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Sample records for low-dose-radiation stimulated natural

  1. Cancer Control Related to Stimulation of Immunity by Low-Dose Radiation

    OpenAIRE

    Liu, Shu-Zheng

    2006-01-01

    Previous studies showed that low dose radiation (LDR) could stimulate the immune system in both animal and human populations. This paper reviews the present status of relevant research as support to the use of LDR in clinical practice for cancer prevention and treatment. It has been demonstrated that radiation-induced changes in immune activity follows an inverse J-shaped curve, i.e., low dose stimulation and high dose suppression. The stimulation of immunity by LDR concerns most anticancer p...

  2. Experimental study of low dose radiation stimulate the haematogenesis reconstitution of the recipient after bone marrow transplantation in mice

    International Nuclear Information System (INIS)

    Zhang Liyuan; Yang Shun; Zhang Ye; Zhang Mingzhi; Jiang Jiagui; Jiang Jianping

    2007-01-01

    Objective: To investigate if low dose radiation can stimulate the haematogenesis reconstitution of the recipient after bone marrow transplantation in mice. Methods: Bone marrow cells were irradiated in vitro by different low dose radiation and then cultured in vitro. 3 H-TdR incorporation was used to measure the reproductive activity of cells, and then the radiation dose with the best stimulating effect was determined. The donator myeloid cells were exposed to low dose radiation before the recipient mice received bone marrow transplantation; then the irradiated myeloid cells were infused to the recipient; and lastly, the counts of peripheral blood cells (PBC) and bone marrow mononuclear cells (BMMNC) were monitored in order to observe the effect of low dose radiation on haematogenesis reconstitution of the recipient animal after bone marrow transplantation. Results: The reproductive activity of the bone marrow cells irradiated by 6 and 8 cGy could be improved significantly in vitro. When the recipient mice received bone marrow transplantation of the myeloid cells after low dose radiation, the counts of BMMNC and PBC were higher than those in the control group (P<0.05). Conclusions: Low dose radiation can stimulate the haematogenesis reconstitution of the recipient after bone marrow transplantation. (authors)

  3. Stimulation effect of early growth in crops by low dose radiation

    International Nuclear Information System (INIS)

    Kim, J.S.; Song, H.S.; Kim, J.K.; Lee, Y.K.; Lee, Y.B.

    1998-01-01

    Germination rate and early growth in crop such as rice,soybean,and perilla were observed after irradiation of γ-ray (Co-60) in order to determine the effects of low does radiation. The low dose radiation was able to improve the early growth in crops and their agricultural characters. Germination rate of 2Gy-irradiatied rice seeds was high and also were seeding height and fresh weight of the 0.5 Gy-irradiated. Germination rate and early growth of soybean were high in 4Gy-irradiated group. Perilla gew of so promisingly after after low dose irradiation, however there slightly increasing effects on germination rate, seeding height and fresh weight at 2Gt-, 1Gy-, and 1Gy irradiated group, respectively. (author)

  4. Stimulating effect of low dose radiation expression of G-CSF receptors in bone marrow cells in mice

    International Nuclear Information System (INIS)

    Zhang Honglai; Liu Shuzheng; Zhang Ming

    1993-01-01

    The expression of G-CSF receptors in bone marrow cells (BMC) was studied by using 125 I labelled G-CSF ( 1 '2 5 I-G-CSF). The results showed that the reaction equilibrium of 125 I-G-CSF bound to BMC at 37 degree C was reached in 60 minutes, the maximum binding (Bmax) to 3 x 10 6 BMC being 15.1 pmol, the dissociation constant (Kd) being 78.6 pmol, and the estimated number of G-CSF receptors per cell being about 3100. The number of G-CSF receptors in BMC in mice 48 hours after whole body exposure to doses of 50, 75 and 100 mGy X-rays increased significantly to 161%, 169% and 342% of controls, respectively. The results suggested that the expression of G-CSF receptors in BMC was enhanced markedly following low dose radiation, which would lead to stimulation of BMC proliferation

  5. Development of Plant Application Technique of Low Dose Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Byung Yeoup; Kim, Jae Sung; Lim, Yong Taek (and others)

    2007-07-15

    The project was carried out to achieve three aims. First, development of application techniques of cell-stimulating effects by low-dose radiation. Following irradiation with gamma-rays of low doses, beneficial effects in crop germination, early growth, and yield were investigated using various plant species and experimental approaches. For the actual field application, corroborative studies were also carried out with a few concerned experimental stations and farmers. Moreover, we attempted to establish a new technique of cell cultivation for industrial mass-production of shikonin, a medicinal compound from Lithospermum erythrorhizon and thereby suggested new application fields for application techniques of low-dose radiation. Second, elucidation of action mechanisms of ionizing radiation in plants. By investigating changes in plant photosynthesis and physiological metabolism, we attempted to elucidate physiological activity-stimulating effects of low-dose radiation and to search for radiation-adaptive cellular components. Besides, analyses of biochemical and molecular biological mechanisms for stimulus-stimulating effects of low-dose radiation were accomplished by examining genes and proteins inducible by low-dose radiation. Third, development of functional crop plants using radiation-resistant factors. Changes in stress-tolerance of plants against environmental stress factors such as light, temperature, salinity and UV-B stress after exposed to low-dose gamma-rays were investigated. Concerned reactive oxygen species, antioxidative enzymes, and antioxidants were also analyzed to develop high value-added and environment-friendly functional plants using radiation-resistant factors. These researches are important to elucidate biological activities increased by low-dose radiation and help to provide leading technologies for improvement of domestic productivity in agriculture and development of high value-added genetic resources.

  6. Development of Plant Application Technique of Low Dose Radiation

    International Nuclear Information System (INIS)

    Chung, Byung Yeoup; Kim, Jae Sung; Lim, Yong Taek

    2007-07-01

    The project was carried out to achieve three aims. First, development of application techniques of cell-stimulating effects by low-dose radiation. Following irradiation with gamma-rays of low doses, beneficial effects in crop germination, early growth, and yield were investigated using various plant species and experimental approaches. For the actual field application, corroborative studies were also carried out with a few concerned experimental stations and farmers. Moreover, we attempted to establish a new technique of cell cultivation for industrial mass-production of shikonin, a medicinal compound from Lithospermum erythrorhizon and thereby suggested new application fields for application techniques of low-dose radiation. Second, elucidation of action mechanisms of ionizing radiation in plants. By investigating changes in plant photosynthesis and physiological metabolism, we attempted to elucidate physiological activity-stimulating effects of low-dose radiation and to search for radiation-adaptive cellular components. Besides, analyses of biochemical and molecular biological mechanisms for stimulus-stimulating effects of low-dose radiation were accomplished by examining genes and proteins inducible by low-dose radiation. Third, development of functional crop plants using radiation-resistant factors. Changes in stress-tolerance of plants against environmental stress factors such as light, temperature, salinity and UV-B stress after exposed to low-dose gamma-rays were investigated. Concerned reactive oxygen species, antioxidative enzymes, and antioxidants were also analyzed to develop high value-added and environment-friendly functional plants using radiation-resistant factors. These researches are important to elucidate biological activities increased by low-dose radiation and help to provide leading technologies for improvement of domestic productivity in agriculture and development of high value-added genetic resources

  7. Carcinogenesis induced by low-dose radiation

    Directory of Open Access Journals (Sweden)

    Piotrowski Igor

    2017-11-01

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

  8. Epigenomic Adaptation to Low Dose Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Gould, Michael N. [Univ. of Wisconsin, Madison, WI (United States)

    2015-06-30

    The overall hypothesis of this grant application is that the adaptive responses elicited by low dose ionizing radiation (LDIR) result in part from heritable DNA methylation changes in the epigenome. In the final budget period at the University of Wisconsin-Madison, we will specifically address this hypothesis by determining if the epigenetically labile, differentially methylated regions (DMRs) that regulate parental-specific expression of imprinted genes are deregulated in agouti mice by low dose radiation exposure during gestation. This information is particularly important to ascertain given the 1) increased human exposure to medical sources of radiation; 2) increased number of people predicted to live and work in space; and 3) enhanced citizen concern about radiation exposure from nuclear power plant accidents and terrorist ‘dirty bombs.’

  9. Effects of low dose radiation on regulatory function between lymphocyte subsets

    International Nuclear Information System (INIS)

    Tian Hailin; Su Liaoyuan; Du Zeji; Zou Huawei; Wang Aiqing

    1997-01-01

    Four kinds of McAbs (anti CD 4 , CD 8 , CD 19 and CD 57 ) were used to separate CD 4 , CD 8 , CD 19 (B) and CD 57 (NK) lymphocyte subsets from human peripheral blood by 'Panning-direct' method. First the natural killing activity of each subsets and the regulatory functions between CD 57 and other subsets were studied. Then the effects of low dose radiation on the function of CD 57 cells and the regulatory functions between CD 57 and other subsets were studied. The results showed that the NK activity was found in all of the four subsets, with CD 57 cell having the strongest activity. When CD 4 and CD 57 cells were co-cultured, the total NK activity was higher than that of the sum of these two single subsets, i.e. there was synergistic effect between CD 4 and CD 57 cells. When CD 8 or CD 19 cells were co-cultured separately with CD 57 cells, no synergistic effect was found. Irradiation by gamma rays at doses of 50 cGy and 80 cGy was able to stimulate the function of CD 57 cells. After Cd 4 or CD 57 cells were irradiated, the total NK activity of their co-culture increased significantly. This phenomenon was not found in other subsets. This suggested that low dose radiation can enhance the synergistic action between CD 4 and CD 57 cells. So at least four subsets (CD 4 , CD 8 , CD 19 , CD 57 ) contribute to the total NK activity of peripheral blood mononuclear cells. (15 refs., 4 tabs.)

  10. Effects of low dose radiation on tumor-bearing mice

    International Nuclear Information System (INIS)

    Feng Li; Hou Dianjun; Huang Shanying; Deng Daping; Wang Linchao; Cheng Yufeng

    2007-01-01

    Objective: To explore the effects of low-dose radiation on tumor-bearing mice and radiotherapy induced by low-dose radiation. Methods: Male Wistar mice were implanted with Walker-256 sarcoma cells in the right armpit. On day 4, the mice were given 75 mGy whole-body X-ray radiation. From the fifth day, tumor volume was measured, allowing for the creation of a graph depicting tumor growth. Lymphocytes activity in mice after whole-body X-ray radiation with LDR was determinned by FCM. Cytokines level were also determined by ELISA. Results: Compared with the radiotherapy group, tumor growth was significantly slower in the mice pre-exposed to low-dose radiation (P<0.05), after 15 days, the average tumor weight in the mice pre- exposed to low-dose radiation was also significantly lower (P<0.05). Lymphocytes activity and the expression of the CK in mice after whole-body y-ray radiation with LDR increased significantly. Conclusions: Low-dose radiation can markedly improve the immune function of the lymphocyte, inhibit the tumor growth, increase the resistant of the high-dose radiotherapy and enhance the effect of radiotherapy. (authors)

  11. Malignant melanoma of the tongue following low-dose radiation

    Energy Technology Data Exchange (ETDEWEB)

    Kalemeris, G.C.; Rosenfeld, L.; Gray, G.F. Jr.; Glick, A.D.

    1985-03-01

    A 47-year-old man had a spindly malignant melanoma of the tongue many years after low-dose radiation therapy for lichen planus. To our knowledge, only 12 melanomas of the tongue have been reported previously, and in none of these was radiation documented.

  12. Malignant melanoma of the tongue following low-dose radiation

    International Nuclear Information System (INIS)

    Kalemeris, G.C.; Rosenfeld, L.; Gray, G.F. Jr.; Glick, A.D.

    1985-01-01

    A 47-year-old man had a spindly malignant melanoma of the tongue many years after low-dose radiation therapy for lichen planus. To our knowledge, only 12 melanomas of the tongue have been reported previously, and in none of these was radiation documented

  13. Health effects of low-dose radiation: Molecular, cellular, and biosystem response

    International Nuclear Information System (INIS)

    Pollycove, M.; Paperiello, C.J.

    1997-01-01

    Since the fifties, the prime concern of radiation protection has been protecting DNA from damage. UNSCEAR initiated a focus on biosystem response to damage with its 1994 report, ''Adaptive Responses to Radiation of Cells and Organisms''. The DNA damage-control biosystem is physiologically operative on both metabolic and radiation induced damage, both effected predominantly by free radicals. These adaptive responses are suppressed by high-dose and stimulated by low dose radiation. Increased biosystem efficiently reduces the number of mutations that accumulate during a lifetime and decrease DNA damage-control with resultant aging and malignancy. Several statistically significant epidemiologic studies have shown risk decrements of cancer mortality and mortality from all causes in populations exposed to low-dose radiation. Further biologic and epidemiologic research is needed to establish a valid threshold below which risk decrements occur. (author)

  14. Effect of low-dose radiation on ocular circulation

    International Nuclear Information System (INIS)

    Baba, Keiko; Hiroishi, Goro; Honda, Masae; Yoshikawa, Hiroshi; Fujisawa, Kimihiko; Ishibashi, Tatsuro

    1999-01-01

    We treated 6 eyes of unilateral age-related macular degeneration by low-dose radiation. Each eye received daily dose of 2 Gy by 4MV lineac totalling 20 Gy over 2 weeks. Color doppler flowmetry was used to determine the mean blood flow velocity (Vmean) and vascular resistive index (RI) in the short posterior ciliary artery, central retinal artery and ophthalmic artery in the treated and fellow eyes before and up to 6 months of treatment. There were no significant differences in Vmean and RI before and after treatment. The findings show the absence of apparent influence of low-dose radiation on the ocular circulation in age-related macular degeneration. (author)

  15. Effect of low-dose radiation on ocular circulation

    Energy Technology Data Exchange (ETDEWEB)

    Baba, Keiko; Hiroishi, Goro; Honda, Masae; Yoshikawa, Hiroshi; Fujisawa, Kimihiko; Ishibashi, Tatsuro [Kyushu Univ., Fukuoka (Japan). Faculty of Medicine

    1999-05-01

    We treated 6 eyes of unilateral age-related macular degeneration by low-dose radiation. Each eye received daily dose of 2 Gy by 4MV lineac totalling 20 Gy over 2 weeks. Color doppler flowmetry was used to determine the mean blood flow velocity (Vmean) and vascular resistive index (RI) in the short posterior ciliary artery, central retinal artery and ophthalmic artery in the treated and fellow eyes before and up to 6 months of treatment. There were no significant differences in Vmean and RI before and after treatment. The findings show the absence of apparent influence of low-dose radiation on the ocular circulation in age-related macular degeneration. (author)

  16. Low-dose radiation-induced endothelial cell retraction

    International Nuclear Information System (INIS)

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

    1993-01-01

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

  17. Effects of low dose radiation and epigenetic regulation

    International Nuclear Information System (INIS)

    Jiao Benzheng; Ma Shumei; Yi Heqing; Kong Dejuan; Zhao Guangtong; Gao Lin; Liu Xiaodong

    2010-01-01

    Purpose: To conclude the relationship between epigenetics regulation and radiation responses, especially in low-dose area. Methods: The literature was examined for papers related to the topics of DNA methylation, histone modifications, chromatin remodeling and non-coding RNA modulation in low-dose radiation responses. Results: DNA methylation and radiation can regulate reciprocally, especially in low-dose radiation responses. The relationship between histone methylation and radiation mainly exists in the high-dose radiation area; histone deacetylase (HDAC) inhibitors show a promising application to enhance radiation sensitivity, no matter whether in low-dose or high-dose areas; the connection between γ-H2AX and LDR has been remained unknown, although γ-H2AX has been shown no radiation sensitivities with 1-15 Gy irradiation; histone ubiquitination play an important role in DNA damage repair mechanism. Moreover, chromatin remodeling has an integral role in DSB repair and the chromatin response, in general, may be precede DNA end resection. Finally, the effect of radiation on miRNA expression seems to vary according to cell type, radiation dose, and post-irradiation time point. Conclusion: Although the advance of epigenetic regulation on radiation responses, which we are managing to elucidate in this review, has been concluded, there are many questions and blind blots deserved to investigated, especially in low-dose radiation area. However, as progress on epigenetics, we believe that many new elements will be identified in the low-dose radiation responses which may put new sights into the mechanisms of radiation responses and radiotherapy. (authors)

  18. Global DNA methylation responses to low dose radiation exposure

    International Nuclear Information System (INIS)

    Newman, M.R.; Ormsby, R.J.; Blyth, B.J.; Sykes, P.J.; Bezak, E.

    2011-01-01

    Full text: High radiation doses cause breaks in the DNA which are considered the critical lesions in initiation of radiation-induced cancer. However, at very low radiation doses relevant for the general public, the induction of such breaks will be rare, and other changes to the DNA such as DNA methylation which affects gene expression may playa role in radiation responses. We are studying global DNA methylation after low dose radiation exposure to determine if low dose radiation has short- and/or long-term effects on chromatin structure. We developed a sensitive high resolution melt assay to measure the levels of DNA methylation across the mouse genome by analysing a stretch of DNA sequence within Long Interspersed Nuclear Elements-I (LINE I) that comprise a very large proportion of the mouse and human genomes. Our initial results suggest no significant short-term or longterm) changes in global NA methylation after low dose whole-body X-radiation of 10 J1Gyor 10 mGy, with a significant transient increase in NA methylation observed I day after a high dose of I Gy. If the low radiation doses tested are inducing changes in bal DNA methylation, these would appear to be smaller than the variation observed between the sexes and following the general stress of the sham-irradiation procedure itself. This research was funded by the Low Dose Radiation Research Program, Biological and Environmental Research, US DOE, Grant DE-FG02-05ER64104 and MN is the recipient of the FMCF/BHP Dose Radiation Research Scholarship.

  19. A consideration of low dose radiation effects on human health

    International Nuclear Information System (INIS)

    Shimada, Yoshiya; Nishimura, Mayumi; Imaoka, Tatsuhiko; Kakinuma, Shizuko

    2011-01-01

    On March 11, 2011, an earthquake categorized as 9 Mw occurred off the northeast coast of Japan. The subsequent destructive tsunami disabled emergency units of Fukushima Dai'ichi Nuclear Power Plant and caused partial meltdown of reactors and explosions. Resulting radiation releases forced large evacuations, bore concerns about food and water and fears against human health. In this manuscript, we described the effect of radiation, especially low dose radiation below 100 mSv, on cancer risk, focusing on fetuses and children. (author)

  20. Anti-tumor effect of low dose radiation in mice

    International Nuclear Information System (INIS)

    Fan Zhengping; Lu Jiaben; Zhu Bingchai

    1997-01-01

    The author reports the effects of the total body irradiation of low dose radiation (LDR) and/or the local irradiation of large dose on average tumor weights and tumor inhibitory rates in 170 mice inoculated S 180 sarcoma cell, and the influence of LDR on average longevity in 40 tumor-bearing animals. Results show (1) LDR in the range of 75∼250 mGy can inhibit tumor growth to some extent; (2) fractionated irradiation of 75 mGy and local irradiation of 10 Gy may produce a synergism in tumor growth inhibition; and (3)LDR may enhance average longevity in ascitic tumor-bearing mice

  1. A Paradigm Shift in Low Dose Radiation Biology

    Directory of Open Access Journals (Sweden)

    Z. Alatas

    2015-08-01

    Full Text Available When ionizing radiation traverses biological material, some energy depositions occur and ionize directly deoxyribonucleic acid (DNA molecules, the critical target. A classical paradigm in radiobiology is that the deposition of energy in the cell nucleus and the resulting damage to DNA are responsible for the detrimental biological effects of radiation. It is presumed that no radiation effect would be expected in cells that receive no direct radiation exposure through nucleus. The risks of exposure to low dose ionizing radiation are estimated by extrapolating from data obtained after exposure to high dose radiation. However, the validity of using this dose-response model is controversial because evidence accumulated over the past decade has indicated that living organisms, including humans, respond differently to low dose radiation than they do to high dose radiation. Moreover, recent experimental evidences from many laboratories reveal the fact that radiation effects also occur in cells that were not exposed to radiation and in the progeny of irradiated cells at delayed times after radiation exposure where cells do not encounter direct DNA damage. Recently, the classical paradigm in radiobiology has been shifted from the nucleus, specifically the DNA, as the principal target for the biological effects of radiation to cells. The universality of target theory has been challenged by phenomena of radiation-induced genomic instability, bystander effect and adaptive response. The new radiation biology paradigm would cover both targeted and non-targeted effects of ionizing radiation. The mechanisms underlying these responses involve biochemical/molecular signals that respond to targeted and non-targeted events. These results brought in understanding that the biological response to low dose radiation at tissue or organism level is a complex process of integrated response of cellular targets as well as extra-cellular factors. Biological understanding of

  2. Review of European research trends of low dose radiation risk

    International Nuclear Information System (INIS)

    Iwasaki, Toshiyasu; Yoshida, Kazuo

    2010-01-01

    Large research projects on low dose radiation effects in Europe and US over the past decade have provided limited scientific knowledge which could underpin the validation of radiation protection systems. Recently in Europe, there have been repeated discussions and dialogues to improve the situation, and as the consequence, the circumstances surrounding low dose radiation risks are changing. In 2009, Multidisciplinary European Low Dose Initiative (MELODI) was established as a trans-national organization capable of ensuring appropriate governance of research in the pursuit of a long term shared vision, and Low Dose Research towards Multidisciplinary Integration (DoReMi) network was launched in 2010 to achieve fairly short term results in order to prove the validity of the MELODI approach. It is expected to be very effective and powerful activities to facilitate the reduction of uncertainties in the understanding of low dose risks, but the regulatory requests rushing the reinforcement of radiological protection regulations based on the precautional principles are more increasing. To develop reasonable radiological protection systems based on scientific evidences, we need to accelerate to collect scientific evidences which could directly underpin more appropriate radiation protection systems even in Japan. For the purpose, we Japan need to develop from an independent standpoint and share as a multidisciplinary vision a long term and holistic research strategy which enables to enhance Japanese advantages such as low dose rate facilities and animal facilities, as soon as possible. (author)

  3. Effect of low dose radiation on apoptosis in mouse spleen

    International Nuclear Information System (INIS)

    Chen Dong; Liu Jiamei; Chen Aijun; Liu Shuzheng

    1999-01-01

    Objective: To study the effect of whole body irradiation (WBI) with different doses of X-ray on apoptosis in mouse spleen. Methods: Time course changes and dose-effect relationship of apoptosis in mouse spleen induced by WBI were observed with transmission electron microscopy (TEM) qualitatively and TUNEL method semi-quantitatively. Results: Many typical apoptotic lymphocytes were found by TEM in mouse spleen after WBI with 2 Gy. No marked alterations of ultrastructure were found following WBI with 0.075 Gy. It was observed by TUNEL that the apoptosis of splenocytes increased after high dose radiation and decreased following low dose radiation (LDR). The dose-effect relationship of radiation-induced apoptosis showed a J-shaped curve. Conclusion: The effect of different doses of ionizing radiation on apoptosis in mouse spleen was distinct. And the decrease of apoptosis after LDR is considered a manifestation of radiation hormesis

  4. Low dose radiation enhances the Locomotor activity of D. melanogaster

    Energy Technology Data Exchange (ETDEWEB)

    Seong, Ki Moon; Lee, Buyng Sub; Nam Seon Young; Kim, Ji Young; Yang, Kwang Hee; Choi, Tae In; Kim, Cha Soon [Radiation Effect Research Team, Radiation Health Research Institute, Korea Hydro and Nuclear Power Co., Ltd., Gyeongju (Korea, Republic of)

    2013-04-15

    Mild stresses at low level including radiation can induce the beneficial effects in many vertebrate and invertebrate species. However, a large amount of studies in radiation biology have focused on the detrimental effects of high dose radiation (HDR) such as the increased incidence of cancers and developmental diseases. Low dose radiation (LDR) induces biologically favorable effects in diverse fields, for example, cancer development, genomic instability, immune response, and longevity. Our previous data indicated that LDR promotes cells proliferation of which degree is not much but significant, and microarray data explained that LDR irradiated fruit flies showing the augmented immunity significantly changed the program for gene expression of many genes in Gene Ontology (GO) categories related to metabolic process. Metabolic process in development one of major contributors in organism growth, interbreeding, motility, and aging. Therefore, it is valuable to examine whether LDR change the physiological parameters related to metabolism, and how LDR regulates the metabolism in D. melanogaster. In this study, to investigate that LDR influences change of the metabolism, a representative parameter, locomotor activity. In addition, the activation of several cellular signal molecules was determined to investigate the specific molecular mechanism of LDR effects on the metabolism. We explored whether ionizing radiation affects the motility activity. We performed the RING assays to evaluate the locomotor activity, a representative parameter presenting motility of fruit flies. HDR dramatically decreased the motor activity of irradiated flies. Surprisingly, the irradiated flies at low dose radiation in both acute and chronic showed the significantly increased locomotor activity, compared to non-irradiated flies. Irradiation would induce change of the several signal pathways for flies to respond to it. The activation of some proteins involved in the cells proliferation and stress

  5. Final Report - Epigenetics of low dose radiation effects in an animal model

    Energy Technology Data Exchange (ETDEWEB)

    Kovalchuk, Olga

    2014-10-22

    This project sought mechanistic understanding of the epigenetic response of tissues as well as the consequences of those responses, when induced by low dose irradiation in a well-established model system (mouse). Based on solid and extensive preliminary data we investigated the molecular epigenetic mechanisms of in vivo radiation responses, particularly – effects of low, occupationally relevant radiation exposures on the genome stability and adaptive response in mammalian tissues and organisms. We accumulated evidence that low dose irradiation altered epigenetic profiles and impacted radiation target organs of the exposed animals. The main long-term goal was to dissect the epigenetic basis of induction of the low dose radiation-induced genome instability and adaptive response and the specific fundamental roles of epigenetic changes (i.e. DNA methylation, histone modifications and miRNAs) in their generation. We hypothesized that changes in global and regional DNA methylation, global histone modifications and regulatory microRNAs played pivotal roles in the generation and maintenance low-dose radiation-induced genome instability and adaptive response. We predicted that epigenetic changes influenced the levels of genetic rearrangements (transposone reactivation). We hypothesized that epigenetic responses from low dose irradiation were dependent on exposure regimes, and would be greatest when organisms are exposed in a protracted/fractionated manner: fractionated exposures > acute exposures. We anticipated that the epigenetic responses were correlated with the gene expression levels. Our immediate objectives were: • To investigate the exact nature of the global and locus-specific DNA methylation changes in the LDR exposed cells and tissues and dissect their roles in adaptive response • To investigate the roles of histone modifications in the low dose radiation effects and adaptive response • To dissect the roles of regulatory microRNAs and their targets in low

  6. Effect of low dose radiation on thymocyte cytosol and nuclei protein synthesis in mice

    International Nuclear Information System (INIS)

    Meng Qingyong; Chen Shali; Liu Shuzheng

    2003-01-01

    Objective: To the effect of low dose radiation on thymocyte cytosol and nuclei protein synthesis in mice. Methods: The expression of proteins was analyzed by gel filtration with Sephadex G-100 and HPLC based on separation of proteins on thymocyte cytosol and nuclei after whole-body irradiation with 75 mGy X-rays and sham-irradiation, and their biological activity was examined by mouse splenocyte proliferation and chromosome aberration of human peripheral blood lymphocytes. Results: HPLC analysis showed that there was a marked increase in expression of 61.4 kD protein in the extract of thymocyte cytosol and 30.4 kD protein in the extract of thymocyte nuclei in comparison with the corresponding fractions from the sham-irradiated control mice. These protein fractions from the thymocyte cytosol and nuclei of the irradiated mice showed both stimulating effect on normal T cell proliferation and protective effect on chromosome damage induced by high dose radiation. Conclusion: These findings might have implications in study of mechanism of immunoenhancement and cytogenetic adaptive response induced by low dose radiation

  7. The effects of low dose radiation (LDR) on mice of immune function

    International Nuclear Information System (INIS)

    Feng Li; Deng Daping

    2007-01-01

    Objective: To find out the Effects of Low Dose Radiation(LDR) on mice of immune function. Methods: Through flow cytometry to observe and analyse the effects of the leukomonocyte. Through immunohistochemistry to study IL-2, TNF-α. Results: At dose of 100mGy the stimulative effect on CD 4 + cells, CD 8 + cells and NK activity was higher than that at other doses. At dose of 500mGy leukomonocyte activity was lower. At dose of 100mGy, the colorations about IL-2, TNF-α deepen. Conclusion: LDR could stimulate immune function, especially at dose of 100mGy. while at dose of 500mGy, radiation could restrain the leukomonocyte activity. (authors)

  8. Progress of research on activation function of NK cell exposed to low dose radiation in adoptive cellular immunotherapy

    International Nuclear Information System (INIS)

    Pan Xiaosong; Shi Yujia; Yao Yimin; Xu Hong; Liu Fenju

    2009-01-01

    Natural killer cells is an important immunological factor in killing malignant cells. Low dose radiation can enhance proliferation and biological activity of NK cell. The involvement of P38MAPK signal pathway and endogenous glutathione induced by LDR may be the probable mechanism. Natural killer cell, especially adherent natural killer cell, is the preferential choice for adoptive cellular immunotherapy, which has a remarkable foreground in malignancy therapy.(authors)

  9. Low-dose radiation suppresses Pokemon expression under hypoxic conditions.

    Science.gov (United States)

    Kim, Seung-Whan; Yu, Kweon; Shin, Kee-Sun; Kwon, Kisang; Hwang, Tae-Sik; Kwon, O-Yu

    2014-01-01

    Our previous data demonstrated that CoCl2-induced hypoxia controls endoplasmic reticulum (ER) stress-associated and other intracellular factors. One of them, the transcription factor Pokemon, was differentially regulated by low-dose radiation (LDR). There are limited data regarding how this transcription factor is involved in expression of the unfolded protein response (UPR) under hypoxic conditions. The purpose of this study was to obtain clues on how Pokemon is involved in the UPR. Pokemon was selected as a differentially expressed gene under hypoxic conditions; however, its regulation was clearly repressed by LDR. It was also demonstrated that both expression of ER chaperones and ER stress sensors were affected by hypoxic conditions, and the same results were obtained when cells in which Pokemon was up- or down-regulated were used. The current state of UPR and LDR research associated with the Pokemon pathway offers an important opportunity to understand the oncogenesis, senescence, and differentiation of cells, as well as to facilitate introduction of new therapeutic radiopharmaceuticals.

