventions With Neurologically Intact Survival Among Patients With Bystander-Witnessed Out-of-Hospital Cardiac Arrest in Japan.

    Science.gov (United States)

    Nakahara, Shinji; Tomio, Jun; Ichikawa, Masao; Nakamura, Fumiaki; Nishida, Masamichi; Takahashi, Hideto; Morimura, Naoto; Sakamoto, Tetsuya

    2015-07-21

    Neurologically intact survival after out-of-hospital cardiac arrest (OHCA) has been increasing in Japan. However, associations between increased prehospital care, including bystander interventions and increases in survival, have not been well estimated. To estimate the associations between bystander interventions and changes in neurologically intact survival among patients with OHCA in Japan. Retrospective descriptive study using data from Japan's nationwide OHCA registry, which started in January 2005. The registry includes all patients with OHCA transported to the hospital by emergency medical services (EMS) and recorded patients' characteristics, prehospital interventions, and outcomes. Participants were 167,912 patients with bystander-witnessed OHCA of presumed cardiac origin in the registry between January 2005 and December 2012. Prehospital interventions by bystander, including defibrillation using public-access automated external defibrillators and chest compression. Neurologically intact survival was defined as Glasgow-Pittsburgh cerebral performance category score 1 or 2 and overall performance category scores 1 or 2 at 1 month or at discharge. The association between the interventions and neurologically intact survival was evaluated. From 2005 to 2012, the number of bystander-witnessed OHCAs of presumed cardiac origin increased from 17,882 (14.0 per 100,000 persons [95% CI, 13.8-14.2]) to 23,797 (18.7 per 100,000 persons [95% CI, 18.4-18.9]), and neurologically intact survival increased from 587 cases (age-adjusted proportion, 3.3% [95% CI, 3.0%-3.5%]) to 1710 cases (8.2% [95% CI, 7.8%-8.6%]). The rates of bystander chest compression increased from 38.6% to 50.9%, bystander-only defibrillation increased from 0.1% to 2.3%, bystander defibrillation combined with EMS defibrillation increased from 0.1% to 1.4%, and EMS-only defibrillation decreased from 26.6% to 23.5%. Performance of bystander chest compression, compared with no bystander chest compression

  9. Rescue Effects: Irradiated Cells Helped by Unirradiated Bystander Cells

    Science.gov (United States)

    Lam, R. K. K.; Fung, Y. K.; Han, W.; Yu, K. N.

    2015-01-01

    The rescue effect describes the phenomenon where irradiated cells or organisms derive benefits from the feedback signals sent from the bystander unirradiated cells or organisms. An example of the benefit is the mitigation of radiation-induced DNA damages in the irradiated cells. The rescue effect can compromise the efficacy of radioimmunotherapy (RIT) (and actually all radiotherapy). In this paper, the discovery and subsequent confirmation studies on the rescue effect were reviewed. The mechanisms and the chemical messengers responsible for the rescue effect studied to date were summarized. The rescue effect between irradiated and bystander unirradiated zebrafish embryos in vivo sharing the same medium was also described. In the discussion section, the mechanism proposed for the rescue effect involving activation of the nuclear factor κB (NF-κB) pathway was scrutinized. This mechanism could explain the promotion of cellular survival and correct repair of DNA damage, dependence on cyclic adenosine monophosphate (cAMP) and modulation of intracellular reactive oxygen species (ROS) level in irradiated cells. Exploitation of the NF-κB pathway to improve the effectiveness of RIT was proposed. Finally, the possibility of using zebrafish embryos as the model to study the efficacy of RIT in treating solid tumors was also discussed. PMID:25625514

  10. X-ray-induced bystander response reduce spontaneous mutations in V79 cells

    International Nuclear Information System (INIS)

    Maeda, Munetoshi; Kobayashi, Katsumi; Matsumoto, Hideki; Usami, Noriko; Tomiya, Masanori

    2013-01-01

    The potential for carcinogenic risks is increased by radiation-induced bystander responses; these responses are the biological effects in unirradiated cells that receive signals from the neighboring irradiated cells. Bystander responses have attracted attention in modern radiobiology because they are characterized by non-linear responses to low-dose radiation. We used a synchrotron X-ray microbeam irradiation system developed at the Photon Factory, High Energy Accelerator Research Organization, KEK, and showed that nitric oxide (NO)-mediated bystander cell death increased biphasically in a dose-dependent manner. Here, we irradiated five cell nuclei using 10 × 10 µm 2 5.35 keV X-ray beams and then measured the mutation frequency at the hypoxanthine-guanosine phosphoribosyl transferase (HPRT) locus in bystander cells. The mutation frequency with the null radiation dose was 2.6 × 10 -5 (background level), and the frequency decreased to 5.3 × 10 -6 with a dose of approximately 1 Gy (absorbed dose in the nucleus of irradiated cells). At high doses, the mutation frequency returned to the background level. A similar biphasic dose-response effect was observed for bystander cell death. Furthermore, we found that incubation with 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (carboxy-PTIO), a specific scavenger of NO, suppressed not only the biphasic increase in bystander cell death but also the biphasic reduction in mutation frequency of bystander cells. These results indicate that the increase in bystander cell death involves mechanisms that suppress mutagenesis. This study has thus shown that radiation-induced bystander responses could affect processes that protect the cell against naturally occurring alterations such as mutations. (author)

  11. Dispatcher-assisted bystander cardiopulmonary resuscitation and survival in out-of-hospital cardiac arrest.

    Science.gov (United States)

    Hagihara, Akihito; Onozuka, Daisuke; Shibuta, Hidetoshi; Hasegawa, Manabu; Nagata, Takashi

    2018-04-19

    Bystander cardiopulmonary resuscitation (CPR) is critical to the survival of patients with out-of-hospital cardiac arrest (OHCA). However, it is unknown whether bystander CPR with or without dispatcher assistance is more effective or why. Thus, we evaluated the association between dispatcher-assisted bystander CPR (vs. bystander CPR without dispatcher assistance) and survival of patients with OHCA. This is a retrospective, nonrandomized, observational study using national registry data for all OHCAs. We performed a propensity analysis. Patients with OHCA of cardiac origin were 18-100 years of age and received bystander chest compression in Japan between 2005 and 2014. Outcome measures were bystander rescue breathing, return of spontaneous circulation (ROSC) before hospital arrival, and survival and Cerebral Performance Category (CPC) 1 or 2 at 1 month after the event. During the study period, 1,176,351 OHCAs occurred, and 87,400 cases met the inclusion criteria. Among propensity-matched patients, a negative association was observed between dispatcher-assisted bystander CPR and outcome measures in a fully-adjusted model [odds ratio (OR) (95% CI) for ROSC = 0.87 (0.78-0.97), P < 0.05; OR (95% CI) for 1-month survival = 0.81 (0.65-1.00), P < 0.05; OR (95% CI) for CPC 1 or 2 = 0.64 (0.43-0.93), P < 0.05]. OR of survival for dispatcher-assisted bystander CPR tended to decrease as the emergency medical services response time increased. Survival benefit was less for dispatcher-assisted bystander CPR with dispatcher assistance than without dispatcher assistance. Low quality is hypothesized to be the cause of the reduced benefit. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Radiation induced bystander effects: mechanisms and implication for low dose radiation risk assessment

    International Nuclear Information System (INIS)

    Hei, T.L.; Randers-Pehrson, G.; Zhou, H.

    2003-01-01

    Using a precision microbeam to target an exact fraction of cells in a population and irradiated their nuclei with exactly one alpha particle each, we found that the frequencies of induced mutations and chromosomal changes in populations where some known fractions of nuclei were hit are consistent with non-hit cells contributing significantly to the response. In fact, irradiation of 10% of a mammalian cell population with a single alpha particle per cell results in a mutant yield similar to that observed when all of the cells in the population are irradiated. Although the bystander observations have been well established, the underlying mechanism(s) remain largely unknown. There are indications that multiple pathways are involved in the bystander phenomenon and different cell types respond differently to the bystander signaling. In confluent monolayers, there is evident that gap junctional communication is crucial in mediating the bystander effect whereas reactive oxygen and reactive nitrogen species have been implicated as the mediating molecules in sub-confluent cultures. Although p53 is not necessary for the expression of bystander effect, there is evident that repair deficient cells may express a higher bystander response. Using cDNA microarrays, a number of cellular signaling genes have been shown to be differentially expressed among bystander cells. The functional roles of these genes in the bystander effect will be discussed. The bystander observations imply that the relevant target for various radiobiological endpoints is larger than an individual cell and suggest a need to reconsider the validity of the linear extrapolation in making risk estimate for low dose radiation exposure. (Work supported by NIH grants CA 49062 and CA-RR11623)

  13. Nitric oxide-mediated bystander signal transduction induced by heavy-ion microbeam irradiation

    Science.gov (United States)

    Tomita, Masanori; Matsumoto, Hideki; Funayama, Tomoo; Yokota, Yuichiro; Otsuka, Kensuke; Maeda, Munetoshi; Kobayashi, Yasuhiko

    2015-07-01

    In general, a radiation-induced bystander response is known to be a cellular response induced in non-irradiated cells after receiving bystander signaling factors released from directly irradiated cells within a cell population. Bystander responses induced by high-linear energy transfer (LET) heavy ions at low fluence are an important health problem for astronauts in space. Bystander responses are mediated via physical cell-cell contact, such as gap-junction intercellular communication (GJIC) and/or diffusive factors released into the medium in cell culture conditions. Nitric oxide (NO) is a well-known major initiator/mediator of intercellular signaling within culture medium during bystander responses. In this study, we investigated the NO-mediated bystander signal transduction induced by high-LET argon (Ar)-ion microbeam irradiation of normal human fibroblasts. Foci formation by DNA double-strand break repair proteins was induced in non-irradiated cells, which were co-cultured with those irradiated by high-LET Ar-ion microbeams in the same culture plate. Foci formation was suppressed significantly by pretreatment with an NO scavenger. Furthermore, NO-mediated reproductive cell death was also induced in bystander cells. Phosphorylation of NF-κB and Akt were induced during NO-mediated bystander signaling in the irradiated and bystander cells. However, the activation of these proteins depended on the incubation time after irradiation. The accumulation of cyclooxygenase-2 (COX-2), a downstream target of NO and NF-κB, was observed in the bystander cells 6 h after irradiation but not in the directly irradiated cells. Our findings suggest that Akt- and NF-κB-dependent signaling pathways involving COX-2 play important roles in NO-mediated high-LET heavy-ion-induced bystander responses. In addition, COX-2 may be used as a molecular marker of high-LET heavy-ion-induced bystander cells to distinguish them from directly irradiated cells, although this may depend on the time

  14. Does Non-Targeted Community CPR Training Increase Bystander CPR Frequency?

    Science.gov (United States)

    Uber, Amy; Sadler, Richard C; Chassee, Todd; Reynolds, Joshua C

    2018-05-01

    Only 37% of out-of-hospital cardiac arrests (OHCA) receive bystander Cardiopulmonary resuscitation (CPR) in Kent County, MI. In May 2014, prehospital providers offered one-time, point-of-contact compression-only CPR training to 2,253 passersby at 7 public locations in Grand Rapids, Michigan. To assess the impact of this intervention, we compared bystander CPR frequency and clinical outcomes in regions surrounding training sites before and after the intervention, adjusting for prehospital covariates. We aimed to assess the effect of this broad, non-targeted intervention on bystander CPR frequency, type of CPR utilized, and clinical outcomes. We also tested for differences in geospatial variation of bystander CPR and clinical outcomes clustered around training sites. Retrospective, observational, before-after study of adult, EMS-treated OHCA in Kent County from January 1, 2010 to December 31, 2015. We generated a 5-kilometer radius surrounding each training site to estimate any geospatial influence that training sites might have on bystander CPR frequency in nearby OHCA cases. Chi-squared, Fisher's exact, and t-tests assessed differences in subject features. Difference-in-differences analysis with generalized estimating equation (GEE) modeling assessed bystander CPR frequency, adjusting for training site, covariates (age, sex, witnessed, shockable rhythm, public location), and clustering around training sites. Similar modeling tested for changes in bystander CPR type, return of spontaneous circulation (ROSC), survival to hospital discharge, and cerebral performance category (CPC) of 1-2 at hospital discharge. We included 899 cases before and 587 cases post-intervention. Overall, we observed no increase in the frequency of bystander CPR or favorable clinical outcomes. We did observe an increase in compression-only CPR, but this was paradoxically restricted to OHCA cases falling outside radii around training sites. In adjusted modeling, the bystander CPR training

  15. DMPD: TLR3 in antiviral immunity: key player or bystander? [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 16027039 TLR3 in antiviral immunity: key player or bystander? Schroder M, Bowie AG.... Trends Immunol. 2005 Sep;26(9):462-8. (.png) (.svg) (.html) (.csml) Show TLR3 in antiviral immunity: key player... or bystander? PubmedID 16027039 Title TLR3 in antiviral immunity: key player or bystander? Authors Schr... File (.png) SVG File (.svg) HTML File (.html) CSML File (.csml) Open .csml file with CIOPlayer Open .csml file with CIOPlayer... - ※CIO Playerのご利用上の注意 Open .csml file with CIO Open .csml file with CIO - ※CIOのご利用上の注意 ...

  16. Association of bystander interventions and hospital length of stay and admission to intensive care unit in out-of-hospital cardiac arrest survivors.

    Science.gov (United States)

    Riddersholm, Signe; Kragholm, Kristian; Mortensen, Rikke Nørmark; Pape, Marianne; Hansen, Carolina Malta; Lippert, Freddy K; Torp-Pedersen, Christian; Christiansen, Christian F; Rasmussen, Bodil Steen

    2017-10-01

    The impact of bystander interventions on post-arrest hospital course is sparsely studied. We examined the association between bystander interventions and length of hospital stay and admission to intensive care unit (ICU) in one-day survivors after OHCA. This cohort study linked data of 4641 one-day OHCA survivors from 2001 to 2014 to data on hospital length of stay and ICU admission. We examined associations between bystander efforts and outcomes using regression, adjusted for age, sex, comorbidities, calendar year and witnessed status. We divided bystander efforts into three categories: 1. No bystander interventions; 2.Bystander CPR only; 3. Bystander defibrillation with or without bystander CPR. For patients surviving to hospital discharge, hospital length of stay was 20days for patients without bystander interventions, compared to 16 for bystander CPR, and 13 for bystander defibrillation. 82% of patients without bystander interventions were admitted to ICU compared to 77.2% for bystander CPR, and 61.2% for bystander defibrillation. In-hospital mortality was 60% in the first category compared to 40.5% and 21.7% in the two latter categories. In regression models, bystander CPR and bystander defibrillation were associated with a reduction of length of hospital stay of 21% (Estimate: 0.79 [95% CI: 0.72-0.86]) and 32% (Estimate: 0.68 [95% CI: 0.59-0.78]), respectively. Both bystander CPR (OR: 0.94 [95% CI: 0.91-0.97]) and bystander defibrillation (OR: 0.81 [0.76-0.85]), were associated with lower risk of ICU admission. Bystander interventions were associated with reduced hospital length of stay and ICU admission, suggesting that these efforts improve recovery in OHCA survivors. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Dietary mutagen exposure and risk of pancreatic cancer.

    Science.gov (United States)

    Li, Donghui; Day, Rena Sue; Bondy, Melissa L; Sinha, Rashmi; Nguyen, Nga T; Evans, Douglas B; Abbruzzese, James L; Hassan, Manal M

    2007-04-01

    To investigate the association between dietary exposure to food mutagens and risk of pancreatic cancer, we conducted a hospital-based case-control study at the University of Texas M. D. Anderson Cancer Center during June 2002 to May 2006. A total of 626 cases and 530 noncancer controls were frequency matched for race, sex and age (+/-5 years). Dietary exposure information was collected via personal interview using a meat preparation questionnaire. A significantly greater portion of the cases than controls showed a preference to well-done pork, bacon, grilled chicken, and pan-fried chicken, but not to hamburger and steak. Cases had a higher daily intake of food mutagens and mutagenicity activity (revertants per gram of daily meat intake) than controls did. The daily intakes of 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (DiMeIQx) and benzo(a)pyrene (BaP), as well as the mutagenic activity, were significant predictors for pancreatic cancer (P = 0.008, 0.031, and 0.029, respectively) with adjustment of other confounders. A significant trend of elevated cancer risk with increasing DiMeIQx intake was observed in quintile analysis (P(trend) = 0.024). A higher intake of dietary mutagens (those in the two top quintiles) was associated with a 2-fold increased risk of pancreatic cancer among those without a family history of cancer but not among those with a family history of cancer. A possible synergistic effect of dietary mutagen exposure and smoking was observed among individuals with the highest level of exposure (top 10%) to PhIP and BaP, P(interaction) = 0.09 and 0.099, respectively. These data support the hypothesis that dietary mutagen exposure alone and in interaction with other factors contribute to the development of pancreatic cancer.

  18. Mutagenicity of irradiated solutions of nuclei acid bases and nucleosides in Salmonella typhimurium

    International Nuclear Information System (INIS)

    Wilmer, J.; Schubert, J.

    1981-01-01

    Solutions of nucleic acid bases, nucleosides and a nucleotide, saturated with either N 2 , N 2 O or O 2 , were irradiated and tested for mutagenicity towards Salmonella typhimurium, with and without pre-incubation. Irradiated solutions of the nuclei acid bases were all non-mutagenic. Irradiated solutions of the nucleosides showed mutagenicity in S. typhimurium TA100 (pre-incubation assay). Generally, the mutagenicity followed the order: N 2 O > N 2 > O 2 . The results show that the formation of mutagenic radiolytic products is initiated by attack of mainly solutions of the nucleotide thymidine-5'-monophosphate, no mutagenicity could be detected. (orig.)

  19. The effects of mutagens on some algae

    International Nuclear Information System (INIS)

    Aranez, A.T.

    1984-01-01

    Pure cultures of Scenedesmus quadricauda (Turp.) Breb. and chlorella pyrenoidosa Chick were subjected to 0.5, 3, 6, 9 and 12 Kr gamma radiation ( 60 Co source) from the Philippine Atomic Energy Commission. Untreated cells were used as control. Dose of 0.5 Kr increased the growth rate of Scenedesmus by 3.12%, 15.27% and 20.48% during the first, third and fourth week respectively. Doses of 6, 9 and 12 decreased the growth rate by 86.33%, 70.7% and 58.2% respectively during the first week. The stimulating effect of low dose (0.5 Kr) was recovered after the fourth week while the inhibiting effect on growth by higher doses was recovered after the first week. Gamma radiation produced morphological changes in the Scenedesmus in the form of enlarged cells, cells with kidney-shape chloroplast, cells in chain, and coenobia with cells that were not in perfect alignment with each other. In chlorella, gamma radiation produced enlarged cells, cells with wrinkled surface and cells that were colourless. Ethyl methanesulfate of 0.1%, 0.4%, 0.8% and 1.25% in phosphate buffer solution was another mutagen used. Algae in distilled water and phosphate buffer were used as control. Treatment with EMS produced coenobia of Scenedesmus with cells that were twice and thrice the normal cells, cells that were rounded or oval in outline, with wavy instead of smooth margin, cells with pseudopodia-like protrusions and coenobia with abnormal number of cells. In Chlorella, EMS produced cells that were twice the size of the normal size of the normal ones, cells that were wavy in outline, abnormal in shape, and cells with no chlorophyll. Scenedesmus was more sensitive to gamma radiation and EMS than chlorella. Of the morphological changes observed, only Scenedesmus with cells around twice the size of the normal ones produced by treatment with either gamma radiation of EMS were successfully propagated. (author)

  20. Cooking with Fire: The Mutagenicity- and PAH-Emission ...

    Science.gov (United States)

    Emissions from solid fuels used for cooking cause ~4 million premature deaths per year. Advanced solid-fuel cookstoves are a potential solution, but they should be assessed by appropriate performance indicators, including biological effects. We evaluated two categories of solid-fuel cookstoves for 8 pollutant- and 4 mutagenicity-emission factors, correlated the mutagenicity-emission factors, and compared them to those of other combustion emissions. We burned red oak in a 3-stone fire (TSF), a natural-draft stove (NDS), and a forced-draft stove (FDS); we combusted propane as a liquified petroleum gas control fuel. We determined emission factors based on useful energy (megajoules delivered, MJd) for carbon monoxide, nitrogen oxides (NOx), black carbon, methane, total hydrocarbons, 32 polycyclic aromatic hydrocarbons, PM2.5, levoglucosan (a wood-smoke marker), and mutagenicity in Salmonella. Other than NOx the emission factors per MJd correlated highly among each other (r2 ≥ 0.92); NOx correlated 0.58-0.76 with the other emission factors. Excluding NOx, the NDS and FDS reduced the emission factors on average 68 and 92%, respectively, relative to the TSF. Nonetheless, the mutagenicity-emission factor based on fuel energy used (MJthermal) for the most efficient stove (FDS) was intermediate to that of a large diesel bus engine and a small diesel generator. Both mutagenicity- and pollutant-emission factors may be informative for characterizing cookstove

  1. Effects of diet composition on mutagenic activity in urine.

    Science.gov (United States)

    Ohara, Akihiro; Matsuhisa, Tsugio

    2004-01-01

    The effects of dietary habits on mutagenic activity in urine were investigated using the umu test based on the use of the genetically engineered bacteria Salmonella typhimurium TA 1535 pSK1002. Genotoxic effects in sample urine were detected by measuring the activation of the SOS response in the bacteria and recording the beta- galactosidase activity. Human subjects consisted of smokers and non-smokers. Urine from subjects who consumed fish showed the highest mutagenic activity, followed by the urine samples from subjects who ate pork or beef. Chicken induced a low level of mutagenic activity. When the subjects ate fried or roasted animal foods, the urine samples gave higher mutagenicity than the urine samples from the subject who consumed non-fried or non-roasted animal foods. When the subject ate vegetables along with a diet rich in animal foods, the activity in urine decreased. Herbs and spices gave the same tendency toward decline as vegetables. Non-smoker urine shower mutagenic activity than samples from smokers.

  2. Empowering public service workers to face bystander conflict : Enhancing resources through a training intervention

    NARCIS (Netherlands)

    van Erp, K.J.P.M.; Gevers, J.M.P.; Rispens, S.; Demerouti, E.

    2018-01-01

    Public service employees work in occupations that are accompanied with high psychosocial risks. Police, firefighters, and paramedics are increasingly being confronted with argumentative, conflicting bystanders that frustrate them in executing their task. We developed a resource-enhancement

  3. Bystander chronic infection negatively impacts development of CD8+ T cell memory

    Science.gov (United States)

    Stelekati, Erietta; Shin, Haina; Doering, Travis A.; Dolfi, Douglas V.; Ziegler, Carly G.; Beiting, Daniel P.; Dawson, Lucas; Liboon, Jennifer; Wolski, David; Ali, Mohammed-Alkhatim A.; Katsikis, Peter D.; Shen, Hao; Roos, David S.; Haining, W. Nicholas; Lauer, Georg M.; Wherry, E. John

    2014-01-01

    Summary Epidemiological evidence suggests that chronic infections impair immune responses to unrelated pathogens and vaccines. The underlying mechanisms, however, are unclear and distinguishing effects on priming versus development of immunological memory has been challenging. We investigated whether bystander chronic infections impact differentiation of memory CD8+ T cells, the hallmark of protective immunity against intracellular pathogens. Chronic bystander infections impaired development of memory CD8+ T cells in several mouse models and humans. These effects were independent of initial priming and were associated with chronic inflammatory signatures. Chronic inflammation negatively impacted the number of bystander CD8+ T cells and their memory development. Distinct underlying mechanisms of altered survival and differentiation were revealed with the latter regulated by the transcription factors T-bet and Blimp-1. Thus, exposure to prolonged bystander inflammation impairs the effector to memory transition. These data have relevance for immunity and vaccination during persisting infections and chronic inflammation. PMID:24837104

  4. The application of microbeam in the research on radiation-induced bystander effects

    International Nuclear Information System (INIS)

    Xiong Jie; Han Ling

    2002-01-01

    There has been more and more attention to the phenomenon known as radiation-induced bystander effects, which will have a tremendous effect on the research in low -dose radiation biological effects. However, due to the stochastic nature of energy deposition and the random position of tracts, direct evidence for bystander effects and exact results of single particle interacts with a cell cannot be provided by using conventional broad-field irradiation. The availability of microbeam, especially the single particle microbeam in the world, whereby individual cells or precise location of cells can be irradiated with either a single or an exact number of particles provides a useful tool for the research on radiation-induced bystander effects. The author describes the radiation -induced bystander effect and the application of microbeam in the research on it

  5. Recognising out-of-hospital cardiac arrest during emergency calls increases bystander cardiopulmonary resuscitation and survival

    DEFF Research Database (Denmark)

    Viereck, Søren; Møller, Thea Palsgaard; Ersbøll, Annette Kjær

    2017-01-01

    BACKGROUND: Initiation of early bystander cardiopulmonary resuscitation (CPR) depends on bystanders' or medical dispatchers' recognition of out-of-hospital cardiac arrest (OHCA). The primary aim of our study was to investigate if OHCA recognition during the emergency call was associated...... with bystander CPR, return of spontaneous circulation (ROSC), and 30-day survival. Our secondary aim was to identify patient-, setting-, and dispatcher-related predictors of OHCA recognition. METHODS: We performed an observational study of all OHCA patients' emergency calls in the Capital Region of Denmark from...... the association between OHCA recognition and bystander CPR, ROSC, and 30-day survival. Univariable logistic regression analyses were applied to identify predictors of OHCA recognition. RESULTS: We included 779 emergency calls in the analyses. During the emergency calls, 70.1% (n=534) of OHCAs were recognised...

  6. BYSTANDER EFFECTS GENOMIC INSTABILITY, ADAPTIVE RESPONSE AND CANCER RISK ASSESSMENT FOR RADIAION AND CHEMICAL EXPOSURES

    Science.gov (United States)

    BYSTANDER EFFECTS, GENOMIC INSTABILITY, ADAPTIVE RESPONSE AND CANCER RISK ASSESSMENT FOR RADIATION AND CHEMICAL EXPOSURESR. Julian PrestonEnvironmental Carcinogenesis Division, U.S. Environmental Protection Agency, Research Triangle Park, N.C. 27711, USAThere ...

  7. Social Capital and Bystander Behavior in Bullying: Internalizing Problems as a Barrier to Prosocial Intervention.

    Science.gov (United States)

    Jenkins, Lyndsay N; Fredrick, Stephanie Secord

    2017-04-01

    Theory and research suggests that individuals with greater social capital (i.e., resources and benefits gained from relationships, experiences, and social interactions) may be more likely to be active, prosocial bystanders in bullying situations. Therefore, the goal of the current study was to examine the association of social capital (social support and social skills) with prosocial bystander behavior, and the role of internalizing problems as a potential barrier to this relation among 299 students (45.8% girls, 95% White) in sixth, seventh, and eighth grades. Results indicate a positive relation between social capital and prosocial bystander behavior. In addition, internalizing problems were a significant risk factor that may hinder youth-particularly girls-from engaging in defending behavior. Prosocial bystanders are an essential component to prevent and reduce bullying and further research is needed to better understand how to foster prosocial behavior in bullying situations, perhaps by utilizing social capital, related to school bullying.

  8. Addressing bystander exposure to agricultural pesticides in life cycle impact assessment

    DEFF Research Database (Denmark)

    Ryberg, Morten Walbech; Rosenbaum, Ralph K.; Mosqueron, Luc

    2018-01-01

    Residents living near agricultural fields may be exposed to pesticides drifting from the fields after application to different field crops. To address this currently missing exposure pathway in life cycle assessment (LCA), we developed a modeling framework for quantifying exposure of bystanders...... magnitude of individual bystanders can be substantially larger than the exposure of populations not living in the proximity to agricultural fields. Our framework for assessing bystander exposure to pesticide applications closes a relevant gap in the exposure assessment included in LCA for agricultural...... to pesticide spray drift from agricultural fields. Our framework consists of three parts addressing: (1) loss of pesticides from an agricultural field via spray drift; (2) environmental fate of pesticide in air outside of the treated field; and (3) exposure of bystanders to pesticides via inhalation...

  9. Lack of Bystander Effects From High LET Radiation For Early Cytogenetic Endpoints.

    Energy Technology Data Exchange (ETDEWEB)

    Groesser, Torsten; Cooper, Brian; Rydberg, Bjorn

    2008-05-07

    The aim of this work was to study radiation-induced bystander effects for early cytogenetic end points in various cell lines using the medium transfer technique after exposure to high- and low-LET radiation. Cells were exposed to 20 MeV/ nucleon nitrogen ions, 968 MeV/nucleon iron ions, or 575 MeV/nucleon iron ions followed by transfer of the conditioned medium from the irradiated cells to unirradiated test cells. The effects studied included DNA double-strand break induction, {gamma}-H2AX focus formation, induction of chromatid breaks in prematurely condensed chromosomes, and micronucleus formation using DNA repair-proficient and -deficient hamster and human cell lines (xrs6, V79, SW48, MO59K and MO59J). Cell survival was also measured in SW48 bystander cells using X rays. Although it was occasionally possible to detect an increase in chromatid break levels using nitrogen ions and to see a higher number of {gamma}-H2AX foci using nitrogen and iron ions in xrs6 bystander cells in single experiments, the results were not reproducible. After we pooled all the data, we could not verify a significant bystander effect for any of these end points. Also, we did not detect a significant bystander effect for DSB induction or micronucleus formation in these cell lines or for clonogenic survival in SW48 cells. The data suggest that DNA damage and cytogenetic changes are not induced in bystander cells. In contrast, data in the literature show pronounced bystander effects in a variety of cell lines, including clonogenic survival in SW48 cells and induction of chromatid breaks and micronuclei in hamster cells. To reconcile these conflicting data, it is possible that the epigenetic status of the specific cell line or the precise culture conditions and medium supplements, such as serum, may be critical for inducing bystander effects.

  10. Lack of Bystander Effects From High-LET Radiation For Early Cytogenetic End Points

    International Nuclear Information System (INIS)

    Groesser, Torsten; Cooper, Brian; Rydberg, Bjorn

    2008-01-01

    The aim of this work was to study radiation-induced bystander effects for early cytogenetic end points in various cell lines using the medium transfer technique after exposure to high- and low-LET radiation. Cells were exposed to 20 MeV/ nucleon nitrogen ions, 968 MeV/nucleon iron ions, or 575 MeV/nucleon iron ions followed by transfer of the conditioned medium from the irradiated cells to unirradiated test cells. The effects studied included DNA double-strand break induction, γ-H2AX focus formation, induction of chromatid breaks in prematurely condensed chromosomes, and micronucleus formation using DNA repair-proficient and -deficient hamster and human cell lines (xrs6, V79, SW48, MO59K and MO59J). Cell survival was also measured in SW48 bystander cells using X rays. Although it was occasionally possible to detect an increase in chromatid break levels using nitrogen ions and to see a higher number of γ-H2AX foci using nitrogen and iron ions in xrs6 bystander cells in single experiments, the results were not reproducible. After we pooled all the data, we could not verify a significant bystander effect for any of these end points. Also, we did not detect a significant bystander effect for DSB induction or micronucleus formation in these cell lines or for clonogenic survival in SW48 cells. The data suggest that DNA damage and cytogenetic changes are not induced in bystander cells. In contrast, data in the literature show pronounced bystander effects in a variety of cell lines, including clonogenic survival in SW48 cells and induction of chromatid breaks and micronuclei in hamster cells. To reconcile these conflicting data, it is possible that the epigenetic status of the specific cell line or the precise culture conditions and medium supplements, such as serum, may be critical for inducing bystander effects.

  11. Temporal variations in dispatcher-assisted and bystander-initiated resuscitation efforts.

    Science.gov (United States)

    Yamashita, Akira; Maeda, Tetsuo; Myojo, Yasuhiro; Wato, Yukihiro; Ohta, Keisuke; Inaba, Hideo

    2018-04-03

    To investigate temporal variations in dispatcher-assisted and bystander-initiated resuscitation efforts and their association with survival after bystander-witnessed out-of-hospital cardiac arrests (OHCAs). We retrospectively analyzed the neurologically favorable 1-month survival and the parameters related to dispatcher assisted cardiopulmonary resuscitation (DA-CPR) and bystander CPR (BCPR) for 227,524 OHCA patients between 2007 and 2013 in Japan. DA-CPR sensitivity for OHCAs, bystander's compliance to DA-CPR assessed by the proportion of bystanders who follow DA-CPR, and performance of BCPR measured by the rate of bystander-initiated CPR in patients without DA-CPR were calculated as indices of resuscitation efforts. Performance of BCPR was only similar to temporal variations in the survival (correlation between hourly paired values, R 2 =0.263, P=0.01): a lower survival rate (3.4% vs 4.2%) and performance of BCPR (23.1% vs 30.8%) during night-time (22:00-5:59) than during non-night-time. In subgroup analyses based on interaction tests, all three indices deteriorated during night-time when OHCAs were witnessed by non-family (adjusted odds ratio, 0.73-0.82), particularly in non-elderly patients. The rate of public access defibrillation for these OHCAs markedly decreased during night-time (adjusted odds ratio, 0.49) with delayed emergency calls and BCPR initiation. Multivariable logistic regression analyses revealed that the survival rate of non-family-witnessed OHCAs was 1.83-fold lower during night-time than during non-night-time. Dispatcher-assisted and bystander-initiated resuscitation efforts are low during night-time in OHCAs witnessed by non-family. A divisional alert system to recruit well-trained individuals is needed in order to improve the outcomes of night-time OHCAs witnessed by non-family bystanders. Copyright © 2018 Elsevier Inc. All rights reserved.

  12. Molecular pathways in the bystander response of cells exposed to very low fluences of alpha particles

    International Nuclear Information System (INIS)

    Little, J.B.

    2000-01-01

    Full text: We have examined biological effects in cell populations exposed to very low mean doses of alpha radiation by which only a small fraction of the cells are actually traversed by an alpha particle. We showed earlier that an enhanced frequency of sister chromatid exchanges and HPRT mutations occur in the non-irradiated, 'bystander' cells. The frequency of mutations induced by a single alpha particle traversing the nucleus of a cell was increased nearly fivefold at the lowest fluence studied, a result of mutations occurring in bystander cells. This was associated with a similar increase in the induction of micronuclei, indicating the induction of DNA damage in bystander cells. In order to gain information concerning molecular pathways, we studied changes in gene expression in bystander cells in confluent cultures of human diploid fibroblasts or mouse embryo-derived fibroblasts (MEFs) by western analysis and in-situ immunofluorescence. The expression levels of p53, p21 Waf1 and p34 cdc2 were significantly modulated in bystander cells. The upregulation of p53 and p21 Waf1 did not occur in cultures irradiated at low density, and was markedly reduced in the presence of the gap junction inhibitor lindane. The importance of gap-junction mediated intercellular communication was confirmed in connexin-43 knockout MEFs. Western blot analyses and electrophoretic mobility shift assays indicate that the bystander response is suppressed by incubation with superoxide dismutase as well as an inhibitor of NADPH oxidase, and is associated with the induction of NFKB, suggesting the effect is mediated by oxidative stress. The stress-activated protein kinase p38 and its downstream effector ATF2 are also induced in bystander cells independent of oxidative stress. These results will be discussed in terms of whether activation of the p53 damage response pathway is the direct result of signaling from irradiated cells, or rather is a consequence of DNA induced damage in the bystander

  13. Bystander-mediated genomic instability after high LET radiation in murine primary haemopoietic stem cells

    International Nuclear Information System (INIS)

    Bowler, Deborah A.; Moore, Stephen R.; Macdonald, Denise A.; Smyth, Sharon H.; Clapham, Peter; Kadhim, Munira A.