  10. Low dose radiation prevents doxorubicin-induced cardiotoxicity.

    Science.gov (United States)

    Jiang, Xin; Hong, Yaqiong; Zhao, Di; Meng, Xinxin; Zhao, Lijing; Du, Yanwei; Wang, Zan; Zheng, Yan; Cai, Lu; Jiang, Hongyu

    2018-01-02

    This study aimed to develop a novel and non-invasive approach, low-dose radiation (LDR, 75 mGy X-rays), to prevent doxorubicin (DOX)-induced cardiotoxicity. BALB/c mice were randomly divided into five groups, Control, LDR (a single exposure), Sham (treated same as LDR group except for irradiation), DOX (a single intraperitoneal injection of DOX at 7.5 mg/kg), and LDR/DOX (received LDR and 72 h later received DOX). Electrocardiogram analysis displayed several kinds of abnormal ECG profiles in DOX-treated mice, but less in LDR/DOX group. Cardiotoxicity indices included histopathological changes, oxidative stress markers, and measurements of mitochondrial membrane permeability. Pretreatment of DOX group with LDR reduced oxidative damages (reactive oxygen species formation, protein nitration, and lipid peroxidation) and increased the activities of antioxidants (superoxide dismutase and glutathione peroxidase) in the heart of LDR/DOX mice compared to DOX mice. Pretreatment of DOX-treated mice with LDR also decreased DOX-induced cardiac cell apoptosis (TUNEL staining and cleaved caspase-3) and mitochondrial apoptotic pathway (increased p53, Bax, and caspase-9 expression and decreased Bcl2 expression and ΔΨm dissipation). These results suggest that LDR could induce adaptation of the heart to DOX-induced toxicity. Cardiac protection by LDR may attribute to attenuate DOX-induced cell death via suppressing mitochondrial-dependent oxidative stress and apoptosis signaling.

  11. Stimulatory effect of low dose radiation on the immune function in tumor-bearing mice

    International Nuclear Information System (INIS)

    Zhang Ying; Li Xiujuan; Li Xiuyi; Liu Shuzheng

    1999-01-01

    Objective: The author aims at investigating the effect of whole body irradiation (WBI) with low dose radiation on immune function in tumor-bearing mice. Methods: C57BL/6J mine implanted with Lewis lung carcinoma cells in the right thighs were used as an experimental animal model. WBI with 75 mGy X-rays was given at the 10 th day after implantation and immunological parameters were detected 18 hours after irradiation. The immunological parameters included the spontaneous incorporation of 3 H-TdR into thymocytes, the number of splenocytes, the reaction of splenocytes to ConA and LPS, the splenic production of IL-2, the cytotoxic activities of natural killer (NK) and lymphokine activated killer cells (LAK) as well as specific cytotoxic T lymphocytes (CTL). Results: The immunological parameters of irradiated tumor-bearing mice were significantly increased compared with those of sham-irradiated tumor-bearing mice (P<0.05∼0.01). Conclusion: Low dose radiation could significantly increase the immune function of tumor-bearing mice, and this stimulatory effect may be of some potential significance in tumor therapy

  12. Study of the effects of low-dose radiation and rhEGF on growth of cultured human epithelial cells

    International Nuclear Information System (INIS)

    Yang Jicheng; Zhao Xiaoyu; Sheng Weihua; Tang Zhongyi

    1998-01-01

    In authors' study, the method of taking skin sample, mincing and trypsinizing the sample are presented. The cells were inoculated on adherent membrane or, for sublethally injured 3T3 cells, in culture dish fed with Eargles' medium supplemented with fetal calf serum and various growth-stimulating factors. The cultures were incubated at 37 degree C in an atmosphere containing 5% CO 2 . The medium was changed every three days. The cultured cells became confluent in about two weeks. At the same time, low-dose-radiation and rhEGF were used to influence the growth of the epithelial cells and to test the effects of dosage and concentration. The results showed that low-dose-radiation in the conditions like authors' study could enhance the growth of human epithelial cells just like rhEGF, and it has synergetic effects with rhEGF. The mechanism is discussed

  13. Single Low-Dose Radiation Induced Regulation of Keratinocyte Differentiation in Calcium-Induced HaCaT Cells

    OpenAIRE

    Hahn, Hyung Jin; Youn, Hae Jeong; Cha, Hwa Jun; Kim, Karam; An, Sungkwan; Ahn, Kyu Joong

    2016-01-01

    Background We are continually exposed to low-dose radiation (LDR) in the range 0.1 Gy from natural sources, medical devices, nuclear energy plants, and other industrial sources of ionizing radiation. There are three models for the biological mechanism of LDR: the linear no-threshold model, the hormetic model, and the threshold model. Objective We used keratinocytes as a model system to investigate the molecular genetic effects of LDR on epidermal cell differentiation. Methods To identify kera...

  14. Plants as warning signal for exposure to low dose radiation

    International Nuclear Information System (INIS)

    Rusli Ibrahim; Norhafiz Talib

    2012-01-01

    carries the advantage of observing meaningful data in a short period of time, being able to meditate effects on human health and to prevent possible accidents, when adopted as periodical monitoring. Tradescantia Pallida Purpurea can be regarded as a biosensor plant or a biological warning signal for exposure to low dose radiation which exhibits a noticeable quantity of cell alteration in a short time following exposure to radiation. Hence, the effects caused on the environment might be anticipated, and by extension on the human being, as a result of its occupation exposition level. The use of this method can be recommended for radiation monitoring, therefore into the environment acclimatization, and may be used, in addition, in the prevention of radiological accidents. (author)

  15. Low dose radiation induced hormesis and its mechanism of free radicals

    International Nuclear Information System (INIS)

    Zhang Liyuan; Huo Hongmei; Zhang Yusong; Zhao Peifeng; Li Wei; Jiang Jiagui

    2008-01-01

    Objective: To investigate whether the supernatant (the stimulating fluid) centrifuged from myeloid cells suspension after low dose radiation in vitro can produce hormesis on the normal or radiation damage cells. The mechanism of free radical was probed. Methods: Mouse myeloid cell suspension was irradiated respectively by 0, 2 and 5 Gy, and cultured in vitro. MTT method was used to measure the reproductive activity of cells. Meanwhile, Cytochrome C reduction method was used to determine the concentration of O 2 - . Lastly, the concentration of O 2 - was decreased or increased by adding DPI or PMA, and the effect of such changes on 'the stimulating fluid' was observed. Results: Co-cultured with 'the stimulating fluid', the reproductive activity of the myeloid cells after large dose radiation or the normal myeloid cells were enhanced. Decreasing the concentration of O 2 - ; may degrade the proliferation of the cells after radiation damage; while increasing it may lead to the opposite result. Conclusions: The stimulating fluid can enhance the proliferation of the myeloid cells after radiation damage and also the normal ones. The mechanism of above-mentioned phenomena might be related with the changes of O 2 - concentration. (authors)

  16. Low-dose radiation attenuates chemical mutagenesis in vivo. Cross adaptation

    International Nuclear Information System (INIS)

    Kakinuma, Shizuko; Yamauchi, Kazumi; Amasaki, Yoshiko; Nishimura, Mayumi; Shimada, Yoshiya

    2009-01-01

    The biological effects of low-dose radiation are not only of social concern but also of scientific interest. The radioadaptive response, which is defined as an increased radioresistance by prior exposure to low-dose radiation, has been extensively studied both in vitro and in vivo. Here we briefly review the radioadaptive response with respect to mutagenesis, survival rate, and carcinogenesis in vivo, and introduce our recent findings of cross adaptation in mouse thymic cells, that is, the suppressive effect of repeated low-dose radiation on mutation induction by the alkylating agent N-ethyl-N-nitrosourea. (author)

  17. Effects of low dose radiation on repair processes in human lymphocytes

    International Nuclear Information System (INIS)

    Tuschl, H.; Altmann, H.; Kovac, R.; Topaloglou, A.; Egg, D.; Guenther, R.

    1978-10-01

    DNA excision repair was investigated in lymphocytes of persons occupationally exposed to low dose radiation of 222 Rn. Autoradiographic studies of unscheduled DNA synthesis and measurement of 3 H-thymidine incorporation by repair replication into double stranded and single-strand containing DNA fractions obtained by BND cellulose chromatography seem to indicate a stimulatory effect of repeated low dose radiation on repair enzymes. (author)

  18. The effects of low dose radiation (LDR) on lymphocytes

    International Nuclear Information System (INIS)

    Su Liaoyuan; Du Zeji; Tian Hailin; Zhao Yujie; Zou Huawei; Zhou Jianhua; Kong Xiangrong; Zhang Jianhua; Shen Wei

    2001-01-01

    LDR could stimulate lymphocyte transformation for adults, children and infants. The effect of LDR on lymphocytes in malnourished children was lower, but higher on lymphocytes in cord blood. The effect of LDR on CD 4 + cells in adult persons was higher than that on CD + cells. NK cells were radioresistant. The stimulative effect of LDR on NK activity in tumor patients was lower than that in normal individuals. For the mice with tumors, LDR could increase the ratio of L 3 T 4 cells in blood, spleen and the number of cytotoxic T cells in the tumors. Extracellular fluid of the lymphocytes operated by LDR could also stimulate the lymphocyte transformation. The preliminary LDR could decrease the injuries to macromolecules, membrane antigens and chromosomes in lymphocytes which were induced by high dose radiation. The LDR- induced protein might be found from mouse spleen cells, and this protein could increase immune function in human and animals

  19. Low dose radiation induced protein and its experimental and ophthalmic clinical research

    International Nuclear Information System (INIS)

    Shen Wei; Su Liaoyuan; Liu Fenju; Ding Jie; Li Longbiao; Pan Chengsi

    2001-01-01

    The protective effects of low dose radiation (LDR) induced protein on cellular impairments caused by some harmful chemical and physical factors were studied. Male Kunming mice were irradiated with LDR, then the spleen cells of the mice were broken with ultrasonic energy and then ultracentrifugalized. The supernatant solution contained with LDR induced protein. The newly emerging protein was detected by gel filtration and its molecular weight was determined by gel electrophoresis. The content of newly emerging protein (LDR induced protein) was determined by Lowry's method. The method of isotope incorporation was used to observe the biological activity and its influence factors, the protective effects of LDR induced protein on the cells impaired by irradiating with ultraviolet (UV), high doses of 60 Co γ-rays and exposed to heat respectively, and the stimulative effects of LDR induced protein on human peripheral blood lymphocytes. Newly emerging protein has been observed in the experiment. The molecular weight of the protein is in the region 76.9 KD+- - 110.0 KD+-, the yield of the protein was 613.33 +- 213.42 μg per 3 x 10 7 spleen cells. DPM values (isotope were incorporated) of normal and injured mice spleen cells increased significantly after stimulating with the solution contained LDR induced protein. It is concluded that LDR induced protein could be obtained from mice spleen cells exposed to 5 - 15 cGy radiation for 2 - 16 h. The protein had biological activity and was able to stimulate the transformation of the spleen cells in vitro. It had obvious protective effects on some impaired cells caused by high dose radiation, UV radiation, heat and so on. It also had stimulative effects on the transformation of peripheral blood T and B lymphocytes of healthy individual and patients with eye diseases. It indicates that LDR induced protein increased immune function of human

  20. Multilevel mechanisms of stimulatory effect of low dose radiation on immunity

    International Nuclear Information System (INIS)

    Shu-Zeng Liu

    1992-01-01

    Attention is paid to the effects of low level ionizing radiation on humans. The conference is devoted to low dose radiation and defense mechanisms of the body. Due to the importance of the immune system in body resistance, special attention has been given to host defense mechanisms following exposure to different doses of ionizing radiation. The immune system has long been known to be highly sensitive to moderate to high doses of ionizing radiation with immuno-depression as one of the most important causes of death in acute radiation syndrome. However, the dose-effect relationship of immune functions has been found to be quite different in the low dose range, especially with doses within 0.1 Gy. With doses above 0.5 Gy most immunologic parameters show a dose dependent depression. With doses between 0.1-0.5 Gy there may be no definite changes in immune functions. Doses within 0.1 Gy, given in single or chronic exposures, have been found to stimulate many immune responses. (author). 16 refs., 2 figs., 7 tabs

  1. Effects of low dose radiation on antioxidant enzymes after radiotherapy of tumor-bearing mice

    International Nuclear Information System (INIS)

    Li Jin; Gao Gang; Wang Qin; Tang Weisheng; Liu Xiaoqiu; Wang Zhiquan

    2005-01-01

    Objective: To search for effects of low dose radiation on the activities of antioxidant enzymes after radiotherapy of tumor-bearing mice. Methods: Superoxide dismutase (SOD), glutathione-S-transferase (GST) and catalase (CAT) were all determined by chemical colorimetry. Results: Low dose radiation increase the activities of antioxidant enzymes superoxide dismutase (SOD), glutathione-S-transferase (GST) and catalase (CAT) in serum of tumor-bearing mice more markedly than those in the unirradiated controls. The activities of antioxidant enzymes SOD, GST, CAT in serum of tumor-bearing mice (d 5 , d 3 ) irradiated with 5cGy 6h before 2.0 Gy radiation are obviously higher than those of the group (c 3 , c 5 ) given with radiotherapy only. Conclusion: The increase in the activities of antioxidant enzymes in serum of tumor-bearing mice triggered by low dose radiation could partly contribute to the protective mechanism. (authors)

  2. Studies of health effects of low dose radiation and its application to medicare

    International Nuclear Information System (INIS)

    Yamaoka, Kiyonori; Ishida, Kenji; Iwasaki, Toshiyasu; Koana, Takao; Magae, Junji; Watanabe, Masami; Sakamoto, Kiyohiko

    2008-01-01

    The articles contain following 7 topics of low dose radiation effects. Studies of Health Effects of Low dose Radiation and Its Application to Medicare'', describes the indication of Rn therapy and investigations of its usefulness mechanism mainly in Misasa Spa, Okayama Pref. ''Challenges for the Paradigm Shift (CRIEPI Studies)'', introduces studies against the paradigm that radiation dose is linearly and proportionally hazardous. ''Studies of High Background Radiation Area (CRIEPI Studies)'', describes global HBRA studies on chromosome affection and effect of smoking in HBRA. ''Is the Radiation Effect on Man Proportional to Dose? (CRIEPI Studies)'', describes studies of immature sperm irradiated at low dose against Linear-Non-threshold Theory (LNT) hypothesis. ''Induction of Radiation Resistance by Low Dose Radiation and Assessment of Its Effect in Models of Human Diseases (CRIEPI Studies)'', explains the adoptive response in radiation effect, suppression of carcinogenesis and immune regulation by previous low dose radiation in the mouse, and improvement of diabetes in the db/db mouse. ''Modulation of Biological Effects of Low Dose Radiation: Adoptive Response, Bystander Effect, Genetic Instability and Radiation Hormesis'', summarizes findings of each item. ''Cancer Treatment with Low dose Radiation to the Whole Body'', describes basic studies in the mouse tumor in relation to suppression of carcinogenesis and metastasis, immune activation and treatment, and successful clinical studies in patients with ovary, colon cancers and malignant lymphoma where survival has been significantly improved: a base of recent European Organization for Research and Treatment of Cancer (EORTC) clinical trials. The mechanism is essentially based on immune activation of patients to cure the disease. (R.T.)

  3. Mechanism of suppressive effect of low dose radiation on cancer cell dissemination in mice

    International Nuclear Information System (INIS)

    Fu Haiqing; Li Xiuyi; Chen Yubing; Zhang Yingchun; Liu Shuzheng

    1997-01-01

    Influence of low dose radiation on immunity in C57 BL/6 mice injected with cancer cells was studied. In mice given 75 mGy WBI 24 h before injection of Lewis lung carcinoma cells or B 16 melanoma cells, the percentage of S-phase thymocytes and CD 3+ thymocytes, the splenic NK cell activity, IL-2 secretion and γIFN secretion were found to be potentiated 2∼8 day after irradiation in comparison with the sham-irradiation mice. The results suggest that low dose radiation might suppress cancer cell dissemination via the enhancement of immune reactivity

  4. Total Risk Management for Low Dose Radiation Exposures

    International Nuclear Information System (INIS)

    Simic, Z.; Mikulicic, V.; Sterc, D.

    2012-01-01

    Our civilization is witnessing about century of nuclear age mixed with enormous promises and cataclysmic threats. Nuclear energy seems to encapsulate both potential for pure good and evil or at least we humans are able to perceive that. These images are continuously with us and they are both helping and distracting from making best of nuclear potentials for civilization. Today with nuclear use significantly present and with huge potential to further improve our life with energy and medical use it is of enormous importance to try to have calmed, rational, and objective view on potential risks and certain benefits. Because all use of nuclear energy proved that their immediate risks are negligible (i.e., Three Mile Island and Fukushima) or much smaller than from the other alternatives (i.e., Chernobyl) it seems that the most important issue is the amount of risk from the long term effects to people from exposure to small doses of radiation. A similar issue is present in the increased use of modern computational tomography and other radiation sources use in medicine for examination and therapy. Finally, extreme natural exposures are third such potential risk sources. Definition of low doses varies depending on the way of delivery (i.e., single, multiple or continuous exposures), and for this paper usual dose of 100 mSv is selected as yearly upper amount. There are three very different scientifically supported views on the potential risks from the low doses exposure. The most conservative theory is that all radiation is harmful, and even small increments from background levels (i.e., 2-3 mSv) present additional risk. This view is called linear no threshold theory (LNT) and it is accepted as a regulatory conservative simple approach which guarantees safety. Risk is derived from the extrapolation of the measured effects of high levels of radiation. Opposite theory to LNT is hormesis which assumes that in fact small doses of radiation are helpful and they are improving our

  5. Low-Dose Radiation Therapy (2 Gy × 2) in the Treatment of Orbital Lymphoma

    Energy Technology Data Exchange (ETDEWEB)

    Fasola, Carolina E. [Department of Radiation Oncology, Stanford University, Stanford, California (United States); Jones, Jennifer C. [Vaccine Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland (United States); Huang, Derek D. [Department of Internal Medicine, University of California-Los Angeles Olive View, Sylmar, California (United States); Le, Quynh-Thu; Hoppe, Richard T. [Department of Radiation Oncology, Stanford University, Stanford, California (United States); Donaldson, Sarah S., E-mail: sarah2@stanford.edu [Department of Radiation Oncology, Stanford University, Stanford, California (United States)

    2013-08-01

    Purpose: Low-dose radiation has become increasingly used in the management of indolent non-Hodgkin lymphoma (NHL), but has not been studied specifically for cases of ocular adnexal involvement. The objective of this study is to investigate the effectiveness of low-dose radiation in the treatment of NHL of the ocular adnexa. Methods and Materials: We reviewed the records of 20 NHL patients with 27 sites of ocular adnexal involvement treated with low-dose radiation consisting of 2 successive fractions of 2 Gy at our institution between 2005 and 2011. The primary endpoint of this study is freedom from local relapse (FFLR). Results: At a median follow-up time of 26 months (range 7-92), the overall response rate for the 27 treated sites was 96%, with a complete response (CR) rate of 85% (n=23) and a partial response rate of 11% (n=3). Among all treated sites with CR, the 2-year FFLR was 100%, with no in-treatment field relapses. The 2-year freedom from regional relapse rate was 96% with 1 case of relapse within the ipsilateral orbit (outside of the treatment field). This patient underwent additional treatment with low-dose radiation of 4 Gy to the area of relapse achieving a CR and no evidence of disease at an additional 42 months of follow-up. Orbital radiation was well tolerated with only mild acute side effects (dry eye, conjunctivitis, transient periorbital edema) in 30% of treated sites without any reports of long-term toxicity. Conclusions: Low-dose radiation with 2 Gy × 2 is effective and well tolerated in the treatment of indolent NHL of the ocular adnexa with high response rates and durable local control with the option of reirradiation in the case of locoregional relapse.

  6. Low-Dose Radiation Therapy (2 Gy × 2) in the Treatment of Orbital Lymphoma

    International Nuclear Information System (INIS)

    Fasola, Carolina E.; Jones, Jennifer C.; Huang, Derek D.; Le, Quynh-Thu; Hoppe, Richard T.; Donaldson, Sarah S.

    2013-01-01

    Purpose: Low-dose radiation has become increasingly used in the management of indolent non-Hodgkin lymphoma (NHL), but has not been studied specifically for cases of ocular adnexal involvement. The objective of this study is to investigate the effectiveness of low-dose radiation in the treatment of NHL of the ocular adnexa. Methods and Materials: We reviewed the records of 20 NHL patients with 27 sites of ocular adnexal involvement treated with low-dose radiation consisting of 2 successive fractions of 2 Gy at our institution between 2005 and 2011. The primary endpoint of this study is freedom from local relapse (FFLR). Results: At a median follow-up time of 26 months (range 7-92), the overall response rate for the 27 treated sites was 96%, with a complete response (CR) rate of 85% (n=23) and a partial response rate of 11% (n=3). Among all treated sites with CR, the 2-year FFLR was 100%, with no in-treatment field relapses. The 2-year freedom from regional relapse rate was 96% with 1 case of relapse within the ipsilateral orbit (outside of the treatment field). This patient underwent additional treatment with low-dose radiation of 4 Gy to the area of relapse achieving a CR and no evidence of disease at an additional 42 months of follow-up. Orbital radiation was well tolerated with only mild acute side effects (dry eye, conjunctivitis, transient periorbital edema) in 30% of treated sites without any reports of long-term toxicity. Conclusions: Low-dose radiation with 2 Gy × 2 is effective and well tolerated in the treatment of indolent NHL of the ocular adnexa with high response rates and durable local control with the option of reirradiation in the case of locoregional relapse

  7. Effect of low dose radiation on Th1 and Th2 of thymocytes and splenocytes in mice

    International Nuclear Information System (INIS)

    Bai Ou; Liu Shuzheng; Mu Ying

    1998-01-01

    Objective: To elucidate the possible mechanism of activation of helper T cells after low dose radiation (LDR) exposure, the influence of whole-body irradiation (WBI) with 75 mGy X-rays on Th1 and Th2 was studied. Methods: Mice were irradiated at a dose rate of 12.5 mGy/min, and IFN-γ and IL-6 mRNA levels of the myocytes and splenocytes were analyzed by dot blot and Northern blot hybridization. Results: It was found that IFN-γ and IL-6 mRNA significantly increased after WBI with 75 mGy X-rays. Conclusion: The gene induction of cytokine profile after LDR indicates that activation of both Th1 and Th2 subtypes may be involved in the stimulation of immune functions by LDR

  8. Study on human mesenchymal stem cells from bone marrow pretreated with low dose radiation

    International Nuclear Information System (INIS)

    Yang Yan; Wang Guangjun; Wang Juan

    2008-01-01

    Objective: To study effects of human bone marrow mesenchymal stem cells (hBM-MSC) from bone marrow pretreated with low dose radiation (LDR). Methods: The cells were the hBM-MSC. They were exposed to X rays at the dose of 50 mGy, 75 mGy, 100 mGy (dose rate 12.5 mGy/min). The growth curve, cell cycle and apoptosis of hBM-MSC treated by LDR were investigated. The content changes of stem cell factor(SCF), interleukin-6 (IL-6), macrophage colony stimulating factor(M-CSF) secreted by hBM-MSC after treated by LDR were determined by enzyme linked immunosorbent assay method. Results: The growth rates of hBM-MSC treated by LDR obviously increase from 72 h. The cell cycle and apoptosis were examined with FORTRAN Atomatic Checkout Systom. The results show that the G 0 /G 1 stage cells decrease after exposure to LDR, the percent of G 0 /G 1 stage cells of 75 mGy at 72 h is the lowest(30.86%). However, the S stage cells percentage gradually increase at 48 h and 72 h. The most one is 75 mGy group at 72 h, which reaches to 68.88%. The apoptosis percentages have increased tendency at 24 h and 48h in all dose groups, especially in 100 mGy at 24 h(25.99%), while have decreased tendency at 72 h and the most decreased group is the 50 mGy(6.8%), transient enhancement of apoptosis in the early stage and soon being decreased. The contents of SCF have increased tendency at 24 h, 48 h. As for IL-6, the contents in different dose groups at 24 h and 48 h have up-regulation. These groups, 50 mGy at 24 h, 48 h, 75 mGy at 24 h, 48 h, 100 mGy at 24 h have statistical difference compared with their control groups respectively. The content of IL-6 has greatest enhancement at dose of 50 mGy. The contents of M-SCF in all the groups at 24 h, 48 h and 72 h except for the 50 mGy dose at 72 h have also been found increased. The greatest increased content occur in the 75 mGy dose group at 72 h. Conclusion: This conclusion show that LDR has hormesis effect on hBM-MSC in cell growth, cell cycle and content

  9. Low-dose radiation epidemiological studies: an assessment of methodological problems

    International Nuclear Information System (INIS)

    Modan, B.

    1991-01-01

    The present report attempts to assess the problems inherent in the analysis of low dose radiation studies, with emphasis on possible sources of methodological errors in the published data, and the consequent relevance to risk estimates. The published data examined concerned populations exposed to nuclear sources such as fallout, weapons' test or in the vicinity of nuclear reactors, occupational exposure, intra-uterine diagnostic X-rays, scattered radiation following X-ray therapy and background irradiation. (UK)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-02-19

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

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

    Science.gov (United States)

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

    2016-01-01

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

  12. James V. Neel and Yuri E. Dubrova: Cold War debates and the genetic effects of low-dose radiation.

    Science.gov (United States)

    Goldstein, Donna M; Stawkowski, Magdalena E

    2015-01-01

    This article traces disagreements about the genetic effects of low-dose radiation exposure as waged by James Neel (1915-2000), a central figure in radiation studies of Japanese populations after World War II, and Yuri Dubrova (1955-), who analyzed the 1986 Chernobyl nuclear power plant accident. In a 1996 article in Nature, Dubrova reported a statistically significant increase in the minisatellite (junk) DNA mutation rate in the children of parents who received a high dose of radiation from the Chernobyl accident, contradicting studies that found no significant inherited genetic effects among offspring of Japanese A-bomb survivors. Neel's subsequent defense of his large-scale longitudinal studies of the genetic effects of ionizing radiation consolidated current scientific understandings of low-dose ionizing radiation. The article seeks to explain how the Hiroshima/Nagasaki data remain hegemonic in radiation studies, contextualizing the debate with attention to the perceived inferiority of Soviet genetic science during the Cold War.

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

    International Nuclear Information System (INIS)

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

    2000-01-01

    Excessive active oxygen produced in vivo by various causes is toxic. Accumulation of oxidation injuries due to excessive active causes cell and tissue injuries, inducing various pathologic conditions such as aging and carcinogenesis. On the other hand, there are chemical defense mechanisms in the body that eliminate active oxygen or repair damaged molecules, defending against resultant injury. It is interesting reports that appropriate oxidation stress activate the chemical biological defense mechanisms. In this study, to elucidate these phenomena and its mechanism by low dose radiation, we studied on the below subjects. Activation of chemical biological defense mechanisms by low dose radiation: (1) The effects radiation on lipid peroxide (LPO) levels in the organs, membrane fluidity and the superoxide dismutase (SOD) activity were examined in rats and rabbits. Rats were irradiated with low dose X-ray over their entire bodies, and rabbits inhaled vaporized radon spring water, which primarily emitted α-ray. The following results were obtained. Unlike high dose X-ray, low dose X-ray and radon inhalation both reduced LPO levels and made the state of the SH-group on membrane-bound proteins closer to that of juvenile animals, although the sensitivity to radioactivity varied depending on the age of the animals and among different organs and tissues. The SOD activity was elevated, suggesting that low dose X-ray and radon both activate the host defensive function. Those changes were particularly marked in the organs related to immune functions of the animals which received low dose X-ray, while they were particularly marked in the brain after radon inhalation. It was also found that those changes continued for longer periods after low dose X-irradiation. (2) Since SOD is an enzyme that mediates the dismutation of O 2 - to H 2 O 2 , the question as to whether the resultant H 2 O 2 is further detoxicated into H 2 O and O 2 or not must still be evaluated. Hence, we studied

  14. Data integration reveals key homeostatic mechanisms following low dose radiation exposure

    Energy Technology Data Exchange (ETDEWEB)

    Tilton, Susan C.; Matzke, Melissa M. [Computational Biology and Bioinformatics, Pacific Northwest National Laboratory, Richland, WA 99338 (United States); Sowa, Marianne B.; Stenoien, David L.; Weber, Thomas J. [Health Impacts and Exposure Science, Pacific Northwest National Laboratory, Richland, WA 99338 (United States); Morgan, William F. [Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99338 (United States); Waters, Katrina M., E-mail: katrina.waters@pnnl.gov [Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99338 (United States)

    2015-05-15

    The goal of this study was to define pathways regulated by low dose radiation to understand how biological systems respond to subtle perturbations in their environment and prioritize pathways for human health assessment. Using an in vitro 3-D human full thickness skin model, we have examined the temporal response of dermal and epidermal layers to 10 cGy X-ray using transcriptomic, proteomic, phosphoproteomic and metabolomic platforms. Bioinformatics analysis of each dataset independently revealed potential signaling mechanisms affected by low dose radiation, and integrating data shed additional insight into the mechanisms regulating low dose responses in human tissue. We examined direct interactions among datasets (top down approach) and defined several hubs as significant regulators, including transcription factors (YY1, MYC and CREB1), kinases (CDK2, PLK1) and a protease (MMP2). These data indicate a shift in response across time — with an increase in DNA repair, tissue remodeling and repression of cell proliferation acutely (24–72 h). Pathway-based integration (bottom up approach) identified common molecular and pathway responses to low dose radiation, including oxidative stress, nitric oxide signaling and transcriptional regulation through the SP1 factor that would not have been identified by the individual data sets. Significant regulation of key downstream metabolites of nitrative stress was measured within these pathways. Among the features identified in our study, the regulation of MMP2 and SP1 was experimentally validated. Our results demonstrate the advantage of data integration to broadly define the pathways and networks that represent the mechanisms by which complex biological systems respond to perturbation. - Highlights: • Low dose ionizing radiation altered homeostasis in 3D skin tissue model. • Global gene/protein/metabolite data integrated using complementary statistical approaches • Time and location-specific change in matrix regulation

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

    International Nuclear Information System (INIS)

    Arinchin, A.N.