    2006-01-01

    Communication between irradiated and unirradiated (bystander) cells can result in responses in unirradiated cells that are similar to responses in their irradiated counterparts. The purpose of the current experiment was to test the hypothesis that bystander responses will be similarly induced in primary murine stem cells under different cell culture conditions. The experimental systems used here, co-culture and media transfer, are similar in that they both restrict communication between irradiated and bystander cells to media borne factors, but are distinct in that with the media transfer technique, cells can only communicate after irradiation, and with co-culture, cells can communication before, during and after irradiation. In this set of parallel experiments, cell type, biological endpoint, and radiation quality and dose, were kept constant. In both experimental systems, clonogenic survival was significantly decreased in all groups, whether irradiated or bystander, suggesting a substantial contribution of bystander effects (BE) to cell killing. Genomic instability (GI) was induced under all radiation and bystander conditions in both experiments, including a situation where unirradiated cells were incubated with media that had been conditioned for 24 h with irradiated cells. The appearance of delayed aberrations (genomic instability) 10-13 population doublings after irradiation was similar to the level of initial chromosomal damage, suggesting that the bystander factor is able to induce chromosomal alterations soon after irradiation. Whether these early alterations are related to those observed at later timepoints remains unknown. These results suggest that genomic instability may be significantly induced in a bystander cell population whether or not cells communicate during irradiation

  14. Bystander motivation in bullying incidents: to intervene or not to intervene?

    Science.gov (United States)

    Thornberg, Robert; Tenenbaum, Laura; Varjas, Kris; Meyers, Joel; Jungert, Tomas; Vanegas, Gina

    2012-08-01

    This research sought to extend knowledge about bystanders in bullying situations with a focus on the motivations that lead them to different responses. The 2 primary goals of this study were to investigate the reasons for children's decisions to help or not to help a victim when witnessing bullying, and to generate a grounded theory (or conceptual framework) of bystander motivation in bullying situations. Thirty students ranging in age from 9 to 15 years (M = 11.9; SD = 1.7) from an elementary and middle school in the southeastern United States participated in this study. Open- ended, semi-structured interviews were used, and sessions ranged from 30 to 45 minutes. We conducted qualitative methodology and analyses to gain an in-depth understanding of children's perspectives and concerns when witnessing bullying. A key finding was a conceptual framework of bystander motivation to intervene in bullying situations suggesting that deciding whether to help or not help the victim in a bullying situation depends on how bystanders define and evaluate the situation, the social context, and their own agency. Qualitative analysis revealed 5 themes related to bystander motives and included: interpretation of harm in the bullying situation, emotional reactions, social evaluating, moral evaluating, and intervention self-efficacy. Given the themes that emerged surrounding bystanders' motives to intervene or abstain from intervening, respondents reported 3 key elements that need to be confirmed in future research and that may have implications for future work on bullying prevention. These included: first, the potential importance of clear communication to children that adults expect bystanders to intervene when witnessing bullying; second, the potential of direct education about how bystanders can intervene to increase children's self-efficacy as defenders of those who are victims of bullying; and third, the assumption that it may be effective to encourage children's belief that

  15. Bystander apoptosis in human cells mediated by irradiated blood plasma

    Energy Technology Data Exchange (ETDEWEB)

    Vinnikov, Volodymyr, E-mail: vlad.vinnikov@mail.ru [Grigoriev Institute for Medical Radiology of the National Academy of Medical Science of Ukraine (Ukraine); Lloyd, David; Finnon, Paul [Centre for Radiation, Chemical and Environmental Hazards of the Health Protection Agency of the United Kingdom (United Kingdom)

    2012-03-01

    Following exposure to high doses of ionizing radiation, due to an accident or during radiotherapy, bystander signalling poses a potential hazard to unirradiated cells and tissues. This process can be mediated by factors circulating in blood plasma. Thus, we assessed the ability of plasma taken from in vitro irradiated human blood to produce a direct cytotoxic effect, by inducing apoptosis in primary human peripheral blood mononuclear cells (PBM), which mainly comprised G{sub 0}-stage lymphocytes. Plasma was collected from healthy donors' blood irradiated in vitro to 0-40 Gy acute {gamma}-rays. Reporter PBM were separated from unirradiated blood with Histopaque and held in medium with the test plasma for 24 h at 37 Degree-Sign C. Additionally, plasma from in vitro irradiated and unirradiated blood was tested against PBM collected from blood given 4 Gy. Apoptosis in reporter PBM was measured by the Annexin V test using flow cytometry. Plasma collected from unirradiated and irradiated blood did not produce any apoptotic response above the control level in unirradiated reporter PBM. Surprisingly, plasma from irradiated blood caused a dose-dependent reduction of apoptosis in irradiated reporter PBM. The yields of radiation-induced cell death in irradiated reporter PBM (after subtracting the respective values in unirradiated reporter PBM) were 22.2 {+-} 1.8% in plasma-free cultures, 21.6 {+-} 1.1% in cultures treated with plasma from unirradiated blood, 20.2 {+-} 1.4% in cultures with plasma from blood given 2-4 Gy and 16.7 {+-} 3.2% in cultures with plasma from blood given 6-10 Gy. These results suggested that irradiated blood plasma did not cause a radiation-induced bystander cell-killing effect. Instead, a reduction of apoptosis in irradiated reporter cells cultured with irradiated blood plasma has implications concerning oncogenic risk from mutated cells surviving after high dose in vivo irradiation (e.g. radiotherapy) and requires further study.

  16. 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.

  17. Bystander apoptosis in human cells mediated by irradiated blood plasma

    International Nuclear Information System (INIS)

    Vinnikov, Volodymyr; Lloyd, David; Finnon, Paul

    2012-01-01

    Following exposure to high doses of ionizing radiation, due to an accident or during radiotherapy, bystander signalling poses a potential hazard to unirradiated cells and tissues. This process can be mediated by factors circulating in blood plasma. Thus, we assessed the ability of plasma taken from in vitro irradiated human blood to produce a direct cytotoxic effect, by inducing apoptosis in primary human peripheral blood mononuclear cells (PBM), which mainly comprised G 0 -stage lymphocytes. Plasma was collected from healthy donors’ blood irradiated in vitro to 0–40 Gy acute γ-rays. Reporter PBM were separated from unirradiated blood with Histopaque and held in medium with the test plasma for 24 h at 37 °C. Additionally, plasma from in vitro irradiated and unirradiated blood was tested against PBM collected from blood given 4 Gy. Apoptosis in reporter PBM was measured by the Annexin V test using flow cytometry. Plasma collected from unirradiated and irradiated blood did not produce any apoptotic response above the control level in unirradiated reporter PBM. Surprisingly, plasma from irradiated blood caused a dose-dependent reduction of apoptosis in irradiated reporter PBM. The yields of radiation-induced cell death in irradiated reporter PBM (after subtracting the respective values in unirradiated reporter PBM) were 22.2 ± 1.8% in plasma-free cultures, 21.6 ± 1.1% in cultures treated with plasma from unirradiated blood, 20.2 ± 1.4% in cultures with plasma from blood given 2–4 Gy and 16.7 ± 3.2% in cultures with plasma from blood given 6–10 Gy. These results suggested that irradiated blood plasma did not cause a radiation-induced bystander cell-killing effect. Instead, a reduction of apoptosis in irradiated reporter cells cultured with irradiated blood plasma has implications concerning oncogenic risk from mutated cells surviving after high dose in vivo irradiation (e.g. radiotherapy) and requires further study.

  18. Bystander's willingness to report theft, physical assault, and sexual assault: the impact of gender, anonymity, and relationship with the offender.

    Science.gov (United States)

    Nicksa, Sarah C

    2014-01-01

    This research examines bystander willingness to report three different crimes to the police or campus authorities among a college student sample (n = 295). Twelve original vignettes varied anonymity when reporting, bystander's relationship with the offender (friend or stranger), and crime type. A factorial analysis of variance showed that main effects were found for crime type, bystander's gender, and bystander's relationship with the offender; anonymity was not significant. The physical assault was the most likely to be reported (4.47), followed by theft (3.26), and sexual assault (2.36). Women were more likely than men to report each crime type, and bystanders who were good friends of the offender were less likely to report than strangers. No two- or three-way interactions were significant, but a significant four-way interaction indicated that anonymity, relationship with the offender, and bystander's gender predicted willingness to report for the sexual assault scenario.

  19. Critical role of gap junction communication, calcium and nitric oxide signaling in bystander responses to focal photodynamic injury.

    Science.gov (United States)

    Calì, Bianca; Ceolin, Stefano; Ceriani, Federico; Bortolozzi, Mario; Agnellini, Andrielly H R; Zorzi, Veronica; Predonzani, Andrea; Bronte, Vincenzo; Molon, Barbara; Mammano, Fabio

    2015-04-30

    Ionizing and nonionizing radiation affect not only directly targeted cells but also surrounding "bystander" cells. The underlying mechanisms and therapeutic role of bystander responses remain incompletely defined. Here we show that photosentizer activation in a single cell triggers apoptosis in bystander cancer cells, which are electrically coupled by gap junction channels and support the propagation of a Ca2+ wave initiated in the irradiated cell. The latter also acts as source of nitric oxide (NO) that diffuses to bystander cells, in which NO levels are further increased by a mechanism compatible with Ca(2+)-dependent enzymatic production. We detected similar signals in tumors grown in dorsal skinfold chambers applied to live mice. Pharmacological blockade of connexin channels significantly reduced the extent of apoptosis in bystander cells, consistent with a critical role played by intercellular communication, Ca2+ and NO in the bystander effects triggered by photodynamic therapy.

  20. Absence of mutagenicity of plants used to treat gastrointestinal disorders

    Directory of Open Access Journals (Sweden)

    Santos F.V.

    2013-01-01

    Full Text Available The Brazilian Savanna (locally called “Cerrado” is an important biome presenting several plants that are used in popular medicine. However, the risks associated with the consumption of derivatives from these plants are generally unknown. Studies with compounds obtained from different species have shown the risks of DNA damage. The present work assessed the in vivo mutagenicity of three plant species used in popular medicine to treat human gastrointestinal disorders (Mouriri pusa, Qualea grandiflora and Qualea multiflora. The micronucleus assay was performed in peripheral blood of mice submitted to acute treatments. Results showed that no assessed extracts were mutagenic in vivo. In fact, the absence of mutagenicity in the present study indicates that the extracts do not contain compounds capable of inducing DNA breaks or chromosomal loss. However, further analysis should be performed in others systems to guarantee their safety, mainly to human chronic use.

  1. Sources of mutagenic activity in urban fine particles

    International Nuclear Information System (INIS)

    Stevens, R.K.; Lewis, C.W.; Dzubay, T.G.; Cupitt, L.T.; Lewtas, J.

    1990-01-01

    Samples were collected during the winter of 1984-1985 in the cities of Albuquerque, NM and Raleigh NC as part of a US Environmental Protection Agency study to evaluate methods to determine the emission sources contributing to the mutagenic properties of extractable organic matter (EOM) present in fine particles. Data derived from the analysis of the composition of these fine particles served as input to a multi-linear regression (MLR) model used to calculate the relative contribution of wood burning and motor vehicle sources to mutagenic activity observed in the extractable organic matter. At both sites the mutagenic potency of EOM was found to be greater (3-5 times) for mobile sources when compared to wood smoke extractable organics. Carbon-14 measurements which give a direct determination of the amount of EOM that originated from wood burning were in close agreement with the source apportionment results derived from the MLR model

  2. Mutagenicity studies on alcohol extracts from gamma-irradiated potatoes

    International Nuclear Information System (INIS)

    Ishidate, M. Jr.; Yoshikawa, Kunie; Sofuni, Toshio; Iwahara, Shigeo; Sibuya, Tohru.

    1981-01-01

    The alcohol extracts freshly prepared from gamma-irradiated potatoes were examined for their mutagenic activity in bacterial and mammalian cell systems. Negative results were obtained from all following test systems: Mutation assays with Salmonella typhimurium His - strains such as TA 100, TA 98, TA 1535, TA 1537, and streptomycin-dependent mutant (SM sup(d)) strain, TA 100 - 10, inductests with Escherichia coli strains, K 12 GY 5027 and K 12 C600, chromosomal aberration tests with Chinese hamster cells in culture, as well as micronucleus tests in mice. In addition, no difference in the mutagenic activities was found between extracts prepared from the irradiated and the unirradiated potatoes, suggesting that no mutagenic substance was produced in potatoes following gamma-irradiation. (author)

  3. Bystanders' responses to offline bullying and cyberbullying: The role of empathy and normative beliefs about aggression.

    Science.gov (United States)

    Machackova, Hana; Pfetsch, Jan

    2016-04-01

    Cyberbullying often takes place with the virtual presence or knowledge of bystanders. While we have some evidence about the determinants of bystanders' responses to offline bullying, we lack empirical studies concerning the variables that influence bystanders' responses to cyberbullying. The current study examines bystanders' responses to offline bullying and cyberbullying incidents. Two types of responses were captured: support toward the victims and the reinforcement of bullies' actions. Using data from 321 German adolescents (ages 12-18; M = 14.99; 44% girls), the association between bystanders' responses and normative beliefs about verbal aggression and cyberaggression, and affective and cognitive empathy, were tested in a path model. Both types of normative beliefs positively predicted the reinforcement of bullies, and normative belief about verbal aggression also predicted support for the victims of offline bullying. Both types of empathy predicted support in offline bullying, but only affective empathy predicted support in cyberbullying. There was no link between affective or cognitive empathy to the reinforcement of bullies. Moreover, bystanders' tendencies to respond supportively to the victim or to reinforce the bully were rather consistent in both cyber- and offline bullying, but there was no link between support and reinforcement. The findings are discussed with regard to implications for prevention and intervention efforts. © 2016 Scandinavian Psychological Associations and John Wiley & Sons Ltd.

  4. An Online Bystander Intervention Program for the Prevention of Sexual Violence.

    Science.gov (United States)

    Kleinsasser, Anne; Jouriles, Ernest N; McDonald, Renee; Rosenfield, David

    2015-07-01

    Because of its high prevalence and serious consequences for victims, sexual violence is a significant problem on college campuses. Sexual assault prevention programs based on the bystander intervention model have been shown to be effective; however, current programs are limited in terms of ease of distribution. To address this issue, we developed and evaluated "Take Care," an online bystander intervention program. To our knowledge, this is the first empirical evaluation of an online bystander intervention program designed to prevent sexual violence. Ninety-three participants (80.6% female, 19.4% male) recruited from social psychology classes at a mid-size university were randomly assigned to view one of two online programs: Take Care or a control program on study skills. Before viewing the programs, participants completed measures of bystander behaviors and feelings of efficacy for performing such behaviors. Measures were administered again post-intervention and at a two-month follow-up assessment. Participants who viewed Take Care reported greater efficacy for engaging in bystander behaviors at post-treatment and two months following treatment, compared to those who viewed the control program. In addition, participants who viewed Take Care reported performing relatively more bystander behaviors for friends at the two-month follow-up assessment, compared to participants who viewed the control program. These results suggest that sexual violence prevention programs may be effectively adapted to an online format.

  5. Detection of chromosomal instability in α-irradiated and bystander human fibroblasts

    International Nuclear Information System (INIS)

    Ponnaiya, Brian; Jenkins-Baker, Gloria; Bigelow, Alan; Marino, Stephen; Geard, Charles R.

    2004-01-01

    There is increasing evidence biological responses to ionizing radiation are not confined to those cells that are directly hit, but may be seen in the progeny at subsequent generations (genomic instability) and in non-irradiated neighbors of irradiated cells (bystander effects). These so called non-targeted phenomena would have significant contributions to radiation-induced carcinogenesis, especially at low doses where only a limited number of cells in a population are directed hit. Here we present data using a co-culturing protocol examining chromosomal instability in α-irradiated and bystander human fibroblasts BJ1-htert. At the first cell division following exposure to 0.1 and 1 Gy α-particles, irradiated populations demonstrated a dose dependent increase in chromosome-type aberrations. At this time bystander BJ1-htert populations demonstrated elevated chromatid-type aberrations when compared to controls. Irradiated and bystander populations were also analyzed for chromosomal aberrations as a function of time post-irradiation. When considered over 25 doublings, all irradiated and bystander populations had significantly higher frequencies of chromatid aberrations when compared to controls (2-3-fold over controls) and were not dependent on dose. The results presented here support the link between the radiation-induced phenomena of genomic instability and the bystander effect

  6. Dispatcher instruction of chest compression-only CPR increases actual provision of bystander CPR.

    Science.gov (United States)

    Shimamoto, Tomonari; Iwami, Taku; Kitamura, Tetsuhisa; Nishiyama, Chika; Sakai, Tomohiko; Nishiuchi, Tatsuya; Hayashi, Yasuyuki; Kawamura, Takashi

    2015-11-01

    A preceding randomized controlled trial demonstrated that chest compression-only cardiopulmonary resuscitation (CPR) instruction by dispatcher was more effective to increase bystander CPR than conventional CPR instruction. However, the actual condition of implementation of each type of dispatcher instruction (chest compression-only CPR [CCCPR] or conventional CPR with rescue breathing) and provision of bystander CPR in real prehospital settings has not been sufficiently investigated. This registry prospectively enrolled patients aged =>18 years suffering an out-of-hospital cardiac arrest (OHCA) of non-traumatic causes before emergency-medical-service (EMS) arrival, who were considered as target subjects of dispatcher instruction, resuscitated by EMS personnel, and transported to medical institutions in Osaka, Japan from January 2005 through December 2012. The primary outcome measure was provision of CPR by a bystander. Multiple logistic regression analysis was used to assess factors that were potentially associated with provision of bystander CPR. Among 37,283 target subjects of dispatcher instruction, 5743 received CCCPR instruction and 13,926 received conventional CPR instruction. The proportion of CCCPR instruction increased from 5.7% in 2005 to 25.6% in 2012 (p for trend bystander CPR more frequently than conventional CPR instruction group (70.0% versus 62.1%, pbystander CPR compared with conventional CPR instruction (adjusted odds ratio 1.44, 95% CI 1.34-1.55). CCCPR dispatcher instruction among adult OHCA patients significantly increased the actual provision of bystander CPR. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  7. Radiation-induced bystander effects. Mechanisms, biological implications, and current investigations at the Leipzig LIPSION facility

    International Nuclear Information System (INIS)

    Oesterreicher, J.; Prise, K.M.; Michael, B.D.; Vogt, J.; Butz, T.; Tanner, J.M.

    2003-01-01

    Background: The bystander effect is a relatively new area of radiobiological research, which is aimed at studying post-radiation changes in neighboring non-hit cells or tissues. The bystander effect of ionizing irradiation is important after low-dose irradiation in the range of up to 0.2 Gy, where a higher incidence of stochastic damage was observed than was expected from a linear-quadratic model. It is also important when the irradiation of a cell population is highly non-uniform. Objective: This review summarizes most of the important results and proposed bystander effect mechanisms as well as their impact on theory and clinical practice. The literature, in parts contradictory, is collected, the main topics are outlined, and some basic papers are described in more detail. In order to illustrate the microbeam technique, which is considered relevant for the bystander effect research, the state of the Leipzig LIPSION nanoprobe facility is described. Results: The existence of a radiation-induced bystander effect is now generally accepted. The current state of knowledge on it is summarized here. Several groups worldwide are working on understanding its different aspects and its impact on radiobiology and radiation protection. Conclusion: The observation of a bystander effect has posed many questions, and answering them is a challenging topic for radiobiology in the future. (orig.)

  8. Radiation-induced bystander effects. Mechanisms, biological implications, and current investigations at the Leipzig LIPSION facility

    Energy Technology Data Exchange (ETDEWEB)

    Oesterreicher, J. [Dept. of Nuclear Solid State Physics, Univ. of Leipzig (Germany); Dept. of Radiobiology and Immunology, Purkyne Military Medical Academy, Hradec Kralove (Czech Republic); Prise, K.M.; Michael, B.D. [Gray Cancer Inst., Mount Vernon Hospital, Northwood, Middlesex (United Kingdom); Vogt, J.; Butz, T. [Dept. of Nuclear Solid State Physics, Univ. of Leipzig (Germany); Tanner, J.M. [Clinic and Polyclinic of Radiation Oncology, Martin Luther Univ. Halle-Wittenberg (Germany)

    2003-02-01

    Background: The bystander effect is a relatively new area of radiobiological research, which is aimed at studying post-radiation changes in neighboring non-hit cells or tissues. The bystander effect of ionizing irradiation is important after low-dose irradiation in the range of up to 0.2 Gy, where a higher incidence of stochastic damage was observed than was expected from a linear-quadratic model. It is also important when the irradiation of a cell population is highly non-uniform. Objective: This review summarizes most of the important results and proposed bystander effect mechanisms as well as their impact on theory and clinical practice. The literature, in parts contradictory, is collected, the main topics are outlined, and some basic papers are described in more detail. In order to illustrate the microbeam technique, which is considered relevant for the bystander effect research, the state of the Leipzig LIPSION nanoprobe facility is described. Results: The existence of a radiation-induced bystander effect is now generally accepted. The current state of knowledge on it is summarized here. Several groups worldwide are working on understanding its different aspects and its impact on radiobiology and radiation protection. Conclusion: The observation of a bystander effect has posed many questions, and answering them is a challenging topic for radiobiology in the future. (orig.)

  9. 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)

  10. Potential association of bystander-patient relationship with bystander response and patient survival in daytime out-of-hospital cardiac arrest.

    Science.gov (United States)

    Tanaka, Yoshio; Maeda, Tetsuo; Kamikura, Takahisa; Nishi, Taiki; Omi, Wataru; Hashimoto, Masaaki; Sakagami, Satoru; Inaba, Hideo

    2015-01-01

    To investigate whether the bystander-patient relationship affects bystander response to out-of-hospital cardiac arrest (OHCA) and patient outcomes depending on the time of day. This population-based observational study in Japan involving 139,265 bystander-witnessed OHCAs (90,426 family members, 10,479 friends/colleagues, and 38,360 others) without prehospital physician involvement was conducted from 2005 to 2009. Factors associated with better bystander response [early emergency call and bystander cardiopulmonary resuscitation (BCPR)] and 1-month neurologically favourable survival were assessed. The rates of dispatcher-assisted CPR during daytime (7:00-18:59) and nighttime (19:00-6:59) were highest in family members (45.6% and 46.1%, respectively, for family members; 28.7% and 29.2%, respectively, for friends/colleagues; and 28.1% and 25.3%, respectively, for others). However, the BCPR rates were lowest in family members (35.5% and 37.8%, respectively, for family members; 43.7% and 37.8%, respectively, for friends/colleagues; and 59.3% and 50.0%, respectively, for others). Large delays (≥ 5 min) in placing emergency calls and initiating BCPR were most frequent in family members. The overall survival rate was lowest (2.7%) for family members and highest (9.1%) for friends/colleagues during daytime. Logistic regression analysis revealed that the effect of bystander relationship on survival was significant only during daytime [adjusted odds ratios (95% CI) for survival from daytime OHCAs with family as reference were 1.51 (1.36-1.68) for friends/colleagues and 1.23 (1.13-1.34) for others]. Family members are least likely to perform BCPR and OHCAs witnessed by family members are least likely to survive during daytime. Different strategies are required for family-witnessed OHCAs. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  11. Association of initial rhythm with neurologically favorable survival in non-shockable out-of-hospital cardiac arrest without a bystander witness or bystander cardiopulmonary resuscitation.

    Science.gov (United States)

    Fukuda, Tatsuma; Ohashi-Fukuda, Naoko; Matsubara, Takehiro; Doi, Kent; Kitsuta, Yoichi; Nakajima, Susumu; Yahagi, Naoki

    2016-05-01

    Out-of-hospital cardiac arrest (OHCA) has a predominantly non-shockable rhythm. Non-shockable rhythm, and the absence of a bystander witness or bystander cardiopulmonary resuscitation (CPR) are associated with poor outcomes. However, the association between the type of non-shockable rhythm and outcomes is not well known. To examine the association between the initial rhythm and neurologically favorable outcomes after non-shockable OHCA without a bystander witness or bystander CPR. In a nationwide, population-based, cohort study, we analyzed 213,984 adult OHCA patients with a non-shockable rhythm who had neither a bystander witness nor bystander CPR. They were identified through the Japanese national OHCA registry data from January 1, 2005 to December 31, 2010. The primary outcome was neurologically favorable survival. Among 213,984 patients, the initial rhythm was Pulseless Electrical Activity (PEA) in 31,179 patients (14.6%) and Asystole in 182,805 patients (85.4%). The neurological outcome was more favorable in PEA than in Asystole (1.4% vs. 0.2%, padvanced airway management, time from call to contact with patient, and calendar year, PEA was associated with an increased neurologically favorable survival rate (odds ratio 7.86; 95% confidence interval 6.81-9.07). In subgroup analysis stratified by age group (18-64, 65-84, or ≥85years), the neurologically favorable survival rate was ≥1% in PEA, even for patients aged ≥85years, but <1% in Asystole among all age groups. PEA and Asystole should not be considered to be identical to non-shockable rhythm, but rather should be clearly distinguished from each other from the perspective of quantitative medical futility. Copyright © 2016 European Federation of Internal Medicine. Published by Elsevier B.V. All rights reserved.

  12. Optimal Mutagen Doses for Emiliania huxleyi

    Science.gov (United States)

    Byrne, P.

    2016-02-01

    Emiliania huxleyi (E. huxleyi) is one of the most prominent coccolithophores. Given favorable conditions, E. huxleyi blooms can reach sizes exceeding 100,000km2, with densities of 107 cells per L (Olson & Strom 2002). With increasing demand and limited supply of fossil fuels, it has become increasingly popular to look toward alternative renewable fuel sources. E. Huxleyi store energy predominately as uniquely structured polyunsaturated long chain (C37-39) alkenes, alkenones and alkenoates (abbreviated as PULCAs) (Eltgroth et al 2005). Unlike the stored energy of macroalgae and higher order plants, triacylglycerols (TAGs), PULCAs provide a similar composition to native petroleum crude oils (Yamane 2013), which offers a more cost effective and higher yielding extraction process (Wu et al 1999). A number of factors have been shown to influence the alkenone content of E. huxleyi, such as nitrogen deficiency, phosphate limitation (Li et al 2014), and temperature (Shiraiwa et al 2005). For these reasons E. huxleyi has the potential to be an attractive system for algal biofuel. The broad and long-term objective of our research is to elucidate the alkenone biosynthesis pathway in E. Huxleyi, using random mutagenesis techniques. We propose to use UV light and methylmethane sulfonate (MMS) to create a mutant population, from which clones unable to synthesize alkenones will be selected. Identifying genes whose specific mutations underlie the loss-of-function phenotype will then reveal genes of interest. The aim of this research was to determine the UV and MMS dose response rates for E. huxleyi to ascertain optimal doses defined as a 50% survival rate for each of the two mutagens. Preliminary data indicate that E. huxleyi appear to be highly sensitive to UV mutagenesis, with an LD50 of 0.57mJ/cm2 for the calcifying strain M217 and 0.96mJ/cm2 for the non-calcifying strain CCMP1516. Both calcifying and non-calcifying strains exhibit similar LD50 values for MMS at 1-2% (v/v).

  13. Urine mutagenicity of steel workers exposed to coke oven emissions

    Energy Technology Data Exchange (ETDEWEB)

    De Meo, M.P.; Dumenil, G.; Botta, A.H.; Laget, M.; Zabaloueff, V.; Mathias, A.

    1987-03-01

    Urine mutagenicity of 19 individuals was investigated at a steel mill. All the subjects worked on the coal processing unit. Urine samples were collected at the end of a working day. Urine samples of two exposed workers were collected at the end of two periods of rest and two periods of working. Mutagens were extracted on XAD-2 resin and tested by the Salmonella microsomal assay and the SOS spot test. Mutagenic potencies of exposed smokers and exposed non-smokers were 8.62 +/- 6.56 and 1.1 +/- 0.48 revertants/mg creatinine respectively with Salmonella typhimurium strain TA98 + S9. Both values were significantly higher than those of unexposed smokers and non-smokers (5.07 +/- 3.33 and 0.47 +/- 0.72 revertants/mg creatinine respectively). The urinary mutagenic potency of the two exposed individuals increased at the end of periods of working (15.97 +/- 2.57 revertants/mg creatinine) and decreased at the end of periods of rest (12.31 +/- 2.45 revertants/mg creatinine). Urinary mutagens were detected with S. typhimurium strain TA100 + S9 to a lesser extent. No direct-acting mutagens were detected by the SOS spot test. Atmospheric benzo(a)pyrene (BaP) were also measured by h.p.l.c. on the coke battery. BaP concentrations ranged between 0.01 and 0.6 microgram/m3 air at the different working sites. Biological monitoring with short-term tests is discussed.

  14. Mutagenicity of heated sugar-casein systems: effect of the Maillard reaction.

    Science.gov (United States)

    Brands, C M; Alink, G M; van Boekel, M A; Jongen, W M

    2000-06-01

    The formation of mutagens after the heating of sugar-casein model systems at 120 degrees C was examined by the Ames test, using Salmonella typhimurium strain TA100. Several sugars (glucose, fructose, galactose, tagatose, lactose, and lactulose) were compared in their mutagenicities. Mutagenicity could be fully ascribed to Maillard reaction products and strongly varied with the kind of sugar. The differences in mutagenicity among the sugar-casein systems were caused by a difference in reaction rate and a difference in reaction mechanism. Sugars with a comparable reaction mechanism (glucose and galactose) showed a higher mutagenic activity corresponding with a higher Maillard reactivity. Disaccharides showed no mutagenic activity (lactose) or a lower mutagenic activity (lactulose) than their corresponding monosaccharides. Ketose sugars (fructose and tagatose) showed a remarkably higher mutagenicity compared with their aldose isomers (glucose and galactose), which was due to a difference in reaction mechanism.

  15. Regions With Low Rates of Bystander Cardiopulmonary Resuscitation (CPR) Have Lower Rates of CPR Training in Victoria, Australia.

    Science.gov (United States)

    Bray, Janet E; Straney, Lahn; Smith, Karen; Cartledge, Susie; Case, Rosalind; Bernard, Stephen; Finn, Judith

    2017-06-05

    Bystander cardiopulmonary resuscitation (CPR) more than doubles the chance of surviving an out-of-hospital cardiac arrest. Recent data have shown considerable regional variation in bystander CPR rates across the Australian state of Victoria. This study aims to determine whether there is associated regional variation in rates of CPR training and willingness to perform CPR in these communities. We categorized each Victorian postcode as either a low or high bystander CPR region using data on adult, bystander-witnessed, out-of-hospital cardiac arrests of presumed cardiac etiology (n=7175) from the Victorian Ambulance Cardiac Arrest Registry. We then surveyed adult Victorians (n=404) and compared CPR training data of the respondents from low and high bystander CPR regions. Of the 404 adults surveyed, 223 (55%) resided in regions with low bystander CPR. Compared with respondents from high bystander CPR regions, respondents residing in regions with low bystander CPR had lower rates of CPR training (62% versus 75%, P =0.009) and lower self-ratings for their overall knowledge of CPR (76% versus 84%, P =0.04). There were no differences between the regions in their reasons for not having undergone CPR training or in their willingness to perform CPR. Rates of survival for bystander-witnessed, out-of-hospital cardiac arrests were significantly lower in low bystander CPR regions (15.7% versus 17.0%, P CPR training and lower survival in regions with lower rates of bystander CPR in Victoria, Australia. Targeting these regions with CPR training programs may improve bystander CPR rates and out-of-hospital cardiac arrest outcomes. © 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

  16. Damaging and protective bystander cross-talk between human lung cancer and normal cells after proton microbeam irradiation

    International Nuclear Information System (INIS)

    Desai, Sejal; Kobayashi, Alisa; Konishi, Teruaki; Oikawa, Masakazu; Pandey, Badri N.

    2014-01-01

    Graphical abstract: - Highlights: • Proton-microbeam irradiated A549 cells send damaging signals to bystander A549 cells. • Irradiated A549–A549 bystander response is through gap junctional communication. • Bystander WI38 cells exert protective signalling in irradiated A549 cells. • Rescue of irradiated A549 cells by WI38 cells is independent of gap junctions. - Abstract: Most of the studies of radiation-induced bystander effects (RIBE) have been focused on understanding the radiobiological changes observed in bystander cells in response to the signals from irradiated cells in a normal cell population with implications to radiation risk assessment. However, reports on RIBE with relevance to cancer radiotherapy especially investigating the bidirectional and criss-cross bystander communications between cancer and normal cells are limited. Hence, in present study employing co-culture approach, we have investigated the bystander cross-talk between lung cancer (A549) and normal (WI38) cells after proton-microbeam irradiation using γ-H2AX foci fluorescence as a measure of DNA double-strand breaks (DSBs). We observed that in A549–A549 co-cultures, irradiated A549 cells exert damaging effects in bystander A549 cells, which were found to be mediated through gap junctional intercellular communication (GJIC). However, in A549–WI38 co-cultures, irradiated A549 did not affect bystander WI38 cells. Rather, bystander WI38 cells induced inverse protective signalling (rescue effect) in irradiated A549 cells, which was independent of GJIC. On the other hand, in response to irradiated WI38 cells neither of the bystander cells (A549 or WI38) showed significant increase in γ-H2AX foci. The observed bystander signalling between tumour and normal cells may have potential implications in therapeutic outcome of cancer radiotherapy

  17. Damaging and protective bystander cross-talk between human lung cancer and normal cells after proton microbeam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Desai, Sejal [Radiation Signalling and Cancer Biology Section, Radiation Biology and Health Sciences Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Kobayashi, Alisa; Konishi, Teruaki; Oikawa, Masakazu [Radiation System and Engineering Section, Department of Technical Support and Development, Research, Development and Support Center, National Institute of Radiological Sciences, Chiba 263-8555 (Japan); Pandey, Badri N., E-mail: badrinarain@yahoo.co.in [Radiation Signalling and Cancer Biology Section, Radiation Biology and Health Sciences Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India)

    2014-05-15

    Graphical abstract: - Highlights: • Proton-microbeam irradiated A549 cells send damaging signals to bystander A549 cells. • Irradiated A549–A549 bystander response is through gap junctional communication. • Bystander WI38 cells exert protective signalling in irradiated A549 cells. • Rescue of irradiated A549 cells by WI38 cells is independent of gap junctions. - Abstract: Most of the studies of radiation-induced bystander effects (RIBE) have been focused on understanding the radiobiological changes observed in bystander cells in response to the signals from irradiated cells in a normal cell population with implications to radiation risk assessment. However, reports on RIBE with relevance to cancer radiotherapy especially investigating the bidirectional and criss-cross bystander communications between cancer and normal cells are limited. Hence, in present study employing co-culture approach, we have investigated the bystander cross-talk between lung cancer (A549) and normal (WI38) cells after proton-microbeam irradiation using γ-H2AX foci fluorescence as a measure of DNA double-strand breaks (DSBs). We observed that in A549–A549 co-cultures, irradiated A549 cells exert damaging effects in bystander A549 cells, which were found to be mediated through gap junctional intercellular communication (GJIC). However, in A549–WI38 co-cultures, irradiated A549 did not affect bystander WI38 cells. Rather, bystander WI38 cells induced inverse protective signalling (rescue effect) in irradiated A549 cells, which was independent of GJIC. On the other hand, in response to irradiated WI38 cells neither of the bystander cells (A549 or WI38) showed significant increase in γ-H2AX foci. The observed bystander signalling between tumour and normal cells may have potential implications in therapeutic outcome of cancer radiotherapy.

  18. Determining effective radiation mutagen dose for garlic (Allium sativum L.)

    International Nuclear Information System (INIS)

    Taner, Y.; Kunter, B.

    2004-01-01

    This study was carried out to get database for future garlic mutation breeding studies. For this aim, 0, 5, 10, 15, 20, 25 and 30 Gy doses of Cs 137 (gamma-ray) were applied on garlic cloves as a physical mutagen. 50 cloves were used for each dose. Sixty days after treatment, germination rate and shoot development of cloves were determined. The Effective Mutagen Dose (ED 50 ) was calculated by regression analyses. According to the results, 4.455 Gy dose was found to be effective as ED 50 . (author)

  19. Mutagen induced variability in Ragi (Eleucine coracana Gaertn)

    International Nuclear Information System (INIS)

    Haider, Z.A.; Mahto, J.L.; Kumar, Binod

    1996-01-01

    Varieties A-404 and HR-374 of Ragi (Eleucine coracana Gaertn) when subjected to different doses of gamma rays, EMS and their combination treatments showed a linear reverse relationship between doses and germination percentage. The same was true for seedling survival and pollen fertility. Variety A-404 proved to be more sensitive to all mutagenic treatments as compared to the variety HR-374. There was, however, a general gain with respect to panicle length in most of the treatments, where as for a number of fingers per panicle no order could be observed in any of the mutagen used. (author). 10 refs., 2 tabs

  20. Study on increasing mutagenic efficiency of radiation breeding for rice

    International Nuclear Information System (INIS)

    Wan Xianguo; Pang Boliang; Zhu Xiaoqi

    1993-04-01

    Increasing mutagenic efficiency and improving selection method are of important topics for crop mutation breeding. Investigation on the radiation breeding for rice (Oryza Sativa L.) showed that the crossing in combination with gamma ray irradiation or laser irradiation and proper selection of dosage rate can increase mutagenic efficiency. According to the correlation of phenotype in M 1 generation and mutation frequency in M 2 for rice, the materials with certain characters were chose as seeds, thus the works of generation selections will be reduced

  1. Environmental chemical mutagens and genetic risks: Lessons from radiation genetics

    International Nuclear Information System (INIS)

    Sankaranarayanan, K.

    1996-01-01

    The last three decades have witnessed substantial progress in the development and use of a variety of in vitro and in vivo assay systems for the testing of environmental chemicals which may pose a mutagenic hazard to humans. This is also true of basic studies in chemical mutagenesis on mechanisms, DNA repair, molecular dosimetry, structure-activity relationships, etc. However, the field of quantitative evaluation of genetic risks of environmental chemicals to humans is still in it infancy. This commentary addresses the question of how our experience in estimating genetic risks of exposure to ionizing radiation can be helpful in similar endeavors with environmental chemical mutagens. 24 refs., 3 tabs

  2. Characteristics and mechanisms of the bystander response in monolayer cell cultures exposed to very low fluences of alpha particles

    International Nuclear Information System (INIS)

    Little, John B.; Azzam, Edouard I.; Toledo, Sonia M. de; Nagasawa, Hatsumi

    2005-01-01

    When confluent cultures of mammalian cells are irradiated with very low fluences of alpha particles whereby only occasional cells receive any radiation exposure, genetic changes are observed in the non-irradiated ('bystander') cells. Upregulation of the p53 damage-response pathway as well as activation of proteins in the MAPK family occurred in bystander cells; p53 was phosphorylated on the serine 15 residue suggesting that the upregulation of p53 was a consequence of DNA damage. Damage signals were transmitted to bystander cells through gap junctions, as confirmed by the use of genetically manipulated cells including connexin43 knockouts. Expression of connexin43 was markedly enhanced by irradiation. A moderate bystander effect was observed for specific gene mutations and chromosomal aberrations. This effect was markedly enhanced in cells defective in the non-homologous end joining DNA repair pathway. Finally, an upregulation of oxidative metabolism occurred in bystander cells; the increased levels of reactive oxygen species appeared to be derived from flavine-containing oxidase enzymes. We hypothesize that genetic effects observed in non-irradiated bystander cells are a consequence of oxidative base damage; >90% of mutations in bystander cells were point mutations. When bystander cells cannot repair DNA double strand breaks, they become much more sensitive to the induction of chromosomal aberrations and mutations, the latter consisting primarily of deletion mutants. While we propose that the genetic effects occurring in bystander cells are a consequence of oxidative stress, the nature of the signal that initiates this process remains to be determined

  3. Evaluation of the Green Dot Bystander Intervention to Reduce Interpersonal Violence Among College Students Across Three Campuses

    Science.gov (United States)

    Coker, Ann L.; Fisher, Bonnie S.; Bush, Heather M.; Swan, Suzanne C.; Williams, Corrine M.; Clear, Emily R.; DeGue, Sarah

    2018-01-01

    Evidence suggests that interventions to engage bystanders in violence prevention increase bystander intentions and efficacy to intervene, yet the impact of such programs on violence remains unknown. This study compared rates of violence by type among undergraduate students attending a college campus with the Green Dot bystander intervention (n = 2,768) with students at two colleges without bystander programs (n = 4,258). Violent victimization rates were significantly (p Violence perpetration rates were lower among males attending the intervention campus. Implications of these results for research and practice are discussed. PMID:25125493

  4. Evaluation of the Green Dot Bystander Intervention to Reduce Interpersonal Violence Among College Students Across Three Campuses.

    Science.gov (United States)

    Coker, Ann L; Fisher, Bonnie S; Bush, Heather M; Swan, Suzanne C; Williams, Corrine M; Clear, Emily R; DeGue, Sarah

    2015-12-01

    Evidence suggests that interventions to engage bystanders in violence prevention increase bystander intentions and efficacy to intervene, yet the impact of such programs on violence remains unknown. This study compared rates of violence by type among undergraduate students attending a college campus with the Green Dot bystander intervention (n = 2,768) with students at two colleges without bystander programs (n = 4,258). Violent victimization rates were significantly (p < .01) lower among students attending the campus with Green Dot relative to the two comparison campuses. Violence perpetration rates were lower among males attending the intervention campus. Implications of these results for research and practice are discussed. © The Author(s) 2014.

  5. 40 Years of the Salmonella Mutagenicity Assay: Implications for 21st Century Toxicology

    Science.gov (United States)

    The Salmonella (Ames) mutagenicity assay was developed and introduced by Bruce Ames and colleagues in 1971. Since then, it has become the standard assay for hazard identification of mutagens worldwide. It is a first-tier test for mutagenic activity in the pharmaceutical and chemi...

  6. Mutagenic and antimutagenic activities of bioflavonoids and structural analogues in the Ames/Salmonella test

    NARCIS (Netherlands)

    Mohn GR; Van der Stel JJ; Stavenuiter JFC; Hamzink MRJ; Kreijl CF; LEO; LBO

    1996-01-01

    The mutagenic and antimutagenic properties of bioflavonoids were determined in the bacterial mutagenicity test of Ames, using Salmonella typhimurium strains TA98 and TA100. The decreasing order of mutagenic activity found in both strains was quercetin>myricetin-kaempferol>morin hydrate. The

  7. Mutagenicity of heated sugar-casein systems : effect of the Maillard :reaction

    NARCIS (Netherlands)

    Brands, C.M.J.; Alink, G.M.; Boekel, van M.A.J.S.; Jongen, W.M.F.

    2000-01-01

    The formation of mutagens after the heating of sugar-casein model systems at 120 C was examined by the Ames test, using Salmonella typhimurium strain TA100. Several sugars (glucose, fructose, galactose, tagatose, lactose, and lactulose) were compared in their mutagenicities. Mutagenicity could be

  8. 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

  9. Single cell low dose studies of bystander cell killing with targeted ultrasoft x-rays

    International Nuclear Information System (INIS)

    Schettino, G.; Prise, K.M.; Folkard, M.; Vojnovic, B.; Michael, B.D.; Wu, L.; Held, K.D.

    2003-01-01

    Full text: Bystander responses have attracted considerable interest in the recent years and several investigations have reported a binary behavior with the effect triggered by very small doses and immediately reaching a plateau. The Ultrasoft X-ray Microprobe in operation at the GCI is a facility designed to precisely assess the biological response of individual cells in vitro irradiated with a sub-micron size X-ray beam . Although recent improvements have upgrade the facility with AlK and TiK X-rays, most of the bystander studies have been performed using CK X-rays of 278 eV. The high sensitivity and the accurate irradiation and revisiting of the individual samples allowed us to investigate specific characteristics of the bystander phenomenon. In particular, evidences of a dose dependency of cell killing by bystander effect have been found at doses below 0.2 Gy where no differences is observed between all cell and single cell irradiation. Recent improvements have also allowed us to individually identify the phase of the cell cycle of all samples exposed. Although the G2-S phase have been found the most sensitive in responding to the bystander signal (a factor of 1.3), cells in the G1 phase also respond significantly while the phase of the irradiated cell doesn't seem to play a critical role. The time scale of the bystander effect has also been investigated by irradiating the same sample(s) twice with a few hours gap between exposures. Results indicate that the bystander signal is transmitted within a few minutes from the irradiation as replacing the medium immediately after irradiation does not influence the response, and it doesn't depend on the number of cells irradiated (up to 5). However, after a resting time of a few hours (3 h), the system seems to reset itself and a second irradiation has been shown to trigger a further bystander effect. Finally, by considering the total amount of energy deposited in to the sample population as critical parameter (instead

  10. Assessment of mutagenic, antimutagenic and genotoxicity effects of Mimosa tenuiflora

    Directory of Open Access Journals (Sweden)

    Viviane A. Silva

    2013-02-01

    Full Text Available Genotoxic effects of Mimosa tenuiflora (Willd. Poir, Fabaceae, were investigated by using both micronucleus test and bacterial reverse mutation assay in Salmonella typhimurium TA97, TA98, TA100, TA102 respectively. In respect of Ames test results show that the extract does not induce mutations in any strains of Salmonella typhimurium tested since the mutagenicity index is less than 2. In the antimutagenic effect was observed that the extract at the concentrations tested significantly decreased the mutagenicity index of all strains tested which characterized the extract as antimutagenic in these conditions. In the micronucleus test in vivo, we observed that the concentrations used did not induce an increase in the frequency of micronucleus in normochromatic erythrocytes of mice. Therefore, we concluded that the extract of M. tenuiflora is not mutagenic in the absence of exogenous metabolizing system and does not induce an increase in the frequency of the micronucleus characterized as an agent not mutagenic in these conditions. Further studies of toxicity need to be made to the use of this plant in the treatment of diseases to be stimulated.

  11. Assessment of mutagenic, antimutagenic and genotoxicity effects of Mimosa tenuiflora

    Directory of Open Access Journals (Sweden)

    Viviane A. Silva

    2013-04-01

    Full Text Available Genotoxic effects of Mimosa tenuiflora (Willd. Poir, Fabaceae, were investigated by using both micronucleus test and bacterial reverse mutation assay in Salmonella typhimurium TA97, TA98, TA100, TA102 respectively. In respect of Ames test results show that the extract does not induce mutations in any strains of Salmonella typhimurium tested since the mutagenicity index is less than 2. In the antimutagenic effect was observed that the extract at the concentrations tested significantly decreased the mutagenicity index of all strains tested which characterized the extract as antimutagenic in these conditions. In the micronucleus test in vivo, we observed that the concentrations used did not induce an increase in the frequency of micronucleus in normochromatic erythrocytes of mice. Therefore, we concluded that the extract of M. tenuiflora is not mutagenic in the absence of exogenous metabolizing system and does not induce an increase in the frequency of the micronucleus characterized as an agent not mutagenic in these conditions. Further studies of toxicity need to be made to the use of this plant in the treatment of diseases to be stimulated.

  12. Effectiveness and efficiency of chemical mutagens in cowpea (Vigna ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-11-19

    Nov 19, 2008 ... A study was undertaken in a cowpea (Vigna unguiculata (L.) Walp.) variety CO 6 to assess the efficiency and effectiveness of chemical mutagens; ethyl methane sulphonate (EMS), diethyl sulphate (DES) and sodium azide (SA). EMS treatments were found highly effective than the other chemicals.

  13. The molecular properties of nitrobenzanthrone isomers and their mutagenic activities.

    Science.gov (United States)

    Ostojić, Bojana D; Stanković, Branislav; Ðorđević, Dragana S

    2014-06-01

    The mutagenic activity of five mono-substituted nitrobenzanthrones (NBA) has been determined in the Ames assay (Takamura-Enya et al., 2006). In the present study, a theoretical investigation of the electronic properties of all mono-substituted NBA isomers and their relation to mutagenic activity are presented. Equilibrium geometries, vertical ionization potentials (VIP), vertical electron affinities (VEA), relative energies, dipole moments and electronic dipole polarizabilities, and the IR and Raman spectra of NBA isomers calculated by Density Functional Theory (DFT) methods are presented. The position of the nitro group affects the spectral features of the IR and Raman spectra of the NBA isomers. The results show that a good linear relationship exists between the summation of Raman activities (∑ARaman) over all the 3N-6 vibrational modes and the mutagenic activity of the NBA isomers in Salmonella typhimurium strains. The spectroscopic results suggest that the unknown mutagenic activities of 4-NBA, 5-NBA, 6-NBA, 8-NBA and 10-NBA are predicted to follow the order 4-NBA>10-NBA>5-NBA>8-NBA>6-NBA. Copyright © 2013 Elsevier Ltd. All rights reserved.

  14. Micronuclei frequency in children exposed to environmental mutagens: a review

    DEFF Research Database (Denmark)

    Neri, Monica; Fucic, Aleksandra; Knudsen, Lisbeth E

    2003-01-01

    studies in children are a promising field, since because of evident differences in the uptake, metabolism, distribution and excretion of mutagens this population seems to be more susceptible than adults. Further, the effect of major confounders such as cigarettes smoking, occupation, life...

  15. Absence of Mutagenicity in Three Nigerian Medicinal Plants ...

    African Journals Online (AJOL)

    Erah

    of the medicinal plant trade in the region [2]. One of the basic criteria set by World Health. Organization (WHO) for the use of herbs as medicines is that they should be shown to be non-toxic [3,4]. Bacterial reverse mutation assay (Ames test) was used in this work to evaluate the mutagenic potential of the methanolic extracts ...

  16. (Anti)mutagenic and immunomodulatory properties of quercetin glycosides

    Czech Academy of Sciences Publication Activity Database

    Valentová, Kateřina; Šíma, Petr; Rybková, Z.; Křižan, Jiří; Malachová, K.; Křen, Vladimír

    2016-01-01

    Roč. 96, č. 5 (2016), s. 1492-1499 ISSN 0022-5142 R&D Projects: GA ČR(CZ) GAP301/11/0767; GA MŠk(CZ) LD14096 Institutional support: RVO:61388971 Keywords : quercetin glycosides * (anti)mutagenicity * mice Subject RIV: EE - Microbiology, Virology Impact factor: 2.463, year: 2016

  17. Genotoxicity and mutagenicity of solid waste leachates: A review

    African Journals Online (AJOL)

    user

    2013-07-03

    Jul 3, 2013 ... There is need for a shift from waste disposal to sustainable waste management. Awareness on possible health ... Key words: Solid waste leachate, genotoxicity, mutagenicity, environmental pollution. INTRODUCTION. Solid wastes .... landfills and incineration residues from Japan include persistent organic ...

  18. Spontaneous mutation by mutagenic repair of spontaneous lesions in DNA

    International Nuclear Information System (INIS)

    Hastings, P.J.; Quah, S.-K.; Borstel, R.C. von

    1976-01-01

    It is stated that strains of yeast carrying mutations in many of the steps in pathways repairing radiation-induced damage to DNA have enhanced spontaneous mutation rates. Most strains isolated because they have enhanced spontaneous mutation carry mutations in DNA repair systems. This suggests that much spontaneous mutation arises by mutagenic repair of spontaneous lesions. (author)

  19. Mutagenic and antimutagenic potentials of fruit juices of five ...

    African Journals Online (AJOL)

    Mutagenic and antimutagenic activities of freeze dried fruit juices (FDFJ) of Morinda elliptica Ridl. (Rubiaceae), Morinda citrifolia L. (Rubiaceae), Averrhoa bilimbi L. (Oxalidaceae), Phyllantus acidus (L.) Skeels (Phyllantaceae) and Myristica fragrans Houtt. (Myristicaceae) in Allium cepa L was evaluated. Testing the ...

  20. 28. Annual Meeting of the European Environmental Mutagen Society

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-09-01

    The 28{sup th} Annual Meeting of the European Environmental Mutagen Society took place in Salzburg from September 7{sup th} till September 11{sup th}, 1998. A lot of presentations also dealt with many radiation effects on cells, chromosomal aberrations and genetic effects caused by radioactive irradiation. In vivo and in vitro experiments concerning radiation injuries and carcinomas are analyzed. (Cecil)

  1. 28. Annual Meeting of the European Environmental Mutagen Society

    International Nuclear Information System (INIS)

    1998-09-01

    The 28 th Annual Meeting of the European Environmental Mutagen Society took place in Salzburg from September 7 th till September 11 th , 1998. A lot of presentations also dealt with many radiation effects on cells, chromosomal aberrations and genetic effects caused by radioactive irradiation. In vivo and in vitro experiments concerning radiation injuries and carcinomas are analyzed. (Cecil)

  2. Mutagenicity and chemical characterization of two petroleum distillates.

    Science.gov (United States)

    Carver, J H; MacGregor, J A; King, R W

    1984-08-01

    To investigate if the Salmonella/microsome assay could reliably screen complex petroleum samples for their carcinogenic potential, two high boiling (700-1070 degrees F) petroleum distillates with known activity in a dermal carcinogenesis bioassay were fully characterized with respect to their hydrocarbon composition and polynuclear aromatic hydrocarbon (PNA) content and assayed for mutagenic activity. Mutagenicity assays were also carried out on the aromatic hydrocarbon aggregates separated from these oils by adsorption chromatography. The composition of the distillates differed substantially, and reflected the fact that they were derived from crude oils that were extremely divergent in hydrocarbon character. Both the distillate and aromatic samples consistently induced a very slight increase in revertant TA98 and TA100 colonies; however, an increase of 2-4-fold over background was observed when the S-9 concentration was increased 5-10 times that of the standard assay. The maximal response was less than that expected from the samples' known PNA content and observed potency in the dermal carcinogenesis bioassay. In the Salmonella/microsome assay, all samples inhibited the mutagenic activity of added benzo[a]pyrene. Discordance between the magnitude of the samples' mutagenic activity and their known PNA content may be related to direct or indirect inhibition of sample PNAs by other components of the complex petroleum fractions. Observed inhibitory effects support the use of elevated S-9 concentration in the in vitro assays assessing the carcinogenic potential of petroleum-derived materials.

  3. Mutagenic potentials of crataegus and laxaricin in human blood ...

    African Journals Online (AJOL)

    Single cell gel electrophoresis (SCGE) or comet assay was introduced as a microelectrophoretic method for direct visualization of DNA damage in individual cells. Green plants in general contain mutagenic and carcinogenic substances, but there is little information. Due to the increased use and availability of herbal ...

  4. MUTAGEN: Multi-user tool for annotating GENomes

    DEFF Research Database (Denmark)

    Brugger, K.; Redder, P.; Skovgaard, Marie

    2003-01-01

    MUTAGEN is a free prokaryotic annotation system. It offers the advantages of genome comparison, graphical sequence browsers, search facilities and open-source for user-specific adjustments. The web-interface allows several users to access the system from standard desktop computers. The Sulfolobus...

  5. Bystander first aid in trauma - prevalence and quality: a prospective observational study.

    Science.gov (United States)

    Bakke, H K; Steinvik, T; Eidissen, S-I; Gilbert, M; Wisborg, T

    2015-10-01

    Bystander first aid and basic life support can likely improve victim survival in trauma. In contrast to bystander first aid and out-of-hospital cardiac arrest, little is known about the role of bystanders in trauma response. Our aim was to determine how frequently first aid is given to trauma victims by bystanders, the quality of this aid, the professional background of first-aid providers, and whether previous first-aid training affects aid quality. We conducted a prospective 18-month study in two mixed urban-rural Norwegian counties. The personnel on the first ambulance responding to trauma calls assessed and documented first aid performed by bystanders using a standard form. A total of 330 trauma calls were included, with bystanders present in 97% of cases. Securing an open airway was correctly performed for 76% of the 43 patients in need of this first-aid measure. Bleeding control was provided correctly for 81% of 63 patients for whom this measure was indicated, and prevention of hypothermia for 62% of 204 patients. Among the first-aid providers studied, 35% had some training in first aid. Bystanders with documented first-aid training gave better first aid than those where first-aid training status was unknown. A majority of the trauma patients studied received correct pre-hospital first aid, but still there is need for considerable improvement, particularly hypothermia prevention. Previous first-aid training seems to improve the quality of first aid provided. The effect on patient survival needs to be investigated. © 2015 The Authors. The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  6. Target irradiation induced bystander effects between stem-like and non stem-like cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yu [State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China); Space Radiation Research Unit, International Open Laboratory, National Institute of Radiological Sciences, 4-9-1 Inage-ku, Chiba 263-8555 (Japan); Kobayashi, Alisa [Space Radiation Research Unit, International Open Laboratory, National Institute of Radiological Sciences, 4-9-1 Inage-ku, Chiba 263-8555 (Japan); Department of Technical Support and Development, National Institute of Radiological Sciences, 4-9-1 Inage-ku, Chiba 263-8555 (Japan); Maeda, Takeshi [Department of Technical Support and Development, National Institute of Radiological Sciences, 4-9-1 Inage-ku, Chiba 263-8555 (Japan); Fu, Qibin [State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China); Oikawa, Masakazu [Department of Technical Support and Development, National Institute of Radiological Sciences, 4-9-1 Inage-ku, Chiba 263-8555 (Japan); Yang, Gen, E-mail: gen.yang@pku.edu.cn [State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China); Space Radiation Research Unit, International Open Laboratory, National Institute of Radiological Sciences, 4-9-1 Inage-ku, Chiba 263-8555 (Japan); Konishi, Teruaki, E-mail: tkonishi@nirs.go.jp [Space Radiation Research Unit, International Open Laboratory, National Institute of Radiological Sciences, 4-9-1 Inage-ku, Chiba 263-8555 (Japan); Department of Technical Support and Development, National Institute of Radiological Sciences, 4-9-1 Inage-ku, Chiba 263-8555 (Japan); Uchihori, Yukio [Space Radiation Research Unit, International Open Laboratory, National Institute of Radiological Sciences, 4-9-1 Inage-ku, Chiba 263-8555 (Japan); Department of Technical Support and Development, National Institute of Radiological Sciences, 4-9-1 Inage-ku, Chiba 263-8555 (Japan); and others

    2015-03-15

    Highlights: • Existence of radiation induced bystander effects (RIBE) between cancer stem-like cells (CSCs) and non stem-like cancer cells (NSCCs) in human fibrosarcoma HT1080 cells. • Existence of significant difference in generation and response of bystander signals between CSCs and NSCCs. • CSCs are significantly less sensitive to NO scavenger than that of NSCCs in terms of DNA double strand breaks induced by RIBE. - Abstract: Tumors are heterogeneous in nature and consist of multiple cell types. Among them, cancer stem-like cells (CSCs) are suggested to be the principal cause of tumor metastasis, resistance and recurrence. Therefore, understanding the behavior of CSCs in direct and indirect irradiations is crucial for clinical radiotherapy. Here, the CSCs and their counterpart non stem-like cancer cells (NSCCs) in human HT1080 fibrosarcoma cell line were sorted and labeled, then the two cell subtypes were mixed together and chosen separately to be irradiated via a proton microbeam. The radiation-induced bystander effect (RIBE) between the CSCs and NSCCs was measured by imaging 53BP1 foci, a widely used indicator for DNA double strand break (DSB). CSCs were found to be less active than NSCCs in both the generation and the response of bystander signals. Moreover, the nitric oxide (NO) scavenger c-PTIO can effectively alleviate the bystander effect in bystander NSCCs but not in bystander CSCs, indicating a difference of the two cell subtypes in NO signal response. To our knowledge, this is the first report shedding light on the RIBE between CSCs and NSCCs, which might contribute to a further understanding of the out-of-field effect in cancer radiotherapy.

  7. Target irradiation induced bystander effects between stem-like and non stem-like cancer cells

    International Nuclear Information System (INIS)

    Liu, Yu; Kobayashi, Alisa; Maeda, Takeshi; Fu, Qibin; Oikawa, Masakazu; Yang, Gen; Konishi, Teruaki; Uchihori, Yukio

    2015-01-01

    Highlights: • Existence of radiation induced bystander effects (RIBE) between cancer stem-like cells (CSCs) and non stem-like cancer cells (NSCCs) in human fibrosarcoma HT1080 cells. • Existence of significant difference in generation and response of bystander signals between CSCs and NSCCs. • CSCs are significantly less sensitive to NO scavenger than that of NSCCs in terms of DNA double strand breaks induced by RIBE. - Abstract: Tumors are heterogeneous in nature and consist of multiple cell types. Among them, cancer stem-like cells (CSCs) are suggested to be the principal cause of tumor metastasis, resistance and recurrence. Therefore, understanding the behavior of CSCs in direct and indirect irradiations is crucial for clinical radiotherapy. Here, the CSCs and their counterpart non stem-like cancer cells (NSCCs) in human HT1080 fibrosarcoma cell line were sorted and labeled, then the two cell subtypes were mixed together and chosen separately to be irradiated via a proton microbeam. The radiation-induced bystander effect (RIBE) between the CSCs and NSCCs was measured by imaging 53BP1 foci, a widely used indicator for DNA double strand break (DSB). CSCs were found to be less active than NSCCs in both the generation and the response of bystander signals. Moreover, the nitric oxide (NO) scavenger c-PTIO can effectively alleviate the bystander effect in bystander NSCCs but not in bystander CSCs, indicating a difference of the two cell subtypes in NO signal response. To our knowledge, this is the first report shedding light on the RIBE between CSCs and NSCCs, which might contribute to a further understanding of the out-of-field effect in cancer radiotherapy

  8. An extracellular DNA mediated bystander effect produced from low dose irradiated endothelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Ermakov, Aleksei V., E-mail: avePlato@mail.ru [Research Centre for Medical Genetics, Russian Academy of Medical Sciences, Moscow (Russian Federation); Konkova, Marina S.; Kostyuk, Svetlana V.; Smirnova, Tatiana D.; Malinovskaya, Elena M.; Efremova, Liudmila V.; Veiko, Natalya N. [Research Centre for Medical Genetics, Russian Academy of Medical Sciences, Moscow (Russian Federation)

    2011-07-01

    The human umbilical vein endothelial cells culture was exposed to X-ray radiation in a low dose of 10 cGy. The fragments of extracellular genomic DNA (ecDNA{sup R}) were isolated from the culture medium after the short-term incubation. A culture medium of unirradiated endothelial cells was then supplemented with ecDNA{sup R}, followed by analysing the cells along the series of parameters (bystander effect). The exposed cells and bystander endotheliocytes showed similar response to low doses: approximation of the 1q12 loci of chromosome 1 and their transposition into the cellular nucleus, change in shape of the endotheliocytic nucleus, activation of the nucleolus organizing regions (NORs), actin polymerization, and an elevated level of DNA double-stranded breaks. Following blockade of TLR9 receptors with oligonucleotide-inhibitor or chloroquine in the bystander cells these effects - except of activation of NORs - on exposure to ecDNA{sup R} disappeared, with no bystander response thus observed. The presence of the radiation-induced apoptosis in the bystander effect being studied suggests a possibility for radiation-modified ecDNA fragments (i.e., stress signaling factors) to be released into the culture medium, whereas inhibition of TLR9 suggests the binding these ligands to the recipient cells. A similar DNA-signaling pathway in the bystander effect we previously described for human lymphocytes. Integrity of data makes it possible to suppose that a similar signaling mechanism which we demonstrated for lymphocytes (humoral system) might also be mediated in a monolayer culture of cells (cellular tissue) after the development of the bystander effect in them and transfer of stress signaling factors (ecDNA{sup R}) through the culture medium.

  9. An extracellular DNA mediated bystander effect produced from low dose irradiated endothelial cells

    International Nuclear Information System (INIS)

    Ermakov, Aleksei V.; Konkova, Marina S.; Kostyuk, Svetlana V.; Smirnova, Tatiana D.; Malinovskaya, Elena M.; Efremova, Liudmila V.; Veiko, Natalya N.

    2011-01-01

    The human umbilical vein endothelial cells culture was exposed to X-ray radiation in a low dose of 10 cGy. The fragments of extracellular genomic DNA (ecDNA R ) were isolated from the culture medium after the short-term incubation. A culture medium of unirradiated endothelial cells was then supplemented with ecDNA R , followed by analysing the cells along the series of parameters (bystander effect). The exposed cells and bystander endotheliocytes showed similar response to low doses: approximation of the 1q12 loci of chromosome 1 and their transposition into the cellular nucleus, change in shape of the endotheliocytic nucleus, activation of the nucleolus organizing regions (NORs), actin polymerization, and an elevated level of DNA double-stranded breaks. Following blockade of TLR9 receptors with oligonucleotide-inhibitor or chloroquine in the bystander cells these effects - except of activation of NORs - on exposure to ecDNA R disappeared, with no bystander response thus observed. The presence of the radiation-induced apoptosis in the bystander effect being studied suggests a possibility for radiation-modified ecDNA fragments (i.e., stress signaling factors) to be released into the culture medium, whereas inhibition of TLR9 suggests the binding these ligands to the recipient cells. A similar DNA-signaling pathway in the bystander effect we previously described for human lymphocytes. Integrity of data makes it possible to suppose that a similar signaling mechanism which we demonstrated for lymphocytes (humoral system) might also be mediated in a monolayer culture of cells (cellular tissue) after the development of the bystander effect in them and transfer of stress signaling factors (ecDNA R ) through the culture medium.

  10. Differential Bystander Signaling Between Radioresistant Chondrosarcoma Cells and Fibroblasts After X-Ray, Proton, Iron Ion and Carbon Ion Exposures

    Energy Technology Data Exchange (ETDEWEB)

    Wakatsuki, Masaru, E-mail: wa@mbe.nifty.com [Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, Chiba (Japan); Department of Radiation Oncology, Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts (United States); Magpayo, Nicole; Kawamura, Hidemasa; Held, Kathryn D. [Department of Radiation Oncology, Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts (United States)

    2012-09-01

    Purpose: Chondrosarcoma is well known as a radioresistant tumor, but the mechanisms underlying that resistance are still unclear. The bystander effect is well documented in the field of radiation biology. We investigated the bystander response induced by X-rays, protons, carbon ions, and iron ions in chondrosarcoma cells using a transwell insert co-culture system that precludes physical contact between targeted and bystander cells. Methods and Materials: Human chondrosarcoma cells were irradiated with 0.1-, 0.5-, 1-, and 2-Gy X-rays, protons, carbon ions or iron ions using a transwell insert co-culture system. Formation of micronuclei and p53 binding protein 1 staining in bystander and irradiated cells were analyzed and bystander signaling between mixed cultures of chondrosarcoma cells, and normal human skin fibroblasts was investigated. Results: In this study, we show that the fraction of cells with DNA damages in irradiated chondrosarcoma cells showed dose-dependent increases with all beams. However, the fraction of cells with DNA damages in all bystander chondrosarcoma cells did not show any change from the levels in control cells. In the bystander signaling between mixed cultures of chondrosarcoma cells and fibroblasts, the amount of micronucleus formation in all bystander chondrosarcoma cells co-cultured with irradiated fibroblasts were the same as the levels for control cells. However, all bystander fibroblasts co-cultured with irradiated chondrosarcoma cells showed significant increases in the fraction of micronucleated cells compared to the rate of control cells. Conclusions: We conclude that chondrosarcoma cells in the transwell insert co-culture system could release bystander stimulations but could not develop bystander responses.

  11. Differential Bystander Signaling Between Radioresistant Chondrosarcoma Cells and Fibroblasts After X-Ray, Proton, Iron Ion and Carbon Ion Exposures

    International Nuclear Information System (INIS)

    Wakatsuki, Masaru; Magpayo, Nicole; Kawamura, Hidemasa; Held, Kathryn D.

    2012-01-01

    Purpose: Chondrosarcoma is well known as a radioresistant tumor, but the mechanisms underlying that resistance are still unclear. The bystander effect is well documented in the field of radiation biology. We investigated the bystander response induced by X-rays, protons, carbon ions, and iron ions in chondrosarcoma cells using a transwell insert co-culture system that precludes physical contact between targeted and bystander cells. Methods and Materials: Human chondrosarcoma cells were irradiated with 0.1-, 0.5-, 1-, and 2-Gy X-rays, protons, carbon ions or iron ions using a transwell insert co-culture system. Formation of micronuclei and p53 binding protein 1 staining in bystander and irradiated cells were analyzed and bystander signaling between mixed cultures of chondrosarcoma cells, and normal human skin fibroblasts was investigated. Results: In this study, we show that the fraction of cells with DNA damages in irradiated chondrosarcoma cells showed dose-dependent increases with all beams. However, the fraction of cells with DNA damages in all bystander chondrosarcoma cells did not show any change from the levels in control cells. In the bystander signaling between mixed cultures of chondrosarcoma cells and fibroblasts, the amount of micronucleus formation in all bystander chondrosarcoma cells co-cultured with irradiated fibroblasts were the same as the levels for control cells. However, all bystander fibroblasts co-cultured with irradiated chondrosarcoma cells showed significant increases in the fraction of micronucleated cells compared to the rate of control cells. Conclusions: We conclude that chondrosarcoma cells in the transwell insert co-culture system could release bystander stimulations but could not develop bystander responses.