    2000-01-01

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

  16. Low dose radiation induced protein and its effect on expression of CD25 molecule in lymphocytes

    International Nuclear Information System (INIS)

    Lu Duicai; Su Liaoyuan

    2001-01-01

    Objective: To find the substantial basis for effects of low dose radiation, on development, extraction, and the biogical activity of the low-dose radiation-induced proteins, and the effects of LDR induced proteins on CD25 molecule expression of human lymphocytes. Methods: 1. Healthy Kumning male mice exposed to radiation of 226 Ra γ-rays at 5, 10 and 15 cGy respectively. The mice were killed 2 hours after exposure, the spleen cells were broken with ultrasonic energy and then ultra-centrifugalized at low temperature (4 degree C). The LDR-induced proteins were obtained in the supernatant solution. Then the changes of CD25 molecule was measured by flow cytometry (FCM) with immunofluorescence technique, which was used to reflect the effect of LDR induced proteins on CD25 molecule expression of human lymphocytes. Results: LDR induced proteins were obtained from spleen cells in mice exposed to 5-15 cGy whole body radiation. Conclusion: The expression of CD25 molecule of lymphocytes was increased significantly after use of LDR induced proteins. LDR induced proteins can enhance expression of CD25 molecule of lymphocytes slightly

  17. Low-dose radiation therapy for choroidal neovascularization in age-related macular degeneration

    International Nuclear Information System (INIS)

    Matsuhashi, Hideaki; Takahashi, Daisuke; Mariya, Yasushi; Tarusawa, Nobuko; Yoshimoto, Hiroshi; Matsuyama, Shuichi; Noda, Yasuko.

    1996-01-01

    The efficacy of low-dose radiation was evaluated in the treatment of eyes with subfoveal or juxtafoveal choroidal neovascularization in age-related macular degeneration. Ten eyes of ten patients received a total dose of 14 Gy of 10 MV X-rays in seven fractions and the mean follow-up time was 12 months (range 9-18 months). Thirteen control eyes of thirteen patients were followed for an average of 18 months (range 12-24 months). Visual acuity was improved in 2 eyes (20%), unchanged in 3 eyes (30%), and deteriorated in 5 eyes (50%) of treated patients, and it was improved in no eyes (0%), unchanged in 5 eyes (32%), and deteriorated in 8 eyes (50%) of the control patients at their last follow-up examinations. Funduscopic and angiographic findings were improved in 3 eyes (30%), unchanged in 2 eyes (20%), and deteriorated in 5 eyes (50%) of treated patients, and they were improved in no eyes (0%), unchanged in 5 eyes (32%), and deteriorated in 8 eyes (50%) of the control patients. These results suggested that low-dose radiation is beneficial for the management of subfoveal or juxtafoveal choroidal neovascularization in age-related macular degeneration. (author)

  18. Low-dose radiation therapy for choroidal neovascularization in age-related macular degeneration

    Energy Technology Data Exchange (ETDEWEB)

    Matsuhashi, Hideaki; Takahashi, Daisuke; Mariya, Yasushi; Tarusawa, Nobuko; Yoshimoto, Hiroshi; Matsuyama, Shuichi [Hirosaki Univ., Aomori (Japan). School of Medicine; Noda, Yasuko

    1996-10-01

    The efficacy of low-dose radiation was evaluated in the treatment of eyes with subfoveal or juxtafoveal choroidal neovascularization in age-related macular degeneration. Ten eyes of ten patients received a total dose of 14 Gy of 10 MV X-rays in seven fractions and the mean follow-up time was 12 months (range 9-18 months). Thirteen control eyes of thirteen patients were followed for an average of 18 months (range 12-24 months). Visual acuity was improved in 2 eyes (20%), unchanged in 3 eyes (30%), and deteriorated in 5 eyes (50%) of treated patients, and it was improved in no eyes (0%), unchanged in 5 eyes (32%), and deteriorated in 8 eyes (50%) of the control patients at their last follow-up examinations. Funduscopic and angiographic findings were improved in 3 eyes (30%), unchanged in 2 eyes (20%), and deteriorated in 5 eyes (50%) of treated patients, and they were improved in no eyes (0%), unchanged in 5 eyes (32%), and deteriorated in 8 eyes (50%) of the control patients. These results suggested that low-dose radiation is beneficial for the management of subfoveal or juxtafoveal choroidal neovascularization in age-related macular degeneration. (author)

  19. The bovine tuberculosis burden in cattle herds in zones with low dose radiation pollution in Ukraine

    Directory of Open Access Journals (Sweden)

    Svitlana Pozmogova

    2009-06-01

    Full Text Available The authors describe a study of the tuberculosis (TB incidence in cattle exposed to low doses of radiation resulting from the Chernobyl (pronounced ‘Chornobyl’ in Ukrainian nuclear plant catastrophe in 1986. The purpose of the study was to determine if ionising radiation influences the number of outbreaks of bovine TB and their severity on farms in the Kyiv, Cherkasy and Chernigiv regions of Ukraine. These farms are all located within a 200 km radius of Chernobyl and have had low-dose radiation pollution. Pathological and blood samples were taken from cattle in those regions that had positive TB skin tests. Mycobacterium spp. were isolated, differentiated by PCR, analysed and tested in guinea-pigs and rabbits. Species differentiation showed a significant percentage of atypical mycobacteria, which resulted in the allergic reactions to tuberculin antigen in the skin test. Mixed infection of M. bovis and M. avium subsp. hominissuis was found in three cases. The results concluded that low-dose radiation plays a major role in the occurrence of bovine TB in regions affected by the Chernobyl nuclear disaster.

  20. Involvement of p27CIP/KIP in HSP25 or HSP70 Mediated Adaptive Response by Low Dose Radiation

    International Nuclear Information System (INIS)

    Seo, Hang Rhan; Lee, Yoon Jin; Lee, Su Jae; Bae, Sang woo; Lee, Yun Sil

    2005-01-01

    Adaptive responses that reduce the harmful effects of subsequent exposure to high-dose radiation have demonstrated in chromosome aberration, cell survival, sister chromatid exchanges, micronucleus induction, mutation and neoplastic transformation. The mechanisms and conditions for the adaptive response to radiation have not been clarified, although the continuous production of free radicals from radiation and other sources has stimulated cells to evolve a repair system for chromosome breaks. An alteration of the DNA molecule triggers the repair system, and frequent activation may increase the general repair capacity, irrespective of the cause of the damage. Besides, cell cycle regulation systems, antioxidant defense systems, molecular chaperone or stress-response systems. Our previous data showed that when cells were preirradiated with 1cGy, they showed the adaptive response. A reduction of apoptosis by low-dose preirradiation is another potential mechanism for this effect. We previously demonstrated that mouse RIF cells, which did not induce HSP25 and HSP70 did not exhibit a adaptive response after 1cGy preirradiation. whereas the thermoresistant TR cells, which expressed inducible HSP25 and HSP70 showed a response. Moreover, when HSP70 and HSP25 were transfected to RIF cells, the cells acquired adaptive response. In this study, to elucidate the mechanisms in induction of adaptiveresponse, we compared cell cycle distribution by low dose radiation after HSP25 or HSP70 transfected cells and p27CIP/KIP is responsible for the different induction of adaptive response

  1. Evaluation of genome damage and transcription profile of DNA damage/repair response genes in peripheral blood mononuclear cells exposed to low dose radiation

    International Nuclear Information System (INIS)

    Soren, D.C.; Saini, Divyalakshmi; Das, Birajalaxmi

    2016-01-01

    Humans are exposed to various physical and chemical mutagens in their life time. Physical mutagens, like ionizing radiation (IR), may induce adverse effect at high acute dose exposures in human cells. However, there are inconsistent results on the effect of low dose radiation exposure in human cells. There are a variety of DNA damage endpoints to evaluate the effect of low dose radiation in human cells. DNA damage response (DDR) may lead to changes in expression profile of many genes. In the present study, an attempt has been made to evaluate genome damage at low dose IR exposure in human blood lymphocytes. Cytochalasin blocked micronuclei (CBMN) assay has been used to determine the frequency of micronuclei in binucleated cells in PBMCs exposed to IR. Transcription profile of ATM, P53, GADD45A, CDKN1A, TRF1 and TRF2 genes was studied using real time quantitative PCR. Venous blood samples collected from 10 random healthy donors were irradiated with different doses of γ-radiation ( 137 Cs) along with sham irradiated control. Whole blood culture was set up using microculture technique. Blood samples were stimulated with phytohemagglutinin, and CBMN assay was performed. An average of 2,500 binucleated cells was scored for each dose point. For gene expression analysis, total RNA was isolated, cDNA was prepared, and gene expression analysis for ATM, P53, CDKN1A, GADD45A, TRF1 and TRF2 was done using real time PCR. Our results revealed no significant increase in the frequency of MN up to 100 mGy as compared to control. However, no significant alteration in gene expression profile was observed. In conclusion, no significant dose response was observed at the frequency of MN as well as the expression profile of DDR/repair genes, suggesting low dose radiation did not induce significant DNA damage at these acute dose exposures. (author)

  2. Low-dose radiation induces drosophila innate immunity through toll pathway activation

    International Nuclear Information System (INIS)

    Seong, Ki Moon; Kim, Cha Soon; Lee, Byung-Sub; Nam, Seon Young; Yang, Kwang Hee; Kim, Ji-Young; Jin, Young-Woo; Park, Joong-Jean; Min, Kyung-Jin

    2012-01-01

    Numerous studies report that exposing certain organisms to low-dose radiation induces beneficial effects on lifespan, tumorigenesis, and immunity. By analyzing survival after bacterial infection and antimicrobial peptide gene expression in irradiated flies, we demonstrate that low-dose irradiation of Drosophila enhances innate immunity. Low-dose irradiation of flies significantly increased resistance against gram-positive and gram-negative bacterial infections, as well as expression of several antimicrobial peptide genes. Additionally, low-dose irradiation also resulted in a specific increase in expression of key proteins of the Toll signaling pathway and phosphorylated forms of p38 and N-terminal kinase (JNK). These results indicate that innate immunity is activated after low-dose irradiation through Toll signaling pathway in Drosophila. (author)

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

    International Nuclear Information System (INIS)

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

    1989-01-01

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

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

    International Nuclear Information System (INIS)

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

    1988-01-01

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

  5. Effects of low dose radiation on differential expression of serum protein in mice

    International Nuclear Information System (INIS)

    Chen Wei; He Ying; Shen Xianrong

    2014-01-01

    The aim is to find out the key proteins related with low dose radiation (Ld) by parametric technology, which provided the theory foundation for LDR protection Two-dimensional electrophoresis (2-DE) was performed on serum protein Differential expression proteins were identified by matrix assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS) and database analysis Compared with the control group, 7 altered proteins was definite in terms of apolipoprotein C-Ⅲ, beta-globin parotid secretory protein alpha-2-macroglobulin precursor, mouse transthyretin, C1qc protein and clusterin. Some proteins related with LDR are found. It may provide some new explanations for the mechanism of LDR. (authors)

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

    International Nuclear Information System (INIS)

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

    2010-01-01

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

  7. The effect of low dose radiation on the neuronal cell proliferation in diabetic rats

    International Nuclear Information System (INIS)

    Kim, Doo Soon; Kang, Jin Oh; Hong, Seong Eon; Kim, Sang Ki; Lee, Taeck Hyun; Kim, Chang Ju

    2005-01-01

    To investigate the effect of low dose radiation on neuronal cell proliferation in diabetic rats. A group of rats (first group) were divided into three subgroups (nondiabetic control, nondiabetic 0.1 Gy and nondiabetic 10 Gy groups) to determine the effect of radiation on normal hippocampal neuronal cell proliferation. A further group of rats (second group) were divided into six subgroups (nondiabetic control, diabetic control, diabetic 0.01 Gy, diabetic 0.1 Gy, diabetic 1 Gy and diabetic 10 Gy groups) to determine the effect of radiation on hippocampal neuronal cell proliferation under diabetic conditions. Using immunohistochemistry for 5-bromo-2'-deoxyuridine (BrdU), the number of neuronal cells in the dentate gyrus of all the groups was counted. The number of BrdU-positive cells in the dentate Gyrus of the nondiabetic control, nondiabetic 0.1 Gy and nondiabetic 10 Gy subgroups of the first group were 45.96 ± 3.42, 59.34 ± 5.20 and 19.26 ± 2.98/mm 2 , respectively. The number of BrdU-positive cells in the dentate gyrus of the diabetic control, diabetic 0.01 Gy, diabetic 0.1 Gy, diabetic 1 Gy and diabetic 10 Gy subgroups of the second group were 55.44 ± 8.57, 33.33 ±6.46, 67.75 ± 10.54, 66.63 ± 10.05, 23.59 ± 6.37 and 14.34± 7.22/mm 2 , respectively. Low dose radiation enhances cell proliferation in the dentate gyrus of STZ-induced diabetic rats

  8. Single Low-Dose Radiation Induced Regulation of Keratinocyte Differentiation in Calcium-Induced HaCaT Cells

    Science.gov (United States)

    Hahn, Hyung Jin; Youn, Hae Jeong; Cha, Hwa Jun; Kim, Karam; An, Sungkwan

    2016-01-01

    Background We are continually exposed to low-dose radiation (LDR) in the range 0.1 Gy from natural sources, medical devices, nuclear energy plants, and other industrial sources of ionizing radiation. There are three models for the biological mechanism of LDR: the linear no-threshold model, the hormetic model, and the threshold model. Objective We used keratinocytes as a model system to investigate the molecular genetic effects of LDR on epidermal cell differentiation. Methods To identify keratinocyte differentiation, we performed western blots using a specific antibody for involucrin, which is a precursor protein of the keratinocyte cornified envelope and a marker for keratinocyte terminal differentiation. We also performed quantitative polymerase chain reaction. We examined whether LDR induces changes in involucrin messenger RNA (mRNA) and protein levels in calcium-induced keratinocyte differentiation. Results Exposure of HaCaT cells to LDR (0.1 Gy) induced p21 expression. p21 is a key regulator that induces growth arrest and represses stemness, which accelerates keratinocyte differentiation. We correlated involucrin expression with keratinocyte differentiation, and examined the effects of LDR on involucrin levels and keratinocyte development. LDR significantly increased involucrin mRNA and protein levels during calcium-induced keratinocyte differentiation. Conclusion These studies provide new evidence for the biological role of LDR, and identify the potential to utilize LDR to regulate or induce keratinocyte differentiation. PMID:27489424

  9. Donor-specific cell-based assays in studying sensitivity to low-dose radiation: a population-based perspective

    Directory of Open Access Journals (Sweden)

    Dora eIl'yasova

    2014-11-01

    Full Text Available Currently, a linear no-threshold model is used to estimate health risks associated with exposure to low-dose radiation, a prevalent exposure in the general population, because the direct estimation from epidemiological studies suffers from uncertainty. This model has been criticized based on unique biology of low-dose radiation. Whether the departure from linearity is toward increased or decreased risk is intensely debated. We present an approach based on individual radiosensitivity testing and discuss how individual radiosensitivity can be assessed with the goal to develop a quantifiable measure of cellular response that can be conducted via high-throughput population testing.

  10. Low-dose radiation (LDR) induces hematopoietic hormesis: LDR-induced mobilization of hematopoietic progenitor cells into peripheral blood circulation.

    Science.gov (United States)

    Li, Wei; Wang, Guanjun; Cui, Jiuwei; Xue, Lu; Cai, Lu

    2004-11-01

    The aim of this study was to investigate the stimulating effect of low-dose radiation (LDR) on bone marrow hematopoietic progenitor cell (HPC) proliferation and peripheral blood mobilization. Mice were exposed to 25- to 100-mGy x-rays. Bone marrow and peripheral blood HPCs (BFU-E, CFU-GM, and c-kit+ cells) were measured, and GM-CSF, G-CSF, and IL-3 protein and mRNA expression were detected using ELISA, slot blot hybridization, and Northern blot methods. To functionally evaluate LDR-stimulated and -mobilized HPCs, repopulation of peripheral blood cells in lethally irradiated recipients after transplantation of LDR-treated donor HPCs was examined by WBC counts, animal survival, and colony-forming units in the recipient spleens (CFUs-S). 75-mGy x-rays induced a maximal stimulation for bone marrow HPC proliferation (CFU-GM and BFU-E formation) 48 hours postirradiation, along with a significant increase in HPC mobilization into peripheral blood 48 to 72 hours postradiation, as shown by increases in CFU-GM formation and proportion of c-kit+ cells in the peripheral mononuclear cells. 75-mGy x-rays also maximally induced increases in G-CSF and GM-CSF mRNA expression in splenocytes and levels of serum GM-CSF. To define the critical role of these hematopoietic-stimulating factors in HPC peripheral mobilization, direct administration of G-CSF at a dose of 300 microg/kg/day or 150 microg/kg/day was applied and found to significantly stimulate GM-CFU formation and increase c-kit+ cells in the peripheral mononuclear cells. More importantly, 75-mGy x-rays plus 150 microg/kg/day G-CSF (LDR/150-G-CSF) produced a similar effect to that of 300 microg/kg/day G-CSF alone. Furthermore, the capability of LDR-mobilized donor HPCs to repopulate blood cells was confirmed in lethally irradiated recipient mice by counting peripheral WBC and CFUs-S. These results suggest that LDR induces hematopoietic hormesis, as demonstrated by HPC proliferation and peripheral mobilization, providing a

  11. Effect of low dose radiation on expression of hematopoietic growth factors secreted by human mesenchymal stem cells from bone marrow

    International Nuclear Information System (INIS)

    Yang Yan; Wang Guanjun; Zhu Jingyan; Wang Juan

    2008-01-01

    Objective: To study the changes of hematopoietic growth factors secreted by human mesenchymal stem cells from bone marrow (BM-MSC) pretreated with low dose radiation (LDR). Methods: The cultured P4 and P5 BM-MSCs were exposed to X rays at the doses of 50, 75 and 100 mGy (dose rate 12.5 mGy·min -1 ). The changes of levels of stem cell factor (SCF), IL-6, macrophage colony-stimulating factor (M-CSF) secreted by BM- MSCs pretreated with LDR were determined by ELISA method. Results: As compared with control group at the same time, the levels of SCF in experimental group had a tendency of increasing after 24 h and 48 h radiation, but only in 75 mGy group the SCF level was obviously increased (P<0.05). The levels of IL-6 in 50 and 75 mGy groups at 24 h and 48 h, in 100 mGy group at 24 h were obviously increased compared with control group (P< 0.05). The levels of M-CSF in all the groups at 24 h, 48 h and 72 h except for the 50 mGy dose at 72 h were also increased (P<0.05), it increased markedly in 75 mGy dose group at 72 h. Conclusion: LDR has hormesis effect on BM-MSCs. After LDR, the BM-MSCs grow faster and in a certain phase the expression levels of hematopoietic growth factors are increased. (authors)

  12. Effect of low dose radiation on cell cycle and expression of its related proteins of HCT-8 cells

    International Nuclear Information System (INIS)

    Xu Ying; Ma Kewei; Li Wei; Wang Guanjun

    2009-01-01

    Objective: To study the effects of low dose radiation (LDR) on cell cycle and the expression of its related proteins of HCT-8 cells and provide theoretical basis for clinical application of LDR. Methods: Human colon carcinoma cells (HCT-8) cultivated in vitro were divided into seven groups: sham radiation group (0 mGy), LDR groups (25, 50, 75, 100 and 200 mGy) and high dose radiation group (1000 mGy). The proliferation rate was detected with the method of cell count and MTT, the ratios of G 0 /G 1 , S, G 2 /M in cell cycle were determined with flow cytometry after LDR, The cell cycle and expressions of related signal proteins were analyzed with protein assay system. Results: The results of cell count and MTT showed that there were no significant differences of proliferation rate of HCT-8 cells between 25, 50, 75, 100, 200 mGy LDR groups and sham radiation group (P>0.05); compared with high dose radiation group, there were significant differences (P 0 /G 1 phase of HCT-8 cells increased (P>0.05), the ratio of S phase decreased significantly (P 2 /M phase increased obviously (P 0 /G 1 , S, and G 2 /M phases of HCT-8 cells 48 h after radiation compared with sham radiation group (P>0.05). The protein assay result indicated that the expressions of AKt, PCNA, p27, CDK2, cyclin E, EGFR, ERK1/2, p-ERK, p-GSK-32/β in HCT-8 cells after LDR decreased compared with sham radiation group. Conclusion: LDR has no stimulating effect on HCT-8 cells. However, to some extent LDR suppress the expressions of some proteins related to proliferation and cell cycle. (authors)

  13. Biological effects of low-dose radiation on human population living in high-background radiation areas of Kerala coast

    International Nuclear Information System (INIS)

    Das, Birajalaxmi

    2016-01-01

    High-level natural radiation areas (HLNRA) of Kerala coast is densely populated and known for its wide variation in background radiation dose levels due to uneven distribution of monazite in the beach sand. The background radiation dose varies from 1 to 45 mGv/y. The areas with >1.5mGy/y is considered as HLNRA. Human population inhabiting in this area are exposed to low-dose chronic radiation since generations. Hence, this population provides an ideal situation to study dose response and adaptive response, if any, due to natural chronic low-dose exposure. It has been investigated extensively to study the biological and health effects of long-term low-dose/low-dose radiation exposure. So far over 150, 000 newborns monitored from hospital-based study did not reveal any significant difference in the incidence of any of the malformations and stillbirth between HLNRA and adjacent control areas. A case-control study on cleft lip/palate and mental retardation did not show any association with background radiation dose. Cytogenetic investigation of over 27,000 newborns did not show any significant increase in the frequency of chromosome aberrations and karyotype anomalies. DNA damage endpoints, such as micronuclei, telomere length and DNA strand breaks, did not reveal any significant difference between control and exposed population. Studies on DNA damage and repair revealed efficient repair of DNA strand breaks in HLNRA individuals. Molecular studies using high throughput microarray analysis indicated a large number of genes involved in various molecular and cellular pathways. Indications of in vivo radioadaptive response due to natural chronic low-dose exposure in this population have important implications to human health. (author)

  14. Dynamic changes of the early protein synthesis in murine immune cells after low dose radiation

    International Nuclear Information System (INIS)

    Chen Shali; Liu Shuzheng

    1997-01-01

    It was shown that there was a marked increase in protein synthesis of thymocytes that were metabolically labelled with 3 H-Leu for 4,6,8 and 12 hours in low dose irradiated mice showing 33.26%, 51.48%, 51.54% and 34.98% increase respectively at different time intervals of incubation when the thymic and splenic cells were sampled 4 hours after whole body irradiation (WBI) with 75 mGy X-rays. The results suggest that there is an increase in protein synthesis with its peak at 6∼8 hours after radiation. Changes in protein synthesis of immune cells in mice 4 hours after radiation and incubated for 4∼12 h were observed with SDS-PAGE followed by densitometrical scanning. It is revealed that 28 kD protein synthesis was increased gradually within 12 hours of incubation and 43 kD protein synthesis was increased in the thymocytes rapidly reaching a maximum 2 hours after incubation. It was also exhibited that the synthesis of 43 kD protein and 32 kD protein was increased in the splenocytes 2 hours after incubation. These findings may have implications in the mechanism of immunoenhancement and adaptive response induced by low dose radiation

  15. Apoptosis of bone marrow leukemia cells in mice after low dose radiation at different time

    International Nuclear Information System (INIS)

    Li Guangyu; Yu Mingming; Li Xianjun; Liu Zhixiang

    2007-01-01

    Objective: To investigate the apoptosis of bone marrow leukemia cell in mice after low dose radiation (LDR) at different time and the experimental basis for LDR auxiliary therapy on leukemia. Methods: WEHI-3 cells were injected into BALB/c mice through tail veins to make an experimental mice model of myelornonocytic leukemia. 60 leukemia mice models were divided half-and half. 30 mice models in experimental group were irradiated with LDR of 75mGy at the same time while the others 30 in the control group were not. 6 mice models with LDR and 6 mice models without LDR would be killed at the time the 1st day, the 2nd day, the 3rd day, the 5th day- and the l0th day after LDR in order to extract bone marrow samples. The apoptosis percentage of leukemia cells in bone marrow was examined. Results: The apoptosis percentage of leukemia cells in experimental group was increasing after LDR and went to top on the 2nd day and the 3rd day. The apoptosis percentage of leukemia cells was remarkably different between experimental and control group, all P<0.05. Conclusion: LDR could significantly increase the apoptosis percentage of bone marrow leukemia cells in mice. Its mechanism is remarkably different in kill and wound of big dose radiation to tumour cells. It is probably related to of the increase immune exciting response as to promote some cytokine secretion, in leukemia mice. (authors)

  16. Low-dose radiation as an environmental agent affecting intrauterine development

    International Nuclear Information System (INIS)

    Kameyama, Yoshiro

    1982-01-01

    The low-dose radiation effects which have been recognized in mammalian teratological studies are direct injuries to the particularly radiosensitive tissues of embryo and fetus, and increased incidences of spontaneous malformations and minor anomalies. The lowest radiation doses for manifestation of those effects in mice and rats are: 5 rad for resorption of preimplantation embryos; 5-10 rad for acute cytological changes such as pyknosis, cytoplasmic degeneration and mitotic delay; 5 rad for increasing frequency of spontaneous minor anomalies of the skeleton; 15-20 rad for malformations of the eye, brain and spinal cord; 20-25 rad for histogenetic and functional disorders of the central nervous system; and 20-25 rad for impaired fertility. Pregnant women who are subject to X-ray examination are much concerned about potential hazard of radiation to their offspring in utero. The above experimental findings suggest that the possibility of teratogenic effects of diagnostic radiation on human embryos and fetuses is extremely low, and probably negligible, given the proper dose control measures. (author)

  17. Immunologic mechanism of the suppressive effect of low dose radiation on thymic lymphoma induced by radiation

    International Nuclear Information System (INIS)

    Li Xiujuan; Yang Ying; Li Xiuyi; Liu Shuzheng

    1999-01-01

    To study immunologic mechanism of the suppressive effect of low dose radiation (LDR) on thymic lymphoma (TL) induced by high dose radiation (HDR). The authors adopted the model that C57BL/6J mice were administered whole body irradiation with 1.75 Gy X-rays one time every week for 4 weeks to induce TL. It was examined that splenic NK cytotoxic activity, IL-2 and γ-IFN secretion activity, peritoneal macrophage phagocytosis and its TNF-α secretion activity in mice with different dose 1 month after irradiation. The results showed that all the immunologic functions mentioned above in mice given 75 mGy 12 h before 1.75 Gy every time were higher than that in mice given only 1.75 Gy, and approached to the sham-irradiation mice. It suggested that the suppressive effect of LDR on TL induced by HDR may be related to the adaptive response induced by LDR and decreasing immunological functions damage caused by HDR

  18. Effect of low dose radiation on POMC transcription level in mouse hypothalamus and immune organs

    International Nuclear Information System (INIS)

    Wan Hong; Liu Shuzheng

    1998-01-01

    Objective: To disclose the changes in mRNA transcription level of POMC in the hypothalamus and immune organs after low dose radiation. Method: In situ hybridization was used to examine the changes of POMC mRNA transcription level in mouse hypothalamus and immune organs following whole body irradiation (WBI) with 75 mGy X-rays. Results: There was a basal expression of POMC mRNA in both the hypothalamus and immune organs. POMC mRNA-positive neutron were located in the arcuate nucleus of hypothalamus. WBI with 75 mGy X-rays could significantly down-regulate the POMC transcription level that was remarkable within 1h and remained low in the observation period of 12h. POMC transcription level in mouse immune organs increased with time within 8h after irradiation and then began to decrease but still remained at a higher than normal level. The changes of POMC transcription level were more marked in the spleen than in other immune organs. Conclusion: These findings suggest that the immediate decrease of POMC transcription level in the hypothalamus might be the direct cause of the down-regulation of the hypothalamus-pituitary-adrenocortical axis after WBI with 75 mGy X-rays, accompanied with an increase in POMC transcription in immune organs

  19. Effects of low dose radiation on differentiation, activation and apoptosis of thymocytes in mice

    International Nuclear Information System (INIS)

    Su Xu; Zhang Yingchun; Wan Hong; Liu Shuzheng

    1997-01-01

    Objective: To elucidate the possible mechanism of immunoenhancement after low dose radiation (LDR), the differentiation, activation and apoptosis of thymocytes following low dose irradiation were studied. Method: Kunming mice were whole-body irradiated (WBI) with low dose X-rays. The expressions of CD4, CD8, TCR, CD3, IL-2R, (Ca 2+ ) i , Bcl-2 Bax and apoptosis of thymocytes were analyzed by flow cytometry. Results: It was found that the ratio of T H /T S showed no significant changes after LDR. Thymocyte apoptosis was not increased after LDR. The increase of Bcl-2/Bax ratio after LDR might be one of its mechanisms. LDR could expedites the process of differentiation of, and facilitate the signal transduction in, thymocytes. Conclusion: The results indicate that the mechanism of immunoenhancement might be related to the expedition of the maturation, differentiation and activation of thymocytes, thus up-regulating the capability of supplying more mature T lymphocytes to the periphery by the thymus after LDR

  20. Effects of low dose radiation pretreatment on radiation injuried brain's free radicle

    International Nuclear Information System (INIS)

    Xu Fuqi; Wang Cheng; Xie Hong; Tian Ye

    2006-01-01

    Objective: To investigate the effect of low dose radiation pretreatment on radiation in- juried brain's free radicle to provide some useful data of brain radiation injury protection. Methods: One hundred mGy was selected as the pretreatment does, 25 Gy was selected as the challenge does. Experiment rats were divided into three groups randomly, group one as simple group:the group irradiated without exposing to pre-irradiation; group two as 6 h-group: the group irradiated with LDR pretreatment 6 h before exposing to 25 Gy irradiation; group three as 24 h-group:the group irradiated with LDR pretreatment 24 h before 25 Gy irradiation. The observation was done 6 hour's after irradiation, the effect of LDR pretreatment on increasing activity of the superoxide dismutase(SOD) and the content of malondialdehyde(MDA) after the brain tissue homogenate were detected. Results: Com- pared with the simple group, the group with LDR pretreatment showed increasing of SOD and decreasing of MDA at the 6th hour after 25Gy irradiation. In addition, there was no difference between the 6 h-group and the 24 h-group. Conclusion: LDR pretreatment can increase SOD and decrease MDA in some period. It could infer that the suitable LDR pretreatment could play a protective role in the brain radiation injury. (authors)

  1. Estimation of low-dose radiation-responsive proteins in the absence of genomic instability in normal human fibroblast cells.

    Science.gov (United States)

    Yim, Ji-Hye; Yun, Jung Mi; Kim, Ji Young; Nam, Seon Young; Kim, Cha Soon

    2017-11-01

    Low-dose radiation has various biological effects such as adaptive responses, low-dose hypersensitivity, as well as beneficial effects. However, little is known about the particular proteins involved in these effects. Here, we sought to identify low-dose radiation-responsive phosphoproteins in normal fibroblast cells. We assessed genomic instability and proliferation of fibroblast cells after γ-irradiation by γ-H2AX foci and micronucleus formation analyses and BrdU incorporation assay, respectively. We screened fibroblast cells 8 h after low-dose (0.05 Gy) γ-irradiation using Phospho Explorer Antibody Microarray and validated two differentially expressed phosphoproteins using Western blotting. Cell proliferation proceeded normally in the absence of genomic instability after low-dose γ-irradiation. Phospho antibody microarray analysis and Western blotting revealed increased expression of two phosphoproteins, phospho-NFκB (Ser536) and phospho-P70S6K (Ser418), 8 h after low-dose radiation. Our findings suggest that low-dose radiation of normal fibroblast cells activates the expression of phospho-NFκB (Ser536) and phospho-P70S6K (Ser418) in the absence of genomic instability. Therefore, these proteins may be involved in DNA damage repair processes.

  2. Low dose radiation enhance the anti-tumor effect of high dose radiation on human glioma cell U251

    International Nuclear Information System (INIS)

    Wang Chang; Wang Guanjun; Tan Yehui; Jiang Hongyu; Li Wei

    2008-01-01

    Objective: To detect the effect on the growth of human glioma cell U251 induced by low dose irradiation and low dose irradiation combined with large dose irradiation. Methods: Human glioma cell line U251 and nude mice carried with human glioma were used. The tumor cells and the mice were treated with low dose, high dose, and low dose combined high dose radiation. Cells growth curve, MTT and flow cytometry were used to detect the proliferation, cell cycle and apoptosis of the cells; and the tumor inhibition rate was used to assess the growth of tumor in vivo. Results: After low dose irradiation, there was no difference between experimental group and control group in cell count, MTT and flow cytometry. Single high dose group and low dose combined high dose group both show significantly the suppressing effect on tumor cells, the apoptosis increased and there was cell cycle blocked in G 2 period, but there was no difference between two groups. In vivo apparent anti-tumor effect in high dose radiation group and the combining group was observed, and that was more significant in the combining group; the prior low dose radiation alleviated the injury of hematological system. There was no difference between single low dose radiation group and control. Conclusions: There is no significant effect on human glioma cell induced by low dose radiation, and low dose radiation could not induce adaptive response. But in vivo experience, low dose radiation could enhance the anti-tumor effect of high dose radiation and alleviated the injury of hematological system. (authors)

  3. Effects of low dose radiation on kidney function and morphology of diabetic mice

    International Nuclear Information System (INIS)

    Zhang Chi; Li Xiaokun; Gong Shouliang; Meng Tao; Li Cai; Cai Lu

    2010-01-01

    Objective: To study the effect of low dose radiation (LDR) on the kidney function and morphology in C57BL/6J mice with diabetic nephropathy (DN) induced by streptozotocin (STZ) and illuminate the protective function of LDR on kidney damage caused by diabetes mellitus (DM). Methods: The healthy and right age C57BL/6J mice were divided into 4 groups including control, DM, LDR and DM/LDR. The mice in DM and DM/LDR groups were injected intraperitoneally with STZ to set up DM models. The mice in DM/LDR and LDR groups were irradiated with 25 mGy X-rays every other day for 4 weeks. The changes of blood glucose level, urine index level and the morphology of glomerular were detected at 2, 4, 8, 12, 16 weeks after radiation. Results: The blood glucose levels of mice in DM and DM/LDR groups after STZ-induced DM model preparation were higher than those in LDR and control groups (P<0.05). After treated with LDR for 2 weeks, the blood glucose level in DM/LDR group was supressed and significantly lower than that in DM group (P<0.05). Moreover the the change had been kept to 16 weeks. In addition, compared with DM group, the level of urine micro albumin(MALB) in DM/LDR group was decreased and the urine creatinine (Cre) level was increased. Compared with DM group, the morphological results showed that the glomerular mesangial expansion and mesangial cell proliferation were significantly supressed in DM/LDR group (P<0.05). Conclusion: LDR can promote the decease of blood glucose level efficiently, relief the change of kidney function, supress and delay the pathological changes of DN. (authors)

  4. Low-dose radiation enhances therapeutic HPV DNA vaccination in tumor-bearing hosts.

    Science.gov (United States)

    Tseng, Chih-Wen; Trimble, Cornelia; Zeng, Qi; Monie, Archana; Alvarez, Ronald D; Huh, Warner K; Hoory, Talia; Wang, Mei-Cheng; Hung, Chien-Fu; Wu, T-C

    2009-05-01

    Current therapeutic approaches to treatment of patients with bulky cervical cancer are based on conventional in situ ablative modalities including cisplatin-based chemotherapy and radiation therapy. The 5-year survival of patients with nonresectable disease is dismal. Because over 99% of squamous cervical cancer is caused by persistent infection with an oncogenic strain of human papillomavirus (HPV), particularly type 16 and viral oncoproteins E6 and E7 are functionally required for disease initiation and persistence, HPV-targeted immune strategies present a compelling opportunity in which to demonstrate proof of principle. Sublethal doses of radiation and chemotherapeutic agents have been shown to have synergistic effect in combination with either vaccination against cancer-specific antigens, or with passive transfer of tumor-specific cytotoxic T lymphocytes (CTLs). Here, we explored the combination of low-dose radiation therapy with DNA vaccination with calreticulin (CRT) linked to the mutated form of HPV-16 E7 antigen (E7(detox)), CRT/E7(detox) in the treatment of E7-expressing TC-1 tumors. We observed that TC-1 tumor-bearing mice treated with radiotherapy combined with CRT/E7(detox) DNA vaccination generated significant therapeutic antitumor effects and the highest frequency of E7-specific CD8(+) T cells in the tumors and spleens of treated mice. Furthermore, treatment with radiotherapy was shown to render the TC-1 tumor cells more susceptible to lysis by E7-specific CTLs. In addition, we observed that treatment with radiotherapy during the second DNA vaccination generated the highest frequency of E7-specific CD8(+) T cells in the tumors and spleens of TC-1 tumor-bearing mice. Finally, TC-1 tumor-bearing mice treated with the chemotherapy in combination with radiation and CRT/E7(detox) DNA vaccination generate significantly enhanced therapeutic antitumor effects. The clinical implications of the study are discussed.

  5. Imprinted genes and transpositions: epigenomic targets for low dose radiation effects. Final report

    International Nuclear Information System (INIS)

    Jirtle, Randy L.

    2012-01-01

    The overall hypothesis of this grant application is that low dose ionizing radiation (LDIR) elicits adaptive responses in part by causing heritable DNA methylation changes in the epigenome. This novel postulate was tested by determining if the level of DNA methylation at the Agouti viable yellow (A vy ) metastable locus is altered, in a dose-dependent manner, by low dose radiation exposure ( vy locus in a sex-specific manner (p=0.004). Average DNA methylation was significantly increased in male offspring exposed to doses between 0.7 cGy and 7.6 cGy with maximum effects at 1.4 cGy and 3.0 cGy (p<0.01). Offspring coat color was concomitantly shifted towards pseudoagouti (p<0.01). Maternal dietary antioxidant supplementation mitigated both the DNA methylation changes and coat color shift in the irradiated offspring (p<0.05). Thus, LDIR exposure during gestation elicits epigenetic alterations that lead to positive adaptive phenotypic changes that are negated with antioxidants, indicating they are mediated in part by oxidative stress. These findings provide evidence that in the isogenic Avy mouse model epigenetic alterations resulting from LDIR play a role in radiation hormesis, bringing into question the assumption that every dose of radiation is harmful. Our findings not only have significant implications concerning the mechanism of hormesis, but they also emphasize the potential importance of this phenomenon in determining human risk at low radiation doses. Since the epigenetic regulation of genes varies markedly between species, the effect of LDIR on other epigenetically labile genes (e.g. imprinted genes) in animals and humans needs to be defined

  6. 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)

  7. Identification and Characterization of Soluble Factors Involved in Delayed Effects of Low Dose Radiation. Final report

    International Nuclear Information System (INIS)

    Baulch, Janet

    2013-01-01

    This is a 'glue grant' that was part of a DOE Low Dose project entitled 'Identification and Characterization of Soluble Factors Involved in Delayed Effects of Low Dose Radiation'. This collaborative program has involved Drs. David L. Springer from Pacific Northwest National Laboratory (PNNL), John H. Miller from Washington State University, Tri-cities (WSU) and William F. Morgan then from the University of Maryland, Baltimore (UMB). In July 2008, Dr. Morgan moved to PNNL and Dr. Janet E. Baulch became PI for this project at University of Maryland. In November of 2008, a one year extension with no new funds was requested to complete the proteomic analyses. The project stemmed from studies in the Morgan laboratory demonstrating that genomically unstable cells secret a soluble factor or factors into the culture medium, that cause cytogenetic aberrations and apoptosis in normal parental GM10115 cells. The purpose of this project was to identify the death inducing effect (DIE) factor or factors, estimate their relative abundance, identify the cell signaling pathways involved and finally recapitulate DIE in normal cells by exogenous manipulation of putative DIE factors in culture medium. As reported in detail in the previous progress report, analysis of culture medium from the parental cell line, and stable and unstable clones demonstrated inconsistent proteomic profiles as relate to candidate DIE factors. While the proposed proteomic analyses did not provide information that would allow DIE factors to be identified, the analyses provided another important set of observations. Proteomic analysis suggested that proteins associated with the cellular response to oxidative stress and mitochondrial function were elevated in the medium from unstable clones in a manner consistent with mitochondrial dysfunction. These findings correlate with previous studies of these clones that demonstrated functional differences between the mitochondria of stable and unstable clones. These

  8. Identification and Characterization of Soluble Factors Involved in Delayed Effects of Low Dose Radiation. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Baulch, Janet

    2013-09-11

    This is a 'glue grant' that was part of a DOE Low Dose project entitled 'Identification and Characterization of Soluble Factors Involved in Delayed Effects of Low Dose Radiation'. This collaborative program has involved Drs. David L. Springer from Pacific Northwest National Laboratory (PNNL), John H. Miller from Washington State University, Tri-cities (WSU) and William F. Morgan then from the University of Maryland, Baltimore (UMB). In July 2008, Dr. Morgan moved to PNNL and Dr. Janet E. Baulch became PI for this project at University of Maryland. In November of 2008, a one year extension with no new funds was requested to complete the proteomic analyses. The project stemmed from studies in the Morgan laboratory demonstrating that genomically unstable cells secret a soluble factor or factors into the culture medium, that cause cytogenetic aberrations and apoptosis in normal parental GM10115 cells. The purpose of this project was to identify the death inducing effect (DIE) factor or factors, estimate their relative abundance, identify the cell signaling pathways involved and finally recapitulate DIE in normal cells by exogenous manipulation of putative DIE factors in culture medium. As reported in detail in the previous progress report, analysis of culture medium from the parental cell line, and stable and unstable clones demonstrated inconsistent proteomic profiles as relate to candidate DIE factors. While the proposed proteomic analyses did not provide information that would allow DIE factors to be identified, the analyses provided another important set of observations. Proteomic analysis suggested that proteins associated with the cellular response to oxidative stress and mitochondrial function were elevated in the medium from unstable clones in a manner consistent with mitochondrial dysfunction. These findings correlate with previous studies of these clones that demonstrated functional differences between the mitochondria of stable and

  9. Application of low-dose radiation protocols in survey CT scans

    International Nuclear Information System (INIS)

    Fu Qiang; Liu Ting; Lu Tao; Xu Ke; Zhang Lin

    2009-01-01

    Objective: To characterize the protocols with low-dose radiation in survey CT scans for localization. Methods: Eighty standard adult patients, head and body phantoms were recruited. Default protocols provided by operator's manual setting were that all the tube voltage for head, chest, abdomen and lumbar was 120 kV; the tube currents were 20,10,20 and 40 mA, respectively. Values of kV and mA in the low-dose experiments were optimized according to the device options. For chest and abdomen, the tube position were compared between default (0 degree) and 180 degree. Phantoms were scanned with above protocols, and the radiation doses were measured respectively. Paired t-test were used for comparisons of standard deviation in CT value, noise and exposure surface dose (ESD) between group with default protocols and group with optimized protocols. Results: The optimized protocols in low-dose CT survey scans were 80 kV, 10 mA for head, 80 kV, 10 mA for chest, 80 kV, 10 mA for abdomen and 100 kV, 10 mA for lumbar. The values of ESD for phantom scan in default and optimized protocols were 0.38 mGy/0.16 mGy in head, 0.30 mGy/0.20 mGy in chest, 0.74 mGy/0.30 mGy in abdomen and 0.81 mGy/0.44 mGy in lumbar, respectively. Compared with default protocols, the optimized protocols reduced the radiation doses 59%, 33%, 59% and 46% in head, chest, abdomen and lumbar. When tube position changed from 0 degree to 180 degree, the ESD were 0.24 mGy/0.20 mGy for chest; 0.37 mGy/0.30 mGy for abdomen, and the radiation doses were reduced 20% and 17%. Conclusion: A certain amount of image noise is increased in low-dose protocols, but image quality is still acceptable without problem in CT localization. The reduction of radiation dose and the radiation harm to patients are the superiority. (authors)

  10. What kind of prior low dose radiation does the adaptive response induce?

    International Nuclear Information System (INIS)

    Suzuki, Masao

    2009-01-01

    Described are the adaptive response (AR) and genetic instability (GI) induced by different kind of low dose radiation (LDR) and their relation with the bystander effect. For this, human normal cells were placed at 2.65 m distance from the target of National Institute of Radiological Sciences (NIRS) Heavy Ion Medical Accelerator in Chiba (HIMAC) to see the biological effect of LDR of mixed radiations (1-1.5 mGy/day; mixture of 94% gamma ray, 1.9% neutron (N) and particle ions mainly containing proton (P) in the rest). Cells were then irradiated with 1.5 Gy X-ray. No effect on the lethality was observed as compared with control cells without LDR. The mutation on hprt gene was found significantly elevated 2-30 days after LDR, suggesting that GI had been induced. To see the effect of each radiation on GI, gamma ray ( 137 Cs), N ( 241 Am-Be) and heavy ion (HIMAC He, C and Fe) as LDR were separately irradiated to cells with total 1 mGy/7-8 hr and then acutely with the X-ray. He and C ions were found to promote mutation 1.9 and 4.0 times higher on frequencies, respectively, and N, to reduce the mutation rate to 15% (AR). Results indicated that cell responses were quite different dependently on linear energy transfer. The probability of hit number of ions in the cell population was calculated to be 61, 15 and 2% for He, C and Fe, respectively, suggesting an existence of considerable number of cells not irradiated. Presence of a gap-junction specific inhibitor (GSI) at LDR resulted in normalization of mutation rate in all groups of cells, suggesting that the bystander effect through cell-cell signal transduction affected the cell response to X-irradiation. For AR induction by N, when 1.5% of cells in culture were irradiated by P in NIRS SPICE as LDR, AR in mutation was observed and was inhibited by GSI, suggesting that N completely destroyed the hit cell but concomitantly yielded recoil P substantially acted as LDR. Above findings indicated that the exact radiation risk can

  11. Imprinted genes and transpositions: epigenomic targets for low dose radiation effects. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Jirtle, Randy L.

    2012-10-11

    The overall hypothesis of this grant application is that low dose ionizing radiation (LDIR) elicits adaptive responses in part by causing heritable DNA methylation changes in the epigenome. This novel postulate was tested by determining if the level of DNA methylation at the Agouti viable yellow (A{sup vy}) metastable locus is altered, in a dose-dependent manner, by low dose radiation exposure (<10 cGy) during early gestation. This information is particularly important to ascertain given the increased use of CT scans in disease diagnosis, increased number of people predicted to live and work in space, and the present concern about radiological terrorism. We showed for the first time that LDIR significantly increased DNA methylation at the A{sup vy} locus in a sex-specific manner (p=0.004). Average DNA methylation was significantly increased in male offspring exposed to doses between 0.7 cGy and 7.6 cGy with maximum effects at 1.4 cGy and 3.0 cGy (p<0.01). Offspring coat color was concomitantly shifted towards pseudoagouti (p<0.01). Maternal dietary antioxidant supplementation mitigated both the DNA methylation changes and coat color shift in the irradiated offspring (p<0.05). Thus, LDIR exposure during gestation elicits epigenetic alterations that lead to positive adaptive phenotypic changes that are negated with antioxidants, indicating they are mediated in part by oxidative stress. These findings provide evidence that in the isogenic Avy mouse model epigenetic alterations resulting from LDIR play a role in radiation hormesis, bringing into question the assumption that every dose of radiation is harmful. Our findings not only have significant implications concerning the mechanism of hormesis, but they also emphasize the potential importance of this phenomenon in determining human risk at low radiation doses. Since the epigenetic regulation of genes varies markedly between species, the effect of LDIR on other epigenetically labile genes (e.g. imprinted genes) in

  12. Low dose radiation effects: an integrative european approach (Risc-Rad Project) coordinated by the Cea

    International Nuclear Information System (INIS)

    Sabatier, L.

    2006-01-01

    IR and of the impact of the major defence pathways (DNA repair, cell cycle checkpoints, apoptosis) on radiation induced damage and radiosensitivity. Chromosomal abnormalities and gene mutations induced by IR are thought to be transmitted to future cell generations. The topic of WP2 is to characterize the delayed and epigenetic effects of IR in the progeny of irradiated cells and in non-irradiated neighbourhood. A major challenge is to understand the interplay between cellular ageing and genomic instability in the progeny of irradiated cells. WP3 overall objective is to obtain a more precise description of the temporal sequence of genetic and epigenetic events which underlie radiation carcinogenesis in skin, intestine, bone, lung and the haematopoietic system. Using animal model systems, these studies aim to provide quantitative information on the events leading to radiation induced cancer. In this regard, very early stage pre-neoplastic lesions need to be studied. WP4 aims to provide a biological basis for the inclusion of molecular genetic parameters in models of low dose radiation risk. In order to more accurately reflect the genetic component of risk WP4 has initiated experiments designed to identify the genes that modify individual susceptibility. The work of WP4 is designed to exploit animal models of radiation carcinogenesis as a tool for the discovery of critical modifier genes. Contributing to the project's objectives, WP5 utilizes other WP experimental results to provide models aimed at improving quantitative risk assessment of the effects of low doses. (author)

  13. Nuclear energy and health: and the benefits of low-dose radiation hormesis.

    Science.gov (United States)

    Cuttler, Jerry M; Pollycove, Myron

    2009-01-01

    Energy needs worldwide are expected to increase for the foreseeable future, but fuel supplies are limited. Nuclear reactors could supply much of the energy demand in a safe, sustainable manner were it not for fear of potential releases of radioactivity. Such releases would likely deliver a low dose or dose rate of radiation, within the range of naturally occurring radiation, to which life is already accustomed. The key areas of concern are discussed. Studies of actual health effects, especially thyroid cancers, following exposures are assessed. Radiation hormesis is explained, pointing out that beneficial effects are expected following a low dose or dose rate because protective responses against stresses are stimulated. The notions that no amount of radiation is small enough to be harmless and that a nuclear accident could kill hundreds of thousands are challenged in light of experience: more than a century with radiation and six decades with reactors. If nuclear energy is to play a significant role in meeting future needs, regulatory authorities must examine the scientific evidence and communicate the real health effects of nuclear radiation. Negative images and implications of health risks derived by unscientific extrapolations of harmful effects of high doses must be dispelled.

  14. Mechanisms of Low Dose Radiation-induced T helper Cell Function

    International Nuclear Information System (INIS)

    Gridley, Daila S.

    2008-01-01

    Exposure to radiation above levels normally encountered on Earth can occur during wartime, accidents such as those at Three Mile Island and Chernobyl, and detonation of 'dirty bombs' by terrorists. Relatively high levels of radiation exposure can also occur in certain occupations (low-level waste sites, nuclear power plants, nuclear medicine facilities, airline industry, and space agencies). Depression or dysfunction of the highly radiosensitive cells of the immune system can lead to serious consequences, including increased risk for infections, cancer, hypersensitivity reactions, poor wound healing, and other pathologies. The focus of this research was on the T helper (Th) subset of lymphocytes that secrete cytokines (proteins), and thus control many actions and interactions of other cell types that make up what is collectively known as the immune system. The Department of Energy (DOE) Low Dose Radiation Program is concerned with mechanisms altered by exposure to high energy photons (x- and gamma-rays), protons and electrons. This study compared, for the first time, the low-dose effects of two of these radiation forms, photons and protons, on the response of Th cells, as well as other cell types with which they communicate. The research provided insights regarding gene expression patterns and capacity to secrete potent immunostimulatory and immunosuppressive cytokines, some of which are implicated in pathophysiological processes. Furthermore, the photon versus proton comparison was important not only to healthy individuals who may be exposed, but also to patients undergoing radiotherapy, since many medical centers in the United States, as well as worldwide, are now building proton accelerators. The overall hypothesis of this study was that whole-body exposure to low-dose photons (gamma-rays) will alter CD4+ Th cell function. We further proposed that exposure to low-dose proton radiation will induce a different pattern of gene and functional changes compared to

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

    International Nuclear Information System (INIS)

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

    1993-01-01

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

  16. Reduction in life span on normal human fibroblasts exposed to low-dose radiation in heavy-ion radiation field

    International Nuclear Information System (INIS)

    Suzuki, Masao; Yamaguchi, Chizuru; Yasuda, Hiroshi; Uchihori, Yukio; Fujitaka, Kazunobu

    2003-01-01

    We studied the effect of in vitro life span in normal human fibroblasts exposed to chronically low-dose radiation in heavy-ion radiation field. Cells were cultured in a CO 2 incubator, which was set in the irradiation room for biological study of heavy ions in the Heavy Ion Medical Accelerator in Chiba (HIMAC) at National Institute of Radiological Sciences (NIRS), and exposed to scattered radiations produced with heavy-ion beams throughout the life span of the cell population. Absorbed dose, which was measured using a thermoluminescence dosimeter(TLD) and a Si-semiconductor detector, was to be 1.4 mGy per day when operating the HIMAC machine for biological experiments. The total population doubling number of the exposed cells reduced to 79-93% of non-exposed control cells in the three independent experiments. There is evidence that the exposure of chronically low-dose radiation in heavy-ion radiation field promotes the life-span reduction in cellular level. (author)

  17. The bovine tuberculosis burden in cattle herds in zones with low dose radiation pollution in the Ukraine

    Energy Technology Data Exchange (ETDEWEB)

    Weller, Richard E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Skrypnyk, Artem [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Zavgorodniy, Andriy [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Stegniy, Borys [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Gerilovych, Anton [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Kutsan, Oleksandr [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Pozmogova, Svitlana [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Sapko, Svitlana [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2009-02-01

    The authors describe a study of the tuberculosis (TB) incidence in cattle exposed to low doses of radiation resulting from the Chernobyl (pronounced ‘Chornobyl’ in Ukrainian) nuclear plant catastrophe in 1986. The purpose of the study was to determine if ionising radiation influences the number of outbreaks of bovine TB and their severity on farms in the Kyiv, Cherkasy and Chernigiv regions of the Ukraine. These farms are all located within a 200 km radius of Chernobyl and have had low-dose radiation pollution. Pathological and blood samples were taken from cattle in those regions that had positive TB skin tests. Mycobacterium spp. were isolated, differentiated by PCR, analysed and tested in guinea pigs and rabbits. Species differentiation showed a significant percentage of atypical mycobacteria, which resulted in the allergic reactions to tuberculin antigen in the skin test. Mixed infection of M. bovis and M. avium subsp. hominissuis was found in three cases. The results concluded that low-dose radiation plays a major role in the occurrence of bovine TB in regions affected by the Chernobyl nuclear disaster.

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

    International Nuclear Information System (INIS)

    Zhou Pingkun; Sui Jianli

    2002-01-01

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

  19. Identification of cellular responses to low-dose radiation by antibody array in human B-lymphoblasts IM-9 cells

    Energy Technology Data Exchange (ETDEWEB)

    Eom, Hyeon Soo; Kim, Ji Young; Nam, Seon Young [Low-dose Radiation Research Team, Radiation Health Institute, Korea Hydro and Nuclear Power Co. LTD., Seoul (Korea, Republic of)

    2017-04-15

    The low-dose radiation (LDR)-induced various responses can reduce genetic mutation, enhance cell survival, and increase infection resistance (1). The antibody array for global analysis of phosphorylated proteins might be very useful to study signaling networks of LDR-induced cellular responses (2). Therefore, global analysis of phospho- proteins in cells exposed to radiation is important to understand the signaling mechanisms induced by changes of protein phosphorylation which lead to various biological effects by radiation. The aim is to explore the possibility of LDR-specific signaling for various beneficial effects and elucidate the potential signaling pathways representing LDR responses. Our results suggest that LDR did not affect cell death and that the increased proteins phosphorylation by LDR might be involved in various cellular responses for cell homeostasis. These results might be useful to further studies aimed at investigating potential regulatory markers that represent responses to LDR.

  20. Identification of cellular responses to low-dose radiation by antibody array in human B-lymphoblasts IM-9 cells

    International Nuclear Information System (INIS)

    Eom, Hyeon Soo; Kim, Ji Young; Nam, Seon Young

    2017-01-01

    The low-dose radiation (LDR)-induced various responses can reduce genetic mutation, enhance cell survival, and increase infection resistance (1). The antibody array for global analysis of phosphorylated proteins might be very useful to study signaling networks of LDR-induced cellular responses (2). Therefore, global analysis of phospho- proteins in cells exposed to radiation is important to understand the signaling mechanisms induced by changes of protein phosphorylation which lead to various biological effects by radiation. The aim is to explore the possibility of LDR-specific signaling for various beneficial effects and elucidate the potential signaling pathways representing LDR responses. Our results suggest that LDR did not affect cell death and that the increased proteins phosphorylation by LDR might be involved in various cellular responses for cell homeostasis. These results might be useful to further studies aimed at investigating potential regulatory markers that represent responses to LDR

  1. [Complex pathogenetic treatment schemes of vascular dyscirculatory disorders in the remote period after exposure to low dose radiation].

    Science.gov (United States)

    Holodova, N B; Zhavoronkova, L A; Ryzhov, B N

    2013-01-01

    Complex studies including modern methods of investigation of structures and functions of nervous system: electroencephalograsphy (EEG), coherent analysis, neuropsychological study and methods of neuroimaging were performed in 517 participants in liquidation of consequences of the accident (LCA) at the Chernobyl NPP in 1986-1987. Dyscirculatory metabolic encephalopathy was revealed to be the main pathology with the etiological mechanism based on dyscirculatorhypoxic and metabolic disorders. Complexity of the revealed symptoms testified to an early organism aging in remote periods after exposure to low dose radiation. Pathogenetic schemes were developed for treatment of dyscirculatory encephalopathy in liquidators, which include drugs improving blood supply, antiaggregants, antioxidants and metabolites of the brains in various combinations. Taking into consideration that early appearance of vascular dyscirculatory disorders observed in liquidators is the sign of early aging of the organism, geroprotectors were added to treatment schemes.