  12. Mutagenic effects of alkylating agents on prophage lambda

    Energy Technology Data Exchange (ETDEWEB)

    Bresler, S.; Kalinin, V.L.; Kuznetsova, L.V.

    1984-06-01

    An evaluation was made of the relative contribution of repair and reparative mechanisms to the mutagenic potency of several alkylating agents on thermoinducible prophage lambdacI857 ind/sup -/ in several stains of E. coli. Following treatment of lysogenic E. coli with the mutagens and heat induction, 0.02 N-nitroso-N-methylurea (NMU) induced c mutations with a high frequency (ca. 10%) in both wild type E. coli and cells with repair mutations (recA13, lexA102, uvrA6, umuC36, xthA9, recF143, polA1, uvrD3, uvrD502). It appears that NUM-induced mutations are stabilized as replicative errors due to mismatched, altered bases. Delay in induction following exposure to NMU improves prophage survival and diminishes c mutant formation, regardless of the E. coli genotype. Evidently, carbamoylation is not involved in NMU mutagenicity since 0.02 M KNCO is nonmutagenic and is virtually without effect on prophage viability. Replicative mechanisms are also involved in N-methyl-N'-nitro-N-nitrosoguanidine (15%) and ethyl methanesulfonate (2%) induced mutations, since the maximum yield of mutants was independent of recA/sup +/ genotype. However, the mutagenicity of methyl methanesulfonate was abolished by the recA mutation, indicating that the mutagenicity of this agent is repair-dependent. Mitomycin C (0.1%) and acridine mustard (0.3%) induce c mutations regardless of recA/sup +/ and, therefore, appear to do so by intercalation. 26 references, 6 figures.

  13. 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.

  14. Assessment of the Mutagenicity of Sediments from Yangtze River Estuary Using Salmonella Typhimurium/Microsome Assay

    Science.gov (United States)

    Liu, Li; Chen, Ling; Floehr, Tilman; Xiao, Hongxia; Bluhm, Kerstin; Hollert, Henner; Wu, Lingling

    2015-01-01

    Sediments in estuaries are of important environmental concern because they may act as pollution sinks and sources to the overlying water body. These sediments can be accumulated by benthic organisms. This study assessed the mutagenic potential of sediment extracts from the Yangtze River estuary by using the Ames fluctuation assay with the Salmonella typhimurium his (−) strain TA98 (frameshift mutagen indicator) and TA100 (baseshift mutagen indicator). Most of the sediment samples were mutagenic to the strain TA98, regardless of the presence or absence of exogenous metabolic activation (S9 induction by β-naphthoflavone/phenobarbital). However, none of the samples were mutagenic to the strain TA100. Thus, the mutagenicity pattern was mainly frameshift mutation, and the responsible toxicants were both direct (without S9 mix) and indirect (with S9 mix) mutagens. The mutagenicity of the sediment extracts increased when S9 was added. Chemical analysis showed a poor correlation between the content of priority polycyclic aromatic hydrocarbons and the detected mutagenicity in each sample. The concept of effect-directed analysis was used to analyze possible compounds responsible for the detected mutagenic effects. With regard to the mutagenicity of sediment fractions, non-polar compounds as well as weakly and moderately polar compounds played a main role. Further investigations should be conducted to identify the responsible components. PMID:26606056

  15. Bystander effects in radiotherapy of non-small cell lung cancer

    International Nuclear Information System (INIS)

    McKenzie, D.R.

    2011-01-01

    Full text: School of Physics, The University of Sydney, Australia Objectives The bystander effect causes a response in unirradiated cells that are in communication with cells that receive a radiation dose. In recent work we have shown that there are 3 types bystander effect and that the expression of these effects follows a Ii course. The aim of this work is to identify the conditions for the three types of bystander effects in radiotherapy of non-small cell II cancer. A human non small cell lung cancer cell line (NCI-H460) was irradiated with a 6 MV photon beam produced from a Varian I i near accelerator to doses of 2, 4, 6 and 8 Gy. These cells v termed donor cells. At selected time intervals after exposure (5,15 and 60 min), the medium was transferred to receiver cells of the cell line in separate flasks. The clonogenic survival fraction of the receiver cells was determined following 5 days of incubation comparing cells receiving transfer of medium from exposed cells to cell receiving transfer from sham exposed cells. The experimental design controlled for the density of cells in the donor flask, the e of irradiation on the medium alone and on the donor cell metabolites. The results show a strong time course for the bystander signal expression, which is dependent on the density of cells in the donor receiver flasks. Sub lethal doses of radiation resulted in a proliferative response at short time intervals after exposure [15 min] but a toxic response when medium transfer was carried out after 60 min. A higher cell density in the donor flasks produces an increased response in the receiver flasks for the same volume of medium transferred. The latter response corresponds to Bystander Effect type 1 in which a reduced survival is observed in cells receiving medium from cells that receive a high but not lethal dose. The proliferative response, corresponding to Bystander Effect type 3 is more general and is not strongly dependent on dose. Following a lethal dose of

  16. Bystander Efforts and 1-Year Outcomes in Out-of-Hospital Cardiac Arrest.

    Science.gov (United States)

    Kragholm, Kristian; Wissenberg, Mads; Mortensen, Rikke N; Hansen, Steen M; Malta Hansen, Carolina; Thorsteinsson, Kristinn; Rajan, Shahzleen; Lippert, Freddy; Folke, Fredrik; Gislason, Gunnar; Køber, Lars; Fonager, Kirsten; Jensen, Svend E; Gerds, Thomas A; Torp-Pedersen, Christian; Rasmussen, Bodil S

    2017-05-04

    The effect of bystander interventions on long-term functional outcomes among survivors of out-of-hospital cardiac arrest has not been extensively studied. We linked nationwide data on out-of-hospital cardiac arrests in Denmark to functional outcome data and reported the 1-year risks of anoxic brain damage or nursing home admission and of death from any cause among patients who survived to day 30 after an out-of-hospital cardiac arrest. We analyzed risks according to whether bystander cardiopulmonary resuscitation (CPR) or defibrillation was performed and evaluated temporal changes in bystander interventions and outcomes. Among the 2855 patients who were 30-day survivors of an out-of-hospital cardiac arrest during the period from 2001 through 2012, a total of 10.5% had brain damage or were admitted to a nursing home and 9.7% died during the 1-year follow-up period. During the study period, among the 2084 patients who had cardiac arrests that were not witnessed by emergency medical services (EMS) personnel, the rate of bystander CPR increased from 66.7% to 80.6% (Pbystander defibrillation increased from 2.1% to 16.8% (Pbystander CPR was associated with a risk of brain damage or nursing home admission that was significantly lower than that associated with no bystander resuscitation (hazard ratio, 0.62; 95% confidence interval [CI], 0.47 to 0.82), as well as a lower risk of death from any cause (hazard ratio, 0.70; 95% CI, 0.50 to 0.99) and a lower risk of the composite end point of brain damage, nursing home admission, or death (hazard ratio, 0.67; 95% CI, 0.53 to 0.84). The risks of these outcomes were even lower among patients who received bystander defibrillation as compared with no bystander resuscitation. In our study, we found that bystander CPR and defibrillation were associated with risks of brain damage or nursing home admission and of death from any cause that were significantly lower than those associated with no bystander resuscitation. (Funded by Tryg

  17. Detection of genomic instability in α-irradiated and bystander human fibroblasts

    International Nuclear Information System (INIS)

    Ponnaiya, B.; Jenkins-Baker, G.; Bigelow, A.; Marino, S.; Geard, C.R.

    2003-01-01

    Full text: We have previously demonstrated a radiation induced bystander effect using novel co-culturing techniques where irradiated and bystander cells were cultured on two surfaces of mylar separated by media. Here we present data from experiments designed to investigate the induction of chromosomal aberrations in irradiated and bystander fibroblasts using these co-culturing techniques. Immortalized fibroblasts ((BJ1-tert) were cultured on both mylar surfaces and cells on one side were irradiated with 0.1 or 1 Gy -particles (an average of 1 and 10 particles per cell nucleus respectively), the two sides were separated 1 hour post irradiation and analyzed for chromosomal aberrations using standard Giemsa staining at either immediate or delayed time points. At 24-30 hours post irradiation, frequencies of chromosomal aberrations in irradiated populations were increased in a dose dependent manner as expected. Populations that received 0.1 and 1 Gy had 0.3 and 1.3 aberrations/cell; these aberrations were almost exclusively chromosome type aberrations. In contrast, at these times bystander populations had elevated yields of chromatid-type aberrations. When assayed at later times (15-20 population doublings post irradiation) both irradiated and bystander cells demonstrated elevated frequencies of chromatid-type aberrations. Frequencies in the irradiated populations ranged from 0.07 to 0.09 aberrations/ cell at 15 doublings, and 0.09-0.14/cell at 20 doublings, with no apparent dose response. Aberration frequencies in the bystander populations were between 0.08-0.14 per cell at the delayed time points assayed. Interestingly, the chromatid-type aberrations observed immediately post irradiation in the bystander cells, and at later times in both the irradiated and bystander populations were qualitatively similar to those previously observed at delayed times in neutron irradiated epithelial cells. Furthermore, there was a similar lack of a dose response in those studies as

  18. Disparities in Survival with Bystander CPR following Cardiopulmonary Arrest Based on Neighborhood Characteristics

    Directory of Open Access Journals (Sweden)

    Nina Thakkar Rivera

    2016-01-01

    Full Text Available The American Heart Association reports the annual incidence of out-of-hospital cardiopulmonary arrests (OHCA is greater than 300,000 with a survival rate of 9.5%. Bystander cardiopulmonary resuscitation (CPR saves one life for every 30, with a 10% decrease in survival associated with every minute of delay in CPR initiation. Bystander CPR and training vary widely by region. We conducted a retrospective study of 320 persons who suffered OHCA in South Florida over 25 months. Increased survival, overall and with bystander CPR, was seen with increasing income (p=0.05, with a stronger disparity between low- and high-income neighborhoods (p=0.01 and p=0.03, resp.. Survival with bystander CPR was statistically greater in white- versus black-predominant neighborhoods (p=0.04. Increased survival, overall and with bystander CPR, was seen with high- versus low-education neighborhoods (p=0.03. Neighborhoods with more high school age persons displayed the lowest survival. We discovered a significant disparity in OHCA survival within neighborhoods of low-income, black-predominance, and low-education. Reduced survival was seen in neighborhoods with larger populations of high school students. This group is a potential target for training, and instruction can conceivably change survival outcomes in these neighborhoods, closing the gap, thus improving survival for all.

  19. First aid: level of knowledge of relatives and bystanders in emergency situations.

    Science.gov (United States)

    Tomruk, Onder; Soysal, Suna; Gunay, Turkan; Cimrin, Arif H

    2007-01-01

    Bystanders who are able to provide immediate first aid to patients who require emergency care can make a big difference in the outcome. Thus, first-aid training should be made available to as many people as possible. The aims of this study were to assess the level of first-aid knowledge among bystanders in emergency situations and to identify factors that affected this level of knowledge. At Dokuz Eylul University Emergency Service between February 1 and February 15, 2002, 318 bystanders were given a questionnaire. The first part of the questionnaire was concerned with demographic characteristics and factors that would affect first-aid knowledge level. The second part consisted of 16 multiple choice questions about first aid. Bystanders answered an average of 7.16+/-3.14 questions correctly. Bystanders who had graduated from a university, were health care personnel, had taken a first-aid course, had a first-aid certificate, or had a driver's license were considered to be more successful.

  20. The bystander effect in experimental systems and compatibility with radon-induced lung cancer in humans

    International Nuclear Information System (INIS)

    Little, M.P.; Wakeford, R.

    2002-01-01

    Bystander effects following exposure to α-particles have been observed in C3H 10T 1/2 cells and in other experimental systems, and imply that linearly extrapolating low-dose risks from high-dose data might materially underestimate risk. The ratio of lung cancer risk among persons exposed to low and high doses of radon daughters is 2.4-4.0, with an upper 95% confidence limit (CL) of about 14. Assuming that the bystander effect observed in the C3H 10T 1/2 data applies to human lung cells in vivo, the epidemiological data imply that the number of neighbouring cells that can contribute to the bystander effect is between 0 and 1, with an upper 95% CL of about 7. As a consequence, the bystander effect observed in the C3H 10T 1/2 system probably does not play a large part in the process of radon-induced lung carcinogenesis in humans. Other experimental data relating to the bystander effect after α-particle exposure are surveyed; some of these data are more compatible with the epidemiological data. (author)

  1. Bystander effects and compartmental stress response to X-ray irradiation in L929 cells.

    Science.gov (United States)

    Temelie, Mihaela; Stroe, Daniela; Petcu, Ileana; Mustaciosu, Cosmin; Moisoi, Nicoleta; Savu, Diana

    2016-08-01

    Bystander effects are indirect consequences of radiation and many other stress factors. They occur in cells that are not directly exposed to these factors, but receive signals from affected cells either by gap junctions or by molecules released in the medium. Characterizing these effects and deciphering the underlying mechanisms involved in radiation-induced bystander effects are relevant for cancer radiotherapy and radioprotection. At doses of X-ray radiation 0.5 and 1 Gy, we detected bystander effects as increased numbers of micronuclei shortly after the treatment, through medium transfer and by co-cultures. Interestingly, bystander cells did not exhibit long-term adverse changes in viability. Evaluation of several compartmental stress markers (CHOP, BiP, mtHsp60, cytHsp70) by qRT-PCR did not reveal expression changes at transcriptional level. We investigated the involvement of ROS and NO in this process by addition of specific scavengers of these molecules, DMSO or c-PTIO in the transferred medium. This approach proved that ROS but not NO is involved in the induction of lesions in the acceptor cells. These results indicate that L929 cells are susceptible to stress effects of radiation-induced bystander signaling.

  2. Role of nitric oxide in the radiation-induced bystander effect.

    Science.gov (United States)

    Yakovlev, Vasily A

    2015-12-01

    Cells that are not irradiated but are affected by "stress signal factors" released from irradiated cells are called bystander cells. These cells, as well as directly irradiated ones, express DNA damage-related proteins and display excess DNA damage, chromosome aberrations, mutations, and malignant transformation. This phenomenon has been studied widely in the past 20 years, since its first description by Nagasawa and Little in 1992, and is known as the radiation-induced bystander effect (RIBE). Several factors have been identified as playing a role in the bystander response. This review will focus on one of them, nitric oxide (NO), and its role in the stimulation and propagation of RIBE. The hydrophobic properties of NO, which permit its diffusion through the cytoplasm and plasma membranes, allow this signaling molecule to easily spread from irradiated cells to bystander cells without the involvement of gap junction intercellular communication. NO produced in irradiated tissues mediates cellular regulation through posttranslational modification of a number of regulatory proteins. The best studied of these modifications are S-nitrosylation (reversible oxidation of cysteine) and tyrosine nitration. These modifications can up- or down-regulate the functions of many proteins modulating different NO-dependent effects. These NO-dependent effects include the stimulation of genomic instability (GI) and the accumulation of DNA errors in bystander cells without direct DNA damage. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

  3. A reaction-diffusion model for radiation-induced bystander effects.

    Science.gov (United States)

    Olobatuyi, Oluwole; de Vries, Gerda; Hillen, Thomas

    2017-08-01

    We develop and analyze a reaction-diffusion model to investigate the dynamics of the lifespan of a bystander signal emitted when cells are exposed to radiation. Experimental studies by Mothersill and Seymour 1997, using malignant epithelial cell lines, found that an emitted bystander signal can still cause bystander effects in cells even 60 h after its emission. Several other experiments have also shown that the signal can persist for months and even years. Also, bystander effects have been hypothesized as one of the factors responsible for the phenomenon of low-dose hyper-radiosensitivity and increased radioresistance (HRS/IRR). Here, we confirm this hypothesis with a mathematical model, which we fit to Joiner's data on HRS/IRR in a T98G glioma cell line. Furthermore, we use phase plane analysis to understand the full dynamics of the signal's lifespan. We find that both single and multiple radiation exposure can lead to bystander signals that either persist temporarily or permanently. We also found that, in an heterogeneous environment, the size of the domain exposed to radiation and the number of radiation exposures can determine whether a signal will persist temporarily or permanently. Finally, we use sensitivity analysis to identify those cell parameters that affect the signal's lifespan and the signal-induced cell death the most.

  4. Bystander responses in three-dimensional cultures containing radiolabelled and unlabelled human cells

    International Nuclear Information System (INIS)

    Pinto, M.; Azzam, E. I.; Howell, R. W.

    2006-01-01

    Research on the radiation-induced bystander effect has been carried out mainly in 2-D tissue culture systems. This study uses a 3-D model, wherein apparently normal human diploid fibroblasts (AG1522) are grown in a carbon scaffold, to investigate the induction of a G 1 checkpoint in bystander cells present alongside radiolabelled cells. Cultures were simultaneously pulse-labelled with 3 H-deoxycytidine ( 3 HdC) to selectively irradiate a minor fraction of cells, and bromodeoxyuridine (BrdU) to identify the radiolabelled cells. After thorough washing of cultures, iododeoxyuridine (IdU) was administered to detect proliferating bystander cells. The cultures were harvested at various times thereafter, and cells were reacted with two monoclonal antibodies specific to IdU/BrdU or BrdU, respectively, stained with propidium iodide, and subjected to multi-parameter flow cytometry. Cell-cycle progression was followed in radiolabelled cells (BrdU + ) that were chronically irradiated by low energy beta particles emitted by DNA-incorporated 3 H, and in unlabelled bystander cells (BrdU - ) by a flow cytometry based cumulative labelling index assay. As expected, radiolabelled cells were delayed, in a dose-dependent manner, in G 2 and subsequently G 1 . No delay occurred in progression of bystander cells through G 1 , when the labelled cells were irradiated at dose rates up to 0.32 Gy h -1 . (authors)

  5. Measurement of the bystander intervention model for bullying and sexual harassment.

    Science.gov (United States)

    Nickerson, Amanda B; Aloe, Ariel M; Livingston, Jennifer A; Feeley, Thomas Hugh

    2014-06-01

    Although peer bystanders can exacerbate or prevent bullying and sexual harassment, research has been hindered by the absence of a validated assessment tool to measure the process and sequential steps of the bystander intervention model. A measure was developed based on the five steps of Latané and Darley's (1970) bystander intervention model applied to bullying and sexual harassment. Confirmatory factor analysis with a sample of 562 secondary school students confirmed the five-factor structure of the measure. Structural equation modeling revealed that all the steps were influenced by the previous step in the model, as the theory proposed. In addition, the bystander intervention measure was positively correlated with empathy, attitudes toward bullying and sexual harassment, and awareness of bullying and sexual harassment facts. This measure can be used for future research and to inform intervention efforts related to the process of bystander intervention for bullying and sexual harassment. Copyright © 2014 The Foundation for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.

  6. Study on bystander effect and associated mechanism mediated through culture medium

    International Nuclear Information System (INIS)

    Tu Xumin; Lei Suwen; Zhang Zhixing; Lv Huimin

    2005-01-01

    Objective: To study the bystander effect and associated mechanism mediated through the irradiated cell culture medium. Methods: Splenic natural killer (NK) cells were obtained from healthy male ICR strain mice. Culture medium irradiated with different doses of 60 Co γ-rays was used for culturing Yac-I lymphoma cells. The degree of injury of the latter by activated NK cells was observed. A part of the culture media were pretreated with 1% DMSO, a scavenger of reactive oxygen species (ROS), in order to investigate the possible mechanism of a radiation-induced bystander response. Results: Severer injury was induced in Yac-I cells cultured in the media pre-irradiated with different doses of γ-rays than that in Yac-I cells cultured in unirradiated medium, as shown by increased sensitivity to murine splenic NK cells (P<0.01). Culturing Yac-I cells in DMSO-pretreated medium considerably reduced the activation of NK cells, especially in 0.25 Gy and 0.5 Gy γ-irradiated media. Therefore, it can be expected that DMSO can partly suppress ROS-induced bystander effect. Conclusion: The irradiated culture medium of Yac-I cells can trigger bystander effect. ROS likely plays an important role in radiation-induced bystander effect that can be partly suppressed by pretreatment with DMSO. (authors)

  7. Mutagenic activity of halogenated propanes and propenes: effect of bromine and chlorine positioning.

    Science.gov (United States)

    Låg, M; Omichinski, J G; Dybing, E; Nelson, S D; Søderlund, E J

    1994-10-01

    A series of halogenated propanes and propenes were studied for mutagenic effects in Salmonella typhimurium TA100 in the absence or presence of NADPH plus liver microsomes from phenobarbital-induced rats as an exogenous metabolism system. The cytotoxic and mutagenic effects of the halogenated propane 1,2-dibromo-3-chloropropane (DBCP) has previously been studied in our laboratories. These studies showed that metabolic activation of DBCP was required to exert its detrimental effects. All of the trihalogenated propane analogues were mutagenic when the microsomal activation system was included. The highest mutagenic activity was obtained with 1,2,3-tribromopropane, with approximately 50-fold higher activity than the least mutagenic trihalogenated propane, 1,2,3-trichloropropane. The order of mutagenicity was as follows: 1,2,3-tribromopropane > or = 1,2-dibromo- 3-chloropropane > 1,3-dibromo-2-chloropropane > or = 1,3-dichloro-2-bromopropane > 1-bromo-2,3-dichloropropane > 1,2,3-trichloropropane. Compared to DBCP, the dihalogenated propanes were substantially less mutagenic. Only 1,2-dibromopropane was mutagenic and its mutagenic potential was approximately 1/30 of that of DBCP. In contrast to DBCP, 1,2-dibromopropane showed similar mutagenic activity with and without the addition of an activation system. The halogenated propenes 2,3-dibromopropene and 2-bromo-3-chloropropene were mutagenic to the bacteria both in the absence and presence of the activation system, whereas 2,3-dichloropropene did not show any mutagenic effect. The large differences in mutagenic potential between the various halogenated propanes and propenes are proposed to be due to the formation of different possible proximate and ultimate mutagenic metabolites resulting from the microsomal metabolism of the various halogenated propanes and propenes, and to differences in the rate of formation of the metabolites. Pathways are proposed for the formation of genotoxic metabolites of di- and trihalogenated

  8. Radiation induced bystander signals are independent of DNA damage and DNA repair capacity of the irradiated cells

    Energy Technology Data Exchange (ETDEWEB)

    Kashino, Genro [Gray Cancer Institute, P.O. Box 100, Mount Vernon Hospital, Northwood, Middlesex HA6 2JR (United Kingdom); Particle Radiation Oncology Research Center, Research Reactor Institute, Kyoto University, 2-1010 Asashiro-nishi, Kumatori-cho, Sennan-gun, Osaka 590-0494 (Japan); Suzuki, Keiji [Division of Radiation Biology, Department of Radiology and Radiation Biology, Course of Life Sciences and Radiation Research, Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521 (Japan); Matsuda, Naoki [Division of Radiation Biology and Protection, Center for Frontier Life Sciences, Nagasaki University, Nagasaki 852-8102 (Japan); Kodama, Seiji [Radiation Biology Laboratory, Radiation Research Center, Frontier Science Innovation Center, Organization for University-Industry-Government Cooperation, Osaka Prefecture University, 1-2 Gakuen-cho, Sakai, Osaka 599-8570 (Japan); Ono, Koji [Particle Radiation Oncology Research Center, Research Reactor Institute, Kyoto University, 2-1010 Asashiro-nishi, Kumatori-cho, Sennan-gun, Osaka 590-0494 (Japan); Watanabe, Masami [Laboratory of Radiation Biology, Division of Radiation Life Science, Department of Radiation Life Science and Radiation Medical Science, Kyoto University Research Reactor Institute, 2-1010 Asashiro-nishi, Kumatori-cho, Sennan-gun, Osaka 590-0494 (Japan); Prise, Kevin M [Gray Cancer Institute, P.O. Box 100, Mount Vernon Hospital, Northwood, Middlesex HA6 2JR (United Kingdom) and Centre for Cancer Research and Cell Biology, Queen' s University Belfast, Lisburn Road, Belfast BT9 7AB (United Kingdom)]. E-mail: prise@gci.ac.uk

    2007-06-01

    Evidence is accumulating that irradiated cells produce signals, which interact with non-exposed cells in the same population. Here, we analysed the mechanism for bystander signal arising in wild-type CHO cells and repair deficient varients, focussing on the relationship between DNA repair capacity and bystander signal arising in irradiated cells. In order to investigate the bystander effect, we carried out medium transfer experiments after X-irradiation where micronuclei were scored in non-targeted DSB repair deficient xrs5 cells. When conditioned medium from irradiated cells was transferred to unirradiated xrs5 cells, the level of induction was independent of whether the medium came from irradiated wild-type, ssb or dsb repair deficient cells. This result suggests that the activation of a bystander signal is independent of the DNA repair capacity of the irradiated cells. Also, pre-treatment of the irradiated cells with 0.5% DMSO, which suppresses micronuclei induction in CHO but not in xrs5 cells, suppressed bystander effects completely in both conditioned media, suggesting that DMSO is effective for suppression of bystander signal arising independently of DNA damage in irradiated cells. Overall the work presented here adds to the understanding that it is the repair phenotype of the cells receiving bystander signals, which determines overall response rather than that of the cell producing the bystander signal.

  9. Bystander effect studies using heavy-ion microbeam

    International Nuclear Information System (INIS)

    Kobayashi, Yasuhiko; Funayama, Tomoo; Sakashita, Tetsuya; Wada, Seiichi; Yokota, Yuichiro; Kakizaki, Takehiko; Hamada, Nobuyuki; Hara, Takamitsu; Fukamoto, Kana; Suzuki, Michiyo; Ni, M.; Furusawa, Yoshiya

    2007-01-01

    We have established a single cell irradiation system, which allows selected cells to be individually hit with defined number of heavy charged particles, using a collimated heavy-ion microbeam apparatus at JAEA-Takasaki. This system has been developed to study radiobiological processes in hit cells and bystander cells exposed to low dose and low dose-rate high-LET radiations, in ways that cannot be achieved using conventional broad-field exposures. Individual cultured cells grown in special dishes were irradiated in the atmosphere with a single or defined numbers of 18.3 MeV/amu 12 C, 13.0 or 17.5 MeV/amu 20 Ne, and 11.5 MeV/amu 40 Ar ions. Targeting and irradiation of the cells were performed automatically according to the positional data of the target cells microscopically obtained before irradiation. The actual number of particle tracks that pass through target cells was detected with prompt etching of the bottom of the cell dish made of ion track detector TNF-1 (modified CR-39). (author)

  10. Innocent Bystanders and Smoking Guns: Dwarf Carbon Stars

    Science.gov (United States)

    Green, Paul J.

    2014-01-01

    As far as we know, most carbon throughout the Universe is created and dispersed by AGB stars. So it was at first surprising to find that the carbon stars most prevalent in the Galaxy are in fact dwarfs. We suspect that dC stars are most likely innocent bystanders in post-mass transfer binaries, and may be predominantly metal-poor. Among 1200 C stars found in the SDSS (Green 2013), we confirm 724 dCs, of which a dozen are DA/dC stars in composite spectrum binaries, quadrupling the total sample of these "smoking guns" for AGB binary mass transfer. The dCs likely span absolute magnitudes M_i from about 6.5 to 10.5. G-type dC stars with weak CN and relatively blue colors are probably the most massive dCs still cool enough to show C_2 bands. Eleven very red C stars with strong red CN bands appear to be N-type AGB stars at large Galactocentric distances, one likely a new discovery in the dIrr galaxy Le A. Two such stars within 30arcmin of each other may trace a previously unidentified dwarf galaxy or tidal stream at ~40 kpc. We describe follow-up projects to study the spatial, kinematic, and binary properties of these C-enriched dwarfs.

  11. Hybrid model of the radiation-induced bystander effect

    International Nuclear Information System (INIS)

    Braga, Viviane V.B.; Faria, Fernando Pereira de; Grynberg, Suely Epsztein

    2013-01-01

    The radiation-induced bystander effect (RIBE) refer to biological alterations in non-irradiated cells that occupy the same medium (culture or tissue) of irradiated cells. The biochemical mechanisms of the RIBE are not completely elucidated. However, several experiments indicate its existence. The objective of this work is to quantify the effect via stochastic and deterministic approaches. The hypotheses of the model are: a) one non-irradiated healthy cell interacts with signals that propagate through the medium. These signals are released by irradiated cells. At the time of interaction cell-signal, the cell can become damaged and signaling or damage and not signaling; b) Both types of damage cells repair with certain rate becoming health cells; c) The diffusion of signals obey the discrete diffusion equation with decay in two dimensions. d) The signal concentration released by irradiated cells depends on the dose in the low dose range (< 0.3 Gy) and saturates for higher dose values. As expected, the temporal analysis of the model as a function of the repair rate shows that the survival fraction decreases as the repair rate is reduced. The analysis of the extent of damage triggered by a signal concentration released by a single irradiated cell at time zero show that the damage grows with the maximum simulation time. The results show good agreement with the experimental data. The stochastic and deterministic methods used are in qualitative agreement, as expected. (author)

  12. Hybrid model of the radiation-induced bystander effect

    Energy Technology Data Exchange (ETDEWEB)

    Braga, Viviane V.B.; Faria, Fernando Pereira de; Grynberg, Suely Epsztein, E-mail: vitoriabraga06@gmail.com, E-mail: fernandopereirabh@gmail.com, E-mail: seg@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2013-07-01

    The radiation-induced bystander effect (RIBE) refer to biological alterations in non-irradiated cells that occupy the same medium (culture or tissue) of irradiated cells. The biochemical mechanisms of the RIBE are not completely elucidated. However, several experiments indicate its existence. The objective of this work is to quantify the effect via stochastic and deterministic approaches. The hypotheses of the model are: a) one non-irradiated healthy cell interacts with signals that propagate through the medium. These signals are released by irradiated cells. At the time of interaction cell-signal, the cell can become damaged and signaling or damage and not signaling; b) Both types of damage cells repair with certain rate becoming health cells; c) The diffusion of signals obey the discrete diffusion equation with decay in two dimensions. d) The signal concentration released by irradiated cells depends on the dose in the low dose range (< 0.3 Gy) and saturates for higher dose values. As expected, the temporal analysis of the model as a function of the repair rate shows that the survival fraction decreases as the repair rate is reduced. The analysis of the extent of damage triggered by a signal concentration released by a single irradiated cell at time zero show that the damage grows with the maximum simulation time. The results show good agreement with the experimental data. The stochastic and deterministic methods used are in qualitative agreement, as expected. (author)

  13. Bystander Intervention Prior to The Arrival of Emergency Medical Services: Comparing Assistance across Types of Medical Emergencies.

    Science.gov (United States)

    Faul, Mark; Aikman, Shelley N; Sasser, Scott M

    2016-01-01

    To determine the situational circumstances associated with bystander interventions to render aid during a medical emergency. This study examined 16.2 million Emergency Medical Service (EMS) events contained within the National Emergency Medical Services Information System. The records of patients following a 9-1-1 call for emergency medical assistance were analyzed using logistic regression to determine what factors influenced bystander interventions. The dependent variable of the model was whether or not a bystander intervened. EMS providers recorded bystander assistance 11% of the time. The logistic regression model correctly predicted bystander intervention occurrence 71.4% of the time. Bystanders were more likely to intervene when the patient was male (aOR = 1.12, 95% CI = 1.12-1.3) and if the patient was older (progressive aOR = 1.10, 1.46 age group 20-29 through age group 60-99). Bystanders were less likely to intervene in rural areas compared to urban areas (aOR = 0.58, 95% CI = 0.58-0.59). The highest likelihood of bystander intervention occurred in a residential institution (aOR = 1.86, 95% CI = 1.85-1.86) and the lowest occurred on a street or a highway (aOR = 0.96, 95% CI = 0.95-0.96). Using death as a reference group, bystanders were most likely to intervene when the patient had cardiac distress/chest pain (aOR = 11.38, 95% CI = 10.93-11.86), followed by allergic reaction (aOR = 7.63, 95% CI = 7.30-7.99), smoke inhalation (aOR = 6.65, 95% CI = 5.98-7.39), and respiration arrest/distress (aOR = 6.43, 95% CI = 6.17-6.70). A traumatic injury was the most commonly recorded known event, and it was also associated with a relatively high level of bystander intervention (aOR = 5.81, 95% CI = 5.58-6.05). The type of injury/illness that prompted the lowest likelihood of bystander assistance was Sexual Assault/Rape (aOR = 1.57, 95% CI = 1.32-1.84) followed by behavioral/psychiatric disorder (aOR = 1.64, 95% CI = 1.57-1.71). Bystander intervention varies greatly on

  14. Lay Bystanders' Perspectives on What Facilitates Cardiopulmonary Resuscitation and Use of Automated External Defibrillators in Real Cardiac Arrests

    DEFF Research Database (Denmark)

    Malta Hansen, Carolina; Rosenkranz, Simone Mørk; Folke, Fredrik

    2017-01-01

    BACKGROUND: Many patients who suffer an out-of-hospital cardiac arrest will fail to receive bystander intervention (cardiopulmonary resuscitation [CPR] or defibrillation) despite widespread CPR training and the dissemination of automated external defibrillators (AEDs). We sought to investigate what...... factors encourage lay bystanders to initiate CPR and AED use in a cohort of bystanders previously trained in CPR techniques who were present at an out-of-hospital cardiac arrest. METHODS AND RESULTS: One-hundred and twenty-eight semistructured qualitative interviews with CPR-trained lay bystanders...... to consecutive out-of-hospital cardiac arrest, where an AED was present were conducted (from January 2012 to April 2015, in Denmark). Purposive maximum variation sampling was used to establish the breadth of the bystander perspective. Twenty-six of the 128 interviews were chosen for further in-depth analyses...

  15. A Simulation Study of the Radiation-Induced Bystander Effect: Modeling with Stochastically Defined Signal Reemission

    Directory of Open Access Journals (Sweden)

    Kohei Sasaki

    2012-01-01

    Full Text Available The radiation-induced bystander effect (RIBE has been experimentally observed for different types of radiation, cell types, and cell culture conditions. However, the behavior of signal transmission between unirradiated and irradiated cells is not well known. In this study, we have developed a new model for RIBE based on the diffusion of soluble factors in cell cultures using a Monte Carlo technique. The model involves the signal emission probability from bystander cells following Poisson statistics. Simulations with this model show that the spatial configuration of the bystander cells agrees well with that of corresponding experiments, where the optimal emission probability is estimated through a large number of simulation runs. It was suggested that the most likely probability falls within 0.63–0.92 for mean number of the emission signals ranging from 1.0 to 2.5.