  2. Cytogenetic effects of cardioangiography on blood lymphocytes in children and in vitro effects of contrast medium and low dose radiation

    International Nuclear Information System (INIS)

    Nikula, E.; Kiviniitty, K.

    1987-01-01

    Structural chromosome aberrations were analysed in the peripheral blood lymphocytes of 15 children, aged 1 to 13 years, before, immediately after, 24 hours after and 6 to 8 months after cardioangiographic examination. Statistically significant increases were only demonstrated in the frequency of gaps and, consequently, in the frequency of aberrant cells immediately after cardioangiography. Most of the chromosome damage clearly disappeared within 24 hours. In addition, whole blood cultures were exposed in vitro to low dose radiation, a contrast medium, and radiation together with the contrast medium. No statistically significant differences could be observed in the chromosome aberration frequencies. It was concluded that the modern radiographic procedure, which uses very low radiation doses and less contrast medium, does not cause a consistent, permanent increase of chromosomal damage in the lymphocytes of children. However, the situation may be different if the child undergoes many radiography examinations or the radiation doses are high. (orig./MG)

  3. Health effects of low-dose radiation on atomic workers: a case study of employer-directed research

    International Nuclear Information System (INIS)

    Sterling, T.D.

    1980-01-01

    The 15-year history of a study on the health effects of low-dose radiation on workers at the Hanford Atomic Plant in Washington State demonstrates different facets of political control by employers over investigations of employee working conditions. Evidence obtained through the Freedom of Information Act shows that the original study, under the guidance of Dr. Thomas Mancuso, an experienced and respected occupational health epidemiologist, was proof to employees that their exposure levels were safe. When it turned out that the study might show an increase in cancer rates among plant employees, its control was transferred to the employer. Lessons from these events are that it may be necessary for organized labor to negotiate the conduct of occupational health investigations as part of negotiated settlements

  4. Low-Dose Radiation Activates Akt and Nrf2 in the Kidney of Diabetic Mice: A Potential Mechanism to Prevent Diabetic Nephropathy

    Directory of Open Access Journals (Sweden)

    Xiao Xing

    2012-01-01

    Full Text Available Repetitive exposure of diabetic mice to low-dose radiation (LDR at 25 mGy could significantly attenuate diabetes-induced renal inflammation, oxidative damage, remodeling, and dysfunction, for which, however, the underlying mechanism remained unknown. The present study explored the effects of LDR on the expression and function of Akt and Nrf2 in the kidney of diabetic mice. C57BL/6J mice were used to induce type 1 diabetes with multiple low-dose streptozotocin. Diabetic and age-matched control mice were irradiated with whole body X-rays at either single 25 mGy and 75 mGy or accumulated 75 mGy (25 mGy daily for 3 days and then sacrificed at 1–12 h for examining renal Akt phosphorylation and Nrf2 expression and function. We found that 75 mGy of X-rays can stimulate Akt signaling pathway and upregulate Nrf2 expression and function in diabetic kidneys; single exposure of 25 mGy did not, but three exposures to 25 mGy of X-rays could offer a similar effect as single exposure to 75 mGy on the stimulation of Akt phosphorylation and the upregulation of Nrf2 expression and transcription function. These results suggest that single 75 mGy or multiple 25 mGy of X-rays can stimulate Akt phosphorylation and upregulate Nrf2 expression and function, which may explain the prevention of LDR against the diabetic nephropathy mentioned above.

  5. A Systems Genetic Approach to Identify Low Dose Radiation-Induced Lymphoma Susceptibility/DOE2013FinalReport

    Energy Technology Data Exchange (ETDEWEB)

    Balmain, Allan [University of California, San Francisco; Song, Ihn Young [University of California, San Francisco

    2013-05-15

    The ultimate goal of this project is to identify the combinations of genetic variants that confer an individual's susceptibility to the effects of low dose (0.1 Gy) gamma-radiation, in particular with regard to tumor development. In contrast to the known effects of high dose radiation in cancer induction, the responses to low dose radiation (defined as 0.1 Gy or less) are much less well understood, and have been proposed to involve a protective anti-tumor effect in some in vivo scientific models. These conflicting results confound attempts to develop predictive models of the risk of exposure to low dose radiation, particularly when combined with the strong effects of inherited genetic variants on both radiation effects and cancer susceptibility. We have used a Systems Genetics approach in mice that combines genetic background analysis with responses to low and high dose radiation, in order to develop insights that will allow us to reconcile these disparate observations. Using this comprehensive approach we have analyzed normal tissue gene expression (in this case the skin and thymus), together with the changes that take place in this gene expression architecture a) in response to low or high- dose radiation and b) during tumor development. Additionally, we have demonstrated that using our expression analysis approach in our genetically heterogeneous/defined radiation-induced tumor mouse models can uniquely identify genes and pathways relevant to human T-ALL, and uncover interactions between common genetic variants of genes which may lead to tumor susceptibility.

  6. What physicians think about the need for informed consent for communicating the risk of cancer from low-dose radiation

    International Nuclear Information System (INIS)

    Karsli, Tijen; Kalra, Mannudeep K.; Self, Julie L.; Rosenfeld, Jason Anders; Butler, Susan; Simoneaux, Stephen

    2009-01-01

    The National Institute of Environmental Health Sciences, a subsidiary of the Food and Drug Administration, has declared that X-ray radiation at low doses is a human carcinogen. The purpose of our study was to determine if informed consent should be obtained for communicating the risk of radiation-induced cancer from radiation-based imaging. Institutional review board approval was obtained for the prospective survey of 456 physicians affiliated with three tertiary hospitals by means of a written questionnaire. Physicians were asked to state their subspecialty, number of years in practice, frequency of referral for CT scanning, level of awareness about the risk of radiation-induced cancer associated with CT, knowledge of whether such information is provided to patients undergoing CT, and opinions about the need for obtaining informed consent as well as who should provide information about the radiation-induced cancer risk to patients. Physicians were also asked to specify their preference among different formats of informed consent for communicating the potential risk of radiation-induced cancer. Statistical analyses were performed using the chi-squared test. Most physicians stated that informed consent should be obtained from patients undergoing radiation-based imaging (71.3%, 325/456) and the radiology department should provide information about the risk of radiation-induced cancer to these patients (54.6%, 249/456). The informed consent format that most physicians agreed with included modifications to the National Institute of Environmental Health Services report on cancer risk from low-dose radiation (20.2%, 92/456) or included information on the risk of cancer from background radiation compared to that from low-dose radiation (39.5%, 180/456). Most physicians do not know if patients are informed about cancer risk from radiation-based imaging in their institutions. However, they believe that informed consent for communicating the risk of radiation-induced cancer

  7. Application of low dose radiation and low concentration contrast media in enhanced CT scans in children with congenital heart disease.

    Science.gov (United States)

    Liu, Zhimin; Song, Lei; Yu, Tong; Gao, Jun; Zhang, Qifeng; Jiang, Ling; Liu, Yong; Peng, Yun

    2016-09-01

    The aim of this study was to explore the feasibility of using low dose radiation and low concentration contrast media in enhanced CT examinations in children with congenital heart disease. Ninety patients with congenital heart disease were randomly divided into three groups of 30 patients each who underwent contrast-enhanced cardiac scans on a Discovery CT750 HD scanner. Group A received 270 mg I/mL iodixanol, and group B received 320 mg I/mL iodixanol contrast media and was scanned with prospective ECG triggering mode. Group C received 320 mg I/mL iodixanol and was scanned with conventional retrospective ECG gating mode. The same weight-based contrast injection protocol was used for all three groups. Images were reconstructed using a 30% adaptive statistical iterative reconstruction (ASIR) algorithm and a 50% ASIR in groups A and B and a 30% ASIR in group C. The subjective and objective image quality evaluations, diagnostic accuracies, radiation doses and amounts of contrast media in the three groups were measured and compared. All images in the three groups met the diagnostic requirements, with the same diagnostic accuracy and image quality scores greater than 3 in a 4-point scoring system. However, ventricular enhancement and the objective noise, signal-to-noise ratio, contrast-to-noise ratio and subjective image quality scores in group C were better than those in groups A and B (all Pcontrast dose (14% lower than that of groups B and C). Enhanced CT scan images with low dose radiation and low concentration contrast media can meet the diagnostic requirements for examining children with congenital heart disease while reducing the potential risk of radiation damage and contrast-induced nephropathy. © 2016 John Wiley & Sons Ltd.

  8. Changes of mitochondrial structure, ATPase and Ca2+ concentration in spermatogenic cells of mouse testes induced by low dose radiation

    International Nuclear Information System (INIS)

    Wang Zhicheng; Liu Shuchun; Li Pengwu; Kang Shunai; Liang Shuo; Zhao Gang; Gong Shouliang

    2009-01-01

    Objective: To observe the ultrastructure, ATPase activity and Ca 2+ concentration ([Ca 2+ ]i) of mitochondria in the sperematogenic cells of mouse testes 3-24 h after low dose radiation with 0.025-0.200 Gy X-rays, and illuminate the effects of mitochondrion structure and relative biological function on apoptosis. Methods: The ultrastructure changes of mitochondria in the spermatogenic cells were observed with transmission electron microscope; the ATPase activity was measured with protein enzymic method; [Ca 2+ ]i was measured indirectly by flow cytometry with Fluo-3 probes. Results: The mitochondria swelled and vacuolizated, and their cristae were broken in the spermatogonia and spermatocytes 12 h after irradiation, and their nuclei were karyopyknosis, the acrosomal vesicle structure was ambiguity, the membrane structure was unclear, and the mitochondria in spermatids were vacuolization. The activities of Na + -K + -ATPase in mouse testis tissue 12 h after irradiated with 0.025-0.200 Gy decreased compared with those with 0 Gy, the Na + -K + -ATPase activities of the cells irradiated with 0.05-0.200 Gy decreased significantly compared with those with 0 Gy (P 2+ -ATPase of the cells irradiated with 0.025-0.200 Gy decreased significantly compared with those with 0 Gy (P 2+ ]i in mouse testis spermatogenic cells had similar dose-response relationship, [Ca 2+ ]i after irradiated with 0.075 Gy decreased compared with those with 0 Gy (P + -K + -ATPase in mouse testis tissues decreased obviously compared with those at 0 h (P 2+ -ATPase in mouse testis tissues increased slightly at 3 h, then decreased at 6-24 h compared with those at 0 h (P 2+ ]i in mouse testis spermatogenic cells had similar time course-response relationship, [Ca 2+ ]i at 12 h decreased significantly compared with at 0 h (P 2+ ]i induced by low dose radiation. (authors)

  9. Exposure to low-dose radiation and the risk of breast cancer among women with a familial or genetic predisposition: a meta-analysis

    International Nuclear Information System (INIS)

    Jansen-van der Weide, Marijke C.; Greuter, Marcel J.W.; Pijnappel, Ruud M.; Jansen, Liesbeth; Oosterwijk, Jan C.; Bock, Geertruida H. de

    2010-01-01

    Women with familial or genetic aggregation of breast cancer are offered screening outside the population screening programme. However, the possible benefit of mammography screening could be reduced due to the risk of radiation-induced tumours. A systematic search was conducted addressing the question of how low-dose radiation exposure affects breast cancer risk among high-risk women. A systematic search was conducted for articles addressing breast cancer, mammography screening, radiation and high-risk women. Effects of low-dose radiation on breast cancer risk were presented in terms of pooled odds ratios (OR). Of 127 articles found, 7 were selected for the meta-analysis. Pooled OR revealed an increased risk of breast cancer among high-risk women due to low-dose radiation exposure (OR = 1.3, 95% CI: 0.9- 1.8). Exposure before age 20 (OR = 2.0, 95% CI: 1.3-3.1) or a mean of ≥5 exposures (OR = 1.8, 95% CI: 1.1-3.0) was significantly associated with a higher radiation-induced breast cancer risk. Low-dose radiation increases breast cancer risk among high-risk women. When using low-dose radiation among high-risk women, a careful approach is needed, by means of reducing repeated exposure, avoidance of exposure at a younger age and using non-ionising screening techniques. (orig.)

  10. Delayed immunologic effects of low dose radiation in Japanese A-bomb survivors. Technical progress report

    International Nuclear Information System (INIS)

    Makinodan, Takashi.

    1985-01-01

    Samples collected from 832 A-bomb survivors were analyzed for natural killer activity, interleukin production, interferon production, serum interferon levels, and circulating immune complex levels. The most striking finding was a significant radiation-sex interaction for NK activity. The NK of females exposed to 100+ rads was decreased compared to those exposed to 0 to 99 rads. A significant increase in NK activity with age ATB was observed, as well as an increase with age in circulating immune complex

  11. Effect of Low Dose Radiation Upon Antioxidant Parameters in Skeletal Muscle of Chick Embryo

    International Nuclear Information System (INIS)

    Vilic, M.; Pirsljin, J.; Beer Ljubic, B.; Miljanic, S.; Kraljevic, P.

    2008-01-01

    In this paper an attempt was made to determine the effect of irradiation of eggs with low dose ionizing radiation upon lipid peroxide (TBARS) level, glutathione (GSH) level, activity of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and catalase (CAT) in skeletal muscle of chick embryo and newly hatched chicks. The eggs of a heavy breeding chickens were irradiated with a dose of 0.3 Gy gamma radiation (60Co source) on the 19th day of incubation. Along with the irradiated chick embryos, there was a control group of non-irradiated chick embryos. The antioxidant parameters were measured in breast muscle (m. pectoralis superficialis) and thigh muscle (m. biceps femoris) of chick embryos on 1, 3, 6, 24 and 72 h after egg irradiation. All parameters were determined spectrophotometrically. Lipid peroxidation, GSH level and CAT activity decreased in the breast and thigh muscle of chick embryos on the first hour after irradiation, while the activity of GSH-Px increased in the thigh muscle on the 1st hour after irradiation. CAT activity decreased in the breast muscle of chick embryos on the hour 24 after irradiation. The GSH level increased in the breast and thigh muscle of chick embryos on the hour 72 after irradiation while the activity of GSH-Px increased in the breast muscle. At the same time CAT activity decreased in breast muscle while lipid peroxidation decreased in thigh muscle. The obtained results showed that acute irradiation of chicken eggs on the 19th day of incubation with the dose of 0.3 Gy gamma radiation could be an oxidative stress in both types of muscles immediately after irradiation. However, at the one-day old chicks (72 hours after irradiation) this dose could have a stimulating effect upon GSH level in both breast and thigh muscle.(author)

  12. Low dose radiation in the treatment of HIV related benign lymphoepithelial lesions of the parotid gland

    International Nuclear Information System (INIS)

    Tchelebi, Anca E.; Ming Teng; Moscatello, Augustine; Moorthy, Chitti R.; Kaufmann, Thomas; Ahmed, Tauseef

    1996-01-01

    Purpose/Objective: To determine the effectiveness of Radiation Therapy (RT) in the treatment of human immunodeficiency virus (HIV) related benign lymphoepithelial (BLL) of the parotid gland. Materials and Methods: The records of 16 patients treated between 1991 to 1995 with BLL were retrospectively reviewed. Three patients had bilateral disease, thus 19 parotid glands were radiated. Only (2(16)) had AIDS. Virtually all patients were on antiretroviral therapy. There were 11 males and 5 females. The median age was 38 years (range 31 to 58 years). The median duration of parotid enlargement was 1.5 years (range 1 month to 6 years). All patients had biopsy prior to treatment. Histopathology revealed two patterns: solid or cystic. Patient were treated using electron beam RT. The beam energy was determined by computed transaxial tomography. The median dose delivered was 1000 cGy in 5 fractions over 5 days (range 600 cGy to 2160 cGy in daily fractions ranging from 180 cGy to 200 cGy). Results: Six parotid glands achieved a complete response (CR), 5 a partial response (PR), while 8 were non-responders (NR). Our overall response rate was therefore 58% Of the NR's, 3 patients were re-treated. Two achieved a PR, one was an NR. Toxicity was minimal and limited to mild xerostomia. Conclusion: RT in patients with HIV related BLL is well tolerated. Our preliminary results show that while this modality of treatment has marked activity in the solid pattern. Higher doses may be required for large lesions or cystic in nature

  13. Local superficial hyperthermia in combination with low-dose radiation therapy for palliation of superficially localized metastases

    International Nuclear Information System (INIS)

    Owczarek, G.; Miszczyk, L.

    2005-01-01

    Full text: The aim of this study is to evaluate the response of superficially located metastases and local toxicity to microwave hyperthermia combined with radiation therapy. From May 2003 through December 2004 58 patients (33 male, 25 female; mean age 60 years) with lymph nodes or skin metastases were treated with microwave superficial hyperthermia combined with low-dose radiation therapy. Hyperthermia was administered twice weekly with high frequency applicator (∼900 Mhz) with water bolus. The temperature was set to 43 o C for 45 minutes. Radiotherapy was performed daily with dose 2 Gy or 4 Gy per fraction, to a total dose 20 Gy. There were 47 patients with carcinoma, 4 with sarcoma, 7 with melanoma. Treated regions were: head and neck (37 patients), chest wall 8, abdomen wall and groins 4, upper and lower limb 2 and 8 patients respectively. Primary tumor sites were: head and neck region (9 patients), lung 15, alimentary tract 8, breast 5, soft tissue 8, urogenital 4 and 9 patients with primary tumor site unknown. The toxicity was evaluated using 6 step scale: 0-no skin reaction, 1-faint red mark, 2-distinct red mark, 3-blisters, 4-brown mark, 5-necrosis. Presence of pain and its intensity were also analyzed. Diameter of tumor after the treatment was observed. Complete response was achieved in 5 patients (8.5 %), and partial response in 29 patients (50 %), no response was observed in 12 patients (20 %) and progression of tumor in 7 patients (12 %). No skin reaction was observed in 3 patients, faint red mark in 14 patients, distinct red mark in 28 patients, blisters in 8 patients, brown mark in 4 patients and necrosis in 1 patient. The pain occurred in 9 patients but it was no the cause of stopping treatment. Local superficial hyperthermia combined with low-dose radiation therapy is an effective method of treatment in a proportion of patients with superficial metastases. This combination of treatment modalities is well tolerated and is useful for palliation

  14. Quantitative and informatics tools for studying the effect of low dose radiation on tissue and cell culture

    International Nuclear Information System (INIS)

    Parvin, B.; Yang, Q.; Fontenay, G.; Barcellos-Hoff, M.H.

    2003-01-01

    Full text: The challenge of the post-genomic era is functional genomics, i.e., understanding how the genome is expressed to produce myriad cell phenotypes. To use genomic information to understand the biology of complex organisms, one must understand the dynamics of phenotype generation and maintenance. A phenotype is the result of selective expression of the genome. In order to define cell 'phenomes,' one would track the kinetics and quantities of multiple constituent proteins, their cellular context and morphological features in large populations. Our aim is to extend the development of the BioSig imaging bioinformatics system for understanding how ionizing radiation alters tissue homeostasis and responses in cell culture experiments. Given several thousand antibodies and reagents for differentiating cell-specific protein components, biological heterogeneity, and other variables that affect cellular responses, there is a clear requirements for managing images and information about these images. Our focus is on the development of (1) quantitative methods for protein expression either in tissue or cell culture studies, (2) a adequate data model that couples quantitative results with the experimental variables, and (3) browsing and visualization tools that enable exploration of large scale image data in feature space in the context of biological heterogeneity. The framework provides the basis for studying the effect of low-dose radiation on the cellular microenvironment, inter-cell communication, and the underlying mechanisms. In turn, this information can then be used to more accurately predict more complex multicellular biological responses following exposure to different types of inhibitors. The BioSig informatics approach to microscopy and quantitative image analysis has been used to build a more detailed picture of the signaling that occurs between cells, as a result of an exogenous stimulus such as radiation, or as a consequence of endogenous programs leading

  15. Effect of low dose radiation on cytochrome c and caspase-3 protein expressions in spermatogenic cells of mouse testis

    International Nuclear Information System (INIS)

    Wang Zhicheng; Zhao Hongguang; Piao Chunnan; Liu Guangwei; Liu Shuchun; Lv Zhe; Gong Shouliang

    2006-01-01

    Objective: To investigate the effect of low dose radiation on the expressions of cytochrome e (Cyt c) and caspase-3 proteins in spermatogenic cells of mouse testis. Methods: The relationships of dose- and time-effect of Cyt c and caspase-3 protein expressions with different dose of X-rays were observed in the spermatogenic cells of mouse testis with immunohistochemical technique (SABC). Results: After irradiation with 0, 0.025, 0.05, 0.075, 0.1 and 0.2 Gy, Cyt c and caspase-3 proteins expressed differently in all kinds of spermatogenic cells, and principally in spermatogonia and spermatocytes, and less in spermatids and spermatozoa. And the expressions increased with the increasing of irradiation dose. The expressions of both proteins after irradiation with 0.075 Gy increased with the lapse of time and reached to the peak at 12 h, and then decreased. Conclusion: Dose-and time-effect exists on the low-dose irradiation induced expressions of Cyt e and caspase-3 proteins in spermatogenic cells of mouse testis. (authors)

  16. Role of changes in functional status of hypothalamic-pituitary-adrenocortical axis in immunoenhancement after low dose radiation

    International Nuclear Information System (INIS)

    Liu Shuzheng; Zhao Yong; Han Zhenbo

    1994-01-01

    Whole-body irradiation (WBI) of mice with 75 mGy X-rays caused increase in 5-hydroxytryptamine (5HT) content of hypothalamus and decrease in serum adrenocorticotropic hormone (ACTH) and corticosterone (CS) level, accompanied with potentiation of immune functions, expressed as increased spontaneous incorporation of 3 H-TdR into thymocytes, augmented proliferative reaction of the splenocytes to Con A and increased production of interleukin-2 by the splenocytes. After intra hypothalamic injection of 5HT there occurred a lowering of serum ACTH level and enhancement of immune reactivity of the splenic and thymic lymphocytes. It is assumed that low dose radiation could influence the central 5-hydroxytryptaminergic neurons causing increase in hypothalamic 5HT content and this, in turn, decreases pituitary secretion of ACTH with a down-regulation of the adrenocortical function. This would partially release the tonic suppression normally exerted on the immune organs by the hypothalamic-pituitary-adrenocortical axis, thus leading to potentiation of immune functions. These neuroendocrine changes should be considered as an important factor in the analysis of the mechanism of immunoenhancement after WBI with low doses

  17. Effect of Bcl-2/Bax gene expression on apoptosis of spermatogenic cells of mouse testes induced by low dose radiation

    International Nuclear Information System (INIS)

    Liu Guangwei; Wang Chunyan; Lu Zhe; Liu Shunchun; Gong Shouliang

    2003-01-01

    The different kinds of spermatogenic cells were separated using density gradient centrifugation and their apoptosis and Bcl-2 and Bax protein expression were measured with flow cytometry and immunohistochemical method, respectively. The results showed the apoptosis in all kinds of spermatogenic cells induced by low dose radiation (LDR) had a obvious regularity. When the doses were 0.025 and 0.05 Gy, spermatogonia apoptosis was dominant. With the increase of irradiation dose (0.075-0.2 Gy), spermatocytes also showed an apoptotic change, but the apoptotic percentage of spermatogonia was significantly higher than that of spermatocytes. Moreover, the apoptosis of spermatids and spermatozoa scarcely occurred after LDR. Bax protein was primarily expressed in spermatogonia and spermatocytes, and the former was significantly higher than that of the latter after LDR. With the increase of irradiation dose, Bax protein expression showed a upgrading tendency, but that of spermatids and spermatozoa scarcely occurred. Bcl-2 protein was primarily expressed in spermatids and spermatozoa, but the Bcl-2 protein expressions of spermatogonia and spermatocytes scarcely occurred after LDR. These results imply that the interacting regulation of Bcl-2 and Bax gene expression might be involved in selective apoptosis of spermatogenic cells induced by LDR, which provided an experimental evidence for further exploring the apoptotic mechanism of adaptive response of spermatogenic cells by LDR

  18. Effects of multiple low dose radiation on spleen T lymphocyte subgroups in eight-week diabetic rats

    International Nuclear Information System (INIS)

    Guan Feng; Li Yanbo; Zhao Hongguang; Guo Wei; Wang Zhicheng; Gong Shouliang; Guo Caixia

    2008-01-01

    Objective: To explore the changes of spleen lymphocyte subgroups in diabetic rats after multiple low dose radiation (LDR). Methods: The experiment was divided into normal control group, pure diabetes mellitus (DM) group, and DM plus different doses of irradiation groups (the irradiation doses were 0.025, 0.050 and 0.075 Gy, respectively). The diabetic rat model was induced by intraperitoneal injection of streptozotocin. After the diabetic rats were irradiated 15 times, the percentages of spleen CD4 + and CD8 + T cells and ratio of CD4 + /CD8 + T cells were detected with flow cytometry on the fourth weekend. Results: The diabetic rats manifested obvious polydipsia, polyphagia, polyuria and weight loss. On the fourth weekend after irradiation, as compared with normal control group, the percentage of spleen CD4 + T cells increased significantly (P + T cells decreased significantly (P + /CD8 + T cells was increased significantly (P + T cells were declined markedly in both 0.050 and 0.075 Gy plus DM groups (P + T cells increased significantly in LDR plus DM groups (P + /CD8 + T cells was declined obviously (P<0.01). Conclusion: The multiple LDR could regulate the immune function in diabetic rats, and rectificate the immunological imbalance in order to protect body. (authors)

  19. Validating the pivotal role of the immune system in low-dose radiation-induced tumor inhibition in Lewis lung cancer-bearing mice.

    Science.gov (United States)

    Zhou, Lei; Zhang, Xiaoying; Li, Hui; Niu, Chao; Yu, Dehai; Yang, Guozi; Liang, Xinyue; Wen, Xue; Li, Min; Cui, Jiuwei

    2018-04-01

    Although low-dose radiation (LDR) possesses the two distinct functions of inducing hormesis and adaptive responses, which result in immune enhancement and tumor inhibition, its clinical applications have not yet been elucidated. The major obstacle that hinders the application of LDR in the clinical setting is that the mechanisms underlying induction of tumor inhibition are unclear, and the risks associated with LDR are still unknown. Thus, to overcome this obstacle and elucidate the mechanisms mediating the antitumor effects of LDR, in this study, we established an in vivo lung cancer model to investigate the participation of the immune system in LDR-induced tumor inhibition and validated the pivotal role of the immune system by impairing immunity with high-dose radiation (HDR) of 1 Gy. Additionally, the LDR-induced adaptive response of the immune system was also observed by sequential HDR treatment in this mouse model. We found that LDR-activated T cells and natural killer cells and increased the cytotoxicity of splenocytes and the infiltration of T cells in the tumor tissues. In contrast, when immune function was impaired by HDR pretreatment, LDR could not induce tumor inhibition. However, when LDR was administered before HDR, the immunity could be protected from impairment, and tumor growth could be inhibited to some extent, indicating the induction of the immune adaptive response by LDR. Therefore, we demonstrated that immune enhancement played a key role in LDR-induced tumor inhibition. These findings emphasized the importance of the immune response in tumor radiotherapy and may help promote the application of LDR as a novel approach in clinical practice. © 2018 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.

  20. In vivo sensitivity of the embryonic and adult neural stem cell compartments to low-dose radiation

    International Nuclear Information System (INIS)

    Barazzuol, Lara; Jeggo, Penny A.

    2016-01-01

    The embryonic brain is radiation-sensitive, with cognitive deficits being observed after exposure to low radiation doses. Exposure of neonates to radiation can cause intracranial carcinogenesis. To gain insight into the basis underlying these outcomes, we examined the response of the embryonic, neonatal and adult brain to low-dose radiation, focusing on the neural stem cell compartments. This review summarizes our recent findings. At E13.5–14.5 the embryonic neocortex encompasses rapidly proliferating stem and progenitor cells. Exploiting mice with a hypomorphic mutation in DNA ligase IV (Lig4 Y288C ), we found a high level of DNA double-strand breaks (DSBs) at E14.5, which we attribute to the rapid proliferation. We observed endogenous apoptosis in Lig4 Y288C embryos and in WT embryos following exposure to low radiation doses. An examination of DSB levels and apoptosis in adult neural stem cell compartments, the subventricular zone (SVZ) and the subgranular zone (SGZ) revealed low DSB levels in Lig4 Y288C mice, comparable with the levels in differentiated neuronal tissues. We conclude that the adult SVZ does not incur high levels of DNA breakage, but sensitively activates apoptosis; apoptosis was less sensitively activated in the SGZ, and differentiated neuronal tissues did not activate apoptosis. P5/P15 mice showed intermediate DSB levels, suggesting that DSBs generated in the embryo can be transmitted to neonates and undergo slow repair. Interestingly, this analysis revealed a stage of high endogenous apoptosis in the neonatal SVZ. Collectively, these studies reveal that the adult neural stem cell compartment, like the embryonic counterpart, can sensitively activate apoptosis

  1. In vivo sensitivity of the embryonic and adult neural stem cell compartments to low-dose radiation.

    Science.gov (United States)

    Barazzuol, Lara; Jeggo, Penny A

    2016-08-01

    The embryonic brain is radiation-sensitive, with cognitive deficits being observed after exposure to low radiation doses. Exposure of neonates to radiation can cause intracranial carcinogenesis. To gain insight into the basis underlying these outcomes, we examined the response of the embryonic, neonatal and adult brain to low-dose radiation, focusing on the neural stem cell compartments. This review summarizes our recent findings. At E13.5-14.5 the embryonic neocortex encompasses rapidly proliferating stem and progenitor cells. Exploiting mice with a hypomorphic mutation in DNA ligase IV (Lig4(Y288C) ), we found a high level of DNA double-strand breaks (DSBs) at E14.5, which we attribute to the rapid proliferation. We observed endogenous apoptosis in Lig4(Y288C) embryos and in WT embryos following exposure to low radiation doses. An examination of DSB levels and apoptosis in adult neural stem cell compartments, the subventricular zone (SVZ) and the subgranular zone (SGZ) revealed low DSB levels in Lig4(Y288C) mice, comparable with the levels in differentiated neuronal tissues. We conclude that the adult SVZ does not incur high levels of DNA breakage, but sensitively activates apoptosis; apoptosis was less sensitively activated in the SGZ, and differentiated neuronal tissues did not activate apoptosis. P5/P15 mice showed intermediate DSB levels, suggesting that DSBs generated in the embryo can be transmitted to neonates and undergo slow repair. Interestingly, this analysis revealed a stage of high endogenous apoptosis in the neonatal SVZ. Collectively, these studies reveal that the adult neural stem cell compartment, like the embryonic counterpart, can sensitively activate apoptosis. © The Author 2016. Published by Oxford University Press on behalf of The Japan Radiation Research Society and Japanese Society for Radiation Oncology.

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

    Science.gov (United States)

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

    2018-04-01

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

  3. Effects of multiple low dose radiation on the apoptosis of splenocytes and immune factor in male diabetic rats

    International Nuclear Information System (INIS)

    Li Yanbo; Guo Caixia; Dong Lihua; Wang Jianfeng; Liu Shuchun; Lu Zhe; Gong Shouliang

    2009-01-01

    Objective: To explore the effect of multiple low dose radiation (LDR) on the apoptosis of splenocytes and immune factors in diabetes mellitus (DM) rats. Methods: The rats were randomly divided into control, DM and DM + LDR groups. The irradiation doses were 25, 50 and 75 mGy, and the irradiated times were 15. At the fourth weekend after the DM rats irradiated, the apoptotic rate and TCRαβ percentage of splenocytes were detected by flow cytometry, and the content of IL-2 in both serum and supernatant of cultured splenocytes were detected by ELISA. Results: Compared with that in the control, the body weight (BW) decreased in the DM and DM + LDR groups,particularly in DM group. The blood glucose (BG) level in the DM + LDR groups was higher than that in the control, but decreased significantly as compared with that in the DM group (P < 0.01). As compared with those in the control, the apoptotic rate in DM + 50 mGy (P < 0.05) and the content of serum IL-2 in DM + 75 mGy group (P < 0.01) all increased significantly, while the content of IL-2 in supernatant of cultured splenocytes decreased significantly in the DM + LDR groups. Compared with those in the DM group, the apoptotic rate and the percentage of TCRαβ in splenocytes in the DM + LDR groups (P < 0.01-P < 0.001) and the content of IL-2 in serum in DM + 50 mGy group (P < 0.01) decreased significantly. Conclusions: The multiple LDR could weaken the loss of BW and increase of BG caused by DM, decrease the splenocyte apoptosis induced by DM, and regulate the immune factors. (authors)

  4. Potential pre-cataractous markers induced by low-dose radiation effects in cultured human lens cells

    Science.gov (United States)

    Blakely, E.; McNamara, M.; Bjornstad, K.; Chang, P.

    The human lens is one of the most radiosensitive organs of the body. Cataract, the opacification of the lens, is a late-appearing response to radiation damage. Recent evidence indicates that exposure to relatively low doses of space radiation are associated with an increased incidence and early appearance of human cataracts (Cucinotta et al., Radiat. Res. 156:460-466, 2001). Basic research in this area is needed to integrate the early responses of various late-responding tissues into our understanding and estimation of radiation risk for space travel. In addition, these studies may contribute to the development of countermeasures for the early lenticular changes, in order to prevent the late sequelae. Radiation damage to the lens is not life threatening but, if severe, can affect vision unless surgically corrected with synthetic lens replacement. The lens, however, may be a sensitive detector of radiation effects for other cells of ectodermal origin in the body for which there are not currently clear endpoints of low-dose radiation effects. We have investigated the dose-dependent expression of several radiation-responsive endpoints using our in vitro model of differentiating human lens epithelial cells (Blakely et al., Investigative Ophthalmology &Visual Sciences, 41(12):3898-3907, 2000). We have investigated radiation effects on several gene families that include, or relate to, DNA damage, cytokines, cell-cycle regulators, cell adhesion molecules, cell cytoskeletal function and apoptotic cell death. In this paper we will summarize some of our dose-dependent data from several radiation types, and describe the model of molecular and cellular events that we believe may be associated with precataractous events in the human lens after radiation exposure. This work was supported by NASA Grant #T-965W.

  5. Low dose radiation enhancing inhibitory effect of tumor-associated antigen peptide extract on H-22 hepatocarcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Zuyue, Sun; Jingyi, Fu; Yong, Zhao [Transplantation Biology Research Division, State Key Laboratory of Biomembrane and Membrane Biotechnology, Inst. of Zoology, Chinese Academy of Sciences, Beijing (China); Jianxiang, Liu; Zhibo, Fu; Xiuyi, Li; Shuzheng, Liu; Shouliang, Gong

    2005-06-15

    Objective: To determine whether there is synergically inhibitory effect of low dose radiation (LDR) and tumor-associated antigen peptides (TAP) on tumor growth in vivo, which may provide experimental basis for potential clinical co-application of these two approaches to treat cancers. Methods: TAP extract (MW {<=}3x10{sup 6}) from tumor cell membrane was prepared with mild acid elution method , as reported. The mice were whole-bodily irradiated with 75 mGy X-rays 12 h before immunization with TAP extract. After immunization , the levels of CD3, CD69, TCR{alpha}{beta} cells and T cell subsets in the spleen were detected with FACS. The tumor growth rate was estimated, and the responses to Con A, the cytokine productions and CTL activities of splenocytes were also analyzed 7 d after immunization with TAP. Results: The present experimental results showed that the TAP extract significantly reduced the incidence of the transplanted tumor, delayed the average appearing time and decreased the growth speed of the tumor. The response of splenocytes from mice immunized with TAP extract to Con A increased significantly compared with that in the control group. Irradiation with 75 mGy X-rays 12 h before immunization further enhanced the inhibitory effect of TAP extract on tumor growth, and increased the percentage of CD8{sup +} splenocytes. Conclusion: These results suggest that whole-body irradiation with LDR exerts a synergic inhibitory effect with TAP on tumor growth in vivo, in which enhanced cellular immune responses may be involved. (authors)

  6. Effects of low dose radiation on expressions of ICAM-1 mRNA and protein in kidney of diabetic mice

    International Nuclear Information System (INIS)

    Zhang Chi; Li Xiaokun; Gong Shouliang; Liu Xiaoju; Zhao Xue; Liu Xiaoju; Zhao Xue; Shen Wenjie; Li Cai; Cai Lu

    2010-01-01

    Objective: To study the effects of low dose radiation (LDR) on the expressions of intercellular adhesion molecule-1 (ICAM-1) mRNA and protein in kidney of diabetes mellitus (DM) mice and illuminate that anti-inflammation of LDR is a main mechanism for diabetic therapy. Methods: The healthy and right age C57BL/6J mice were divided into 4 groups including control, DM, LDR and DM/LDR. The mice in DM and DM/LDR groups were injected intraperitoneally with streptozocin (STZ) to set up DM models. The mice in DM/LDR and LDR groups were irradiated with 25 mGy every other day for 4 weeks. The expressions of ICAM-1 mRNA and protein in kidney were detected with RT-PCR and Western blotting 2, 4, 8, 12 and 16 weeks after irradiation. Results: The expressions of ICAM-1 mRNA and protein in kidney had no significant difference among 4 groups before LDR (P>0.05). The expressions of ICAM-1 mRNA and protein 2 weeks after irradiation with LDR were higher than those in the other 3 groups (P<0.05). The expressions of ICAM-1 mRNA and protein in the DM/LDR group 4 weeks after irradiation were also significantly higher than those in non-DM groups (P<0.05), but still significantly lower than those in DM group (P<0.05), and the significant differences were kept to 16 weeks after irradiation. But the expressions of ICAM-1 mRNA and protein in LDR group were significantly higher than those in control group (P<0.05). IHC assay showed that the glomerular and tubular in DM and DM/LDR groups were abnormal and the quantities of the positive staining cells were significantly increased compared with non-DM groups. However the damage of glomerular and tubular in DM/LDR was significantly supressed compared with DM group and the positive staining cells were also decreased. Conclusion: Under the circumstance of DM, LDR can significantly decrease the expressions of ICAM-1 mRNA and protein in mouse kidney to relief the inflammation reaction in kidney; but in normal condition, LDR can improve the immunity and

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

    International Nuclear Information System (INIS)

    Yu Hongsheng; Lu Yanda

    2001-01-01

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

  8. The results of randomized controlled trial of low-dose radiation for wet-type age-related macular degeneration on a 1 year term basis

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2003-06-01

    Evaluation of low dose radiation therapy to the wet-type age-related macular degeneration (AMD) located at the fovea centralis. Patients were irradiated with 10 fractions of 2 Gy external beam or just observed. Between the treated (39) and untreated (31) cases, there was no significant difference in gender, age, initial visual acuity, or size of the neovascular membrane. With the follow-up of 12 months, the visual acuity was significantly well preserved and the size of the neovascular membrane was decreased. These results indicate that low dose irradiation is effective for the wet-type AMD of the stage we treated in the present study. (author)

  9. Effects of low dose radiation combined with cyclophosphamide on tumor cell apoptosis, cell cycle and proliferation of bone marrow in tumor-bearing mice

    International Nuclear Information System (INIS)

    Yu Hongsheng; Fei Conghe; Shen Fangzhen; Liang Jun

    2004-01-01

    Objective: To study the effect of low dose radiation (LDR) combined with cyclophosphamide on tumor cell apoptosis, cell cycle, and proliferation of bone marrow in mice tumor-bearing mice. Methods: Kunming strain male mice were implanted with S180 sarcoma cells in the left hind leg subcutaneously as an experimental animal model. Five and 8 days after implantation, the mice were given 75 mGy whole-body γ-ray radiation and CTX(300 mg/kg) by intraperitoneal injection 36 hour after LDR. All mice were sacrificed to measure the tumor volume, tumor cell apoptosis, and cell cycle; the proliferation of bone marrow was analyzed by flow cytometry. Results: Tumor growth was significantly slowed down in the treated groups. The apoptosis of tumor cells increased significantly after LDR. The tumor cells were arrested in G 1 phase in CTX and CTX+LDR groups, more significantly in the latter group than in the former group. Concentration of bone marrow cells and proliferation index in CTX + LDR group were higher than those in CTX group, although concentration of bone marrow cells in CTX and CTX+LDR groups were much lower than that in normal mice. Conclusion: Low dose radiation combined with cyclophosphamide causes more significant G 1 -phase arrest than cyclophosphamide alone and enhances anti-tumor effect markedly. At the same time LDR significantly protects hematopoietic function of bone marrow, which is of practical significance as an adjuvant chemotherapy

  10. A functional genomics approach using radiation-induced changes in gene expression to study low dose radiation effects in vitro and in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Fornace, Jr, A J

    2007-03-03

    Abstract for final report for project entitled A functional genomics approach using radiation-induced changes in gene expression to study low dose radiation effects in vitro and in vivo which has been supported by the DOE Low Dose Radiation Research Program for approximately 7 years. This project has encompassed two sequential awards, ER62683 and then ER63308, in the Gene Response Section in the Center for Cancer Research at the National Cancer Institute. The project was temporarily suspended during the relocation of the Principal Investigators laboratory to the Dept. of Genetics and Complex Diseases at Harvard School of Public Health at the end of 2004. Remaining support for the final year was transferred to this new site later in 2005 and was assigned the DOE Award Number ER64065. The major aims of this project have been 1) to characterize changes in gene expression in response to low-dose radiation responses; this includes responses in human cells lines, peripheral blood lymphocytes (PBL), and in vivo after human or murine exposures, as well as the effect of dose-rate on gene responses; 2) to characterize changes in gene expression that may be involved in bystander effects, such as may be mediated by cytokines and other intercellular signaling proteins; and 3) to characterize responses in transgenic mouse models with relevance to genomic stability. A variety of approaches have been used to study transcriptional events including microarray hybridization, quantitative single-probe hybridization which was developed in this laboratory, quantitative RT-PCR, and promoter microarray analysis using genomic regulatory motifs. Considering the frequent responsiveness of genes encoding cytokines and related signaling proteins that can affect cellular metabolism, initial efforts were initiated to study radiation responses at the metabolomic level and to correlate with radiation-responsive gene expression. Productivity includes twenty-four published and in press manuscripts

  11. Low-Dose Radiation Induces Cell Proliferation in Human Embryonic Lung Fibroblasts but not in Lung Cancer Cells

    Directory of Open Access Journals (Sweden)

    Xinyue Liang

    2016-01-01

    Full Text Available Hormesis and adaptive responses are 2 important biological effects of low-dose ionizing radiation (LDR. In normal tissue, LDR induces hormesis as evinced by increased cell proliferation; however, whether LDR also increases tumor cell proliferation needs to be investigated. In this study, cell proliferation was assayed by total cell numbers and the Cell Counting Kit 8 assay. Mitogen-activated protein kinases (MAPK/extracellular signal-regulated kinase (ERK and phosphatidylinositol 3′ -kinase(PI3K-Akt (PI3K/AKT phosphorylation were determined by Western blot analysis. Human embryonic lung fibroblast 2BS and lung cancer NCI-H446 cell lines were irradiated with LDR at different doses (20-100 mGy. In response to 20 to 75 mGy X-rays, cell proliferation was significantly increased in 2BS but not in NCI-H446 cells. In 2BS cells, LDR at 20 to 75 mGy also stimulated phosphorylation of MAPK/ERK pathway proteins including ERK, MEK, and Raf and of the PI3K/AKT pathway protein AKT. To test whether ERK1/2 and AKT pathway activation was involved in the stimulation of cell proliferation in 2BS cells, the MAPK/ERK and PI3K/AKT pathways were inhibited using their specific inhibitors, U0126 and LY294002. U0126 decreased the phosphorylation of ERK1/2, and LY294002 decreased the phosphorylation of AKT; each could significantly inhibit LDR-induced 2BS cell proliferation. However, LDR did not stimulate these kinases, and kinase inhibitors also did not affect cell proliferation in the NCI-H446 cells. These results suggest that LDR stimulates cell proliferation via the activation of both MAPK/ERK and PI3K/AKT signaling pathways in 2BS but not in NCI-H446 cells. This finding implies the potential for applying LDR to protect normal tissues from radiotherapy without diminishing the efficacy of tumor therapy.

  12. Correlation between the rate of bioreduction of nitroxide spin label by human tumor cells and their low-dose radiation response

    International Nuclear Information System (INIS)

    Halpern, H.J.; Peric, M.; Nguyen, T.D.; Spencer, D.P.; Bowman, M.K.; Beckett, M.; Weichselbaum, R.R.

    1988-01-01

    The authors discuss a correlation observed between the bioreduction of nitroxide spin label by four human tumor cell lines and a normal tissue fibroblast clone and their low-dose radiation response, specifically their D Q . In measurements of the bioreduction rate of several other cell lines, this correlation appears to persist. In order to define the mechanism of this correlation, they have begun by subtly altering the measurement conditions. The original conditions for measurement involved adding the spin label to cells whose culture medium had been changed (the label was added to the new medium). By delaying the addition of the label to the culture medium, they substantially reduced the variation of the bioreduction rate between the cell lines. This implies that the fresh medium provides a nonspecific irritant or disequilibrium to the cultured cell system to which they response variably by accelerating, among other things, the metabolic process responsible for spin label bioreduction

  13. Effect of extended exposure to low-dose radiation on autoimmune diseases of immunologically suppressed MRL/MpTn-gld/gld mice

    International Nuclear Information System (INIS)

    Ootsuyama, Akira; Okazaki, Ryuji; Norimura, Toshiyuki

    2003-01-01

    The purpose of this paper is to analyze the relationship between alterations of splenic T-cell subpopulations and the amelioration of autoimmune diseases of MRL/MpTn-gld/gld mice (MRL/gld mice) after extended exposure to low-dose radiation. After the onset of disease, 4-month-old MRL/gld mice were exposed to doses of 0.05, 0.2, and 0.5 Gy/day for 4 weeks (5 days/week), for total doses of 1, 4, and 10 Gy, respectively. The MRL/gld mice that were irradiated with 0.2 and 0.5 Gy/day showed an obvious decrease in the proportion of splenic CD4 - CD8 - T cells and remission of their autoimmune diseases. After the last irradiation, apoptotic cells were found in the white pulp of the spleen of the MRL/gld mice irradiated with 0.2 Gy/day, but not in the MRL/MpJ-+/+ mice (MRL/wild mice), which experienced a similar treatment. Before the onset of disease, 3-month-old MRL/gld mice subjected to 0.2 Gy/day showed a decrease in the proportion of splenic CD4 - CD8 - T cells and less remission of their autoimmune diseases than the 4-month-old mice. These results suggest that the accumulated CD4 - CD8 - T cells are more sensitive to radiation than other T cell subpopulations, and that decreasing CD4 - CD8 - T cells with extended exposure to low-dose radiation leads to the amelioration of autoimmune disease. (author)

  14. An Overview of the Regulation of Low Dose Radiation in the Nuclear and Non-nuclear Industries

    International Nuclear Information System (INIS)

    Menon, Shankar; Valencia, Luis; Teunckens, Lucien

    2003-01-01

    Now that increasing numbers of nuclear power stations are reaching the end of their commercially useful lives, the management of the large quantities of very low level radioactive material that arises during their decommissioning has become a major subject of discussion, with very significant economic implications. Much of this material can, in an environmentally advantageous manner, be recycled for reuse without radiological restrictions. Much larger quantities--2-3 orders of magnitude larger--of material, radiologically similar to the candidate material for recycling from the nuclear industry, arise in non-nuclear industries like coal, fertilizer, oil and gas, mining, etc. In such industries, naturally occurring radioactivity is artificially concentrated in products, by-products or waste to form TENORM (Technologically Enhanced Naturally Occurring Radioactive Material). It is only in the last decade that the international community has become aware of the prevalence of TENORM, specially the activity levels and quantities arising in so many non-nuclear industries. The first reaction of international organizations seems to have been to propose different standards for the nuclear and non-nuclear industries, with very stringent release criteria for radioactive material from the regulated nuclear industry and up to thirty to a hundred times more liberal criteria for the release/exemption of TENORM from the as yet unregulated non-nuclear industries. There are significant strategic issues that need to be discussed and resolved. Some examples of these are: - Disposal aspects of long-lived nuclides, - The use of radioactive residues in building materials, - Commercial aspects of differing and discriminating criteria in competing power industries in a world of deregulated electric power production. Of even greater importance is the need for the discussion of certain basic issues, such as - The quantitative risk levels of exposure to ionizing radiation, - The need for in

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

    International Nuclear Information System (INIS)

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

    2003-01-01

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

  16. Effect of extended exposure of low-dose radiation on autoimmune diseases of immunologically depressed MRL/MpJ-gld/gld mice

    International Nuclear Information System (INIS)

    Ootsuyama, A.; Okazaki, R.; Norimura, T.

    2000-01-01

    We analyzed alterations of splenic T cell subpopulations and amelioration of autoimmune disease of MRL/MpJ-gld/gld mice (MRL/gld mice) after the extended exposure to low-dose radiation (LDR). Four-month old MRL/gld mice were exposed to 0.05, 0.2 and 0.5 Gy/day for 4 weeks (5 days/week) with a total dose of 1, 4 and 10 Gy, respectively. The mice irradiated with 0.2 and 0.5 Gy/day showed an obvious decrease in the proportions of splenic CD4 - CD8 - T cells and remission of their autoimmune disease. In the mice irradiated with 0.2 Gy/day, apoptotic cells were found in the white pulp of the spleen after the last irradiation, but not in that of the treated MRL/MpJ-+/+ mice (MRL/wild type mice). It seems that the accumulated CD4 - CD8 - T cells are more sensitive to radiation than other T cell subpopulations and prone to apoptosis, and efficient elimination of abnormal CD4 - CD8 - T cells by radiation-induced apoptosis may lead to the amelioration of autoimmune disease. (author)

  17. Low Dose Radiation Response Curves, Networks and Pathways in Human Lymphoblastoid Cells Exposed from 1 to 10 cGy of Acute Gamma Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Wyrobek, A. J.; Manohar, C. F.; Nelson, D. O.; Furtado, M. R.; Bhattacharya, M. S.; Marchetti, F.; Coleman, M.A.

    2011-04-18

    We investigated the low dose dependency of the transcriptional response of human cells to characterize the shape and biological functions associated with the dose response curve and to identify common and conserved functions of low dose expressed genes across cells and tissues. Human lymphoblastoid (HL) cells from two unrelated individuals were exposed to graded doses of radiation spanning the range of 1-10 cGy were analyzed by transcriptome profiling, qPCR and bioinformatics, in comparison to sham irradiated samples. A set of {approx}80 genes showed consistent responses in both cell lines; these genes were associated with homeostasis mechanisms (e.g., membrane signaling, molecule transport), subcellular locations (e.g., Golgi, and endoplasmic reticulum), and involved diverse signal transduction pathways. The majority of radiation-modulated genes had plateau-like responses across 1-10 cGy, some with suggestive evidence that transcription was modulated at doses below 1 cGy. MYC, FOS and TP53 were the major network nodes of the low-dose response in HL cells. Comparison our low dose expression findings in HL cells with those of prior studies in mouse brain after whole body exposure, in human keratinocyte cultures, and in endothelial cells cultures, indicates that certain components of the low dose radiation response are broadly conserved across cell types and tissues, independent of proliferation status.

  18. Effects of low dose radiation on tumor apoptosis, cell cycle progression and changes of apoptosis-related protein bcl-2 in tumor-bearing mice

    International Nuclear Information System (INIS)

    Yu Hongsheng; Fei Conghe; Shen Fangzhen; Liang Jun

    2003-01-01

    Objective: To study the effect of low dose radiation (LDR) on tumor apoptosis, cell cycle progression and changes of apoptosis-related protein bcl-2 in tumor-bearing mice. Methods: Kunming stain male mice were implanted with S180 sarcoma cells in the left inguen subcutaneously as an in situ experimental animal model. Seven days after implantation, the mice were given 75 mGy whole-body γ-irradiation. At 24 and 48 h after irradiation, all mice were sacrificed to measure the tumor volume, and tumor cell apoptosis, cell cycle progression were analyzed by flow cytometry. The expression of apoptosis-related protein bcl-2 and the apoptotic rate of tumor cells were observed by immunohistochemistry and electron microscopy. Results: Tumor growth was significantly slowed down after LDR (P 1 phase and the expression of bcl-2 protein decreased at 24 h. Apoptotic rate of tumor cells increased significantly at 48 h after LDR. Conclusion: LDR could cause a G 1 -phase arrest and increase the apoptosis of tumor cells through the low level of apoptosis-related protein bcl-2 in the tumor-bearing mice. The organized immune function and anti-tumor ability are markedly increased after LDR. The study provides practical evidence of clinical application to cancer treatment

  19. Biostatnet workshop on Biomedical (Big) Data & DoReMi LD-RadStats: Workshop for statisticians interested in contributing to EU low dose radiation research

    CERN Document Server

    Calle, MLuz; Cardis, Elisabeth; Einbeck, Jochen; Gómez, Guadalupe; Puig, Pere

    2017-01-01

    This two-part volume gathers extended conference abstracts corresponding to selected talks from the "Biostatnet workshop on Biomedical (Big) Data" and from the "DoReMi LD-RadStats: Workshop for statisticians interested in contributing to EU low dose radiation research", which were held at the Centre de Recerca Matemàtica (CRM) in Barcelona from November 26th to 27th, 2015, and at the Institut de Salut Global ISGlobal (former CREAL) from October 26th to 28th, 2015, respectively. Most of the contributions are brief articles, presenting preliminary new results not yet published in regular research journals. The first part is devoted to the challenges of analyzing so called "Biomedical Big Data", tremendous amounts of biomedical and health data that are generated every day due to the use of recent technological advances such as massive genomic sequencing, electronic health records or high-resolution medical imaging, among others. The analysis of this information poses significant challenges for researchers in th...

  20. Early Brain Response to Low-Dose Radiation Exposure Involves Molecular Networks and Pathways Associated with Cognitive Functions, Advanced Aging and Alzheimer's Disease

    International Nuclear Information System (INIS)

    Lowe, Xiu R.; Bhattacharya, Sanchita; Marchetti, Francesco; Wyrobek, Andrew J.

    2008-01-01

    Understanding the cognitive and behavioral consequences of brain exposures to low-dose ionizing radiation has broad relevance for health risks from medical radiation diagnostic procedures, radiotherapy, environmental nuclear contamination, as well as earth orbit and space missions. Analyses of transcriptome profiles of murine brain tissue after whole-body radiation showed that low-dose exposures (10 cGy) induced genes not affected by high dose (2 Gy), and low-dose genes were associated with unique pathways and functions. The low-dose response had two major components: pathways that are consistently seen across tissues, and pathways that were brain tissue specific. Low-dose genes clustered into a saturated network (p -53 ) containing mostly down-regulated genes involving ion channels, long-term potentiation and depression, vascular damage, etc. We identified 9 neural signaling pathways that showed a high degree of concordance in their transcriptional response in mouse brain tissue after low-dose radiation, in the aging human brain (unirradiated), and in brain tissue from patients with Alzheimer's disease. Mice exposed to high-dose radiation did not show these effects and associations. Our findings indicate that the molecular response of the mouse brain within a few hours after low-dose irradiation involves the down-regulation of neural pathways associated with cognitive dysfunctions that are also down regulated in normal human aging and Alzheimer's disease

  1. Low-dose radiation pretreatment improves survival of human ceiling culture-derived proliferative adipocytes (ccdPAs) under hypoxia via HIF-1 alpha and MMP-2 induction

    International Nuclear Information System (INIS)

    Adachi, Naoki; Kubota, Yoshitaka; Kosaka, Kentarou; Akita, Shinsuke; Sasahara, Yoshitarou; Kira, Tomoe; Kuroda, Masayuki; Mitsukawa, Nobuyuki; Bujo, Hideaki; Satoh, Kaneshige

    2015-01-01

    Poor survival is a major problem of adipocyte transplantation. We previously reported that VEGF and MMPs secreted from transplanted adipocytes are essential for angiogenesis and adipogenesis. Pretreatment with low-dose (5 Gy) radiation (LDR) increased VEGF, MMP-2, and HIF-1 alpha mRNA expression in human ceiling culture-derived proliferative adipocytes (hccdPAs). Gene expression after LDR differed between adipose-derived stem cells (hASCs) and hccdPAs. Pretreatment with LDR improved the survival of hccdPAs under hypoxia, which is inevitable in the early stages after transplantation. Upregulation of VEGF and MMP-2 after LDR in hccdPAs is mediated by HIF-1 alpha expression. Our results suggest that pretreatment with LDR may improve adipocyte graft survival in a clinical setting through upregulation of VEGF and MMP-2 via HIF-1 alpha. - Highlights: • Ceiling culture-derived proliferative adipocytes (ccdPAs) react to radiation. • Low-dose radiation (LDR) pretreatment improves survival of ccdPAs under hypoxia. • Gene expression after LDR differs between ccdPAs and adipose-derived stem cells. • LDR-induced increase in MMP-2 and VEGF is dependent on HIF-1 alpha induction. • LDR pretreatment may improve the adipocyte graft survival rate in clinical settings

  2. Low-dose radiation pretreatment improves survival of human ceiling culture-derived proliferative adipocytes (ccdPAs) under hypoxia via HIF-1 alpha and MMP-2 induction

    Energy Technology Data Exchange (ETDEWEB)

    Adachi, Naoki [Department of Plastic Surgery, Chiba University, 1-8-1, Inohana, Chuo-ku, Chiba-city, Chiba, #260-8677 (Japan); Kubota, Yoshitaka, E-mail: kubota-cbu@umin.ac.jp [Department of Plastic Surgery, Chiba University, 1-8-1, Inohana, Chuo-ku, Chiba-city, Chiba, #260-8677 (Japan); Kosaka, Kentarou; Akita, Shinsuke; Sasahara, Yoshitarou; Kira, Tomoe [Department of Plastic Surgery, Chiba University, 1-8-1, Inohana, Chuo-ku, Chiba-city, Chiba, #260-8677 (Japan); Kuroda, Masayuki [Center for Advanced Medicine, Chiba University, 1-8-1, Inohana, Chuo-ku, Chiba-city, Chiba, #260-8677 (Japan); Mitsukawa, Nobuyuki [Department of Plastic Surgery, Chiba University, 1-8-1, Inohana, Chuo-ku, Chiba-city, Chiba, #260-8677 (Japan); Bujo, Hideaki [Department of Clinical-Laboratory and Experimental-Research Medicine, Toho University, Sakura Medical Center, 564-1 Shimoshizu, Sakura-shi, Chiba, #285-8741 (Japan); Satoh, Kaneshige [Department of Plastic Surgery, Chiba University, 1-8-1, Inohana, Chuo-ku, Chiba-city, Chiba, #260-8677 (Japan)

    2015-08-07

    Poor survival is a major problem of adipocyte transplantation. We previously reported that VEGF and MMPs secreted from transplanted adipocytes are essential for angiogenesis and adipogenesis. Pretreatment with low-dose (5 Gy) radiation (LDR) increased VEGF, MMP-2, and HIF-1 alpha mRNA expression in human ceiling culture-derived proliferative adipocytes (hccdPAs). Gene expression after LDR differed between adipose-derived stem cells (hASCs) and hccdPAs. Pretreatment with LDR improved the survival of hccdPAs under hypoxia, which is inevitable in the early stages after transplantation. Upregulation of VEGF and MMP-2 after LDR in hccdPAs is mediated by HIF-1 alpha expression. Our results suggest that pretreatment with LDR may improve adipocyte graft survival in a clinical setting through upregulation of VEGF and MMP-2 via HIF-1 alpha. - Highlights: • Ceiling culture-derived proliferative adipocytes (ccdPAs) react to radiation. • Low-dose radiation (LDR) pretreatment improves survival of ccdPAs under hypoxia. • Gene expression after LDR differs between ccdPAs and adipose-derived stem cells. • LDR-induced increase in MMP-2 and VEGF is dependent on HIF-1 alpha induction. • LDR pretreatment may improve the adipocyte graft survival rate in clinical settings.