  16. Heavy ion irradiation induces autophagy in irradiated C2C12 myoblasts and their bystander cells

    International Nuclear Information System (INIS)

    Hino, Mizuki; Tajika, Yuki; Hamada, Nobuyuki

    2010-01-01

    Autophagy is one of the major processes involved in the degradation of intracellular materials. Here, we examined the potential impact of heavy ion irradiation on the induction of autophagy in irradiated C2C12 mouse myoblasts and their non-targeted bystander cells. In irradiated cells, ultrastructural analysis revealed the accumulation of autophagic structures at various stages of autophagy (id est (i.e.) phagophores, autophagosomes and autolysosomes) within 20 min after irradiation. Multivesicular bodies (MVBs) and autolysosomes containing MVBs (amphisomes) were also observed. Heavy ion irradiation increased the staining of microtubule-associated protein 1 light chain 3 and LysoTracker Red (LTR). Such enhanced staining was suppressed by an autophagy inhibitor 3-methyladenine. In addition to irradiated cells, bystander cells were also positive with LTR staining. Altogether, these results suggest that heavy ion irradiation induces autophagy not only in irradiated myoblasts but also in their bystander cells. (author)

  17. Effects of manipulated aggressive 'interactions' on bystanding male fighting fish, Betta splendens

    DEFF Research Database (Denmark)

    Peake, Thomas More; Matos, Ricardo Jorge; McGregor, Peter Kenneth

    2006-01-01

    Aggressive interactions between animals often take place in a social environment. Third parties not involved in those interactions, bystanders, have the opportunity to extract information from such interactions and such information may direct their future behaviour towards the interactants. Studies...... occurring differences between observed interactants and have therefore lacked this degree of control. We allowed bystanding male fighting fish to observe two male conspecifics that appeared to be interacting, but in reality the two males were displaying to mirrors. The apparent interactions were manipulated...... so as to increase or decrease the aggression of one ‘interactant' while leaving that of the other male constant. When subsequently introduced to the ‘interactants' individually, bystanders responded more strongly to males whose opponents' aggression had been decreased and to the winners of control...

  18. Effect of bystander CPR initiation prior to the emergency call on ROSC and 30day survival

    DEFF Research Database (Denmark)

    Viereck, Søren; Palsgaard Møller, Thea; Kjær Ersbøll, Annette

    2017-01-01

    BACKGROUND: This study aimed at evaluating if time for initiation of bystander cardiopulmonary resuscitation (CPR) - prior to the emergency call (CPRprior) versus during the emergency call following dispatcher-assisted CPR (CPRduring) - was associated with return of spontaneous circulation (ROSC...... and corresponding emergency calls were evaluated. Multivariable logistic regression analyses were applied to evaluate the association between time for initiation of bystander CPR, ROSC, and 30-day survival. Univariable logistic regression analyses were applied to identify predictors of CPRprior. RESULTS: The study...... included 548 emergency calls for OHCA patients receiving bystander CPR, 34.9% (n=191) in the CPRpriorgroup and 65.1% (n=357) in the CPRduringgroup. Multivariable analyses showed no difference in ROSC (OR=0.88, 95% CI: 0.56-1.38) or 30-day survival (OR=1.14, 95% CI: 0.68-1.92) between CPRpriorand CPRduring...

  19. An Application of the Reasoned Action Approach to Bystander Intervention for Sexual Assault.

    Science.gov (United States)

    Lukacena, Kaylee M; Reynolds-Tylus, Tobias; Quick, Brian L

    2017-10-25

    The high prevalence of sexual assault in US college campuses has led to a widespread implementation of bystander intervention programs aimed at preventing sexual assault. The current study examines predictors of college students' intentions to engage in bystander intervention through the theoretical lens of the reasoned action approach. An online survey with college students (N = 186) was conducted at a large Midwestern university. Our results indicated experiential attitudes, instrumental attitudes, descriptive norms, autonomy, and capacity, each positively associated with participants' intentions to intervene to stop a sexual assault. Against expectations, injunctive norms were unrelated to bystander intervention intentions. Finally, in addition to these main effects, an experiential attitude by autonomy interaction was also observed. The results are discussed with a focus on the theoretical and practical implications of our findings.

  20. Bystander CD4+ T lymphocytes survive in HIV-infected human lymphoid tissue

    Science.gov (United States)

    Grivel, Jean-Charles; Biancotto, Angelique; Ito, Yoshinori; Lima, Rosangela G.; Margolis, Leonid B.

    2003-01-01

    HIV infection is associated with depletion of CD4(+) T cells. The mechanisms of this phenomenon remain to be understood. In particular, it remains controversial whether and to what extent uninfected ("bystander") CD4(+) T cells die in HIV-infected individuals. We address this question using a system of human lymphoid tissue ex vivo. Tissue blocks were inoculated with HIV-1. After productive infection was established, they were treated with the reverse transcriptase inhibitor nevirapine to protect from infection those CD4(+) T cells that had not yet been infected. These CD4(+) T cells residing in HIV-infected tissue are by definition bystanders. Our results demonstrate that after nevirapine application the number of bystander CD4(+) T cells is conserved. Thus, in the context of HIV-infected human lymphoid tissue, productive HIV infection kills infected cells but is not sufficient to cause the death of a significant number of uninfected CD4(+) T cells.

  1. Radionuclides in radiation-induced bystander effect; may it share in radionuclide therapy?

    Science.gov (United States)

    Widel, M

    2017-01-01

    For many years in radiobiology and radiotherapy predominated the conviction that cellular DNA is the main target for ionizing radiation, however, the view has changed in the past 20 years. Nowadays, it is assumed that not only directed (targeted) radiation effect, but also an indirect (non-targeted) effect may contribute to the result of radiation treatment. Non-targeted effect is relatively well recognized after external beam irradiation in vitro and in vivo, and comprises such phenomena like radiation-induced bystander effect (RIBE), genomic instability, adaptive response and abscopal (out of field) effect. These stress-induced and molecular signaling mediated phenomena appear in non-targeted cells as variety responses resembling that observed in directly hit cells. Bystander effects can be both detrimental and beneficial in dependence on dose, dose-rate, cell type, genetic status and experimental condition. Less is known about radionuclide-induced non-targeted effects in radionuclide therapy, although, based on characteristics of the radionuclide radiation, on experiments in vitro utilizing classical and 3-D cell cultures, and preclinical study on animals it seems obvious that exposure to radionuclide is accompanied by various bystander effects, mostly damaging, less often protective. This review summarizes existing data on radionuclide induced bystander effects comprising radionuclides emitting beta- and alpha-particles and Auger electrons used in tumor radiotherapy and diagnostics. So far, separation of the direct effect of radionuclide decay from crossfire and bystander effects in clinical targeted radionuclide therapy is impossible because of the lack of methods to assess whether, and to what extent bystander effect is involved in human organism. Considerations on this topic are also included.

  2. The influence of a bystander agent's beliefs on children's and adults' decision-making process.

    Science.gov (United States)

    Buttelmann, Frances; Buttelmann, David

    2017-01-01

    The ability to attribute and represent others' mental states (e.g., beliefs; so-called "theory of mind") is essential for participation in human social interaction. Despite a considerable body of research using tasks in which protagonists in the participants' attentional focus held false or true beliefs, the question of automatic belief attribution to bystander agents has received little attention. In the current study, we presented adults and 6-year-olds (N=92) with an implicit computer-based avoidance false-belief task in which participants were asked to place an object into one of three boxes. While doing so, we manipulated the beliefs of an irrelevant human-like or non-human-like bystander agent who was visible on the screen. Importantly, the bystander agent's beliefs were irrelevant for solving the task. Still, children's decision making was significantly influenced by the bystander agent's beliefs even if this was a non-human-like self-propelled object. Such an influence did not become obvious in adults' deliberate decisions but occurred only in their reaction times, which suggests that they also processed the bystander agent's beliefs but were able to suppress the influence of such beliefs on their behavior regulation. The results of a control study (N=53) ruled out low-level explanations and confirmed that self-propelledness of agents is a necessary factor for belief attribution to occur. Thus, not only do humans spontaneously ascribe beliefs to self-propelled bystander agents, but those beliefs even influence meaningful decisions in children. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Recognising out-of-hospital cardiac arrest during emergency calls increases bystander cardiopulmonary resuscitation and survival.

    Science.gov (United States)

    Viereck, Søren; Møller, Thea Palsgaard; Ersbøll, Annette Kjær; Bækgaard, Josefine Stokholm; Claesson, Andreas; Hollenberg, Jacob; Folke, Fredrik; Lippert, Freddy K

    2017-06-01

    Initiation of early bystander cardiopulmonary resuscitation (CPR) depends on bystanders' or medical dispatchers' recognition of out-of-hospital cardiac arrest (OHCA). The primary aim of our study was to investigate if OHCA recognition during the emergency call was associated with bystander CPR, return of spontaneous circulation (ROSC), and 30-day survival. Our secondary aim was to identify patient-, setting-, and dispatcher-related predictors of OHCA recognition. We performed an observational study of all OHCA patients' emergency calls in the Capital Region of Denmark from 01/01/2013-31/12/2013. OHCAs were collected from the Danish Cardiac Arrest Registry and the Mobile Critical Care Unit database. Emergency call recordings were identified and evaluated. Multivariable logistic regression analyses were applied to all OHCAs and witnessed OHCAs only to analyse the association between OHCA recognition and bystander CPR, ROSC, and 30-day survival. Univariable logistic regression analyses were applied to identify predictors of OHCA recognition. We included 779 emergency calls in the analyses. During the emergency calls, 70.1% (n=534) of OHCAs were recognised; OHCA recognition was positively associated with bystander CPR (odds ratio [OR]=7.84, 95% confidence interval [CI]: 5.10-12.05) in all OHCAs; and ROSC (OR=1.86, 95% CI: 1.13-3.06) and 30-day survival (OR=2.80, 95% CI: 1.58-4.96) in witnessed OHCA. Predictors of OHCA recognition were addressing breathing (OR=1.76, 95% CI: 1.17-2.66) and callers located by the patient's side (OR=2.16, 95% CI: 1.46-3.19). Recognition of OHCA during emergency calls was positively associated with the provision of bystander CPR, ROSC, and 30-day survival in witnessed OHCA. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  4. Role of nitric oxide in targeted-subcellular organelles induced bystander effect

    International Nuclear Information System (INIS)

    Shao Chunlin; Folkard, M.; Prise, K.M.

    2007-01-01

    The work is to investigate the bystander effect and related signaling factor induced by targeted irradiation on tumor cells. Human glioblastoma T98G cells were irradiated with a precise number of helium microbeam ions, which targeted to either nuclear or cytoplasm. Chromosome damage and intracellular NO level were assayed. Influence of a NO free radical scavenger on these radiation responses was measured. Using DEANO, the cellular effect of NO was also studied. It was found that even only one cell with a population was targeted with one particle through either nuclear or cytoplasm, additional cellular damage was induced in other 10s cells through a signaling amplification pathway and related bystander response. Although cell damage induced directly by nuclear irradiation was greater than that induced by cytoplasmic irradiation, bystander responses induced by these two kinds of irradiation were similar. When a fraction of cells were individually irradiated by helium ions, the yield of micronuclei was obviously higher than that assuming no bystander effect. However, these targeted irradiation induced bystander response were inhibited by c-PTIO, a scavenger of nitric oxide (NO) free radical. Detected with a NO molecular probe DAF-AM, it was observed that when only 1% of cells were irradiated either through nuclear or cytoplasm, the percentage of NO-positive cells increased by about 30% so that the NO-related fluorescence intensity increased by 15%. Moreover, micronuclei were induced indeed in T98G cells treated with a NO donor. These indicate that NO is a bystander signaling factor for both nuclear irradiation and cytoplasmic irradiation. (authors)

  5. Neutron Exposures in Human Cells: Bystander Effect and Relative Biological Effectiveness

    Science.gov (United States)

    Seth, Isheeta; Schwartz, Jeffrey L.; Stewart, Robert D.; Emery, Robert; Joiner, Michael C.; Tucker, James D.

    2014-01-01

    Bystander effects have been observed repeatedly in mammalian cells following photon and alpha particle irradiation. However, few studies have been performed to investigate bystander effects arising from neutron irradiation. Here we asked whether neutrons also induce a bystander effect in two normal human lymphoblastoid cell lines. These cells were exposed to fast neutrons produced by targeting a near-monoenergetic 50.5 MeV proton beam at a Be target (17 MeV average neutron energy), and irradiated-cell conditioned media (ICCM) was transferred to unirradiated cells. The cytokinesis-block micronucleus assay was used to quantify genetic damage in radiation-naïve cells exposed to ICCM from cultures that received 0 (control), 0.5, 1, 1.5, 2, 3 or 4 Gy neutrons. Cells grown in ICCM from irradiated cells showed no significant increase in the frequencies of micronuclei or nucleoplasmic bridges compared to cells grown in ICCM from sham irradiated cells for either cell line. However, the neutron beam has a photon dose-contamination of 5%, which may modulate a neutron-induced bystander effect. To determine whether these low doses of contaminating photons can induce a bystander effect, cells were irradiated with cobalt-60 at doses equivalent to the percent contamination for each neutron dose. No significant increase in the frequencies of micronuclei or bridges was observed at these doses of photons for either cell line when cultured in ICCM. As expected, high doses of photons induced a clear bystander effect in both cell lines for micronuclei and bridges (pbystander effect in these cells. Finally, neutrons had a relative biological effectiveness of 2.0±0.13 for micronuclei and 5.8±2.9 for bridges compared to cobalt-60. These results may be relevant to radiation therapy with fast neutrons and for regulatory agencies setting standards for neutron radiation protection and safety. PMID:24896095

  6. "Please. Don't. Die.": A Grounded Theory Study of Bystander Cardiopulmonary Resuscitation.

    Science.gov (United States)

    Mausz, Justin; Snobelen, Paul; Tavares, Walter

    2018-02-01

    Bystander cardiopulmonary resuscitation (CPR) is an important determinant of survival from out-of-hospital cardiac arrest (OHCA), yet rates of bystander CPR are highly variable. In an effort to promote bystander CPR, the procedure has been streamlined, and ultrashort teaching modalities have been introduced. CPR has been increasingly reconceptualized as simple, safe, and easy to perform; however, current methods of CPR instruction may not adequately prepare lay rescuers for the various logistical, conceptual, and emotional challenges of resuscitating a victim of cardiac arrest. We adopted a constructivist grounded theory methodology to qualitatively explore bystander CPR and invited lay rescuers who had recently (ie, within 1 week) intervened in an OHCA to participate in semistructured interviews and focus groups. We used constant comparative analysis until theoretical saturation to derive a midrange explanatory theory of bystander CPR. We constructed a 3-stage theoretical model describing a common experiential process for lay rescuer intervention in OHCA: Being called to act is disturbing, causing panic, shock, and disbelief that must ultimately be overcome. Taking action to save the victim is complicated by several misconceptions about cardiac arrest, where victims are mistakenly believed to be choking, and agonal respirations are misinterpreted to mean the victim is alive. Making sense of the experience is challenging, at least in the short term, where lay rescuers have to contend with self-doubt, unanswered questions, and uncomfortable emotional reactions to a traumatic event. Our study suggests that current CPR training programs may not adequately prepare lay rescuers for the reality of an OHCA and identifies several key knowledge gaps that should be addressed. The long-term psychological consequences of bystander intervention in OHCA remain poorly understood and warrant further study. © 2018 American Heart Association, Inc.

  7. Association of bystander interventions and hospital length of stay and admission to intensive care unit in out-of-hospital cardiac arrest survivors

    DEFF Research Database (Denmark)

    Riddersholm, Signe; Kragholm, Kristian; Mortensen, Rikke Nørmark

    2017-01-01

    for bystander defibrillation. 82% of patients without bystander interventions were admitted to ICU compared to 77.2% for bystander CPR, and 61.2% for bystander defibrillation. In-hospital mortality was 60% in the first category compared to 40.5% and 21.7% in the two latter categories. In regression models.......76-0.85]), were associated with lower risk of ICU admission. CONCLUSIONS: Bystander interventions were associated with reduced hospital length of stay and ICU admission, suggesting that these efforts improve recovery in OHCA survivors....

  8. Cloning of Salmonella typhimurium DNA encoding mutagenic DNA repair

    International Nuclear Information System (INIS)

    Thomas, S.M.; Sedgwick, S.G.

    1989-01-01

    Mutagenic DNA repair in Escherichia coli is encoded by the umuDC operon. Salmonella typhimurium DNA which has homology with E. coli umuC and is able to complement E. coli umuC122::Tn5 and umuC36 mutations has been cloned. Complementation of umuD44 mutants and hybridization with E. coli umuD also occurred, but these activities were much weaker than with umuC. Restriction enzyme mapping indicated that the composition of the cloned fragment is different from the E. coli umuDC operon. Therefore, a umu-like function of S. typhimurium has been found; the phenotype of this function is weaker than that of its E. coli counterpart, which is consistent with the weak mutagenic response of S. typhimurium to UV compared with the response in E. coli

  9. Pollen genetic markers for detection of mutagens in the environment

    International Nuclear Information System (INIS)

    Nilan, R.A.; Rosichan, J.L.; Arenaz, P.; Hodgdon, A.L.; Kleinhofs, A.

    1980-01-01

    To utilize and exploit pollen for in situ mutagen monitoring, screening and toxicology, the range of genetic traits in pollen must be identified and analyzed. To be useful for the development of mutagen detection systems proteins should be: (1) activity stainable or immunologically identifiable in the pollen, (2) the products of one to three loci; and (3) gametophytic and nuclear in origin. Several proteins, including alcohol dehydrogenase in maize, which meet these criteria are discussed. The waxy locus in barley and maize which controls starch deposition for pollen screening and mutant detection. Thirty waxy mutant lines, induced by sodium azide and gamma-rays are characterized for spontaneous and induced reversion frequencies, allelism, karyotype, amylose content, and UDPglucose glucosyltransferase (waxy gene product) activity. Twelve mutant alleles are being mapped by recombinant frequencies

  10. Mutagenic effect of tritated water on spores of Bacillus subtilis

    International Nuclear Information System (INIS)

    Tanooka, H.; Munakata, N.

    1978-01-01

    The mutagenic effect of tritiated water was observed with spores of Bacillus subtilis polA strain suspended in 50 mCi/ml of tritiated water for various intervals. Dose rate given by tritium beta particles to spore core was estimated to be 400 rad/hr from some assumptions and E. coli data computed by Bockrath et al. and Sands et al. The initial mutation rate was 4.2 x 10 -9 mutants/rad, as compared with 2.4 x 10 -9 mutants/rad for 60 Co γ rays and 3.3 x 10 -9 mutants/rad for 30-kVp x rays. The mutagenic effect of tritiated water on spores is most likely due to beta particle ionizing radiation damage

  11. 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

  12. Counteracting quasispecies adaptability: extinction of a ribavirin-resistant virus mutant by an alternative mutagenic treatment.

    Directory of Open Access Journals (Sweden)

    Celia Perales

    Full Text Available BACKGROUND: Lethal mutagenesis, or virus extinction promoted by mutagen-induced elevation of mutation rates of viruses, may meet with the problem of selection of mutagen-resistant variants, as extensively documented for standard, non-mutagenic antiviral inhibitors. Previously, we characterized a mutant of foot-and-mouth disease virus that included in its RNA-dependent RNA polymerase replacement M296I that decreased the sensitivity of the virus to the mutagenic nucleoside analogue ribavirin. METHODOLOGY AND PRINCIPAL FINDINGS: Replacement M296I in the viral polymerase impedes the extinction of the mutant foot-and-mouth disease virus by elevated concentrations of ribavirin. In contrast, wild type virus was extinguished by the same ribavirin treatment and, interestingly, no mutants resistant to ribavirin were selected from the wild type populations. Decreases of infectivity and viral load of the ribavirin-resistant M296I mutant were attained with a combination of the mutagen 5-fluorouracil and the non-mutagenic inhibitor guanidine hydrocloride. However, extinction was achieved with a sequential treatment, first with ribavirin, and then with a minimal dose of 5-fluorouracil in combination with guanidine hydrochloride. Both, wild type and ribavirin-resistant mutant M296I exhibited equal sensitivity to this combination, indicating that replacement M296I in the polymerase did not confer a significant cross-resistance to 5-fluorouracil. We discuss these results in relation to antiviral designs based on lethal mutagenesis. CONCLUSIONS: (i When dominant in the population, a mutation that confers partial resistance to a mutagenic agent can jeopardize virus extinction by elevated doses of the same mutagen. (ii A wild type virus, subjected to identical high mutagenic treatment, need not select a mutagen-resistant variant, and the population can be extinguished. (iii Extinction of the mutagen-resistant variant can be achieved by a sequential treatment of a

  13. I know what you did: The effects of interpersonal deviance on bystanders.

    Science.gov (United States)

    Ferguson, Merideth; Barry, Bruce

    2011-01-01

    Using social information processing theory, we explore how interpersonally directed deviance affects work group members who observe or are aware of these insidious behaviors. In a field study, we find that indirect knowledge of work group member interpersonal deviance leads to subsequent interpersonal deviance of a focal individual. We also find that when work group cohesion is high, direct observation of deviance is more likely to result in subsequent bystander deviance. These findings add concretely to theory and research on the bystander effects of workplace deviance.

  14. Potential implications of the bystander effect on TCP and EUD when considering target volume dose heterogeneity.

    Science.gov (United States)

    Balderson, Michael J; Kirkby, Charles

    2015-01-01

    In light of in vitro evidence suggesting that radiation-induced bystander effects may enhance non-local cell killing, there is potential for impact on radiotherapy treatment planning paradigms such as the goal of delivering a uniform dose throughout the clinical target volume (CTV). This work applies a bystander effect model to calculate equivalent uniform dose (EUD) and tumor control probability (TCP) for external beam prostate treatment and compares the results with a more common model where local response is dictated exclusively by local absorbed dose. The broad assumptions applied in the bystander effect model are intended to place an upper limit on the extent of the results in a clinical context. EUD and TCP of a prostate cancer target volume under conditions of increasing dose heterogeneity were calculated using two models: One incorporating bystander effects derived from previously published in vitro bystander data ( McMahon et al. 2012 , 2013a); and one using a common linear-quadratic (LQ) response that relies exclusively on local absorbed dose. Dose through the CTV was modelled as a normal distribution, where the degree of heterogeneity was then dictated by changing the standard deviation (SD). Also, a representative clinical dose distribution was examined as cold (low dose) sub-volumes were systematically introduced. The bystander model suggests a moderate degree of dose heterogeneity throughout a target volume will yield as good or better outcome compared to a uniform dose in terms of EUD and TCP. For a typical intermediate risk prostate prescription of 78 Gy over 39 fractions maxima in EUD and TCP as a function of increasing SD occurred at SD ∼ 5 Gy. The plots only dropped below the uniform dose values for SD ∼ 10 Gy, almost 13% of the prescribed dose. Small, but potentially significant differences in the outcome metrics between the models were identified in the clinically-derived dose distribution as cold sub-volumes were introduced. In terms of

  15. Modifiers of Neighbors' Bystander Intervention in Intimate Partner Violence: A Concept Mapping Study.

    Science.gov (United States)

    Wee, Sara; Todd, Mary-Justine; Oshiro, Michael; Greene, Emily; Frye, Victoria

    2016-03-01

    Encouraging bystander intervention in intimate partner violence (IPV) against women is potentially an important method of reducing the prevalence of such violence in urban communities. Most existing research has been conducted on campuses and in relation to sexual violence among teens or young adults. Our understanding of which bystander behaviors are feasible is nascent, and our knowledge of which situational factors influence neighbors' self-reported willingness to intervene is underdeveloped. We conducted a concept mapping study to identify potential bystander intervention behaviors in IPV among neighbors in urban settings; we also assessed whether perceived feasibility and effectiveness of those behaviors varied by situational characteristics. Using data collected from 41 residents of a low-income New York City neighborhood in late 2011, concept mapping was used to create a conceptual map of the 74 behaviors identified by participants. We examined participant differences in mean feasibility (i.e., that the participants "could" or "would" enact a behavior), feasibility given two situational characteristics (if the couple was perceived to have a history of IPV, and if children were believed to be involved or present), and perceived effectiveness of bystander behaviors. Differences across select sociodemographic factors of participants were also analyzed. A 13-cluster solution emerged, with clusters of bystander behaviors grouped into four larger cluster areas: victim focused, parenting/education focused, perpetrator focused, and community involvement focused. Bivariate analyses revealed that participants rated the four cluster areas as more feasible when a child was believed to be involved. Male participants rated intervention as less feasible when the couple was believed to have a history of IPV. Participants who reported a history of IPV victimization rated all four cluster areas as less effective on average, as compared with participants without a history of

  16. Micronuclei frequency in children exposed to environmental mutagens: a review

    DEFF Research Database (Denmark)

    Neri, Monica; Fucic, Aleksandra; Knudsen, Lisbeth E

    2003-01-01

    Cytogenetic monitoring has been traditionally used for the surveillance of populations exposed to genotoxic agents. In recent years sensitivity problems emerged in surveys of populations exposed to low levels of mutagens, and therefore alternative approaches have been explored. Biomonitoring....... The limited number of published papers indicates that the conduct of properly designed studies on the effect of environmental pollutants in children may be difficult. This review confirmed the usefulness of MN assay in biomonitoring studies conducted in children, revealing that in many circumstances...

  17. Dietary Mutagen Exposure and Risk of Pancreatic Cancer

    OpenAIRE

    Li, Donghui; Sue Day, Rena; Bondy, Melissa L.; Sinha, Rashmi; Nguyen, Nga T.; Evans, Douglas B.; Abbruzzese, James L.; Hassan, Manal M.

    2007-01-01

    To investigate the association between dietary exposure to food mutagens and risk of pancreatic cancer, we conducted a hospital-based case-control study at the University of Texas M. D. Anderson Cancer Center during June 2002 to May 2006. Atotal of 626 cases and 530 noncancer controls were frequency matched for race, sex and age (±5 years). Dietary exposure information was collected via personal interview using a meat preparation questionnaire. A significantly greater portion of the cases tha...

  18. Differences in mutagenic and recombinational DNA repair in enterobacteria

    International Nuclear Information System (INIS)

    Sedgwick, S.G.; Goodwin, P.A.

    1985-01-01

    The incidence of recombinational DNA repair and inducible mutagenic DNA repair has been examined in Escherichia coli and 11 related species of enterobacteria. Recombinational repair was found to be a common feature of the DNA repair repertoire of at least 6 genera of enterobacteria. This conclusion is based on observations of (i) damage-induced synthesis of RecA-like proteins, (ii) nucleotide hybridization between E. coli recA sequences and some chromosomal DNAs, and (iii) recA-negative complementation by plasmids showing SOS-inducible expression of truncated E. coli recA genes. The mechanism of DNA damage-induced gene expression is therefore sufficiently conserved to allow non-E. coli regulatory elements to govern expression of these cloned truncated E. coli recA genes. In contrast, the process of mutagenic repair, which uses umuC+ umuD+ gene products in E. coli, appeared less widespread. Little ultraviolet light-induced mutagenesis to rifampicin resistance was detected outside the genus Escherichia, and even within the genus induced mutagenesis was detected in only 3 out of 6 species. Nucleotide hybridization showed that sequences like the E. coli umuCD+ gene are not found in these poorly mutable organisms. Evolutionary questions raised by the sporadic incidence of inducible mutagenic repair are discussed

  19. Mutagenicity of some alkyl nitrites used as recreational drugs

    Energy Technology Data Exchange (ETDEWEB)

    Dunkel, V.C.; Cameron, T.P. (National Institute of Health, Bethesda (USA)); Rogers-Back, A.M.; Lawlor, T.E.; Harbell, J.W. (Microbiological Associates Inc., Rockville, MD (USA))

    1989-01-01

    When the AIDS epidemic was in its earliest stages, and prior to identification of HIV as the etiological factor, the use of volatile nitrites by the male homosexual community to enhance sexual activities appeared to have a significant role in this disease. Preliminary observations indicated that that portion of the male homosexual community which developed Kaposi's sarcoma were also heavy nitrite users. These nitrites had been demonstrated to be mutagenic in bacteria and thus it was postulated that they could be responsible for the appearance of the sarcoma. To evaluate further the genotoxic activity of these chemicals, six nitrites, including those most commonly used by homosexuals for sexual gratification, were selected for testing in the mouse lymphoma TK {plus minus} and Salmonell typhimurium mutagenicity assays. One chemical, n-amyl nitrite, was negative in the mouse lymphoma assay, while the other five chemicals, n-butyl, isobutyl, iso-amyl, sec-butyl, and n-propyl nitrite, were positive. All six compounds were positive in the Salmonella assay. The mutagenic and known toxic effects of these chemicals remain a concern because a large population of teenagers and young adults continue to abuse these substances.

  20. DNA replication after mutagenic treatment in Hordeum vulgare.

    Science.gov (United States)

    Kwasniewska, Jolanta; Kus, Arita; Swoboda, Monika; Braszewska-Zalewska, Agnieszka

    2016-12-01

    The temporal and spatial properties of DNA replication in plants related to DNA damage and mutagenesis is poorly understood. Experiments were carried out to explore the relationships between DNA replication, chromatin structure and DNA damage in nuclei from barley root tips. We quantitavely analysed the topological organisation of replication foci using pulse EdU labelling during the S phase and its relationship with the DNA damage induced by mutagenic treatment with maleic hydrazide (MH), nitroso-N-methyl-urea (MNU) and gamma ray. Treatment with mutagens did not change the characteristic S-phase patterns in the nuclei; however, the frequencies of the S-phase-labelled cells after treatment differed from those observed in the control cells. The analyses of DNA replication in barley nuclei were extended to the micronuclei induced by mutagens. Replication in the chromatin of the micronuclei was rare. The results of simultanous TUNEL reaction to identify cells with DNA strand breaks and the labelling of the S-phase cells with EdU revealed the possibility of DNA replication occurring in damaged nuclei. For the first time, the intensity of EdU fluorescence to study the rate of DNA replication was analysed. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Mutagenicity and genotoxicity of coal fly ash water leachate.

    Science.gov (United States)

    Chakraborty, Rajarshi; Mukherjee, Anita

    2009-03-01

    Fly ash is a by-product of coal-fired electricity generation plants. The prevalent practice of disposal is as slurry of ash and water to storage or ash ponds located near power stations. This has lain to waste thousands of hectares of land all over the world. Since leaching is often the cause of off-site contamination and pathway of introduction into the human environment, a study on the genotoxic effects of fly ash leachate is essential. Leachate prepared from the fly ash sample was analyzed for metal content, and tested for mutagenicity and genotoxicity. Analyses of metals show predominance of the metals-sodium, silicon, potassium, calcium, magnesium, iron, manganese, zinc, and sulphate. The Ames Salmonella mutagenicity assay, a short-term bacterial reverse mutation assay, was conducted on two-tester strains of Salmonella typhimurium strains TA97a and TA102. For genotoxicity, the alkaline version of comet assay on fly ash leachate was carried in vitro on human blood cells and in vivo on Nicotiana plants. The leachate was directly mutagenic and induced significant (Ppercentage (%), tail length (mum), and olive tail moment (arbitrary units). Our results indicate that leachate from fly ash dumpsites has the genotoxic potential and may lead to adverse effects on vegetation and on the health of exposed human populations.

  2. DNA repair in mutagen-injured higher plants

    International Nuclear Information System (INIS)

    Veleminsky, J.; Gichner, T.

    1978-01-01

    Data are summarized proving the occurrence of photoreactivation of UV-induced pyrimidine dimers in cells of Nicotiana tabucum, Gingko and carrot, the excision of dimers in cells of Nicotiana tabacum, Gingko and carrot, the excision of dimers in protoplasts of carrot and in embryos of Lathyrus sativus, and the repair of DNA single-strand breaks induced in carrot protoplasts and barley embryonic cells by ionizing radiation. In irradiated barley embryos the unscheduled DNA synthesis and higher accessibility of induced primers to DNA polymerase I of E. coli were observed preferentially in G 1 cells with diffused chromatin. These reactions were inhibited by caffeine and EDTA. Unscheduled DNA synthesis was also observed in synchronized irradiated root cuttings of Vicia faba and in barley embryos treated with 4-nitroquinoline oxide, the latter being inhibited by caffeine and hydroxyurea. Repair synthesis was also established in barley embryos treated with mutagenic N-methyl-N-nitrosourea under conditions that postponed the onset of germination after the treatment. The same conditions enhanced the repair of DNA single-strand breaks induced by this mutagen and several other monofunctional alkylating compounds. From tissues of barley and of Phaseolus multiflorus, endonucleases for apurinic sites were isolated and characterized. Some of them are located in chromatin, others in chloroplasts. The relation between DNA repair and genetic effects of mutagens in higher plants is also discussed. (Auth.)

  3. Preconception exposures to potential germ-cell mutagens

    International Nuclear Information System (INIS)

    Draper, G.