  3. Early Brain Response to Low-Dose Radiation Exposure Involves Molecular Networks and Pathways Associated with Cognitive Functions, Advanced Aging and Alzheimer's Disease

    Energy Technology Data Exchange (ETDEWEB)

    Lowe, Xiu R; Bhattacharya, Sanchita; Marchetti, Francesco; Wyrobek, Andrew J.

    2008-06-06

    Understanding the cognitive and behavioral consequences of brain exposures to low-dose ionizing radiation has broad relevance for health risks from medical radiation diagnostic procedures, radiotherapy, environmental nuclear contamination, as well as earth orbit and space missions. Analyses of transcriptome profiles of murine brain tissue after whole-body radiation showed that low-dose exposures (10 cGy) induced genes not affected by high dose (2 Gy), and low-dose genes were associated with unique pathways and functions. The low-dose response had two major components: pathways that are consistently seen across tissues, and pathways that were brain tissue specific. Low-dose genes clustered into a saturated network (p < 10{sup -53}) containing mostly down-regulated genes involving ion channels, long-term potentiation and depression, vascular damage, etc. We identified 9 neural signaling pathways that showed a high degree of concordance in their transcriptional response in mouse brain tissue after low-dose radiation, in the aging human brain (unirradiated), and in brain tissue from patients with Alzheimer's disease. Mice exposed to high-dose radiation did not show these effects and associations. Our findings indicate that the molecular response of the mouse brain within a few hours after low-dose irradiation involves the down-regulation of neural pathways associated with cognitive dysfunctions that are also down regulated in normal human aging and Alzheimer's disease.

  4. “Denervation” of autonomous nervous system in idiopathic pulmonary arterial hypertension by low-dose radiation: a case report with an unexpected outcome

    Directory of Open Access Journals (Sweden)

    Hohenforst-Schmidt W

    2014-03-01

    in monocrotaline-induced pulmonary hypertension. A 58-year-old woman presented with dyspnea and mild edema of the lower extremities. A bronchoscopy was performed without any suspicious findings suggesting a central tumor or other infiltrative disease. Endobronchial ultrasound revealed enlarged pulmonary arteries containing thrombi, a few enlarged lymph nodes, and enlarged mediastinal tissue anatomy with suspicion for mediastinal infiltration of a malignant process. We estimated that less than 10% of the peripheral vascular bed of the lung was involved in direct consolidated fibrosis as demonstrated in the left upper lobe apex. Further, direct involvement of fibrosis around the main stems of the pulmonary arteries was assumed to be low from positron emission tomography and magnetic resonance imaging scans. Assuming a positive influence of low-dose radiation, it was not expected that this could have reduced pulmonary vascular resistance by over two thirds of the initial result. However; it was noted that this patient had idiopathic pulmonary arterial hypertension mixed with “acute” (mediastinal fibrosis which could have contributed to the unexpected success of reduction of pulmonary vascular resistance. To the best of our knowledge, this is the first report of successful treatment of idiopathic pulmonary arterial hypertension, probably as a result of low-dose radiation to the pulmonary arterial main stems. The patient continues to have no specific complaints concerning her idiopathic pulmonary arterial hypertension.Keywords: radiation, pulmonary hypertension, denervatio

  5. Mechanisms and biological importance of photon-induced bystander responses. Do they have an impact on low-dose radiation responses

    International Nuclear Information System (INIS)

    Tomita, Masanori; Maeda, Munetoshi

    2015-01-01

    Elucidating the biological effect of low linear energy transfer (LET), low-dose and/or low-dose-rate ionizing radiation is essential in ensuring radiation safety. Over the past two decades, non-targeted effects, which are not only a direct consequence of radiation-induced initial lesions produced in cellular DNA but also of intra- and inter-cellular communications involving both targeted and non-targeted cells, have been reported and are currently defining a new paradigm in radiation biology. These effects include radiation-induced adaptive response, low-dose hypersensitivity, genomic instability, and radiation-induced bystander response (RIBR). RIBR is generally defined as a cellular response that is induced in non-irradiated cells that receive bystander signals from directly irradiated cells. RIBR could thus play an important biological role in low-dose irradiation conditions. However, this suggestion was mainly based on findings obtained using high-LET charged-particle radiations. The human population (especially the Japanese, who are exposed to lower doses of radon than the world average) is more frequently exposed to low-LET photons (X-rays or γ-rays) than to high-LET charged-particle radiation on a daily basis. There are currently a growing number of reports describing a distinguishing feature between photon-induced bystander response and high-LET RIBR. In particular, photon-induced by-stander response is strongly influenced by irradiation dose, the irradiated region of the targeted cells, and p53 status. The present review focuses on the photon-induced bystander response, and discusses its impact on the low-dose radiation effect. (author)

  6. Multiple low-dose radiation prevents type 2 diabetes-induced renal damage through attenuation of dyslipidemia and insulin resistance and subsequent renal inflammation and oxidative stress.

    Directory of Open Access Journals (Sweden)

    Minglong Shao

    Full Text Available Dyslipidemia and lipotoxicity-induced insulin resistance, inflammation and oxidative stress are the key pathogeneses of renal damage in type 2 diabetes. Increasing evidence shows that whole-body low dose radiation (LDR plays a critical role in attenuating insulin resistance, inflammation and oxidative stress.The aims of the present study were to investigate whether LDR can prevent type 2 diabetes-induced renal damage and the underlying mechanisms.Mice were fed with a high-fat diet (HFD, 40% of calories from fat for 12 weeks to induce obesity followed by a single intraperitoneal injection of streptozotocin (STZ, 50 mg/kg to develop a type 2 diabetic mouse model. The mice were exposed to LDR at different doses (25, 50 and 75 mGy for 4 or 8 weeks along with HFD treatment. At each time-point, the kidney weight, renal function, blood glucose level and insulin resistance were examined. The pathological changes, renal lipid profiles, inflammation, oxidative stress and fibrosis were also measured.HFD/STZ-induced type 2 diabetic mice exhibited severe pathological changes in the kidney and renal dysfunction. Exposure of the mice to LDR for 4 weeks, especially at 50 and 75 mGy, significantly improved lipid profiles, insulin sensitivity and protein kinase B activation, meanwhile, attenuated inflammation and oxidative stress in the diabetic kidney. The LDR-induced anti-oxidative effect was associated with up-regulation of renal nuclear factor E2-related factor-2 (Nrf-2 expression and function. However, the above beneficial effects were weakened once LDR treatment was extended to 8 weeks.These results suggest that LDR exposure significantly prevented type 2 diabetes-induced kidney injury characterized by renal dysfunction and pathological changes. The protective mechanisms of LDR are complicated but may be mainly attributed to the attenuation of dyslipidemia and the subsequent lipotoxicity-induced insulin resistance, inflammation and oxidative stress.

  7. IL6-174 G>C Polymorphism (rs1800795 Association with Late Effects of Low Dose Radiation Exposure in the Portuguese Tinea Capitis Cohort.

    Directory of Open Access Journals (Sweden)

    Paula Boaventura

    Full Text Available Head and neck cancers, and cardiovascular disease have been described as late effects of low dose radiation (LDR exposure, namely in tinea capitis cohorts. In addition to radiation dose, gender and younger age at exposure, the genetic background might be involved in the susceptibility to LDR late effects. The -174 G>C (rs1800795 SNP in IL6 has been associated with cancer and cardiovascular disease, nevertheless this association is still controversial. We assessed the association of the IL6-174 G>C SNP with LDR effects such as thyroid carcinoma, basal cell carcinoma and carotid atherosclerosis in the Portuguese tinea capitis cohort. The IL6-174 G>C SNP was genotyped in 1269 individuals formerly irradiated for tinea capitis. This sampling group included thyroid cancer (n = 36, basal cell carcinoma (n = 113 and cases without thyroid or basal cell carcinoma (1120. A subgroup was assessed for atherosclerosis by ultrasonography (n = 379 and included matched controls (n = 222. Genotypes were discriminated by real-time PCR using a TaqMan SNP genotyping assay. In the irradiated group, we observed that the CC genotype was significantly associated with carotid plaque risk, both in the genotypic (OR = 3.57, CI = 1.60-7.95, p-value = 0.002 and in the recessive (OR = 3.02, CI = 1.42-6.42, p-value = 0.004 models. Irradiation alone was not a risk factor for carotid atherosclerosis. We did not find a significant association of the IL6-174 C allele with thyroid carcinoma or basal cell carcinoma risk. The IL6-174 CC genotype confers a three-fold risk for carotid atherosclerotic disease suggesting it may represent a genetic susceptibility factor in the LDR context.

  8. Comparison of early gestational development between natural and stimulated pregnancies

    International Nuclear Information System (INIS)

    Jun, Soon Ae; Ahn, M. O.; Yoon, T. K.; Cha, G. Y.

    1990-01-01

    In order to assess the difference in growth and development between the stimulated and natural pregnancies, we compared the sonographic measurement of early embryos from the fifth to seventh gestational week, in terms of mean size of gestational sac, crown rump length, fetal heart rate and yolk sac size between 26 ovulation stimulated pregnancies and 38 natural pre gnancies. The two groups were compared by multiple regression analysis, The data suggest that there is attend that embryos smaller in stimulated pregnancies though significant statistical differences was not proved

  9. The biological response of plucked human hair to low-dose radiation: a measure of individual radiosensitivity and a technique for biological dosimetry

    International Nuclear Information System (INIS)

    Swain, D.

    1997-01-01

    It is often assumed that the effects of radiation are linear with dose and that high dose effects can be extrapolated to low dose levels. However, there are a variety of mechanisms which can alter the response at low doses. The most important of these relate to induced sensitivity or induced repair mechanisms. It is therefore important that this area is studied in more depth by looking at the molecular effects and damage to cells at low doses. It is well known that there are certain rare genetic syndromes which predispose individuals to cancer, e.g. ataxia telangiectasia. It is also probable that there is a large range of sensitivity in the natural variation of individuals to the risk of radiation-induced cancer. It is proposed that radiosensitivity is studied using stimulated lymphocytes from whole blood and the technique extended to look at the effects in cell cultures established from human hair. Radiation treatment of cell cultures established from plucked human hair has been previously advocated as a non-invasive technique for non-uniform biological dosimetry and it is proposed that these techniques are adapted to the use of hair to estimate individual radiosensitivity. The aim is to establish and optimize these techniques for culturing keratinocytes from plucked human hair follicles with a view to study biological markers for the subsequent assessment of radiosensitivity. Preliminary results are promising and suggest that the technique for culturing keratinocytes from hair presents a feasible approach. Results from this primary cell culture technique and results from the comparison of the micronuclei data obtained from the cell cultures and stimulated lymphocytes will be presented. (author)

  10. Assessment of DNA damage and Chromosome aberration in human lymphocyte exposed to low dose radiation detected by FISH(Fluorescence In Situ Hybridization) and SCGE(Single Cell Gel Electrophoresis)

    International Nuclear Information System (INIS)

    Chung, Hai Won; Kim, Su Young; Kim, Byung Mo; Kim, Sun Jin; Ha, Sung Whan; Kim, Tae Hwan; Cho, Chul Koo

    2000-01-01

    Comparative study was performed for the assessment of DNA damage and Chromosomal aberration in human lymphocyte exposed to low dose radiation using Fluorescence In Situ Hybridization(FISH) and Single Cell Gel Electrophoresis(SCGE). Chromosomal aberrations in human lymphocyte exposed to radiation at doses of 5, 10, 30 and 50cGy were analysed with whole chromosome-specific probes by human chromosome 1, 2 and 4 according to PAINT system. FISH with chromosome-specific probe has been used to be a valid and rapid method for detection of chromosome rearrangements induced by low dose radiation. The frequencies of stable translocation per cell equivalents were 0.0116, 0.0375, 0.0407, 0.0727 and 0.0814 for 0, 5, 10, 30 and 50cGy, respectively, and those of dicentric were 0.00, 0.0125, 0.174, 0.0291 and 0.0407 respectively. Radiation induced DNA damage in human lymphocyte in a dose-dependent manner at low doses from 5cGy to 50cGy, which were analysed by single Cell Gel Electrophoresis(SCGE). From above results, FISH seemed to be useful for radiation biodosimetry by which the frequencies of stable aberrations in human lymphocyte can be observed more easily than by conventional method and SCGE also seemed to be sensitive method for detecting DNA damage by low dose radiation exposure, so that those methods will improve our technique to perform meaningful biodosimetry for radiation at low doses

  11. Numerical modeling of shear stimulation in naturally fractured geothermal reservoirs

    OpenAIRE

    Ucar, Eren

    2018-01-01

    Shear-dilation-based hydraulic stimulations are conducted to create enhanced geothermal systems (EGS) from low permeable geothermal reservoirs, which are initially not amenable to energy production. Reservoir stimulations are done by injecting low-pressurized fluid into the naturally fractured formations. The injection aims to activate critically stressed fractures by decreasing frictional strength and ultimately cause a shear failure. The shear failure leads to a permanent ...

  12. Stimulating natural supersedure of honeybee queens, Apis mellifera

    NARCIS (Netherlands)

    Hendriksma, H.P.; Calis, J.N.M.; Boot, W.J.

    2004-01-01

    When a honeybee queen starts to fail, she is often superseded by a young queen that takes over reproduction inside the colony. Natural supersedure in winter leads to an unfertilised young queen and colony loss. To reduce these losses we tried to stimulate supersedure of queens earlier in the season.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-11-15

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

  14. Study of the anti-inflammatory effects of low-dose radiation. The contribution of biphasic regulation of the antioxidative system in endothelial cells

    International Nuclear Information System (INIS)

    Large, Martin; Hehlgans, Stephanie; Reichert, Sebastian; Roedel, Claus; Roedel, Franz; Gaipl, Udo S.; Fournier, Claudia; Weiss, Christian

    2015-01-01

    We examined (a) the expression of the antioxidative factor glutathione peroxidase (GPx) and the transcription factor nuclear factor E2-related factor 2 (Nrf2) following low-dose X-irradiation in endothelial cells (ECs) and (b) the impact of reactive oxygen species (ROS) and Nrf2 on functional properties of ECs to gain further knowledge about the anti-inflammatory mode of action of low doses of ionizing radiation. EA.hy926 ECs and primary human dermal microvascular ECs (HMVEC) were stimulated by tumor necrosis factor-α (TNF-α, 20 ng/ml) 4 h before irradiation with single doses ranging from 0.3 to 3 Gy. The expression and activity of GPx and Nrf2 were analyzed by flow cytometry, colorimetric assays, and real-time PCR. The impact of ROS and Nrf2 on peripheral blood mononuclear cell (PBMC) adhesion was assayed in the presence of the ROS scavenger N-acetyl-L-cysteine (NAC) and Nrf2 activator AI-1. Following a low-dose exposure, we observed in EA.hy926 EC and HMVECs a discontinuous expression and enzymatic activity of GPx concomitant with a lowered expression and DNA binding activity of Nrf2 that was most pronounced at a dose of 0.5 Gy. Scavenging of ROS by NAC and activation of Nrf2 by AI-1 significantly diminished a lowered adhesion of PBMC to EC at a dose of 0.5 Gy. Low-dose irradiation resulted in a nonlinear expression and activity of major compounds of the antioxidative system that might contribute to anti-inflammatory effects in stimulated ECs. (orig.) [de

  15. Study of the anti-inflammatory effects of low-dose radiation. The contribution of biphasic regulation of the antioxidative system in endothelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Large, Martin; Hehlgans, Stephanie; Reichert, Sebastian; Roedel, Claus; Roedel, Franz [Goethe University Frankfurt, Department of Radiotherapy and Oncology, Frankfurt am Main (Germany); Gaipl, Udo S. [University Hospital Erlangen, Department of Radiation Oncology, Erlangen (Germany); Fournier, Claudia [GSI Helmholtz Center for Heavy Ion Research, Department of Biophysics, Darmstadt (Germany); Weiss, Christian [Goethe University Frankfurt, Department of Radiotherapy and Oncology, Frankfurt am Main (Germany); Klinikum Darmstadt, Institute for Radiooncology and Radiotherapy, Darmstadt (Germany)

    2015-09-15

    We examined (a) the expression of the antioxidative factor glutathione peroxidase (GPx) and the transcription factor nuclear factor E2-related factor 2 (Nrf2) following low-dose X-irradiation in endothelial cells (ECs) and (b) the impact of reactive oxygen species (ROS) and Nrf2 on functional properties of ECs to gain further knowledge about the anti-inflammatory mode of action of low doses of ionizing radiation. EA.hy926 ECs and primary human dermal microvascular ECs (HMVEC) were stimulated by tumor necrosis factor-α (TNF-α, 20 ng/ml) 4 h before irradiation with single doses ranging from 0.3 to 3 Gy. The expression and activity of GPx and Nrf2 were analyzed by flow cytometry, colorimetric assays, and real-time PCR. The impact of ROS and Nrf2 on peripheral blood mononuclear cell (PBMC) adhesion was assayed in the presence of the ROS scavenger N-acetyl-L-cysteine (NAC) and Nrf2 activator AI-1. Following a low-dose exposure, we observed in EA.hy926 EC and HMVECs a discontinuous expression and enzymatic activity of GPx concomitant with a lowered expression and DNA binding activity of Nrf2 that was most pronounced at a dose of 0.5 Gy. Scavenging of ROS by NAC and activation of Nrf2 by AI-1 significantly diminished a lowered adhesion of PBMC to EC at a dose of 0.5 Gy. Low-dose irradiation resulted in a nonlinear expression and activity of major compounds of the antioxidative system that might contribute to anti-inflammatory effects in stimulated ECs. (orig.) [German] Ziel der Studie war die Untersuchung der Expression des antioxidativen Enzyms Glutathionperoxidase (GPx) und des Transkriptionsfaktors ''nuclear factor E2-related factor 2'' (Nrf2) in Endothelzellen nach niedrigdosierter Roentgenbestrahlung. Des Weiteren wurde der Einfluss von reaktiven Sauerstoffmetaboliten (ROS) und von Nrf2 auf funktionelle Eigenschaften von Endothelzellen analysiert, um weitere Erkenntnisse ueber die antientzuendliche Wirkung von niedrigdosierten Roentgenstrahlen

  16. Low dose radiation and plant growth

    International Nuclear Information System (INIS)

    Kim, Sung Jae; Lee, Hae Youn; Park, Hong Sook

    2001-03-01

    Ionizing radiation includes cosmic radiation, earth radiation, radionuclides for the medical purpose and nuclear industry, fallout radiation. From the experimental results of various radiation effects on seeds or seedlings, it was found that germination rate, development, respiration rate, reproduction and blooming were accelerated compared with the control. In mammal, hormesis phenomenon manifested itself in increased disease resistance, lifespan, and decreased rate of tumor incidence. In plants, it was shown that germination, sprouting, growth, development, blooming and resistance to disease were accelerated

  17. Cytogenetic effects of low-dose radiation

    International Nuclear Information System (INIS)

    Metalli, P.

    1983-01-01

    The effects of ionizing radiation on chromosomes have been known for several decades and dose-effect relationships are also fairly well established in the mid- and high-dose and dose-rate range for chromosomes of mammalian cells. In the range of low doses and dose rates of different types of radiation few data are available for direct analysis of the dose-effect relationships, and extrapolation from high to low doses is still the unavoidable approach in many cases of interest for risk assessment. A review is presented of the data actually available and of the attempts that have been made to obtain possible generalizations. Attention is focused on some specific chromosomal anomalies experimentally induced by radiation (such as reciprocal translocations and aneuploidies in germinal cells) and on their relevance for the human situation. (author)

  18. Low dose radiation and diabetes mellitus

    International Nuclear Information System (INIS)

    Zhao Hongguang; Gong Shouliang; Cai Lu

    2006-01-01

    Induction of hormesis and adaptive response by low-dose radiatio (LDR) has been extensively indicated. It's mechanism may be related with the protective protein and antioxidants that LDR induced, which take effects on the diabetes mellitus (DM) and other diseases. This review will summarize available dat with emphasis on three points: the preventive effect of LDR on the development of diabetes, the therapeutic effect of LDR on diabetic complications and possible mechanisms by which LDR prevents the development of diabetes and diabetic complications. Finally, the perspectives of LDR clinical, diabetes-related implication are discussed. (authors)

  19. Low dose radiation and plant growth

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sung Jae; Lee, Hae Youn; Park, Hong Sook

    2001-03-01

    Ionizing radiation includes cosmic radiation, earth radiation, radionuclides for the medical purpose and nuclear industry, fallout radiation. From the experimental results of various radiation effects on seeds or seedlings, it was found that germination rate, development, respiration rate, reproduction and blooming were accelerated compared with the control. In mammal, hormesis phenomenon manifested itself in increased disease resistance, lifespan, and decreased rate of tumor incidence. In plants, it was shown that germination, sprouting, growth, development, blooming and resistance to disease were accelerated.

  20. Stimulation of Natural Killer T Cells by Glycolipids

    Directory of Open Access Journals (Sweden)

    Brian L. Anderson

    2013-12-01

    Full Text Available Natural killer T (NKT cells are a subset of T cells that recognize glycolipid antigens presented by the CD1d protein. The initial discovery of immunostimulatory glycolipids from a marine sponge and the T cells that respond to the compounds has led to extensive research by chemists and immunologists to understand how glycolipids are recognized, possible responses by NKT cells, and the structural features of glycolipids necessary for stimulatory activity. The presence of this cell type in humans and most mammals suggests that it plays critical roles in antigen recognition and the interface between innate and adaptive immunity. Both endogenous and exogenous natural antigens for NKT cells have been identified, and it is likely that glycolipid antigens remain to be discovered. Multiple series of structurally varied glycolipids have been synthesized and tested for stimulatory activity. The structural features of glycolipids necessary for NKT cell stimulation are moderately well understood, and designed compounds have proven to be much more potent antigens than their natural counterparts. Nevertheless, control over NKT cell responses by designed glycolipids has not been optimized, and further research will be required to fully reveal the therapeutic potential of this cell type.

  1. Thermally stimulated depolarization currents in the natural fluorite

    International Nuclear Information System (INIS)

    Valerio, Mario Ernesto Giroldo

    1986-01-01

    The present work deals with natural calcium fluoride from Criciuma, Santa Catarina. Thermally Stimulated Depolarization Currents (TSDC) can be used to determine the properties of dipole defects present in this crystal. The TSDC spectrum of this material shows three bands in the temperature range of 80 to 450 K. The first one, at 130 K, is due the dipoles formed by a trivalent impurity and an interstitial fluorine ion in the next nearest position of an impurity ion (nn R s 3+ -F i - ). The second one, at 102 k, is due to the presence of small aggregates of dipoles (like a dimer). The last band, at 360 k is due to the formation of Large Clusters. The continuous distribution model gave the best fit for these bands with mean activation energies of 0.41 eV, 0.595 eV and 1.02 eV for the first, second and third band respectively. Thermal treatments can modify the number of dipoles, dimers and clusters present in the crystal. The variation in the areas under each band can be used to measure this effect. In this work we used thermal treatments between 15 minutes and 10 hours and temperatures between 200 deg C and 500 deg C. For thermal treatments at 300 deg C, the dipoles and dimers are created and the clusters are destroyed as the time of thermal treatment increases. At 400 deg C the clusters are created and the dipoles and dimers and 350 deg C for the clusters. (author)

  2. Optically stimulated luminescence dosimetry using natural and synthetic materials

    DEFF Research Database (Denmark)

    Bøtter-Jensen, L.; McKeever, S.W.S.

    1996-01-01

    The application of optically stimulated luminescence (OSL) for use in radiation dosimetry is reviewed. A broad description is given of OSL techniques developed at Riso National Laboratory and at Oklahoma State University, and recent collaborative investigations on the properties of a variety...

  3. Thermally stimulated depolarization currents in the natural fluorite; Correntes de despolarizacao termicamente estimuladas na fluorita natural

    Energy Technology Data Exchange (ETDEWEB)

    Valerio, Mario Ernesto Giroldo

    1986-12-31

    The present work deals with natural calcium fluoride from Criciuma, Santa Catarina. Thermally Stimulated Depolarization Currents (TSDC) can be used to determine the properties of dipole defects present in this crystal. The TSDC spectrum of this material shows three bands in the temperature range of 80 to 450 K. The first one, at 130 K, is due the dipoles formed by a trivalent impurity and an interstitial fluorine ion in the next nearest position of an impurity ion (nn R{sub s}{sup 3+} -F{sub i}{sup -}). The second one, at 102 k, is due to the presence of small aggregates of dipoles (like a dimer). The last band, at 360 k is due to the formation of Large Clusters. The continuous distribution model gave the best fit for these bands with mean activation energies of 0.41 eV, 0.595 eV and 1.02 eV for the first, second and third band respectively. Thermal treatments can modify the number of dipoles, dimers and clusters present in the crystal. The variation in the areas under each band can be used to measure this effect. In this work we used thermal treatments between 15 minutes and 10 hours and temperatures between 200 deg C and 500 deg C. For thermal treatments at 300 deg C, the dipoles and dimers are created and the clusters are destroyed as the time of thermal treatment increases. At 400 deg C the clusters are created and the dipoles and dimers and 350 deg C for the clusters. (author) 60 refs., 41 figs., 1 tab.

  4. Thermally stimulated depolarization currents in the natural fluorite; Correntes de despolarizacao termicamente estimuladas na fluorita natural

    Energy Technology Data Exchange (ETDEWEB)

    Valerio, Mario Ernesto Giroldo

    1987-12-31

    The present work deals with natural calcium fluoride from Criciuma, Santa Catarina. Thermally Stimulated Depolarization Currents (TSDC) can be used to determine the properties of dipole defects present in this crystal. The TSDC spectrum of this material shows three bands in the temperature range of 80 to 450 K. The first one, at 130 K, is due the dipoles formed by a trivalent impurity and an interstitial fluorine ion in the next nearest position of an impurity ion (nn R{sub s}{sup 3+} -F{sub i}{sup -}). The second one, at 102 k, is due to the presence of small aggregates of dipoles (like a dimer). The last band, at 360 k is due to the formation of Large Clusters. The continuous distribution model gave the best fit for these bands with mean activation energies of 0.41 eV, 0.595 eV and 1.02 eV for the first, second and third band respectively. Thermal treatments can modify the number of dipoles, dimers and clusters present in the crystal. The variation in the areas under each band can be used to measure this effect. In this work we used thermal treatments between 15 minutes and 10 hours and temperatures between 200 deg C and 500 deg C. For thermal treatments at 300 deg C, the dipoles and dimers are created and the clusters are destroyed as the time of thermal treatment increases. At 400 deg C the clusters are created and the dipoles and dimers and 350 deg C for the clusters. (author) 60 refs., 41 figs., 1 tab.

  5. Removing bridge barriers stimulates suicides: an unfortunate natural experiment.

    Science.gov (United States)

    Beautrais, Annette L; Gibb, Sheree J; Fergusson, David M; Horwood, L John; Larkin, Gregory Luke

    2009-06-01

    Safety barriers to prevent suicide by jumping were removed from Grafton Bridge in Auckland, New Zealand, in 1996 after having been in place for 60 years. This study compared the number of suicides due to jumping from the bridge after the reinstallation of safety barriers in 2003. National mortality data for suicide deaths were compared for three time periods: 1991-1995 (old barrier in place); 1997-2002 (no barriers in place); 2003-2006 (after barriers were reinstated). Removal of barriers was followed by a fivefold increase in the number and rate of suicides from the bridge. These increases led to a decision to reinstall safety barriers. Since the reinstallation of barriers, of an improved design, in 2003, there have been no suicides from the bridge. This natural experiment, using a powerful a-b-a (reversal) design, shows that safety barriers are effective in preventing suicide: their removal increases suicides; their reinstatement prevents suicides.

  6. Measurement of optically and thermally stimulated electron emission from natural minerals

    DEFF Research Database (Denmark)

    Ankjærgaard, C.; Murray, A.S.; Denby, P.M.