    2008-01-01

    Radiation and other agents can cause germ-cell mutations in animal systems. No human germ-cell mutagen has been identified, but this does not mean that human germ-cells are not vulnerable to mutagenesis. There has been particular concern about the possible health effects on offspring following parental preconception exposure to ionizing radiation - both occupational and therapeutic. A strong association with preconception radiation exposure in the fathers of the cases was found in a case-control study of young people with leukaemia living near the Sellafield nuclear plant in the UK. Subsequent studies of workers occupationally exposed to ionizing radiation have failed to confirm these findings. No statistically significant effects have been reported from studies of possible indicators of germ-cell mutagenesis in the A-bomb survivors. Studies of offspring of cancer survivors who receive radiotherapy and mutagenic chemotherapy have found no evidence of germ-cell mutagenesis. Failure to detect human germ-cell mutagenic agents may be a consequence of inadequate study sizes or insufficiently sensitive laboratory techniques. (authors)

  4. Role of Reactive Oxygen Species and Nitric Oxide in Mediating Chemotherapeutic Drug Induced Bystander Response in Human Cancer Cells Exposed In-Vitro

    Science.gov (United States)

    Chinnadurai, Mani; Rao, Bhavna S; Deepika, Ramasamy; Paul, Solomon F.D.; Venkatachalam, Perumal

    2012-01-01

    Background The intention of cancer chemotherapy is to control the growth of cancer cells using chemical agents. However, the occurrence of second malignancies has raised concerns, leading to re-evaluation of the current strategy in use for chemotherapeutic agents. Although the mechanisms involved in second malignancy remain ambiguous, therapeutic-agent-induced non-DNA targeted effects like bystander response and genomic instability cannot be eliminated completely. Hence, Bleomycin (BLM) and Neocarzinostatin (NCS), chemotherapeutic drugs with a mode of action similar to ionizing radiation, were used to study the mechanism of bystander response in human cancer cells (A549, CCRF-CEM and HL-60) by employing co-culture methodology. Methods Bystander effect was quantified using micronucleus (MN) assay and in-situ immunofluorescence(γH2AX assay).The role of reactive oxygen species (ROS) and nitric oxide (NO) in mediating the bystander response was explored by pre-treating bystander cells with dimethylsulphoxide (DMSO) and C-PTIO respectively. Results Bystander response was observed only in CCRF-CEM and A549 cells (P bystander response on treatment with DMSO, suggests that ROS has a more significant role in mediating the bystander response.Since the possibility of the ROS and NO in mediating these bystander effect was confirmed, mechanistic control of these signaling molecules could either reduce radiation damage and potential carcinogenicity of normal tissues (by reducing bystander signaling) or maximize cell sterilization during chemotherapy (by amplifying bystander responses in tumors). PMID:29147282

  5. In Vivo Bystander Effect: Cranial X-Irradiation Leads to Elevated DNA Damage, Altered Cellular Proliferation and Apoptosis, and Increased p53 Levels in Shielded Spleen

    International Nuclear Information System (INIS)

    Koturbash, Igor; Loree, Jonathan; Kutanzi, Kristy; Koganow, Clayton; Pogribny, Igor; Kovalchuk, Olga

    2008-01-01

    Purpose: It is well accepted that irradiated cells may 'forward' genome instability to nonirradiated neighboring cells, giving rise to the 'bystander effect' phenomenon. Although bystander effects were well studied by using cell cultures, data for somatic bystander effects in vivo are relatively scarce. Methods and Materials: We set out to analyze the existence and molecular nature of bystander effects in a radiation target-organ spleen by using a mouse model. The animal's head was exposed to X-rays while the remainder of the body was completely protected by a medical-grade shield. Using immunohistochemistry, we addressed levels of DNA damage, cellular proliferation, apoptosis, and p53 protein in the spleen of control animals and completely exposed and head-exposed/body bystander animals. Results: We found that localized head radiation exposure led to the induction of bystander effects in the lead-shielded distant spleen tissue. Namely, cranial irradiation led to increased levels of DNA damage and p53 expression and also altered levels of cellular proliferation and apoptosis in bystander spleen tissue. The observed bystander changes were not caused by radiation scattering and were observed in two different mouse strains; C57BL/6 and BALB/c. Conclusion: Our study proves that bystander effects occur in the distant somatic organs on localized exposures. Additional studies are required to characterize the nature of an enigmatic bystander signal and analyze the long-term persistence of these effects and possible contribution of radiation-induced bystander effects to secondary radiation carcinogenesis

  6. 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

  7. 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

  8. Association of Bystander Cardiopulmonary Resuscitation and Survival According to Ambulance Response Times After Out-of-Hospital Cardiac Arrest.

    Science.gov (United States)

    Rajan, Shahzleen; Wissenberg, Mads; Folke, Fredrik; Hansen, Steen Møller; Gerds, Thomas A; Kragholm, Kristian; Hansen, Carolina Malta; Karlsson, Lena; Lippert, Freddy K; Køber, Lars; Gislason, Gunnar H; Torp-Pedersen, Christian

    2016-12-20

    Bystander-initiated cardiopulmonary resuscitation (CPR) increases patient survival after out-of-hospital cardiac arrest, but it is unknown to what degree bystander CPR remains positively associated with survival with increasing time to potential defibrillation. The main objective was to examine the association of bystander CPR with survival as time to advanced treatment increases. We studied 7623 out-of-hospital cardiac arrest patients between 2005 and 2011, identified through the nationwide Danish Cardiac Arrest Registry. Multiple logistic regression analysis was used to examine the association between time from 911 call to emergency medical service arrival (response time) and survival according to whether bystander CPR was provided (yes or no). Reported are 30-day survival chances with 95% bootstrap confidence intervals. With increasing response times, adjusted 30-day survival chances decreased for both patients with bystander CPR and those without. However, the contrast between the survival chances of patients with versus without bystander CPR increased over time: within 5 minutes, 30-day survival was 14.5% (95% confidence interval [CI]: 12.8-16.4) versus 6.3% (95% CI: 5.1-7.6), corresponding to 2.3 times higher chances of survival associated with bystander CPR; within 10 minutes, 30-day survival chances were 6.7% (95% CI: 5.4-8.1) versus 2.2% (95% CI: 1.5-3.1), corresponding to 3.0 times higher chances of 30-day survival associated with bystander CPR. The contrast in 30-day survival became statistically insignificant when response time was >13 minutes (bystander CPR vs no bystander CPR: 3.7% [95% CI: 2.2-5.4] vs 1.5% [95% CI: 0.6-2.7]), but 30-day survival was still 2.5 times higher associated with bystander CPR. Based on the model and Danish out-of-hospital cardiac arrest statistics, an additional 233 patients could potentially be saved annually if response time was reduced from 10 to 5 minutes and 119 patients if response time was reduced from 7 (the median

  9. Testosterone replacement therapy and the heart: friend, foe or bystander?

    Science.gov (United States)

    Lopez, David S; Canfield, Steven; Wang, Run

    2016-12-01

    The role of testosterone therapy (TTh) in cardiovascular disease (CVD) outcomes is still controversial, and it seems will remain inconclusive for the moment. An extensive body of literature has investigated the association of endogenous testosterone and use of TTh with CVD events including several meta-analyses. In some instances, a number of studies reported beneficial effects of TTh on CVD events and in other instances the body of literature reported detrimental effects or no effects at all. Yet, no review article has scrutinized this body of literature using the magnitude of associations and statistical significance reported from this relationship. We critically reviewed the previous and emerging body of literature that investigated the association of endogenous testosterone and use of TTh with CVD events (only fatal and nonfatal). These studies were divided into three groups, "beneficial (friendly use)", "detrimental (foe)" and "no effects at all (bystander)", based on their magnitude of associations and statistical significance from original research studies and meta-analyses of epidemiological studies and of randomized controlled trials (RCT's). In this review article, the studies reporting a significant association of high levels of testosterone with a reduced risk of CVD events in original prospective studies and meta-analyses of cross-sectional and prospective studies seems to be more consistent. However, the number of meta-analyses of RCT's does not provide a clear picture after we divided it into the beneficial, detrimental or no effects all groups using their magnitudes of association and statistical significance. From this review, we suggest that we need a study or number of studies that have the adequate power, epidemiological, and clinical data to provide a definitive conclusion on whether the effect of TTh on the natural history of CVD is real or not.

  10. Bystander Host Cell Killing Effects of Clostridium perfringens Enterotoxin

    Directory of Open Access Journals (Sweden)

    Archana Shrestha

    2016-12-01

    Full Text Available Clostridium perfringens enterotoxin (CPE binds to claudin receptors, e.g., claudin-4, and then forms a pore that triggers cell death. Pure cultures of host cells that do not express claudin receptors, e.g., fibroblasts, are unaffected by pathophysiologically relevant CPE concentrations in vitro. However, both CPE-insensitive and CPE-sensitive host cells are present in vivo. Therefore, this study tested whether CPE treatment might affect fibroblasts when cocultured with CPE-sensitive claudin-4 fibroblast transfectants or Caco-2 cells. Under these conditions, immunofluorescence microscopy detected increased death of fibroblasts. This cytotoxic effect involved release of a toxic factor from the dying CPE-sensitive cells, since it could be reproduced using culture supernatants from CPE-treated sensitive cells. Supernatants from CPE-treated sensitive cells, particularly Caco-2 cells, were found to contain high levels of membrane vesicles, often containing a CPE species. However, most cytotoxic activity remained in those supernatants even after membrane vesicle depletion, and CPE was not detected in fibroblasts treated with supernatants from CPE-treated sensitive cells. Instead, characterization studies suggest that a major cytotoxic factor present in supernatants from CPE-treated sensitive cells may be a 10- to 30-kDa host serine protease or require the action of that host serine protease. Induction of caspase-3-mediated apoptosis was found to be important for triggering release of the cytotoxic factor(s from CPE-treated sensitive host cells. Furthermore, the cytotoxic factor(s in these supernatants was shown to induce a caspase-3-mediated killing of fibroblasts. This bystander killing effect due to release of cytotoxic factors from CPE-treated sensitive cells could contribute to CPE-mediated disease.

  11. Radiation-induced mutagenicity and lethality in tryptophan-requiring auxotrophs of escherichia coli

    International Nuclear Information System (INIS)

    Xu Rong; Qian Hongwei; Yao Fenying; Gu Shuzhu; Xu Jiaxin; Bi Hekan; Liu Yuying

    1989-01-01

    Mutation and killing caused by X-ray radiation and 60 Co γ-ray radiation were studied in three different tryptophan-requiring auxotrophs (WP2, Wp2A, Cm 891) of Escherichia coli. These testers are sensitive to base pair substitution mutagens. Cm891 carries a R-factor and is more sensitive than WP2 and WP2A to radiation-induced mutation and lethality. The results of the study show that (1) ionizing radiation was mutagenic to E. coli, (2) the order of mutagenic sensitivity among three strains to ionizing radiation was Cm891 > WP2A > WP2, (3) the dose rate of γ-ray influences mutagenicity and lethalty of E. coli strain, (4) the toxicity and mutagenicity of γ-ray were similar to X-ray when Cm891 was tested, however, γ-ray was more toxic and mutagenic than X-ray to WP2A ang WP2

  12. Role of ozone and granular activated carbon in the removal of mutagenic compounds.

    Science.gov (United States)

    Bourbigot, M M; Hascoet, M C; Levi, Y; Erb, F; Pommery, N

    1986-01-01

    The identification of certain organic compounds in drinking water has led water treatment specialists to be increasingly concerned about the eventual risks of such pollutants to the health of consumers. Our experiments focused on the role of ozone and granular activated carbon in removing mutagenic compounds and precursors that become toxic after chlorination. We found that if a sufficient dose of ozone is applied, its use does not lead to the creation of mutagenic compounds in drinking water and can even eliminate the initial mutagenicity of the water. The formation of new mutagenic compounds seems to be induced by ozonation that is too weak, although these mutagens can be removed by GAC filtration. Ozone used with activated carbon can be one of the best means for eliminating the compounds contributing to the mutagenicity of water. A combined treatment of ozone and activated carbon also decreases the chlorine consumption of the treated water and consequently reduces the formation of chlorinated organic compounds. PMID:3816720

  13. Mutagenicity of urine from nurses handling cytostatic drugs, influence of smoking

    Energy Technology Data Exchange (ETDEWEB)

    Bos, R P; Leenaars, A O; Theuws, J L; Henderson, P T

    1982-01-01

    Mutagenicity towards Salmonella typhimurium TA 100 of urine from smoking nurses, who were occupationally involved in the treatment of patients with cytostatic drugs, was significantly increased in comparison with that of smoking control subjects. Mutagenicity towards Salmonella typhimurium TA 100 was not increased in exposed non-smokers when compared to control non-smokers. In smoking subjects urinary mutagenicity appeared increased towards Salmonella typhimurium TA 1538 in the presence of S-9 mix. Rats pretreated with Aroclor 1254 showed higher mutagenicity in their urine than untreated rats after cyclophosphamide administration. Therefore, the synergistic effect of smoking might be due in part to induction of enzymes involved in the mutagenic activation of cytostatic drugs. Further, the animal experiments showed that cyclophosphamide (the most frequently used mutagenic cytostatic drug) can be absorbed after oral or percutaneous administration. Therefore, it is not excluded that differences in working hygiene between smokers and non-smokers also play a role.

  14. Combined effects of a chemical mutagen and radiation sterilized diet in mutagenicity and reproduction studies in the same mouse

    International Nuclear Information System (INIS)

    Renner, H.W.

    1975-01-01

    The possible intensification of the mutagenic effect of cyclophosphamide (Endoxan) by the feeding of a radiation-sterilized diet (dose, 4.5 Mrad) was studied in 2000 NMRI/Han mice. In a dominant lethal test, males were pretreated with 100 mg Endoxan/kg body weight. The greatest sensitivity towards Endoxan was observed during the late-spermatid stage. No significant differences were detected between the control group (Endoxan plus non-irradiated diet) and the experimental group (Endoxan plus radiation-sterilized diet). In this test, radiation-sterilized feed showed no co-mutagenic effect when combined with Endoxan treatment. In a reproduction study of 7 months duration (continuous mating without lactation periods), the females were treated every 2 wk with 20 mg Endoxan/kg body weight. The decline in litter size with increasing number of litters (i.e. with advancing age of the females) was more pronounced after treatment with the chemical mutagen than in the untreated group. Increases in the frequency of abortions and in premature sterility resulted from Endoxan treatment. During the entire observation period, no effects from the intake of radiation-sterilized food were detected. (author)

  15. Association of bystander cardiopulmonary resuscitation and survival according to ambulance response-times after out-of-hospital cardiac arrest

    DEFF Research Database (Denmark)

    Rajan, Shahzleen; Wissenberg, Mads; Folke, Fredrik

    2016-01-01

    30-day survival chances decreased for both patients with bystander CPR and those without. However, the contrast between the survival chances of patients with versus without bystander CPR increased over time: within 5 minutes, 30-day survival was 14.5% (95% confidence interval [CI]: 12.8-16.4) versus...... 6.3% (95% CI: 5.1-7.6), corresponding to 2.3 times higher chances of survival associated with bystander CPR; within 10 minutes, 30-day survival chances were 6.7% (95% CI: 5.4-8.1) versus 2.2% (95% CI: 1.5-3.1), corresponding to 3.0 times higher chances of 30-day survival associated with bystander...... CPR. The contrast in 30-day survival became statistically insignificant when response time was >13 minutes (bystander CPR vs no bystander CPR: 3.7% [95% CI: 2.2-5.4] vs 1.5% [95% CI: 0.6-2.7]), but 30-day survival was still 2.5 times higher associated with bystander CPR. Based on the model and Danish...

  16. Nitric oxide mediated DNA double strand breaks induced in proliferating bystander cells after {alpha}-particle irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Han Wei [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Chen Shaopeng [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Yu, K.N., E-mail: peter.yu@cityu.edu.hk [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Wu Lijun [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China)

    2010-02-03

    Low-dose {alpha}-particle exposures comprise 55% of the environmental dose to the human population and have been shown to induce bystander responses. Previous studies showed that bystander effect could induce stimulated cell growth or genotoxicity, such as excessive DNA double strand breaks (DSBs), micronuclei (MN), mutation and decreased cell viability, in the bystander cell population. In the present study, the stimulated cell growth, detected with flow cytometry (FCM), and the increased MN and DSB, detected with p53 binding protein 1 (53BP1) immunofluorescence, were observed simultaneously in the bystander cell population, which were co-cultured with cells irradiated by low-dose {alpha}-particles (1-10 cGy) in a mixed system. Further studies indicated that nitric oxide (NO) and transforming growth factor {beta}1 (TGF-{beta}1) played very important roles in mediating cell proliferation and inducing MN and DSB in the bystander population through treatments with NO scavenger and TGF-{beta}1 antibody. Low-concentrations of NO, generated by spermidine, were proved to induce cell proliferation, DSB and MN simultaneously. The proliferation or shortened cell cycle in bystander cells gave them insufficient time to repair DSBs. The increased cell division might increase the probability of carcinogenesis in bystander cells since cell proliferation increased the probability of mutation from the mis-repaired or un-repaired DSBs.

  17. X-ray radiation induced bystander effects of human glioblastoma T98G cells under hypoxia condition

    International Nuclear Information System (INIS)

    Zhang Jianghong; Jin Yizun; Shao Chunlin; Prise, K.M.

    2008-01-01

    Non-irradiated bystander human glioblastoma T98G cells were co-cultured (CC) with irradiated cells or treated with conditioned medium (CM) from irradiated cells under hypoxic condition, then micronucleus (MN) of both irradiated cells and bystander cells were measured for the investigation of radiation induced bystander effect and its mechanism. It has been found that the MN yield (Y MN ) of non-irradiated bystander T98G cells is obviously enhanced after the cell co-culture, or CM treatment, but this increment is diminished by free radical scavenger, dimethyl sulfoxide (DMSO). When hypoxic or normoxic T98G cells are treated with CM obtained from irradiated cells under either hypoxic or normoxic condition, the biggest bystander response has been observed in the group of hypoxic by- stander cells treated with CM from irradiated normoxic cells. However, all of these increments of bystander Y MN could be eliminated by aminoguanidine, an iNOS inhibitor. Therefore, under hypoxic condition, free radicals, especially reactive oxygen species and nitric oxide, are involved in the bystander response induced by irradiated T98G cells. (authors)

  18. Nitric oxide mediated DNA double strand breaks induced in proliferating bystander cells after α-particle irradiation

    International Nuclear Information System (INIS)

    Han Wei; Chen Shaopeng; Yu, K.N.; Wu Lijun

    2010-01-01

    Low-dose α-particle exposures comprise 55% of the environmental dose to the human population and have been shown to induce bystander responses. Previous studies showed that bystander effect could induce stimulated cell growth or genotoxicity, such as excessive DNA double strand breaks (DSBs), micronuclei (MN), mutation and decreased cell viability, in the bystander cell population. In the present study, the stimulated cell growth, detected with flow cytometry (FCM), and the increased MN and DSB, detected with p53 binding protein 1 (53BP1) immunofluorescence, were observed simultaneously in the bystander cell population, which were co-cultured with cells irradiated by low-dose α-particles (1-10 cGy) in a mixed system. Further studies indicated that nitric oxide (NO) and transforming growth factor β1 (TGF-β1) played very important roles in mediating cell proliferation and inducing MN and DSB in the bystander population through treatments with NO scavenger and TGF-β1 antibody. Low-concentrations of NO, generated by spermidine, were proved to induce cell proliferation, DSB and MN simultaneously. The proliferation or shortened cell cycle in bystander cells gave them insufficient time to repair DSBs. The increased cell division might increase the probability of carcinogenesis in bystander cells since cell proliferation increased the probability of mutation from the mis-repaired or un-repaired DSBs.

  19. Studying effects of Magnolol on alpha-particle induced bystander effects using PADC-film based dishes

    International Nuclear Information System (INIS)

    Wong, T.P.W.; Tse, A.K.W.; Fong, W.F.; Yu, K.N.

    2009-01-01

    Radiation-induced bystander effect refers to the biological response found in cells (called bystander cells) which are not irradiated directly by ionizing radiation but are next to cells irradiated directly by ionizing radiation. In the present paper, the effects of Magnolol, an extract from the bark of Magnolia officinalis which is used as a traditional Chinese medicine, were studied on alpha-particle induced bystander effects. In our experiments, Chinese hamster ovary (CHO) cells were cultured in PADC-film based dishes and were irradiated with low fluences of alpha particles passing through the PADC films. The precise number of cells traversed or missed by alpha particles could be determined by studying the alpha-particle tracks developed on the PADC films upon subsequent chemical etching. TdT-mediated dUTP Nick-End Labeling (TUNEL) assay was employed to analyze the biological response of bystander cells in terms of DNA strand breaks. With the pretreatment of Magnolol, the DNA strand breaks in bystander cells were reduced, which showed that the alpha-particle induced bystander effects were suppressed with the presence of Magnolol. Since Magnolol is an antioxidant which can scavenge reactive oxygen species (ROS), our results give support to that ROS play a role in the bystander signal transmission in our experiments.

  20. Studying effects of Magnolol on alpha-particle induced bystander effects using PADC-film based dishes

    Energy Technology Data Exchange (ETDEWEB)

    Wong, T.P.W. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Tse, A.K.W.; Fong, W.F. [Research and Development Division, School of Chinese Medicine, Hong Kong Baptist University, Baptist University Road, Kowloon Tong (Hong Kong); Yu, K.N., E-mail: peter.yu@cityu.edu.h [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong)

    2009-10-15

    Radiation-induced bystander effect refers to the biological response found in cells (called bystander cells) which are not irradiated directly by ionizing radiation but are next to cells irradiated directly by ionizing radiation. In the present paper, the effects of Magnolol, an extract from the bark of Magnolia officinalis which is used as a traditional Chinese medicine, were studied on alpha-particle induced bystander effects. In our experiments, Chinese hamster ovary (CHO) cells were cultured in PADC-film based dishes and were irradiated with low fluences of alpha particles passing through the PADC films. The precise number of cells traversed or missed by alpha particles could be determined by studying the alpha-particle tracks developed on the PADC films upon subsequent chemical etching. TdT-mediated dUTP Nick-End Labeling (TUNEL) assay was employed to analyze the biological response of bystander cells in terms of DNA strand breaks. With the pretreatment of Magnolol, the DNA strand breaks in bystander cells were reduced, which showed that the alpha-particle induced bystander effects were suppressed with the presence of Magnolol. Since Magnolol is an antioxidant which can scavenge reactive oxygen species (ROS), our results give support to that ROS play a role in the bystander signal transmission in our experiments.

  1. A High School-Based Evaluation of TakeCARE, a Video Bystander Program to Prevent Adolescent Relationship Violence.

    Science.gov (United States)

    Sargent, Kelli S; Jouriles, Ernest N; Rosenfield, David; McDonald, Renee

    2017-03-01

    Although bystander programs to prevent relationship and sexual violence have been evaluated with college students, few evaluations have been conducted with high school students. This study evaluated the effectiveness of TakeCARE, a brief video bystander program designed to promote helpful bystander behavior in situations involving relationship violence among high school students. Students (N = 1295; 52.5% female; 72.3% Hispanic) reported their bystander behavior at a baseline assessment. Classrooms (N = 66) were randomized to view TakeCARE or to a control condition, and high school counselors administered the video in the classrooms assigned to view TakeCARE. Students again reported their bystander behavior at a follow-up assessment approximately 3 months afterward. Results indicate that students who viewed TakeCARE reported more helpful bystander behavior at the follow-up assessment than students in the control condition. Results of exploratory analyses of the likelihood of encountering and intervening upon specific situations calling for bystander behavior are also reported. TakeCARE is efficacious when implemented in an urban high school by high school counselors.

  2. Sexual side effects induced by psychotropic drugs

    DEFF Research Database (Denmark)

    Kristensen, Ellids

    2002-01-01

    The majority of psychotropic drugs entail sexual side effects. The sexual side effects may reduce quality of life and may give rise to non-compliance. For example, 30-60 per cent of patients treated with antidepressants are known to develop a sexual dysfunction. However, some psychotropic drugs...... with no or very few sexual side effects have begun to emerge. The treatment of sexual side effects induced by psychotropic drugs may consist of: modified sexual habits, reduction in dosage, switching to another medication, possibly in combination with different psychotropic agents, other varieties...

  3. 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

  4. Raising a Red Flag on Dating Violence: Evaluation of a Low-Resource, College-Based Bystander Behavior Intervention Program.

    Science.gov (United States)

    Borsky, Amanda E; McDonnell, Karen; Turner, Monique Mitchell; Rimal, Rajiv

    2016-03-09

    Encouraging bystanders to intervene safely and effectively in situations that could escalate to violence-known as bystander behavior programs-is a growing yet largely untested strategy to prevent dating violence. Using a quasi-experimental design, we evaluate a low-resource, low-intensity intervention aimed at preventing dating violence among college students. The integrated behavioral model (IBM) was used to guide the evaluation. We also assess which IBM variables were most strongly associated with bystander behaviors. Participants were drawn from two Virginia colleges that predominantly train females in the health profession sciences. The intervention group (n = 329) participated in a university-wide bystander behavior intervention consisting of a 30-min presentation on dating violence at new-student orientation and a week-long "red flag" social marketing campaign on campus to raise awareness of dating violence. Controlling for changes at the comparison university, results showed an increase in bystander behaviors, such as encouraging a friend who may be in an abusive relationship to get help, after the intervention and adjusting for potential confounders (increase of 1.41 bystander behaviors, p = .04). However, no significant changes were found for bystander intentions, self-efficacy, social norms, or attitudes related to dating violence from pre- to post-intervention. Self-efficacy had a direct relationship with bystander behaviors. Results suggest that low-resource interventions have a modest effect on increasing bystander behaviors. However, higher resource interventions likely are needed for a larger impact, especially among students who already demonstrate strong baseline intentions to intervene and prevent dating violence. © The Author(s) 2016.

  5. Reducing Sexual Violence on Campus: The Role of Student Leaders as Empowered Bystanders

    Science.gov (United States)

    Banyard, Victoria L.; Moynihan, Mary M.; Crossman, Maria T.

    2009-01-01

    Sexual violence is a widespread problem for college communities. Students, faculty, and staff are increasingly involved in prevention efforts. To date, however, evaluation of sexual violence prevention programs has shown mixed results. One promising new practice teaches segments of college communities to be engaged, positive bystanders. It aims to…

  6. Development of a mathematical model to study the radiation-induced bystander effect

    Energy Technology Data Exchange (ETDEWEB)

    Meireles, Sincler P. de; Santos, Adriano M.; Grynberg, Suely Epsztein, E-mail: spm@cdtn.b, E-mail: amsantos@cdtn.b, E-mail: seg@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Nunes, Maria Eugenia S., E-mail: mariaeugenia@iceb.ufop.b [Universidade Federal de Ouro Preto (UFOP), MG (Brazil)

    2011-07-01

    Living organisms are composed of millions of cells that together perform tasks of great complexity. Although every cell has an internal structure that obeys the laws of chemistry and biochemistry, it is the interactions between cells that generate a range of different phenomena. Until the 1990s it was believed that the DNA was the single molecule affected by radiation, the so-called theory of the single target. But some observations began to challenge this theory; in 1992 the bystander effect was described by Nagasawa and Little. This effect is responsible for a series of responses such as death, chromosomal instability or other abnormalities that occur in non-irradiated cells that came into contact with irradiated cells or medium from irradiated cells. Understanding the bystander effect may have important consequences for therapy and studies of low-dose risk. In this work, we have developed a computational model to study the bystander effect. This computational model is a two-dimensional cellular automata, consisting of two overlapping networks, where the first represents the cell culture, and the second one, the medium in which cells are embedded. The computational model allows the establishment of curves to describe the behavior of the effect for different levels of signals released in the irradiated medium by the irradiated cells or by the bystander cells when a second order effect is considered. The percentage of cell survival obtained from the mathematical model showed to be in good agreement with experimental data available in the literature. (author)

  7. Acting in solidarity : Testing an extended dual pathway model of collective action by bystander group members

    NARCIS (Netherlands)

    Saab, Rim; Tausch, Nicole; Spears, Russell; Cheung, Wing-Yee

    We examined predictors of collective action among bystander group members in solidarity with a disadvantaged group by extending the dual pathway model of collective action, which proposes one efficacy-based and one emotion-based path to collective action (Van Zomeren, Spears, Fischer, & Leach,

  8. Culture of three-dimensional tissue model and its application in bystander-effect research

    International Nuclear Information System (INIS)

    Wu Ruqun; Xu An; Wu Lijun; Hu Burong

    2012-01-01

    Compared with the cultured monolayer (2D) cells, three-dimensional (3D) tissue could be more similar to the environment in vivo including the physical support, chemical factors, cell-cell and cell-matrix interaction and so on. With the development of three-dimensional cell culture techniques (TDCC), 3D tissue is widely used in the areas of bystander effect research. This review focuses on introducing the TDCC method and its application in bystander-effect research. First, the development process of 3D tissue culture method was introduced. Secondly, the induction of radiation induced bystander effects both in 2D cell and 3D tissue and its mechanisms were reviewed. Finally, because heavy ion (carbon ion beam) has been developed as a useful tool to cure solid cancer, and the 3D tissue model is an ideal material to study the damages on body after being irradiated and to understand the underlying mechanisms, future study about heavy ion radiation inducing bystander effect in 3D tissue was discussed. (authors)

  9. Distinction of the memory B cell response to cognate antigen versus bystander inflammatory signals.

    Science.gov (United States)

    Benson, Micah J; Elgueta, Raul; Schpero, William; Molloy, Michael; Zhang, Weijun; Usherwood, Edward; Noelle, Randolph J

    2009-08-31

    The hypothesis that bystander inflammatory signals promote memory B cell (B(MEM)) self-renewal and differentiation in an antigen-independent manner is critically evaluated herein. To comprehensively address this hypothesis, a detailed analysis is presented examining the response profiles of B-2 lineage B220(+)IgG(+) B(MEM) toward cognate protein antigen in comparison to bystander inflammatory signals. After in vivo antigen encounter, quiescent B(MEM) clonally expand. Surprisingly, proliferating B(MEM) do not acquire germinal center (GC) B cell markers before generating daughter B(MEM) and differentiating into plasma cells or form structurally identifiable GCs. In striking contrast to cognate antigen, inflammatory stimuli, including Toll-like receptor agonists or bystander T cell activation, fail to induce even low levels of B(MEM) proliferation or differentiation in vivo. Under the extreme conditions of adjuvanted protein vaccination or acute viral infection, no detectable bystander proliferation or differentiation of B(MEM) occurred. The absence of a B(MEM) response to nonspecific inflammatory signals clearly shows that B(MEM) proliferation and differentiation is a process tightly controlled by the availability of cognate antigen.

  10. Bystander efforts and 1-year outcomes in out-of-hospital cardiac arrest

    DEFF Research Database (Denmark)

    Kragholm, Kristian; Wissenberg, Mads; Mortensen, Rikke N.

    2017-01-01

    changes in bystander interventions and outcomes. RESULTS Among the 2855 patients who were 30-day survivors of an out-of-hospital cardiac arrest during the period from 2001 through 2012, a total of 10.5% had brain damage or were admitted to a nursing home and 9.7% died during the 1-year follow-up period...

  11. Masculinity and Bystander Attitudes: Moderating Effects of Masculine Gender Role Stress.

    Science.gov (United States)

    Leone, Ruschelle M; Parrott, Dominic J; Swartout, Kevin M; Tharp, Andra Teten

    2016-01-01

    The purpose of the current study was to examine the bystander decision-making process as a mechanism by which men's adherence to various dimensions of traditional masculinity is associated with their confidence to intervene in sexually aggressive events. Further, this study examined the stress men experience from their attempts to adhere to traditional male gender roles as a moderator of this mediational path. Participants ( n = 252) completed measures of traditional masculinity, decisional balance (i.e., weighing the pros and cons) for intervening, masculine gender roles stress, and bystander efficacy. The belief that men must attain social status was associated with more confidence in men's ability to intervene. This effect was mediated by greater perceived positive consequences for intervention among men high, but not low, in masculine gender role stress. The belief that men should be tough and aggressive was associated with greater perceived negative consequences for intervention and less confidence to intervene. The belief that men should not act in stereotypically feminine ways was directly associated with less confidence for intervention. Findings highlight the importance of examining masculinity from a multidimensional perspective to better understand how adherence to various norms differentially influences bystander behavior. These findings may help to inform bystander intervention programming.

  12. Participation in High School Sports and Bystander Intentions, Efficacy to Intervene, and Rape Myth Beliefs.

    Science.gov (United States)

    McMahon, Sarah

    2015-10-01

    Debate exists as to whether male athletes are more prone to commit acts of sexual violence and maintain problematic attitudes about sexual assault. To contribute to the literature on this relationship, this study posed the following research questions: (1) Do those students who participated in high school sports and those who did not differ significantly in their attitudes about sexual violence and willingness to intervene as a bystander? Do these differ among types of rape myths and bystander intervention situations? (2) Within a group of athletes, are there significant differences by gender or type of sport (contact sport vs. non-contact?) To answer these questions, surveys were analyzed with a sample of recent high school graduates the summer before entering college (N = 3,588). Results indicate that there were only minor differences between those students who participated in high school varsity sports and those who did not. Students who participated in sports had greater acceptance of three out of five types of rape myths, and less willingness to intervene with perpetrators after an assault; however, the effect sizes were small. There were no significant differences for bystander efficacy. The interaction between sport and gender was significant, but contact sport was not. The findings suggest that there may be aspects of male athletic participation in sports that needs to be addressed, yet there also exists the potential for engaging athletes as leaders who can act as prosocial bystanders. © The Author(s) 2014.

  13. Bystander Automated External Defibrillator Use and Clinical Outcomes after Out-of-Hospital Cardiac Arrest

    DEFF Research Database (Denmark)

    Holmberg, Mathias J; Vognsen, Mikael; Andersen, Mikkel S

    2017-01-01

    Aim: To systematically review studies comparing bystander automated external defibrillator (AED) use to no AED use in regard to clinical outcomes in out-of-hospital cardiac arrest (OHCA), and to provide a descriptive summary of studies on the cost-effectiveness of bystander AED use. Methods: We...... randomized trials, and 13 cost-effectiveness studies were included. Meta-analysis of 6 observational studies without critical risk of bias showed that bystander AED use was associated with survival to hospital discharge (all rhythms OR: 1.73 [95% CI: 1.36, 2.18], shockable rhythms OR: 1.66 [95% CI: 1.54, 1.......79]) and favorable neurological outcome (all rhythms OR: 2.12 [95% CI: 1.36, 3.29], shockable rhythms OR: 2.37 [95% CI: 1.58, 3.57]). There was no association between bystander AED use and neurological outcome for non-shockable rhythms (OR: 0.76 [95% CI: 0.10, 5.87]). The Public-Access Defibrillation trial found...

  14. 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

  15. A Bystander Bullying Psychoeducation Program with Middle School Students: A Preliminary Report

    Science.gov (United States)

    Midgett, Aida; Doumas, Diana; Sears, Dara; Lundquist, Amanda; Hausheer, Robin

    2015-01-01

    This study evaluated the effectiveness of a brief, stand-alone bystander bullying psychoeducation program for middle school students. The purpose of the program was to train students to take action as peer advocates. Pre- and post-tests indicated that after completing the 90-minute psychoeducation program, students reported an increase in their…

  16. Sticks, Stones, and Stigma: Student Bystander Behavior in Response to Hearing the Word "Retard"

    Science.gov (United States)

    Albert, Avery B.; Jacobs, Holly E.; Siperstein, Gary N.

    2016-01-01

    The present study explored the prevalence of the r-word in schools and students' bystander behavior in response to hearing the word. In total, 2,297 students from 12 high schools across the country participated in this study. Results revealed the r-word was used frequently among high school students, most often toward individuals without…

  17. A Meta-Analysis of School-Based Bullying Prevention Programs' Effects on Bystander Intervention Behavior

    Science.gov (United States)

    Polanin, Joshua R.; Espelage, Dorothy L.; Pigott, Therese D.

    2012-01-01

    This meta-analysis synthesized bullying prevention programs' effectiveness at increasing bystander intervention in bullying situations. Evidence from 12 school-based programs, involving 12,874 students, indicated that overall the programs were successful (Hedges's g = 0.20, 95% confidence interval [CI] = 0.11 to 0.29, p = 0.001), with larger…

  18. Bystander Behavior in Bullying Situations: Basic Moral Sensitivity, Moral Disengagement and Defender Self-Efficacy

    Science.gov (United States)

    Thornberg, Robert; Jungert, Tomas

    2013-01-01

    The aim of the present study was to investigate how basic moral sensitivity in bullying, moral disengagement in bullying and defender self-efficacy were related to different bystander behaviors in bullying. Therefore, we examined pathways that linked students' basic moral sensitivity, moral disengagement, and defender self-efficacy to different…

  19. Bystander Involvement in Peer Victimization: The Value of Looking beyond Aggressors and Victims

    Science.gov (United States)

    Wiens, Brenda A.; Dempsey, Allison

    2009-01-01

    Peer victimization has been a focus of both research and prevention program development. This construct is typically measured from the victim and aggressor perspectives. However, prevention programming often includes an additional bystander perspective. The present study evaluated whether questions regarding witnessing peer victimization…

  20. Being a Positive Bystander: Male Antiviolence Allies' Experiences of "Stepping up"

    Science.gov (United States)

    Casey, Erin A.; Ohler, Kristin

    2012-01-01

    As bystander approaches become increasingly prevalent elements of sexual and domestic violence prevention efforts, it is necessary to better understand the factors that support or impede individuals in taking positive action in the face of aggressive or disrespectful behavior from others. This study presents descriptive findings about the…

  1. Aggressive Attitudes and Prevalence of Bullying Bystander Behavior in Middle School

    Science.gov (United States)

    Datta, Pooja; Cornell, Dewey; Huang, Francis

    2016-01-01

    Separate lines of research find that proaggressive attitudes promote peer aggression and that bystanders play a pivotal role in deterring or facilitating bullying behavior. The current study hypothesized that proaggressive attitudes in middle school would deter students from standing up to bullying and encourage them to reinforce bullying…

  2. DNA damage and the bystander response in tumor and normal cells exposed to X-rays.

    Science.gov (United States)

    Subhashree, M; Venkateswarlu, R; Karthik, K; Shangamithra, V; Venkatachalam, P

    2017-09-01

    Monolayer and suspension cultures of tumor (BMG-1, CCRF-CEM), normal (AG1522, HADF, lymphocytes) and ATM-mutant (GM4405) human cells were exposed to X-rays at doses used in radiotherapy (high dose and high dose-rate) or radiological imaging (low dose and low dose-rate). Radiation-induced DNA damage, its persistence, and possible bystander effects were evaluated, based on DNA damage markers (γ-H2AX, p53 ser15 ) and cell-cycle-specific cyclins (cyclin B1 and cyclin D1). Dose-dependent DNA damage and a dose-independent bystander response were seen after exposure to high dose and high dose-rate radiation. The level of induced damage (expression of p53 ser15 , γ-H2AX) depended on ATM status. However, low dose and dose-rate exposures neither increased expression of marker proteins nor induced a bystander response, except in the CCRF-CEM cells. Bystander effects after high-dose irradiation may contribute to stochastic and deterministic effects. Precautions to protect unexposed regions or to inhibit transmission of DNA damage signaling might reduce radiation risks. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Masculinity and Bystander Attitudes: Moderating Effects of Masculine Gender Role Stress

    Science.gov (United States)

    Leone, Ruschelle M.; Parrott, Dominic J.; Swartout, Kevin M.; Tharp, Andra Teten

    2018-01-01

    Objective The purpose of the current study was to examine the bystander decision-making process as a mechanism by which men’s adherence to various dimensions of traditional masculinity is associated with their confidence to intervene in sexually aggressive events. Further, this study examined the stress men experience from their attempts to adhere to traditional male gender roles as a moderator of this mediational path. Method Participants (n = 252) completed measures of traditional masculinity, decisional balance (i.e., weighing the pros and cons) for intervening, masculine gender roles stress, and bystander efficacy. Results The belief that men must attain social status was associated with more confidence in men’s ability to intervene. This effect was mediated by greater perceived positive consequences for intervention among men high, but not low, in masculine gender role stress. The belief that men should be tough and aggressive was associated with greater perceived negative consequences for intervention and less confidence to intervene. The belief that men should not act in stereotypically feminine ways was directly associated with less confidence for intervention. Conclusions Findings highlight the importance of examining masculinity from a multidimensional perspective to better understand how adherence to various norms differentially influences bystander behavior. These findings may help to inform bystander intervention programming. PMID:29593932

  4. Intervene to be seen: The power of a camera in attenuating the bystander effect

    NARCIS (Netherlands)

    van Bommel, M.; van Prooijen, J.W.; Elffers, H.; van Lange, P.A.M.

    2014-01-01

    Security cameras became such a part of everyday life that their presence may escape from our conscious attention. The present research examines the impact of cameras on intervening in crime, a situation in which the classic bystander effect has been uncovered. In our experimental set up,

  5. R.U. Ready?: Peer Education and Bystander Intervention Sexual Assault Programming

    Science.gov (United States)

    Schweer, Jen Luettel; Heather, Katie; Kay, Kathryn; Stewart, K. Leigh; Kovach, Laura

    2012-01-01

    R.U. Ready? at Georgetown University is an annual sexual assault awareness event that incorporates peer education and resources with opportunities for students, staff, and faculty to dialogue about providing bystander intervention throughout the campus community. Beyond dialogue, participants learn about student activism and the resources and…

  6. Development of a mathematical model to study the radiation-induced bystander effect

    International Nuclear Information System (INIS)

    Meireles, Sincler P. de; Santos, Adriano M.; Grynberg, Suely Epsztein; Nunes, Maria Eugenia S.

    2011-01-01

    Living organisms are composed of millions of cells that together perform tasks of great complexity. Although every cell has an internal structure that obeys the laws of chemistry and biochemistry, it is the interactions between cells that generate a range of different phenomena. Until the 1990s it was believed that the DNA was the single molecule affected by radiation, the so-called theory of the single target. But some observations began to challenge this theory; in 1992 the bystander effect was described by Nagasawa and Little. This effect is responsible for a series of responses such as death, chromosomal instability or other abnormalities that occur in non-irradiated cells that came into contact with irradiated cells or medium from irradiated cells. Understanding the bystander effect may have important consequences for therapy and studies of low-dose risk. In this work, we have developed a computational model to study the bystander effect. This computational model is a two-dimensional cellular automata, consisting of two overlapping networks, where the first represents the cell culture, and the second one, the medium in which cells are embedded. The computational model allows the establishment of curves to describe the behavior of the effect for different levels of signals released in the irradiated medium by the irradiated cells or by the bystander cells when a second order effect is considered. The percentage of cell survival obtained from the mathematical model showed to be in good agreement with experimental data available in the literature. (author)

  7. It's Your Place: Development and Evaluation of an Evidence-Based Bystander Intervention Campaign.

    Science.gov (United States)

    Sundstrom, Beth; Ferrara, Merissa; DeMaria, Andrea L; Gabel, Colby; Booth, Kathleen; Cabot, Jeri

    2017-06-28

    Preventing sexual assault on college campuses is a national priority. Bystander intervention offers a promising approach to change social norms and prevent sexual misconduct. This study presents the implementation and evaluation of a theory-based campaign to promote active bystander intervention. The theory of planned behavior (TPB) served as a conceptual framework throughout campaign development and evaluation. Formative research published elsewhere was used to develop campaign strategies, communication channels, and messages, including "It is your place to prevent sexual assault: You're not ruining a good time." The It's Your Place multi-media campaign fosters a culture of bystander intervention through peer-to-peer facilitation and training, as well as traditional and new media platforms. A cross-sectional post-test only web-based survey was designed to evaluate the campaign and test the TPB's ability to accurately predict intention to intervene. Survey data were collected from 1,505 currently enrolled students. The TPB model predicted intention to intervene. There was a significant effect of campaign exposure on attitude, subjective norms, and perceived behavioral intention. This theory-based communication campaign offers implications for promoting active bystander intervention and reducing sexual assault.

  8. Bystander Intervention, Bullying, and Victimization: A Multilevel Analysis of New Zealand High Schools

    Science.gov (United States)

    Denny, Simon; Peterson, Elizabeth R.; Stuart, Jaimee; Utter, Jennifer; Bullen, Pat; Fleming, Theresa; Ameratunga, Shanthi; Clark, Terryann; Milfont, Taciano

    2015-01-01

    This study examines the association between schools and student bullying behaviors and victimization among a nationally representative sample (N = 9,107) of New Zealand high school students. In particular, the study sought to explore the role of characteristics of schools and school culture with respect to bystander behavior, while controlling for…

  9. Using a Multimedia Social Marketing Campaign to Increase Active Bystanders on the College Campus

    Science.gov (United States)

    Potter, Sharyn J.

    2012-01-01

    Objective: To evaluate the campus-wide administration of the Know Your Power bystander-oriented social marketing campaign. Participants: Undergraduate students at a public college were invited to participate in a public awareness survey before and after the 6-week campaign administration in February and March 2009. Methods: Pretest and posttests…

  10. Using Role-Taking and Behavioral Mimicking in Games to Increase Awareness on the Bystander Effect

    DEFF Research Database (Denmark)

    Soegaard Andersen, Josephine; Schoenau-Fog, Henrik

    2015-01-01

    This study presents a concept on how a serious game might raise awareness of the bystander effect by using elements of game theory as well as a few psychological terms. The paper summarizes the theories and concludes with the description of a concept, which is a third person role playing game wit...

  11. Total and Marginal Cost Analysis for a High School Based Bystander Intervention

    Science.gov (United States)

    Bush, Joshua L.; Bush, Heather M.; Coker, Ann L.; Brancato, Candace J.; Clear, Emily R.; Recktenwald, Eileen A.

    2018-01-01

    Costs of providing the Green Dot bystander-based intervention, shown to be effective in the reduction of sexual violence among Kentucky high school students, were estimated based on data from a large cluster-randomized clinical trial. Rape Crisis Center Educators were trained to provide Green Dot curriculum to students. Implementing Green Dot in…

  12. Signaling pathways underpinning the manifestations of ionizing radiation-induced bystander effects.

    Science.gov (United States)

    Hamada, Nobuyuki; Maeda, Munetoshi; Otsuka, Kensuke; Tomita, Masanori

    2011-06-01

    For nearly a century, ionizing radiation has been indispensable to medical diagnosis. Furthermore, various types of electromagnetic and particulate radiation have also been used in cancer therapy. However, the biological mechanism of radiation action remains incompletely understood. In this regard, a rapidly growing body of experimental evidence indicates that radiation exposure induces biological effects in cells whose nucleus has not been irradiated. This phenomenon termed the 'non-targeted effects' challenges the long-held tenet that radiation traversal through the cell nucleus is a prerequisite to elicit genetic damage and biological responses. The non-targeted effects include biological effects in cytoplasm-irradiated cells, bystander effects that arise in non-irradiated cells having received signals from irradiated cells, and genomic instability occurring in the progeny of irradiated cells. Such non-targeted responses are interrelated, and the bystander effect is further related with an adaptive response that manifests itself as the attenuated stressful biological effects of acute high-dose irradiation in cells that have been pre-exposed to low-dose or low-dose-rate radiation. This paper reviews the current body of knowledge about the bystander effect with emphasis on experimental approaches, in vitro and in vivo manifestations, radiation quality dependence, temporal and spatial dependence, proposed mechanisms, and clinical implications. Relations of bystander responses with the effects in cytoplasm-irradiated cells, genomic instability and adaptive response will also be briefly discussed.

  13. Building upon Bystander Intervention: A Multi-Component Prevention Programming Approach for University Sorority Members

    Science.gov (United States)

    Steward, Jennifer M.

    2017-01-01

    Sexual violence on college campuses is a pervasive problem with the potential for extensive physical and psychological health consequences. Institutions have begun implementing prevention programs; however, more research is needed to understand whether these programs are effective. Bystander intervention programs have increased in popularity…

  14. Counseling and the Bystander-Equity Model of Supervisory Helping Behavior: Directions for EAP Research.

    Science.gov (United States)

    Gerstein, Lawrence H.; Bayer, Gregory A.

    1991-01-01

    Discusses contribution of Bystander-Equity Model of Supervisory Helping Behavior to pursuit of employee assistance program (EAP) research based on traditions of field of counseling. Offers structure for pursuing empirical and applied activities in EAP settings. Encourages counseling researchers and practitioners to respond to challenge of working…

  15. Bystanders, parcelling, and an absence of trust in the grooming interactions of wild male chimpanzees.

    Science.gov (United States)

    Kaburu, Stefano S K; Newton-Fisher, Nicholas E

    2016-02-09

    The evolution of cooperation remains a central issue in socio-biology with the fundamental problem of how individuals minimize the risks of being short-changed ('cheated') should their behavioural investment in another not be returned. Economic decisions that individuals make during interactions may depend upon the presence of potential partners nearby, which offers co operators a temptation to defect from the current partner. The parcelling model posits that donors subdivide services into parcels to force cooperation, and that this is contingent on opportunities for defection; that is, the presence of bystanders. Here we test this model and the effect of bystander presence using grooming interactions of wild chimpanzees. We found that with more bystanders, initiators gave less grooming at the beginning of the bout and were more likely to abandon a grooming bout, while bouts were less likely to be reciprocated. We also found that the groomer's initial investment was not higher among frequent groomers or stronger reciprocators, suggesting that contrary to current assumptions, grooming decisions are not based on trust, or bonds, within dyads. Our work highlights the importance of considering immediate social context and the influence of bystanders for understanding the evolution of the behavioural strategies that produce cooperation.

  16. The Role of Self-Efficacy for Bystander Helping Behaviors in Risky Alcohol Situations

    Science.gov (United States)

    Krieger, Heather; Serrano, Surizaday; Neighbors, Clayton

    2017-01-01

    We examined the role of self-efficacy in preventing bystander inaction in dangerous alcohol situations. Participants (N = 504) completed an online survey that assessed whether they had previously witnessed or intervened in alcohol-related emergencies, their self-efficacy for intervening, and their likelihood of intervening in the future.…

  17. Mutagens from the cooking of food. III. Survey by Ames/Salmonella test of mutagen formation in secondary sources of cooked dietary protein

    Energy Technology Data Exchange (ETDEWEB)

    Bjeldanes, L F [Univ. of California, Berkeley; Morris, M M; Felton, J S; Healy, S; Stuermer, D; Berry, P; Timourian, H; Hatch, F T

    1982-01-01

    A survey of mutagen formation during the cooking of a variety of protein-rich foods that are minor sources of protein intake in the American diet is reported (see Bjeldanes, Morris, Felton et al. (1982) for survey of major protein foods). Milk, cheese, tofu and organ meats showed negligible mutagen formation except following high-temperature cooking for long periods of time. Even under the most extreme conditions, tofu, cheese and milk exhibited fewer than 500 Ames/Salmonella typhimurium revertants/100 g equivalents (wet weight of uncooked food), and organ meats only double that amount. Beans showed low mutagen formation after boiling followed by frying (with and without oil). Only boiling of beans followed by baking for 1 hr gave appreciable mutagenicity (3650 revertants/100 g equivalents). Seafood samples gave a variety of results: red snapper, salmon, trout, halibut and rock cod all gave more than 1000 revertants/100 g wet weight equivalents when pan-fried or griddle-fried for about 6 min/side. Baked or poached rock cod and deep-fried shrimp showed no significant mutagen formation. Broiled lamb chops showed mutagen formation similar to that in red meats tested in the preceding paper: 16,000 revertants/100 g equivalents. These findings show that as measured by bioassay in S. typhimurium, most of the food that are minor sources of protein in the American diet are also minor sources of cooking-induced mutagens.

  18. Mutagens from the cooking of food. III. Survey by Ames/Salmonella test of mutagen formation in secondary sources of cooked dietary protein.

    Science.gov (United States)

    Bjeldanes, L F; Morris, M M; Felton, J S; Healy, S; Stuermer, D; Berry, P; Timourian, H; Hatch, F T

    1982-08-01

    A survey of mutagen formation during the cooking of a variety of protein-rich foods that are minor sources of protein intake in the American diet is reported (see Bjeldanes, Morris, Felton et al. (1982) for survey of major protein foods). Milk, cheese, tofu and organ meats showed negligible mutagen formation except following high-temperature cooking for long periods of time. Even under the most extreme conditions, tofu, cheese and milk exhibited fewer than 500 Ames/Salmonella typhimurium revertants/100 g equivalents (wet weight of uncooked food), and organ meats only double that amount. Beans showed low mutagen formation after boiling and boiling followed by frying (with and without oil). Only boiling of beans followed by baking for 1 hr gave appreciable mutagenicity (3650 revertants/100g equivalents). Seafood samples gave a variety of results: red snapper, salmon, trout, halibut and rock cod all gave more than 1000 revertants/100 g wet weight equivalents when pan-fried or griddle-fried for about 6 min/side. Baked or poached rock and deep-fried shrimp showed no significant mutagen formation. Broiled lamb chops showed mutagen formation similar to that in red meats tested in the preceding paper: 16,000 revertants/100 g equivalents. These findings show that as measured by bioassay in S. typhimurium, most of the foods that are minor sources of protein in the American diet are also minor sources of cooking-induced mutagens.

  19. Epigenetic Analysis of Heavy-ion Radiation Induced Bystander Effects in Mice

    Science.gov (United States)

    Zhang, Meng; Sun, Yeqing; Cui, Changna; Xue, Bei

    Abstract: Radiation-induced bystander effect was defined as the induction of damage in neighboring non-hit cells by signals released from directly-irradiated cells. Recently, low dose of high LET radiation induced bystander effects in vivo have been reported more and more. It has been indicated that radiation induced bystander effect was localized not only in bystander tissues but also in distant organs. Genomic, epigenetic and proteomics plays significant roles in regulating heavy-ion radiation stress responses in mice. To identify the molecular mechanism that underlies bystander effects of heavy-ion radiation, the male Balb/c and C57BL mice were exposed head-only to 40, 200, 2000mGy dose of (12) C heavy-ion radiation, while the rest of the animal body was shielded. Directly radiation organ ear and the distant organ liver were detected on 1h, 6h, 12h and 24h after radiation, respectively. Methylation-sensitive amplification polymorphism (MSAP) was used to monitor the level of polymorphic genomic DNA methylation changed with dose and time effects. The results show that heavy-ion irradiated mouse head could induce genomic DNA methylation changes significantly in both the directly radiation organ ear and the distant organ liver. The percent of DNA methylation changes were time-dependent and tissue-specific. Demethylation polymorphism rate was highest separately at 1 h in 200 mGy and 6 h in 2000 mGy after irradiation. The global DNA methylation changes tended to occur in the CG sites. The results illustrated that genomic methylation changes of heavy ion radiation-induced bystander effect in liver could be obvious 1 h after radiation and achieved the maximum at 6 h, while the changes could recover gradually at 12 h. The results suggest that mice head exposed to heavy-ion radiation can induce damage and methylation pattern changed in both directly radiation organ ear and distant organ liver. Moreover, our findings are important to understand the molecular mechanism of

  20. Bystander Motivation in Bullying Incidents: To Intervene or Not to Intervene?

    Directory of Open Access Journals (Sweden)

    Robert Thornberg

    2012-08-01

    Full Text Available Introduction: This research sought to extend knowledge about bystanders in bullying situations with a focus on the motivations that lead them to different responses. The 2 primary goals of this study were to investigate the reasons for children’s decisions to help or not to help a victim when witnessing bullying, and to generate a grounded theory (or conceptual framework of bystander motivation in bullying situations.Methods: Thirty students ranging in age from 9 to 15 years (M=11.9; SD=1.7 from an elementary and middle school in the southeastern United States participated in this study. Open- ended, semistructured interviews were used, and sessions ranged from 30 to 45 minutes. We conducted qualitative methodology and analyses to gain an in-depth understanding of children’s perspectives and concerns when witnessing bullying.Results: A key finding was a conceptual framework of bystander motivation to intervene in bullying situations suggesting that deciding whether to help or not help the victim in a bullying situation depends on how bystanders define and evaluate the situation, the social context, and their own agency. Qualitative analysis revealed 5 themes related to bystander motives and included: interpretation of harm in the bullying situation, emotional reactions, social evaluating, moral evaluating, and intervention self-efficacy.Conclusion: Given the themes that emerged surrounding bystanders’ motives to intervene or abstain from intervening, respondents reported 3 key elements that need to be confirmed in future research and that may have implications for future work on bullying prevention. These included: first, the potential importance of clear communication to children that adults expect bystanders to intervene when witnessing bullying; second, the potential of direct education about how bystanders can interveneto increase children’s self-efficacy as defenders of those who are victims of bullying; and third, the assumption

  1. Mutagens from the cooking of food. II. Survey by Ames/Salmonella test of mutagen formation in the major protein-rich foods of the American diet

    Energy Technology Data Exchange (ETDEWEB)

    Bjeldanes, L.F. (Univ. of California, Berkeley); Morris, M.M.; Felton, J.S.; Healy, S.; Stuermer, D.; Berry, P.; Timourian, H.; Hatch, F.T.

    1982-01-01

    The formation of mutagens in the major cooked protein-rich foods in the US diet was studied in the Ames Salmonella typhimurium test. The nine protein-rich foods most commonly eaten in the USA--ground beef, beef steak, eggs, pork chops, fried chicken, pot-roasted beef, ham, roast beef and bacon--were examined for their mutagenicity towards S. typhimurium TA1538 after normal 'household' cooking (deep frying, griddle/pan frying, baking/roasting, broiling, stewing, braising or boiling at 100-475/sup 0/C). Well-done fried ground beef, beef steak, ham, pork chops and bacon showed significant mutagen formation. For chicken and beef steak high-temperature broiling produced the most mutagenicity, followed by baking/roasting and frying. Stewing, braising and deep frying produced little mutagen. Eggs andd egg products produced mutagens only after cooking at high temperatures (the yolk to a greater extent than the white). Commercially cooked hamburgers showed a wide range of mutagenic activity. We conclude that mutagen formation following cooking of protein-containing foods is a complex function of food type, cooking time and cooking temperature. It seems clear that all the major protein-rich foods if cooked to a well-done state on the griddle (eggs only at temperature above 225/sup 0/C) or by broiling will contain mutagens detectable by the Ames/Salmonella assay. This survey is a step towards determining whether any human health hazard results from cooking protein-rich foods. Further testing in both short- and long-term genotoxicity bioassays and carcinogenesis assays are needed before any human risk extrapolations can be made.

  2. Mutagens from the cooking of food. II. Survey by Ames/Salmonella test of mutagen formation in the major protein-rich foods of the American diet.

    Science.gov (United States)

    Bjeldanes, L F; Morris, M M; Felton, J S; Healy, S; Stuermer, D; Berry, P; Timourian, H; Hatch, F T

    1982-08-01

    The formation of mutagens in the major cooked protein-rich foods in the US diet was studied in the Ames Salmonella typhimurium test. The nine protein-rich foods most commonly eaten in the USA--ground beef, beef steak, eggs, pork chops, fried chicken, pot-roasted beef, ham, roast beef and bacon--were examined for their mutagenicity towards S. typhimurium TA1538 after normal 'household' cooking (deep frying, griddle/pan frying, baking/roasting, broiling, stewing, braising or boiling of 100-475 degrees C). Well-done fried ground beef, beef steak, ham pork chops and bacon showed significant mutagen formation. For chicken and beef steak high-temperature broiling produced the most mutagenicity, followed by baking/roasting and frying. Stewing, braising and deep frying produced little mutagen. Eggs and egg products produced mutagens only after cooking at high temperatures (the yolk to a greater extent than the white). Commercially cooked hamburgers showed a wide range of mutagenic activity. We conclude that mutagen formation following cooking of protein-containing foods is a complex function of food type, cooking time and cooking temperature. It seems clear that all the major protein-rich foods if cooked to a well-done state on the griddle (eggs only at temperatures above 225 degrees C) or by broiling will contain mutagens detectable by the Ames/Salmonella assay. This survey is a step towards determining whether any human health hazard results from cooking protein-rich foods. Further testing in both short- and long-term genotoxicity bioassays and carcinogenesis assays are needed before any human risk extrapolations can be made.

  3. On the Inclusion of Short-distance Bystander Effects into a Logistic Tumor Control Probability Model.

    Science.gov (United States)

    Tempel, David G; Brodin, N Patrik; Tomé, Wolfgang A

    2018-01-01

    Currently, interactions between voxels are neglected in the tumor control probability (TCP) models used in biologically-driven intensity-modulated radiotherapy treatment planning. However, experimental data suggests that this may not always be justified when bystander effects are important. We propose a model inspired by the Ising model, a short-range interaction model, to investigate if and when it is important to include voxel to voxel interactions in biologically-driven treatment planning. This Ising-like model for TCP is derived by first showing that the logistic model of tumor control is mathematically equivalent to a non-interacting Ising model. Using this correspondence, the parameters of the logistic model are mapped to the parameters of an Ising-like model and bystander interactions are introduced as a short-range interaction as is the case for the Ising model. As an example, we apply the model to study the effect of bystander interactions in the case of radiation therapy for prostate cancer. The model shows that it is adequate to neglect bystander interactions for dose distributions that completely cover the treatment target and yield TCP estimates that lie in the shoulder of the dose response curve. However, for dose distributions that yield TCP estimates that lie on the steep part of the dose response curve or for inhomogeneous dose distributions having significant hot and/or cold regions, bystander effects may be important. Furthermore, the proposed model highlights a previously unexplored and potentially fruitful connection between the fields of statistical mechanics and tumor control probability/normal tissue complication probability modeling.

  4. The effect of bystander medium on the apoptotic process in HPV-G cells

    International Nuclear Information System (INIS)

    Maguire, P.; Lyng, F.; Seymour, C.; Mothersill, C.

    2003-01-01

    Full text: It has been shown in recent years that in both in vivo and in vitro situations irradiated cells cause what is known as the bystander effect. This presently unknown factor causes chromosomal aberrations, initiation of apoptosis and reduced clonogenic survival. Using the medium transfer method to study the bystander effect, this study investigated early events in the apoptotic cascade, which leads to cell death in cells receiving medium from irradiated cells but which were not themselves irradiated. Medium from irradiated ( 0.005Gy to 5Gy) human HPV G keratinocytes was harvested one hour after irradiation, sterile filtered and transferred on to unirradiated HPV-G cells. The appearance of apoptotic markers in the apoptotic cascade was monitored over a period of 48 hours following medium transfer. These apoptotic markers include loss of mitochondrial membrane potential, cytochrome c release and the activity of the death inducing caspase 3. Clonogenic survival of HPV-G cells over a nine day period was also monitored to assess the final survival of the cells. A TUNEL assay, which indicated the level of apoptosis over a 72 hour period after exposure to bystander medium was also performed. Data collected in this study indicates that for very low doses (0.005Gy) the appearance of well-characterised early 'apoptotic' markers such as changes in mitochondrial membrane potential doesn't mean the cell has committed to the apoptotic cascade leading to cell death. This has been illustrated for bystander medium from 0.005Gy irradiated cells, which causes mitochondrial membrane potential depolarisation after six-hour exposure but little difference has been noted for clonogenic survival for exposure to 0.005Gy bystander medium from that of the control. The results may help clarify how cells sector to death or survival following receipt of a signal from a radiation event

  5. Damage of chromosoms under irradiation of human blood lymphocytes and development of bystander effect.

    Science.gov (United States)

    Shemetun, O V

    2016-12-01

    the research the distribution of radiation induced damages among chromosomes and their bands in irra diated in vitro human blood lymphocytes and in unirradiated bystander cells.Material and methods of research: cultivation of human peripheral blood lymphocytes by semi micromethod D.A. Hungerford, modeling of radiation induced bystander effect in mixed cultures consisting of irradiated in vitro and non irradiated blood lymphocytes from persons of different gender, GTG staining of metaphase chromosomes and their cytogenetic analysis. Break points in chromosomes under the formation of aberrations were identified in exposed in vitro human peripheral blood lymphocytes in doses 0.25 Gy (95 breaks in 1248 cells) and 1.0 Gy (227 breaks in 726 cells) and in non irradiated bystander cells under their joint cultivation with irradiated in vitro human lymphocytes (51 breaks in 1137 cells at irradiation of adjacent populations of lymphocytes in dose 0.25 Gy and 75 breaks in 1321 cells at irradiation of adjacent population of lymphocytes in a dose 1.0 Gy). The distribution of injuries among the chromo somes and their bands was investigated. in radiation exposed in vitro human peripheral blood lymphocytes as well as in bystander cells the fre quency of damaged bands and number of breaks which localized in them exceeded the control value (p chromosomes were damaged according to their relative length. Location of bands with increasing number of breaks coincided with the «hot spots» of chromosome damage following irradiation and fragile sites. More sensitive to damage were G negative euchromatin chromosome bands, in which were localized 82 88 % breaks. Damageability of telomeric regions in the irradiated cells had no significant difference from the control, while in bystander cells was lower than control value (p < 0.05). O. V. Shemetun.

  6. Studies of Bystander Effects in 3-D Tissue Systems Using a Low-LET Microbeam

    International Nuclear Information System (INIS)

    Brenner, David J.

    2009-01-01

    It is now accepted that biological effects may occur in cells that were not themselves traversed by ionizing radiation but are close to those that were. Little is known about the mechanism underlying such a bystander effect, although cell-to-cell communication is thought to be important. Previous work demonstrated a significant bystander effect for clonogenic survival and oncogenic transformation in C3H 10T(1/2) cells. Additional studies were undertaken to assess the importance of the degree of cell-to-cell contact at the time of irradiation on the magnitude of this bystander effect by varying the cell density. When 10% of cells were exposed to a range of 2-12 alpha particles, a significantly greater number of cells were inactivated when cells were irradiated at high density than at low density. In addition, the oncogenic transformation frequency was significantly higher in high-density cultures. These results suggest that when a cell is hit by radiation, the transmission of the bystander signal through cell-to-cell contact is an important mediator of the effect, implicating the involvement of intracellular communication through gap junctions. Additional studies to address the relationship between the bystander effect and the adaptive response were undertaken. A novel apparatus, where targeted and non-targeted cells were grown in close proximity, was used to investigate these. It was further examined whether a bystander effect or an adaptive response could be induced by a factor(s) present in the supernatants of cells exposed to a high or low dose of X-rays, respectively. When non-hit cells were co-cultured for 24 h with cells irradiated with 5 Gy alpha-particles, a significant increase in both cell killing and oncogenic transformation frequency was observed. If these cells were treated with 2 cGy X-rays 5 h before co-culture with irradiated cells, approximately 95% of the bystander effect was cancelled out. A 2.5-fold decrease in the oncogenic transformation

  7. Mutagenic potential assessment associated with human exposure to natural radioactivity.

    Science.gov (United States)

    Marcon, Alexandre Endres; Navoni, Julio Alejandro; de Oliveira Galvão, Marcos Felipe; Garcia, Anuska Conde Fagundes Soares; do Amaral, Viviane Souza; Petta, Reinaldo Antônio; Campos, Thomas Ferreira da Costa; Panosso, Renata; Quinelato, Antônio Luiz; de Medeiros, Sílvia Regina Batistuzzo

    2017-01-01

    Lucrécia city, known to harbor a high cancer rate, is located in a semiarid region characterized by the presence of mineral reservoirs, facing a high exposure to metal and natural radioactivity. The present study aimed to assess the environmental scenario at a semiarid region located in Northeastern Brazil. Metal concentration, alpha and beta radiation, and cyanobacteria content in tap water along with indoor radon and gamma emitters (U, K and Th) concentrations were measured. In addition, mutagenic and nuclear instability effects were assessed using buccal micronucleus cytome assay. The study included five samplings corresponding to a period between 2007 and 2009. Drinking water from Lucrécia city presented levels of Mn, Ni and Cr along with cyanobacteria in concentrations one to four times higher than regulatory guidelines considered. Furthermore, high levels of all the tested radionuclides were found. A high percentage of the houses included in this study presented indoor radon concentrations over 100 Bq m -3 . The mean annual effective dose from Lucrécia houses was six times higher than observed in a control region. The levels of exposure in most of the Lucrécia houses were classified as middle to high. A significant mutagenic effect, represented as an increase of micronuclei (MN) frequency and nuclear abnormalities as nuclear buds (NB), binucleated cells (BN), and pyknotic cells (PYC) were found. The results obtained highlight the role of high background radioactivity on the observed mutagenic effect and could help to explain the exacerbated cancer rate reported in this locality. Copyright © 2016. Published by Elsevier Ltd.

  8. Mutagenic effect of cadmium on tetranucleotide repeats in human cells

    Energy Technology Data Exchange (ETDEWEB)

    Slebos, Robbert J.C. [Department of Cancer Biology, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN 37232 (United States) and Department of Otolaryngology, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN 37232 (United States)]. E-mail: r.slebos@vanderbilt.edu; Li Ming [Department of Biostatistics, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN 37232 (United States); Evjen, Amy N. [Department of Cancer Biology, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN 37232 (United States); Coffa, Jordy [Department of Cancer Biology, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN 37232 (United States); Shyr, Yu [Department of Biostatistics, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN 37232 (United States); Yarbrough, Wendell G. [Department of Cancer Biology, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN 37232 (United States); Department of Otolaryngology, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN 37232 (United States)

    2006-12-01

    Cadmium is a human carcinogen that affects cell proliferation, apoptosis and DNA repair processes that are all important to carcinogenesis. We previously demonstrated that cadmium inhibits DNA mismatch repair (MMR) in yeast cells and in human cell-free extracts (H.W. Jin, A.B. Clark, R.J.C. Slebos, H. Al-Refai, J.A. Taylor, T.A. Kunkel, M.A. Resnick, D.A. Gordenin, Cadmium is a mutagen that acts by inhibiting mismatch repair, Nat. Genet. 34 (3) (2003) 326-329), but cadmium also inhibits DNA excision repair. For this study, we selected a panel of three hypermutable tetranucleotide markers (MycL1, D7S1482 and DXS981) and studied their suitability as readout for the mutagenic effects of cadmium. We used a clonal derivative of the human fibrosarcoma cell line HT1080 to assess mutation levels in microsatellites after cadmium and/or N-methyl-N-nitro-N-nitrosoguanidine (MNNG) exposure to study effects of cadmium in the presence or absence of base damage. Mutations were measured in clonally expanded cells obtained by limiting dilution after exposure to zero dose, 0.5 {mu}M cadmium, 5 nM MNNG or a combination of 0.5 {mu}M cadmium and 5 nM MNNG. Exposure of HT1080-C1 to cadmium led to statistically significant increases in microsatellite mutations, either with or without concurrent exposure to MNNG. A majority of the observed mutant molecules involved 4-nucleotide shifts consistent with DNA slippage mutations that are normally repaired by MMR. These results provide evidence for the mutagenic effects of low, environmentally relevant levels of cadmium in intact human cells and suggest that inhibition of DNA repair is involved.

  9. Evaluation of different treatment processes with respect to mutagenic activity in drinking water

    Energy Technology Data Exchange (ETDEWEB)

    Kool, H J; Hrubec, J; van Kreijl, C F; Piet, G J

    1985-12-01

    Treatment processes which are applied in The Netherlands during the preparation of drinking water have been evaluated with regard to introduction and removal of organic mutagens as well as halogenated organics. It appeared that the most efficient processes in reducing mutagenic activity were activated carbon filtration and artificial dune recharge. In general these processes were also the most efficient in removing halogenated organics. Using low doses of chlorine dioxide (less than 1 mg C1O2/l) for safety disinfection of drinking water, no change or substantial less mutagenic activity than by chlorination (1 mg Cl/l) was found. This counts too for the formation of halogenated organics. Transport chlorination of stored river Meuse water was able to introduce or activate mutagenic nitro organics which have not been found previously. Ozone treatment under field conditions showed mostly a tendency to decrease the activity of organic mutagens. It was also shown that dependent on the water quality and treatment conditions a slight increase of mutagenic activity occurred, but this activity would be reduced by increasing the ozone dose. It seems possible to optimize the ozone treatment conditions regarding the level of ozone dose and the contact time to avoid an increase of mutagenic activity. Furthermore it was shown that when a mutagenic raw water source was used a proper combination of treatment processes is able to produce drinking water in which no mutagenic activity could be detected under the test conditions. Finally it is stated that before far-reaching decisions with respect to use mutagenicity data for a selection of water sources or treatment processes will be made, more information on the relation mutagenic activity from drinking water and effects on human health should become available.

  10. Formation of new heterocyclic amine mutagens by heating creatinine, alanine, threonine and glucose.

    Science.gov (United States)

    Skog, K; Knize, M G; Felton, J S; Jägerstad, M

    1992-08-01

    A mixture of alanine, threonine, creatinine and glucose was heated in diethylene glycol and water (5:1, v/v) for 15 min at 200 degrees C. The mutagens formed were purified by high-performance liquid chromatography using the Ames/Salmonella mutagenic activity to guide the purification. The structures of the purified mutagens were determined using UV absorption, mass and NMR spectrometry. A new mutagenic compound with a mass number of 217 was found and its mass spectrum did not correspond to any known mutagen derived from food. This new compound accounted for 4% of the total mutagenic activity. Other mutagenic compounds were identified as MeIQx (2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline), 4,8-DiMeIQx (2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline), and a new mutagen 4,7,8-TriMeIQx (2-amino-3,4,7,8-tetramethylimidazo[4,5-f]quinoxaline) with a mutagenic activity of 73,000 TA98 revertants per microgram. The percentage of the mutagenic activity attributable to MeIQx, 4,8-DiMeIQx and 4,7,8-TriMeIQx was 10%, 70% and 3%, respectively. The yield of MeIQx, 4,8-DiMeIQx and 4,7,8-TriMeIQx was 10, 36 and 6 nmole/mmole creatinine. The formation of TriMeIQx from natural meat components suggests that this new quinoxaline mutagen may be present in cooked foods.

  11. The photoreactivable component in the mutagenic action of ionizing radiations

    International Nuclear Information System (INIS)

    Myasnik, M.N.; Morozov, I.I.; Derevyanko, R.I.

    1980-01-01

    The influence of visible light on the lethal and the mutagenic effects of gamma-radiation on E. coli WP 2 uvrA + and E. coli WP 2 uvrA cells was studied. It was shown that visible light appears to reduce the yield of gamma-induced prototrophs in E. coli WP 2 uvrA cells while the yield of prototrophs in E. coli WP 2 uvrA + stays unchanged. Visible light did not change the survival of gamma-irradiated cells. (author)

  12. Hyper production of alkaline protease by mutagenized bacillus subtilis

    International Nuclear Information System (INIS)

    Qureshi, A.M.; Tanseem, F.

    2010-01-01

    The purpose of this work was to augment the alkaline protease production from Bacillus subtilis by using chemical mutagen (MMS) and UV mutagenesis. A number of mutants were isolated which produce high levels of extra cellular proteases. Analysis of culture supernatants of these mutants had shown that the total amounts of proteolysis activity were increased from 1 to 2 fold over the wild strain. Clones showing promote response were further characterized by analyzing different parameters; like of Temperature, pH substrate concentration and incubation period, to study the activity of protease enzyme. (author)

  13. Mutagenic and carcinogenic structural alerts and their mechanisms of action.

    Science.gov (United States)

    Plošnik, Alja; Vračko, Marjan; Dolenc, Marija Sollner

    2016-09-01

    Knowing the mutagenic and carcinogenic properties of chemicals is very important for their hazard (and risk) assessment. One of the crucial events that trigger genotoxic and sometimes carcinogenic effects is the forming of adducts between chemical compounds and nucleic acids and histones. This review takes a look at the mechanisms related to specific functional groups (structural alerts or toxicophores) that may trigger genotoxic or epigenetic effects in the cells. We present up-to-date information about defined structural alerts with their mechanisms and the software based on this knowledge (QSAR models and classification schemes).

  14. Monitoring ambient air for mutagenicity using the higher plant Tradescantia

    International Nuclear Information System (INIS)

    Schairer, L.A.; Sautkulis, R.C.; Tempel, N.R.

    1982-01-01

    The major emphasis for short-term bioassays has been placed on bacterial and mammalian cell lines. However, for increased perspective on the state-of-the-art of specific in vitro assays it is important to consider the environmental impact on whole organisms by reviewing the contributions made by in vivo assays. This paper will deal exclusively with somatic mutation in the Tradescantia stamen hair: describing the system briefly, demonstrating its relevance to environmental mutagen assessment and discussing its adaptation for in situ ambient atmosphere monitoring

  15. Mutagenic effects of irradiated glucose in Drosophila melanogaster

    International Nuclear Information System (INIS)

    Varma, M.B.; Rao, K.P.; Nandan, S.D.; Rao, M.S.

    1982-01-01

    The mutagenic effects of irradiated glucose were studied using the sex-linked recessive lethal test in Drosophila melanogaster. Oregon K males of D. melanogaster reared on a medium containing 20 or 40% glucose irradiated with a dose of 0.02, 0.10, 0.20, 2 or 5 Mrad #betta#-rays were scored for the induction of sex-linked recessive lethals. The results showed no significant increase in the frequency of X-lethals in Drosophila at any of the dose levels. (author)

  16. Studies on bystander effects of 14MeV neutrons in human blood lymphocytes using CBMN assay

    International Nuclear Information System (INIS)

    Bakkiam, D.; Arul Anantha Kumar, A.; Sonwani, Swetha; Alaguraja, E.; Mathiyarasu, R.; Baskaran, R.; Venkatraman, B.

    2018-01-01

    Radiation induced Bystander Effects (RIBE) in cells generally describes the phenomenon that non-irradiated cells respond as if they have themselves been irradiated upon receiving signals from directly irradiated cells, either through partnering or medium transfer. While it has been well established that bystander effects could be induced by gamma radiation and alpha-particle radiation it is still a question whether neutrons induce bystander effects or not. In view of this, experiments were carried out to quantify cytogenetic damage in human blood lymphocytes induced by neutron directly and indirectly i.e. RIBE through medium transfer method. Cytokinesis Blocked MicroNucleus (CBMN) assay was used to study DNA damage events wherein micronuclei (MN) were scored in binucleated cells. Results of MN frequency in neutron direct and indirect irradiated blood lymphocytes (bystander samples) are compared

  17. Study of influence of catechins on bystander responses in alpha-particle radiobiological experiments using thin PADC films

    International Nuclear Information System (INIS)

    Law, Y.L.; Yu, K.N.

    2009-01-01

    In this study, Chinese hamster ovary (CHO) cells were cultured in custom-made petri dishes with thin PADC films as substrates. Alpha particles with energies of 5 MeV were then irradiated from the bottom of PADC films. The DNA strand breaks in the bystander cells induced by irradiation were quantified with the use of terminal dUTP transferase-mediated nick end-labeling (TUNEL) assay. To study the influence of catechins on the bystander responses, catechins were added into the medium before alpha-particle irradiation of the cells. Fewer DNA strand breaks in the bystander cells were observed. As catechins are ROS (reactive oxygen species)-scavengers, the studied bystander cells might have been protected from radiation through scavenging of ROS by catechins.

  18. Study of influence of catechins on bystander responses in alpha-particle radiobiological experiments using thin PADC films

    Energy Technology Data Exchange (ETDEWEB)

    Law, Y.L. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Yu, K.N., E-mail: peter.yu@cityu.edu.h [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong)

    2009-10-15

    In this study, Chinese hamster ovary (CHO) cells were cultured in custom-made petri dishes with thin PADC films as substrates. Alpha particles with energies of 5 MeV were then irradiated from the bottom of PADC films. The DNA strand breaks in the bystander cells induced by irradiation were quantified with the use of terminal dUTP transferase-mediated nick end-labeling (TUNEL) assay. To study the influence of catechins on the bystander responses, catechins were added into the medium before alpha-particle irradiation of the cells. Fewer DNA strand breaks in the bystander cells were observed. As catechins are ROS (reactive oxygen species)-scavengers, the studied bystander cells might have been protected from radiation through scavenging of ROS by catechins.

  19. Bystander Cardiopulmonary Resuscitation Is Clustered and Associated With Neighborhood Socioeconomic Characteristics: A Geospatial Analysis of Kent County, Michigan.

    Science.gov (United States)

    Uber, Amy; Sadler, Richard C; Chassee, Todd; Reynolds, Joshua C

    2017-08-01

    Geographic clustering of bystander cardiopulmonary resuscitation (CPR) is associated with demographic and socioeconomic features of the community where out-of-hospital cardiac arrest (OHCA) occurred, although this association remains largely untested in rural areas. With a significant rural component and relative racial homogeneity, Kent County, Michigan, provides a unique setting to externally validate or identify new community features associated with bystander CPR. Using a large, countywide data set, we tested for geographic clustering of bystander CPR and its associations with community socioeconomic features. Secondary analysis of adult OHCA subjects (2010-2015) in the Cardiac Arrest Registry to Enhance Survival (CARES) data set for Kent County, Michigan. After linking geocoded OHCA cases to U.S. census data, we used Moran's I-test to assess for spatial autocorrelation of population-weighted cardiac arrest rate by census block group. Getis-Ord Gi statistic assessed for spatial clustering of bystander CPR and mixed-effects hierarchical logistic regression estimated adjusted associations between community features and bystander CPR. Of 1,592 subjects, 1,465 met inclusion criteria. Geospatial analysis revealed significant clustering of OHCA in more populated/urban areas. Conversely, bystander CPR was less likely in these areas (99% confidence) and more likely in suburban and rural areas (99% confidence). Adjusting for clinical, demographic, and socioeconomic covariates, bystander CPR was associated with public location (odds ratio [OR] = 1.19; 95% confidence interval [CI] = 1.03-1.39), initially shockable rhythms (OR = 1.48; 95% CI = 1.12-1.96), and those in urban neighborhoods (OR = 0.54; 95% CI = 0.38-0.77). Out-of-hospital cardiac arrest and bystander CPR are geographically clustered in Kent County, Michigan, but bystander CPR is inversely associated with urban designation. These results offer new insight into bystander CPR patterns in mixed urban and rural

  20. [Radiation-induced bystander effect: the important part of ionizing radiation response. Potential clinical implications].

    Science.gov (United States)

    Wideł, Maria; Przybyszewski, Waldemar; Rzeszowska-Wolny, Joanna

    2009-08-18

    It has long been a central radiobiological dogma that the damaging effects of ionizing radiation, such as cell death, cytogenetic changes, apoptosis, mutagenesis, and carcinogenesis, are the results of the direct ionization of cell structures, particularly DNA, or indirect damage via water radiolysis products. However, several years ago attention turned to a third mechanism of radiation, termed the "bystander effect" or "radiation-induced bystander effect" (RIBE). This is induced by agents and signals emitted by directly irradiated cells and manifests as a lowering of survival, cytogenetic damage, apoptosis enhancement, and biochemical changes in neighboring non-irradiated cells. The bystander effect is mainly observed in in vitro experiments using very low doses of alpha particles (range; mGy, cGy), but also after conventional irradiation (X-rays, gamma rays) at low as well as conventional doses. The mechanisms responsible for the bystander effect are complex and still poorly understood. It is believed that molecular signals released from irradiated cells induce different signaling ways in non-irradiated neighboring cells, leading to the observed events. The molecular signals may be transmitted through gap junction intercellular communication and through a medium transfer mechanism. The nature of these transmitted factors are diverse, and still not definitely established. It seems that RIBE may have important clinical implications for health risk associated with radiation exposure. Potentially, this effect may have important implications in the creation of whole-body or localized side effects in tissues beyond the irradiation field and also in low-dose radiological and radioisotope diagnostics. Factors emitted by irradiated cells may result in the risk of genetic instability, mutations, and second primary cancer induction. They might also have their own part in inducing and extending post-radiation side effects in normal tissue. The bystander effect may be a

  1. Radiation-induced bystander effect: The important part of ionizing radiation response. Potential clinical implications

    Directory of Open Access Journals (Sweden)

    Maria Wideł

    2009-08-01

    Full Text Available It has long been a central radiobiological dogma that the damaging effects of ionizing radiation, such as cell death, cytogenetic changes, apoptosis, mutagenesis, and carcinogenesis, are the results of the direct ionization of cell structures, particularly DNA, or indirect damage via water radiolysis products. However, several years ago attention turned to a third mechanism of radiation, termed the “bystander effect” or “radiation-induced bystander effect” (RIBE. This is induced by agents and signals emitted by directly irradiated cells and manifests as a lowering of survival, cytogenetic damage, apoptosis enhancement, and biochemical changes in neighboring non-irradiated cells. The bystander effect is mainly observed in in vitro experiments using very low doses of alpha particles (range; mGy, cGy, but also after conventional irradiation (X-rays, gamma rays at low as well as conventional doses. The mechanisms responsible for the bystander effect are complex and still poorly understood. It is believed that molecular signals released from irradiated cells induce different signaling ways in non-irradiated neighboring cells, leading to the observed events. The molecular signals may be transmitted through gap junction intercellular communication and through a medium transfer mechanism. The nature of these transmitted factors are diverse, and still not defi nitely established. It seems that RIBE may have important clinical implications for health risk associated with radiation exposure. Potentially, this effectmay have important implications in the creation of whole-body or localized side effects in tissues beyond the irradiation fi eld and also in low-dose radiological and radioisotope diagnostics. Factors emitted by irradiated cells may result in the risk of genetic instability, mutations, and second primary cancer induction. They might also have their own part in inducing and extending post-radiation side effects in normal tissue. The

  2. Effect of mutagen combined action on Chlamydomonas reinhardtii cells. I. Lethal effect dependence on the sequence of mutagen application and on cultivation conditions

    Energy Technology Data Exchange (ETDEWEB)

    Vlcek, D; Podstavkova, S; Dubovsky, J [Komenskeho Univ., Bratislava (Czechoslovakia). Prirodovedecka Fakulta

    1978-01-01

    The effect was investigated of single and combined actions of alkylnitrosourea derivatives (N-methyl-N-nitrosourea and N-ethyl-N-nitrosourea) and UV-radiation on the survival of cells of Chlamydomonas reinhardtii algae in dependence on the sequence of application of mutagens and on the given conditions of cultivation following mutagen activity. In particular, the single phases were investigated of the total lethal effect, i.e., the death of cells before division and their death after division. The most pronounced changes in dependence on the sequence of application of mutagens and on the given conditions of cultivation were noted in cell death before division. In dependence on the sequence of application of mutagens, the effect of the combined action on the survival of cells changed from an additive (alkylnitrosourea + UV-radiation) to a protective effect (UV-radiation + alkylnitrosourea).

  3. Regions of High Out-Of-Hospital Cardiac Arrest Incidence and Low Bystander CPR Rates in Victoria, Australia.

    Science.gov (United States)

    Straney, Lahn D; Bray, Janet E; Beck, Ben; Finn, Judith; Bernard, Stephen; Dyson, Kylie; Lijovic, Marijana; Smith, Karen

    2015-01-01

    Out-of-hospital cardiac arrest (OHCA) remains a major public health issue and research has shown that large regional variation in outcomes exists. Of the interventions associated with survival, the provision of bystander CPR is one of the most important modifiable factors. The aim of this study is to identify census areas with high incidence of OHCA and low rates of bystander CPR in Victoria, Australia. We conducted an observational study using prospectively collected population-based OHCA data from the state of Victoria in Australia. Using ArcGIS (ArcMap 10.0), we linked the location of the arrest using the dispatch coordinates (longitude and latitude) to Victorian Local Government Areas (LGAs). We used Bayesian hierarchical models with random effects on each LGA to provide shrunken estimates of the rates of bystander CPR and the incidence rates. Over the study period there were 31,019 adult OHCA attended, of which 21,436 (69.1%) cases were of presumed cardiac etiology. Significant variation in the incidence of OHCA among LGAs was observed. There was a 3 fold difference in the incidence rate between the lowest and highest LGAs, ranging from 38.5 to 115.1 cases per 100,000 person-years. The overall rate of bystander CPR for bystander witnessed OHCAs was 62.4%, with the rate increasing from 56.4% in 2008-2010 to 68.6% in 2010-2013. There was a 25.1% absolute difference in bystander CPR rates between the highest and lowest LGAs. Significant regional variation in OHCA incidence and bystander CPR rates exists throughout Victoria. Regions with high incidence and low bystander CPR participation can be identified and would make suitable targets for interventions to improve CPR participation rates.

  4. Impact of Bystander Automated External Defibrillator Use on Survival and Functional Outcomes in Shockable Observed Public Cardiac Arrests.

    Science.gov (United States)

    Pollack, Ross A; Brown, Siobhan P; Rea, Thomas; Aufderheide, Tom; Barbic, David; Buick, Jason E; Christenson, James; Idris, Ahamed H; Jasti, Jamie; Kampp, Michael; Kudenchuk, Peter; May, Susanne; Muhr, Marc; Nichol, Graham; Ornato, Joseph P; Sopko, George; Vaillancourt, Christian; Morrison, Laurie; Weisfeldt, Myron

    2018-02-26

    Background - Survival following out-of-hospital cardiac arrest (OHCA) with shockable rhythms can be improved with early defibrillation. Although shockable OHCA accounts for only ≈25% of overall arrests, ≈60% of public OHCAs are shockable, offering the possibility of restoring thousands of individuals to full recovery with early defibrillation by bystanders. We sought to determine the association of bystander automated external defibrillator use with survival and functional outcomes in shockable observed public OHCA. Methods - From 2011 to 2015, the Resuscitation Outcomes Consortium prospectively collected detailed information on all cardiac arrests at 9 regional centers. The exposures were shock administration by a bystander-applied automated external defibrillator in comparison with initial defibrillation by emergency medical services. The primary outcome measure was discharge with normal or near-normal (favorable) functional status defined as a modified Rankin Score ≤2. Survival to hospital discharge was the secondary outcome measure. Results -Among 49 555 OHCAs, 4115 (8.3%) observed public OHCAs were analyzed, of which 2500 (60.8%) were shockable. A bystander shock was applied in 18.8% of the shockable arrests. Patients shocked by a bystander were significantly more likely to survive to discharge (66.5% versus 43.0%) and be discharged with favorable functional outcome (57.1% versus 32.7%) than patients initially shocked by emergency medical services. After adjusting for known predictors of outcome, the odds ratio associated with a bystander shock was 2.62 (95% confidence interval, 2.07-3.31) for survival to hospital discharge and 2.73 (95% confidence interval, 2.17-3.44) for discharge with favorable functional outcome. The benefit of bystander shock increased progressively as emergency medical services response time became longer. Conclusions - Bystander automated external defibrillator use before emergency medical services arrival in shockable observed

  5. The involvement of calcium and MAP kinase signaling pathways in the production of radiation-induced bystander effects.

    LENUS (Irish Health Repository)

    Lyng, F M

    2006-04-01

    Much evidence now exists regarding radiation-induced bystander effects, but the mechanisms involved in the transduction of the signal are still unclear. The mitogen-activated protein kinase (MAPK) pathways have been linked to growth factor-mediated regulation of cellular events such as proliferation, senescence, differentiation and apoptosis. Activation of multiple MAPK pathways such as the ERK, JNK and p38 pathways have been shown to occur after exposure of cells to radiation and a variety of other toxic stresses. Previous studies have shown oxidative stress and calcium signaling to be important in radiation-induced bystander effects. The aim of the present study was to investigate MAPK signaling pathways in bystander cells exposed to irradiated cell conditioned medium (ICCM) and the role of oxidative metabolism and calcium signaling in the induction of bystander responses. Human keratinocytes (HPV-G cell line) were irradiated (0.005-5 Gy) using a cobalt-60 teletherapy unit. The medium was harvested 1 h postirradiation and transferred to recipient HPV-G cells. Phosphorylated forms of p38, JNK and ERK were studied by immunofluorescence 30 min-24 h after exposure to ICCM. Inhibitors of the ERK pathway (PD98059 and U0126), the JNK pathway (SP600125), and the p38 pathway (SB203580) were used to investigate whether bystander-induced cell death could be blocked. Cells were also incubated with ICCM in the presence of superoxide dismutase, catalase, EGTA, verapamil, nifedipine and thapsigargin to investigate whether bystander effects could be inhibited because of the known effects on calcium homeostasis. Activated forms of JNK and ERK proteins were observed after exposure to ICCM. Inhibition of the ERK pathway appeared to increase bystander-induced apoptosis, while inhibition of the JNK pathway appeared to decrease apoptosis. In addition, reactive oxygen species, such as superoxide and hydrogen peroxide, and calcium signaling were found to be important modulators of

  6. Mutagenicity of basic fractions derived from lamb and beef cooked by common household methods.

    Science.gov (United States)

    Barrington, P J; Baker, R S; Truswell, A S; Bonin, A M; Ryan, A J; Paulin, A P

    1990-03-01

    Mutagen production was examined in lamb and beef in relation to certain common household cooking methods. Mutagenicity was assessed, after extraction of the basic fraction of cooked meat samples, using Salmonella typhimurium strain TA1538 with added rat-liver S-9 homogenate. Little or no mutagenicity was found in barbecued lamb chops, in microwave-cooked lamb chops, sirloin steak, leg of lamb, or rolled beef loaf, in roasted leg of lamb or rolled beef loaf, in stewed blade steak or in boiled chuck steak. However, the basic fraction from well-done, edible fried or grilled meat contained mutagenic activity equivalent to approximately 30,000 TA1538 revertants/100 g cooked meat. It was found tht the mutagenic activity of grilled lamb chops, sirloin and rump steaks was directly related to the average surface temperatures attained during cooking. Use of butter as a frying medium was particularly associated with higher mutagenicity in meat samples. Fried meats (rump and fillet steaks) generally yielded higher mutagenic activity than did grilled meats (rump steak, lamb chops) at comparable temperatures of the cooking medium. Using similar cooking procedures, lamb did not differ markedly from beef in mutagenic activity.

  7. Mutagenicity and cytotoxicity of two regioisomeric mercapturic acids and cysteine S-conjugates of trichloroethylene.

    NARCIS (Netherlands)

    Commandeur, J.N.M.; Boogaard, P.J.; Mulder, G.J.; Vermeulen, N.P.E.

    1991-01-01

    The mutagenicity, cytotoxicity and metabolism of two regioisomic l-cysteine- and N-acetyl-l-cysteine-S-conjugates of trichloroethylene were studied. The 1,2-dichlorovinyl(1,2-DCV) isomers of both the cysteine conjugate and the mercapturate were much stronger mutagens in the Ames test with Salmonella

  8. Mutagenicity assessment of aerosols in emissions from wood combustion in Portugal

    International Nuclear Information System (INIS)

    Vu, B.; Alves, C.A.; Gonçalves, C.; Pio, C.; Gonçalves, F.; Pereira, R.

    2012-01-01

    Polycyclic aromatic hydrocarbon (PAH) extracts of fine particles (PM 2.5 ) collected from combustion of seven wood species and briquettes were tested for mutagenic activities using Ames test with Salmonella typhimurium TA98 and TA100. The woods were Pinus pinaster (maritime pine), Eucalyptus globulus (eucalypt), Quercus suber (cork oak), Acacia longifolia (golden wattle), Quercus faginea (Portuguese oak), Olea europea (olive), and Quercus ilex rotundifolia (Holm oak). Burning experiments were done using woodstove and fireplace, hot start and cold start conditions. A mutagenic response was recorded for all species except golden wattle, maritime pine, and briquettes. The mutagenic extracts were not correlated with high emission factors of carcinogenic PAHs. These extracts were obtained both from two burning appliances and start-up conditions. However, fireplace seemed to favour the occurrence of mutagenic emissions. The negative result recorded for golden wattle was interesting, in an ecological point of view, since after confirmation, this invasive species, can be recommended for domestic use. - Highlights: ► Both woodstove and fireplace, either with a cold or hot start, produce emissions with mutagenic potential. ► The high level of carcinogenic PAHs in combustion emissions was not correlated with mutagenicity. ► The golden wattle, an invasive species, produced no mutagenic emissions. - Wood smoke from fireplace burning of dominant forest species displayed strong mutagenic activity without a significant correlation with carcinogenic PAHs emission factors.

  9. Induction of forward gene mutations in saccharomycetes. Comparison of efficiencies of different mutagens

    International Nuclear Information System (INIS)

    Zakharov, I.A.; Gracheva, L.M.; Ivanov, E.L.; Koval'tsova, S.V.; Kozhina, T.N.; Korolev, V.G.; Fedorova, I.V.; Shanshiashvili, T.A.; Yadgarov, Kh.T.

    1981-01-01

    The data on the induction of forward mutations in locus ade 2 of the wild haploid of Saccharomyces cerevisiae yeasts by three types of mutagens-chamical mutagens, various radiations and defferent isotopes incorporated in the cell - are generalyzed. The ratio of mutation frequency observed at different doses of mutagen to the survival rate logarithm for the same doses is expressed as rectilinear regression M=m(-1 nS). The application of the same mutation system in the case of all studied mutagens allows to consider the inclination value ''m'' to be the characteristic of mutagen efficiency. We propose to call the ratio of the efficiency of a given mutagen to the efficiency of γ-rays (msub(x)/msub(γ)) - the relative mutagenous effifiency (RME). According to the decrease of this index the studied mutagens have stood in the following succession: ethylene imine (EI), nitrosomethylurea (NMU) 89 Sr, UV rays, 35 S, 91 Y, 33 P, 32 P, acridine-yprite, β-radiation ( 32 P), γ-rays, hard X-rays, 3 H, soft X-rays, neutrons, 125 I [ru

  10. A comparison of mutagen production in fried ground chicken and beef: effect of supplemental creatine.

    Science.gov (United States)

    Knize, M G; Shen, N H; Felton, J S

    1988-11-01

    Ground chicken breast and ground beef with either endogenous or a 10-fold increase in the concentration of creatine were fried at 220 degrees C for 10 min per side. One patty (100 g) of chicken meat yielded 120,000 Salmonella (TA1538) revertants following metabolic activation. The pan residues had 39% of the total activity. Added creatine (10-fold the endogenous level) increased mutagen yields an average of 2-fold. Beef cooked under identical conditions yielded 150,000 revertants/100 g for the meat patties and pan residues combined. Added creatine to beef prior to cooking increased mutagen yields 3-fold. The mutagenic profiles following initial HPLC separation showed that chicken samples with endogenous or added creatine were remarkably similar. Chicken and beef HPLC mutagenicity profiles were also similar to each other, but not identical. This suggests that the general mutagen-forming reactions with the two different types of muscle are qualitatively similar with only minor quantitative differences. The pan residues from both meat types with and without added creatine showed some significant differences in the mutagen peak profile. This work suggests that the types of mutagens formed in chicken are similar to those formed in beef and that creatine appears to be involved in the formation of all the mutagenic compounds produced from fried muscle tissue.

  11. Use of genetic toxicity data in GHS mutagenicity classification and labeling of substances.

    Science.gov (United States)

    Ball, Nicholas S; Hollnagel, Heli M

    2017-06-01

    One of the key outcomes of testing the potential genotoxicity or mutagenicity of a substance is the conclusion on whether the substance should be classified as a germ cell mutagen and the significance of this for other endpoints such as carcinogenicity. The basis for this conclusion are the criteria presented in classification and labelling systems such as the Globally Harmonized System for classification and labeling (GHS). This article reviews the classification criteria for germ cell mutagenicity and carcinogenicity and how they are applied to substances with evidence of mutagenicity. The implications and suitability of such a classification for hazard communication, risk assessment, and risk management are discussed. It is proposed that genotoxicity assessments should not focus on specifically identifying germ cell mutagens, particularly given the challenges associated with communicating this information in a meaningful way. Rather the focus should be on deriving data to characterize the mode of action and for use in the risk assessment of mutagens, which could then feed into a more robust, risk based management of mutagenic substances versus the current more hazard based approaches. Environ. Mol. Mutagen. 58:354-360, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  12. Effect of eugenol on the genotoxicity of established mutagens in the liver

    NARCIS (Netherlands)

    Rompelberg, C.J.M.; Evertz, S.J.C.J.; Bruijntjes-Rozier, G.C.D.M.; Heuvel, P.D. van den; Verhagen, H.

    1996-01-01

    The influence of in vivo treatment with eugenol on established mutagens was studied to determine whether eugenol has antigenotoxic potential. The effects of eugenol in rats was investigated in the unscheduled DNA synthesis (UDS) assay with established mutagens and the Salmonella typhimurium

  13. Carcinogenic and mutagenic properties of chemicals in drinking water

    Energy Technology Data Exchange (ETDEWEB)

    Bull, R J

    1985-12-01

    Isolated cases of careless handling of industrial and domestic waste has lead to a wide variety of dangerous chemicals being inadvertently introduced into drinking water. However, chemicals with established carcinogenic and mutagenic properties that occur with a high frequency and in multiple locations are limited in number. To date, the chief offenders have been chemicals of relatively low carcinogenic potency. Some of the more common chemicals are formed as by-products of disinfection. The latter process is generally regarded as essential to the production of a ''microbiologically safe'' drinking water. Consequently, any reductions in what may be a relatively small carcinogenic risk must be balanced against a potential for a higher frequency of waterborne infectious disease. The results of recent toxicological investigations will be reviewed to place the potential carcinogenic and mutagenic hazards frequently associated with drinking water into perspective. First, evidence for the carcinogenicity of certain volatile organic compounds such as trichloroethylene, tetrachloroethylene and carbon tetrachloride is considered. Second, the carcinogenic activity that can be ascribed to various by-products of chlorination is reviewed in some detail. Finally, recent evidence that other chemicals derived from the treatment and distribution of drinking water is highlighted as an area requiring move systematic attention. 72 references.

  14. The mutagenic potential of high flash aromatic naphtha.

    Science.gov (United States)

    Schreiner, C A; Edwards, D A; McKee, R H; Swanson, M; Wong, Z A; Schmitt, S; Beatty, P

    1989-06-01

    Catalytic reforming is a refining process that converts naphthenes to aromatics by dehydrogenation to make higher octane gasoline blending components. A portion of this wide boiling range hydrocarbon stream can be separated by distillation and used for other purposes. One such application is a mixture of predominantly 9-carbon aromatic molecules (C9 aromatics, primarily isomers of ethyltoluene and trimethylbenzene), which is removed and used as a solvent--high-flash aromatic naphtha. A program was initiated to assess the toxicological properties of high-flash aromatic naphtha since there may be human exposure through inhalation or external body contact. The current study was conducted partly to assess the potential for mutagenic activity and also to assist in an assessment of carcinogenic potential. The specific tests utilized included the Salmonella/mammalian microsome mutagenicity assay, the hypoxanthine-guanine phosphoribosyl transferase (HGPRT) forward mutation assay in CHO cells, in vitro chromosome aberration and sister chromatid exchange (SCE) assays in CHO cells, and an in vivo chromosome aberration assay in rat bone marrow.

  15. Mutagenicity of diesel exhaust soot dispersed in phospholipid surfactants

    Energy Technology Data Exchange (ETDEWEB)

    Wallace, W.; Keane, M.; Xing, S.; Harrison, J.; Gautam, M.; Ong, T.

    1994-06-01

    Organics extractable from respirable diesel exhaust soot particles by organic solvents have been known for some time to be direct acting frameshift mutagens in the Ames Salmonella typhimurium histidine reversion assay. Upon deposition in a pulmonary alveolus or respiratory bronchiole, respirable diesel soot particles will contact first the hypophase which is coated by and laden with surfactants. To model interactions of soot and pulmonary surfactant, the authors dispersed soots in vitro in the primary phospholipid pulmonary surfactant dipalmitoyl glycerophosphorylcholine (lecithin) (DPL) in physiological saline. They have shown that diesel soots dispersed in lecithin surfactant can express mutagenic activity, in the Ames assay system using S. typhimurium TA98, comparable to that expressed by equal amounts of soot extracted by dichloromethane/dimethylsulfoxide (DCM/DMSO). Here the authors report additional data on the same system using additional exhaust soots and also using two other phospholipids, dipalmitoyl glycerophosphoryl ethanolamine (DPPE), and dipalmitoyl phosphatidic acid (DPPA), with different ionic character hydrophilic moieties. A preliminary study of the surfactant dispersed soot in an eucaryotic cell test system also is reported.

  16. Molecular dosimetry of the chemical mutagen ethyl methanesulfonate

    International Nuclear Information System (INIS)

    Zeeland, A.A. van; Aaron, C.S.; Mohn, G.R.; Hung, C.Y.; Brockman, H.E.

    1983-01-01

    Extending previous work with E. coli and mammalian cells in culture, forward-mutation frequencies induced by ethyl methanesulfonate (EMS) were quantitatively compared in Neurospora crassa and Saccharomyces cerevisiae under standardized conditions. Concomitantly, the actual dose to DNA was measured by determining the amount of radioactivity bound to DNA after treatment with tritium-labeled EMS. After exposure to EMS (2.5-50 mM), alkylation levels in N. crassa and S. cerevisiae were similar to those previously determined in E. coli and cultured mammalian cells. Consistently, there was a slightly less than proportional increase of the DNA alkylation level with the exposure concentration of the mutagen. Forward mutagenesis induced in yeast and N. crassa showed exponential kinetics with exponents of 1.5 and 2.6, respectively. These results are similar to those previously reported with E. coli, which differed from the results with cultured mammalian cells, where a linear dose-effect relationship between exposure and genetic effect was observed. These differences may reflect differences in the fate of EMS-induced adducts by c