    2006-01-01

    to a Riso TL/OSL reader, enabling optically stimulated electrons (OSE) and thermally stimulated electrons (TSE) to be measured simultaneously with optically stimulated luminescence (OSL) and thermoluminescence (TL). Repeated irradiation and measurement is possible without removing the sample from...... the counting chamber. Using this equipment both OSE and TSE from loose sand-sized grains of natural minerals has been recorded. It is shown that both the surface electron traps (giving rise to the OSE signals) and the bulk traps (giving rise to OSL) have the same dosimetric properties. A comparison of OSL...

  7. Optically stimulated luminescence of natural NaCl mineral from Dead Sea exposed to gamma radiation

    International Nuclear Information System (INIS)

    Roman L, J.; Cruz Z, E.; Pina L, Y. I.; Marcazzo, J.

    2016-10-01

    Luminescence properties such as radioluminescence, thermoluminescence and optically stimulated luminescence have been studied on natural sodium chloride (NaCl) for dosimetric purposes in retrospective dosimetry (Timar-Gabor et al., 2013; Druzhyna et al., 2016). In this work, the optically stimulated luminescence (Cw-OSL) emissions of natural salt minerals, collected from Dead Sea in summer of 2015, were studied. The Cw-OSL dose response of natural salt was analyzed in the range between 0.2 and 10 Gy gamma dose of "6"0Co. Samples exposed at 3 Gy exhibited good repeatability with a variation coefficient of 4.6%. The thermal stability of the Cw-OSL response was analyzed to different temperatures from 50 up to 250 degrees Celsius using a heating rate of 5 degrees Celsius. The results showed that the natural Dead Sea salt minerals could be applied as natural dosimeter of gamma radiation. (Author)

  8. Optically stimulated luminescence of natural NaCl mineral from Dead Sea exposed to gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Roman L, J.; Cruz Z, E. [UNAM, Instituto de Ciencias Nucleares, Ciudad Universitaria, 04510 Ciudad de Mexico (Mexico); Pina L, Y. I. [UNAM, Facultad de Ciencias, Ciudad Universitaria, 04510 Ciudad de Mexico (Mexico); Marcazzo, J., E-mail: jesus.roman@nucleares.unam.mx [Instituto de Fisica Arroyo Seco - UNICEN, Pinto 399, 7000 Tandil (Argentina)

    2016-10-15

    Luminescence properties such as radioluminescence, thermoluminescence and optically stimulated luminescence have been studied on natural sodium chloride (NaCl) for dosimetric purposes in retrospective dosimetry (Timar-Gabor et al., 2013; Druzhyna et al., 2016). In this work, the optically stimulated luminescence (Cw-OSL) emissions of natural salt minerals, collected from Dead Sea in summer of 2015, were studied. The Cw-OSL dose response of natural salt was analyzed in the range between 0.2 and 10 Gy gamma dose of {sup 60}Co. Samples exposed at 3 Gy exhibited good repeatability with a variation coefficient of 4.6%. The thermal stability of the Cw-OSL response was analyzed to different temperatures from 50 up to 250 degrees Celsius using a heating rate of 5 degrees Celsius. The results showed that the natural Dead Sea salt minerals could be applied as natural dosimeter of gamma radiation. (Author)

  9. Synchronized Firings in Retinal Ganglion Cells in Response to Natural Stimulation

    International Nuclear Information System (INIS)

    Zhang Ying-Ying; Xiao Lei; Liu Wen-Zhong; Gong Hai-Qing; Liang Pei-Ji

    2011-01-01

    The response of synchronously firing groups of population retinal ganglion cells (RGCs) to natural movies (NMs) and pseudo-random white-noise checker-board flickering (CB, as control) are investigated using an information-theoretic algorithm. The main results are: (1) the population RGCs tend to fire in synchrony far more frequently than expected by chance during both NM and CB stimulation; (2) more synchronous groups could be formed and each group contains more neurons under NM than CB stimulation; (3) the individual neurons also participate in more groups and have more distinct partners in NM than CB stimulation. All these results suggest that the synchronized firings in RGCs are more extensive and diverse, which may account for more effective information processing in representing the natural visual environment. (cross-disciplinary physics and related areas of science and technology)

  10. How to Stimulate Single Mothers on Welfare to Find a Job : Evidence from a Natural Experiment

    NARCIS (Netherlands)

    Knoef, M.G.; van Ours, J.C.

    2014-01-01

    We present the results from a natural experiment in which single mothers on welfare were stimulated to find a job. Two policy instruments were introduced: an earnings disregard and job creation. The experiment was performed at the level of municipalities in The Netherlands, a country with relatively

  11. Natural Killer Dendritic Cells Enhance Immune Responses Elicited by α-Galactosylceramide-Stimulated Natural Killer T Cells

    Directory of Open Access Journals (Sweden)

    Sung Won Lee

    2013-01-01

    Full Text Available Natural killer dendritic cells (NKDCs possess potent anti-tumor activity, but the cellular effect of NKDC interactions with other innate immune cells is unclear. In this study, we demonstrate that the interaction of NKDCs and natural killer T (NKT cells is required for the anti-tumor immune responses that are elicited by α-galactosylceramide (α-GC in mice. The rapid and strong expression of interferon-γ by NKDCs after α-GC stimulation was dependent on NKT cells. Various NK and DC molecular markers and cytotoxic molecules were up-regulated following α-GC administration. This up-regulation could improve NKDC presentation of tumor antigens and increase cytotoxicity against tumor cells. NKDCs were required for the stimulation of DCs, NK cells, and NKT cells. The strong anti-tumor immune responses elicited by α-GC may be due to the down-regulation of regulatory T cells. Furthermore, the depletion of NKDCs dampened the tumor clearance mediated by α-GC-stimulated NKT cells in vivo. Taken together, these results indicate that complex interactions of innate immune cells might be required to achieve optimal anti-tumor immune responses during the early stages of tumorigenesis.

  12. Single embryo transfer: the role of natural cycle/minimal stimulation IVF in the future.

    Science.gov (United States)

    Nygren, Karl-Gösta

    2007-05-01

    There are several good reasons to assume that single embryo transfer (SET) eventually will become the norm internationally in IVF treatments. A tendency is clearly visible, as demonstrated in the latest IVF World Report. The Nordic countries and Belgium have been leading the way. Sweden at present has 70% SET, with 5% twins and a pregnancy rate per transfer remaining constant at about 30%. As a consequence, recent data show a drastic reduction of the risk of prematurity and therefore of child morbidity and perinatal mortality. It is now time to discuss alternatives to the current clinical policy of quite an aggressive ovarian stimulation in settings where SET is the norm. When and at what proportion could natural cycle/soft stimulation be used? What group of patients would benefit? What will the consequences be in terms of efficacy, safety, cost, time and quality of life? Selection of the most beneficial, rather than the most aggressive, ovarian stimulation protocol by clinicians and by the couples themselves in the future may well include a much wider use of natural cycle/soft stimulation in IVF.

  13. Using optically stimulated electrons from quartz for the estimation of natural doses

    DEFF Research Database (Denmark)

    Ankjærgaard, Christina; Murray, A.S.; Denby, Phil M.

    2009-01-01

    A flow-through Geiger-Müller pancake electron detector attachment has been fitted to a standard Risø TL/OSL reader enabling optically stimulated electrons (OSE) to be measured simultaneously with optically stimulated luminescence (OSL). Using this detector, OSE and OSL measurements from natural......, a dose recovery test shows that OSE can successfully recover a laboratory dose of 300 Gy given before any laboratory thermal treatment, for preheating temperatures between 160 and 260 °C. Furthermore, for the first time natural OSE decay curves are detected and these signals are used to estimate a burial...... dose using the single-aliquot regenerative-dose (SAR) procedure. Finally, a comparative study of the equivalent doses estimated using both OSE and OSL from 10 quartz samples are presented, and it is shown that OSE has a significant potential in retrospective dosimetry....

  14. Optically stimulated luminescence characteristics of natural and doped quartz and alkali feldspars

    Energy Technology Data Exchange (ETDEWEB)

    Huett, G.; Jaek, I.; Brodski, L. [Institute of Geology at Tallinn Technical University, Tallinn (Estonia); Vasilchenko, V. [Institute of Experimental Physics and Technology of Tartu University, Tartu (Estonia)

    1999-05-01

    Natural alkali feldspars and quartz were doped by Tl and Cu by thermodiffusion and electrodiffusion technology. As a result of doping, intensive UV emission bands were created. The OSL stimulation spectra of irradiated natural and doped quartz and alkali feldspars were measured in the span of 400-1300 nm using UV emission of Tl at 280 nm and of Cu at 380 nm. One-trap centre conception was confirmed for high-temperature palaeodosimetrical TL peaks and OSL stimulation spectrum bands: for alkali feldspars at 880 and 420 nm and visible region of the spectrum for quartz. A thermooptical mechanism of the optical depopulation of the corresponding trap is confirmed in alkali feldspars, but there is no evidence for processes of this kind in quartz. An analogy between the physical background of OSL properties of both minerals is discussed.

  15. Optically stimulated luminescence characteristics of natural and doped quartz and alkali feldspars

    International Nuclear Information System (INIS)

    Huett, G.; Jaek, I.; Brodski, L.; Vasilchenko, V.

    1999-01-01

    Natural alkali feldspars and quartz were doped by Tl and Cu by thermodiffusion and electrodiffusion technology. As a result of doping, intensive UV emission bands were created. The OSL stimulation spectra of irradiated natural and doped quartz and alkali feldspars were measured in the span of 400-1300 nm using UV emission of Tl at 280 nm and of Cu at 380 nm. One-trap centre conception was confirmed for high-temperature palaeodosimetrical TL peaks and OSL stimulation spectrum bands: for alkali feldspars at 880 and 420 nm and visible region of the spectrum for quartz. A thermooptical mechanism of the optical depopulation of the corresponding trap is confirmed in alkali feldspars, but there is no evidence for processes of this kind in quartz. An analogy between the physical background of OSL properties of both minerals is discussed

  16. Search for the dose-sensitive optically stimulated luminescence response in natural carbonates

    International Nuclear Information System (INIS)

    Jaek, Ivar; Huett, Galina; Rammo, Ilmar; Vasilchenko, Valeri

    2001-01-01

    Carbonates of different origin, such as Iceland spar, calcites, and mollusc shells, used as electron spin resonance and thermoluminescence paleodosimeters, were studied in order to determine their suitability for optically stimulated luminescence dating. The stimulation/excitation spectra of the afterglow of the samples were recorded in the wavelength range of 250-1100 nm. The results of the study show that these spectra present either excitation spectra of Mn 2+ ion fluorescence (samples of calcites and Iceland spar, red emission recorded) or the excitation spectra of primary phosphorescence (samples of carbonates, including molluscs shells; short-wave emission bands recorded). The recorded stimulation spectra revealed no spectral bands sensitive to stimulation by ionizing radiation, which would disappear as a result of heating and could thus be related to deep traps in carbonates, needed dating. The cause of this situation which is unusual in luminescent crystals, including luminescence (paleo)dosimeters, and the ways of overcoming the difficulties in optical dating of natural carbonates are discussed. (author)

  17. Optically stimulated luminescence dosimetry performance of natural Brazilian topaz exposed to beta radiation

    International Nuclear Information System (INIS)

    Bernal, R.; Souza, D. N.; Valerio, M. E. G.; Cruz-Vazquez, C.; Barboza-Flores, M.

    2006-01-01

    Optically stimulated luminescence (OSL) has become the technique of choice in many areas of dosimetry. Natural materials like topaz are available in large quantities in Brazil and other countries. They have been studied to investigate the possibility of use its thermoluminescence (TL) properties for dosimetric applications. In this work, we investigate the possibility of utilising the OSL properties of natural Brazilian topaz in dosimetry. Bulk topaz samples were exposed to doses up to 100 Gy of beta radiation and the integrated OSL as a function of the dose showed linear behaviour. The fading occurs in the first 20 min after irradiation but it is <6% of the integrated OSL measured shortly after exposure. We conclude that natural colourless topaz is a very suitable phosphor for OSL dosimetry. (authors)

  18. Calculational techniques for estimating population doses from radioactivity in natural gas from nuclearly stimulated wells

    International Nuclear Information System (INIS)

    Barton, C.J.; Moore, R.E.; Rohwer, P.S.; Kaye, S.V.

    1975-01-01

    Techniques for estimating radiation doses from exposure to combustion products of natural gas obtained from wells created by use of nuclear explosives were first developed in the Gasbuggy Project. These techniques were refined and extended by development of a number of computer codes in studies related to the Rulison Project, the second in the series of joint government-industry efforts to demonstrate the feasibility of increasing natural gas production from low-permeability rock formations by use of nuclear explosives. These techniques are described and dose estimates that illustrate their use are given. These dose estimation studies have been primarily theoretical, but we have tried to make our hypothetical exposure conditions correspond as closely as possible with conditions that could exist if nuclearly stimulated natural gas is used commercially. (author)

  19. Detection of carcinogenicity of low-dose radiation

    International Nuclear Information System (INIS)

    Yokoro, Kenjiro; Sumi, Chiyo; Hamada, Katsutomo

    1978-01-01

    Induction of mammary tumors in female, W/Fu strain rats which were irradiated using an experimental atomic pile--KUR was described. Thermal neutron of 0.025 eV on an average transmitted through a heavy water equipment was emitted into a uranium converter which consists of enriched uranium to atomic fission. This produces fission neutron of 2 MeV on an average, prompt γ-ray, and γ-ray which is emitted from atomic fission products. When a dose of 4.8 rem (2.4 + 2.4), 8.9 rem (4.8 + 4.1), or 19.5 rem (12.5 + 7.5) in the total of fission neutron and γ-ray was irradiated to rats, benign fibroadenoma occurred in one (4.8 rem) of 48 rats after 230 days of latency. When irradiation of the same amount of neutron and γ-ray was given to rats and, in addition, prolactin was given, breast tumor which consisted mainly of adeno carcinoma occurred in 17 of the 48 rats (about 35%). Combination of irradiation (even the least dose, 4.8 rem) and prolactin had a carcinogenetic effect. (Ueda, J.)

  20. Risk of cancer subsequent to low-dose radiation

    International Nuclear Information System (INIS)

    Warren, S.

    1980-01-01

    The author puts low dose irradiation risks in perspective using average background radiation doses for standards. He assailed irresponsible media coverage during the height of public interest in the Three-Mile Island Reactor incident

  1. Intracranial germinomas: a case for low dose radiation therapy alone

    International Nuclear Information System (INIS)

    Harrigan, Patricia M.; Loeffler, Jay S.; Shrieve, Dennis; Tarbell, Nancy J.

    1995-01-01

    Purpose: To determine the optimal dose and treatment outcome of patients treated with radiation for intracranial germinoma. Materials and Methods: Between 1975 and 1995, 39 patients with a diagnosis of intracranial germinoma were treated with radiation (RT) to the central nervous system. All but one pt received whole brain (WB) RT, (median dose: 3240 cGy range: 1500-4437 cGy) and a boost to the tumor volume (median total tumor volume dose: 5200 cGy, range: 3960-5950 cGy). Thirty-one pts received RT to the spine (median dose: 2500, range: 1875-3750). Eleven pts were treated with low dose RT and a tumor volume boost, (WB dose ≤ 2550 cGy, and spine dose ≤ 2160 cGy). Five pts were treated with cisplatin-based chemotherapy and low dose WB RT. Fifteen pts were biopsy-proven and 18 presented with multiple midline germinomas (MMG). Among all pts, 33% had serum or CSF positive for low levels of HCG and none of 19 (9 biopsy-proven) germinomas measured positive for AFP tumor marker. Six of 22 (27%) pts who had spine imaging or CSF cytology had evidence of tumor seeding. The male-to female-ratio was 1.4. Median age at diagnosis was 14 yrs for male pts and 9.5 yrs for females (p=.02, overall age range: 1-31 yrs). Median follow-up for survivors is 64 months (range: 1-226 months). Toxicity of treatment relative to dose was assessed. Results: The 5-yr. actuarial rate of disease-free survival (DFS) and overall survival for presumed germinomas was 97%. No pts died of germinoma. One pt died of a shunt infection who had received concurrent chemotherapy and low dose whole brain RT. Among the low dose RT alone group 6 pts received whole brain RT of ≤ 2550 cGy and 9 pts were treated with spinal RT of ≤ 2160 cGy without chemotherapy. Two of these pts had CSF cytology positive for tumor seeding. Additionally, 8 pts received a total dose to the tumor volume of ≤ 4800 cGy without chemotherapy. The 5-yr DFS was 100%. Five pts were treated with cisplatin-based chemotherapy followed by low dose RT. There were 2 CRs and 1 PR after 3 cycles, and 2 PRs after 1 cycle (chemotherapy was discontinued after 1 cycle due to ototoxicity). Among 18 pts treated with ≤ 3060 cGy WB RT (median follow-up: 35 mos), the most striking toxicity was in (4(5)) pts treated with chemotherapy who developed ototoxicity prior to RT. One pt had worsening of neuropsychological function which was present at diagnosis and 5 pts developed endocrinopathies. Among 20 pts treated with > 3060 cGy WB RT (median follow-up: 72 mos) there were 7 new or worsened neuropsychological outcomes. There were 10 pts who developed endocrinopathies. One female pt who received high dose WB RT was diagnosed with a glioblastoma multiforme within the treatment field 6 yrs after CSI. Conclusions: 1) Germinomas are highly curable with RT alone. 2.) These results suggest that low dose RT alone to the craniospinal axis (2000 cGy) and a boost to the tumor volume (4500 cGy) is effective and associated with few treatment complications. This may be more clearly indicated for pts with MMG or evidence of spinal seeding. Further experience is necessary to confirm this. 3.) The toxicity associated with high dose RT or chemotherapy and low dose RT argues against its use in germinomas

  2. The spectrum of mutation produced by low dose radiation

    International Nuclear Information System (INIS)

    Morley, Alexander A.; Turner, David R.

    2004-01-01

    Inherited mutations are the basis of evolution and acquired mutations in humans are important in ageing, cancer and possibly various forms of tissue degeneration. Mutations are responsible for many of the long-term effects of radiation. However, sensitive direct detection of mutations in humans has been difficult. The aims of the project were to develop methods for the sensitive enumeration of mutations in DNA, to measure mutation frequencies in a wide variety of tissue types and to quantify the mutational effect of direct oxidative damage produced by radiation, at both high and low doses. The project was successful in developing a sensitive method which could detect mutations directly in the genetic material, DNA at a sensitivity of 1 mutated molecule in 1000000000 unmutated molecules. However a number of methodological problems had to be overcome and lack of ongoing funding made it impossible to fulfill all of the aims of the project

  3. Sensitivity to low-dose radiation in radiosensitive ''wasted'' mice

    International Nuclear Information System (INIS)

    Paunesku, T.; Protic, M.; Woloschak, G. E.

    1999-01-01

    Mice homozygous for the autosomal recessive wasted mutation (wst/wst) have abnormalities in T-lymphocytes and in the anterior motor neuron cells of the spinal cord, leading to sensitivity to low doses of ionizing radiation, hind limb paralysis, and immunodeficiency. This defect results in a failure to gain weight by 20 days and death at 28 days of age. The wasted mutation (previously mapped to mouse chromosome 2) is shown to be a 3-bp deletion in a T-cell-specific (and perhaps motor-neuron-specific) regulatory region (promoter) of the proliferating cell nuclear antigen (PCNA) gene on mouse chromosome 2. A regulatory element is also shown to be important in PCNA expression in T-lymphocytes and motor neuron cells afflicted by the 3-bp deletion in the PCNA promoter. The model is as follows: Absence of PCNA expression in the thymuses (and motor neurons) of wasted mice causes cellular apoptosis; this absence of expression is mediated by a positive transactor that can bind to the wild-type but not the wasted mutant PCNA promoter; the bound protein induces late expression of PCNA in T-lymphocytes and prevents onset of radiation sensitivity in the cells

  4. Study on inhibition of hypertension by low dose radiation

    International Nuclear Information System (INIS)

    Yamaoka, Kiyonori; Nakazono, Koichi; Watanabe, Nobukazu; Inoue, Masayasu.

    1992-01-01

    To elucidate the pathogenesis of hypertension, superoxide dismutase (HB-SOD) with high affinity for vascular endothelial cells was administered to spontaneously hypertensive rats (SHR). HB-SOD but not native SOD markedly decreased the blood pressure of SHR but not of control rats. The results suggest that regulation of superoxide and the related metabolites in and around vascular endothelial cells is important for controling blood pressure in hypertensive subjects. (author)

  5. Low-Dose Radiation Induces Genes Promoting Cell Survival

    International Nuclear Information System (INIS)

    Liu, Shu-Zheng; Chen, Dong; Mu, Ying

    1999-01-01

    Apoptosis is an important process controlling homeostasis of the body. It is influenced by stimuli constantly arising from the external and internal environment of the organism. It is well known that radiation could induce apoptosis of cells in vitro and in vivo. However, the dose-effect relationship of apoptosis extending to the low-dose range has scarcely been studied. Here, the molecular basis of the phenomenon is explored by examining the changes in expression of some of the proapoptotic and antiapoptotic genes

  6. Intracranial germinomas: a case for low dose radiation therapy alone

    Energy Technology Data Exchange (ETDEWEB)

    Harrigan, Patricia M; Loeffler, Jay S; Shrieve, Dennis; Tarbell, Nancy J

    1995-07-01

    Purpose: To determine the optimal dose and treatment outcome of patients treated with radiation for intracranial germinoma. Materials and Methods: Between 1975 and 1995, 39 patients with a diagnosis of intracranial germinoma were treated with radiation (RT) to the central nervous system. All but one pt received whole brain (WB) RT, (median dose: 3240 cGy range: 1500-4437 cGy) and a boost to the tumor volume (median total tumor volume dose: 5200 cGy, range: 3960-5950 cGy). Thirty-one pts received RT to the spine (median dose: 2500, range: 1875-3750). Eleven pts were treated with low dose RT and a tumor volume boost, (WB dose {<=} 2550 cGy, and spine dose {<=} 2160 cGy). Five pts were treated with cisplatin-based chemotherapy and low dose WB RT. Fifteen pts were biopsy-proven and 18 presented with multiple midline germinomas (MMG). Among all pts, 33% had serum or CSF positive for low levels of HCG and none of 19 (9 biopsy-proven) germinomas measured positive for AFP tumor marker. Six of 22 (27%) pts who had spine imaging or CSF cytology had evidence of tumor seeding. The male-to female-ratio was 1.4. Median age at diagnosis was 14 yrs for male pts and 9.5 yrs for females (p=.02, overall age range: 1-31 yrs). Median follow-up for survivors is 64 months (range: 1-226 months). Toxicity of treatment relative to dose was assessed. Results: The 5-yr. actuarial rate of disease-free survival (DFS) and overall survival for presumed germinomas was 97%. No pts died of germinoma. One pt died of a shunt infection who had received concurrent chemotherapy and low dose whole brain RT. Among the low dose RT alone group 6 pts received whole brain RT of {<=} 2550 cGy and 9 pts were treated with spinal RT of {<=} 2160 cGy without chemotherapy. Two of these pts had CSF cytology positive for tumor seeding. Additionally, 8 pts received a total dose to the tumor volume of {<=} 4800 cGy without chemotherapy. The 5-yr DFS was 100%. Five pts were treated with cisplatin-based chemotherapy followed by low dose RT. There were 2 CRs and 1 PR after 3 cycles, and 2 PRs after 1 cycle (chemotherapy was discontinued after 1 cycle due to ototoxicity). Among 18 pts treated with {<=} 3060 cGy WB RT (median follow-up: 35 mos), the most striking toxicity was in (4(5)) pts treated with chemotherapy who developed ototoxicity prior to RT. One pt had worsening of neuropsychological function which was present at diagnosis and 5 pts developed endocrinopathies. Among 20 pts treated with > 3060 cGy WB RT (median follow-up: 72 mos) there were 7 new or worsened neuropsychological outcomes. There were 10 pts who developed endocrinopathies. One female pt who received high dose WB RT was diagnosed with a glioblastoma multiforme within the treatment field 6 yrs after CSI. Conclusions: 1) Germinomas are highly curable with RT alone. 2.) These results suggest that low dose RT alone to the craniospinal axis (2000 cGy) and a boost to the tumor volume (4500 cGy) is effective and associated with few treatment complications. This may be more clearly indicated for pts with MMG or evidence of spinal seeding. Further experience is necessary to confirm this. 3.) The toxicity associated with high dose RT or chemotherapy and low dose RT argues against its use in germinomas.

  7. Low Dose Radiation Cancer Risks: Epidemiological and Toxicological Models

    Energy Technology Data Exchange (ETDEWEB)

    David G. Hoel, PhD

    2012-04-19

    The basic purpose of this one year research grant was to extend the two stage clonal expansion model (TSCE) of carcinogenesis to exposures other than the usual single acute exposure. The two-stage clonal expansion model of carcinogenesis incorporates the biological process of carcinogenesis, which involves two mutations and the clonal proliferation of the intermediate cells, in a stochastic, mathematical way. The current TSCE model serves a general purpose of acute exposure models but requires numerical computation of both the survival and hazard functions. The primary objective of this research project was to develop the analytical expressions for the survival function and the hazard function of the occurrence of the first cancer cell for acute, continuous and multiple exposure cases within the framework of the piece-wise constant parameter two-stage clonal expansion model of carcinogenesis. For acute exposure and multiple exposures of acute series, it is either only allowed to have the first mutation rate vary with the dose, or to have all the parameters be dose dependent; for multiple exposures of continuous exposures, all the parameters are allowed to vary with the dose. With these analytical functions, it becomes easy to evaluate the risks of cancer and allows one to deal with the various exposure patterns in cancer risk assessment. A second objective was to apply the TSCE model with varing continuous exposures from the cancer studies of inhaled plutonium in beagle dogs. Using step functions to estimate the retention functions of the pulmonary exposure of plutonium the multiple exposure versions of the TSCE model was to be used to estimate the beagle dog lung cancer risks. The mathematical equations of the multiple exposure versions of the TSCE model were developed. A draft manuscript which is attached provides the results of this mathematical work. The application work using the beagle dog data from plutonium exposure has not been completed due to the fact that the research project did not continue beyond its first year.

  8. Advance of study on hormesis of low dose radiation

    International Nuclear Information System (INIS)

    Su Liaoyuan

    2003-01-01

    There have been growing interests in recent years over the effects of low doses of ionizing radiation on human. The paper gives a brief review on the LDR studies, which include LDR-induced hormesis and adaptive response, LDR experiments in vivo or in vitro and epidemiologic investigation, and clinical applications of LDR as well

  9. Relationship to carcinogenesis of repetitive low-dose radiation exposure

    International Nuclear Information System (INIS)

    Ootsuyama, Akira

    2016-01-01

    We studied the carcinogenic effects caused by repetitive irradiation at a low dose, which has received attention in recent years, and examined the experimental methods used to evaluate radiation-induced carcinogenesis. For this experiment, we selected a mouse with as few autochthonous cancers as possible. Skin cancer was selected as the target for analysis, because it is a rare cancer in mice. Beta-rays were selected as the radiation source. The advantage of using beta-rays is weaker penetration power into tissues, thus protecting organs, such as the digestive and hematogenous organs. The benefit of our experimental method is that only skin cancer requires monitoring, and it is possible to perform long-term experiments. The back skin of mice was exposed repetitively to beta-rays three times a week until the occurrence of cancer or death, and the dose per exposure ranged from 0.5 to 11.8 Gy. With the high-dose range (2.5-11.8 Gy), the latency period and carcinogenic rate were almost the same in each experimental group. When the dose was reduced to 1-1.5 Gy, the latency period increased, but the carcinogenic rate remained. When the dose was further reduced to 0.5 Gy, skin cancer never happened, even though we continued irradiation until death of the last mouse in this group. The lifespan of 0.5 Gy group mice was the same as that of the controls. We showed that the 0.5 Gy dose did not cause cancer, even in mice exposed repetitively throughout their life span, and thus refer to 0.5 Gy as the threshold-like dose. (author)

  10. The assessment of the carcinogenic effects of low dose radiation

    International Nuclear Information System (INIS)

    Tubiana, M.; Lafuma, J.; Masse, R.; Latarjet, R.

    1991-01-01

    It is concluded that the exclusion of patients for the purposes of risk estimation, the choice of a particular relative risk projection model and of a dose reduction factor equal to 2 are all decisions which result in an overestimation of the actual risk. These choices can be understood when the aim is radiation protection and when it is safer to overestimate the risk; however, they are open to criticism if the aim is a realistic assessment of the risk. For low doses, below 50 mSv/year, and when all causes of uncertainty are added, the actual risk might be markedly lower than the risk estimated with the ICRP (1991) carcinogenic risk coefficient and the DRF estimated by ICRP. Future studies should aim at providing direct and more precise assessments of risk coefficients in the low dose region. (Author)

  11. Thyroid neoplasia following low-dose radiation in childhood

    International Nuclear Information System (INIS)

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

    1989-01-01

    The thyroid gland is highly sensitive to the carcinogenic effects of ionizing radiation. Previously, we reported a significant increase of thyroid cancer and adenomas among 10,834 persons in Israel who received radiotherapy to the scalp for ringworm. These findings have now been extended with further follow-up and revised dosimetry. Overall, 98 thyroid tumors were identified among the exposed and 57 among 10,834 nonexposed matched population and 5392 sibling comparison subjects. An estimated thyroid dose of 9 cGy was linked to a fourfold (95% Cl = 2.3-7.9) increase of malignant tumors and a twofold (95% Cl = 1.3-3.0) increase of benign tumors. The dose-response relationship was consistent with linearity. Age was an important modifier of risk with those exposed under 5 years being significantly more prone to develop thyroid tumors than older children. The pattern of radiation risk over time could be described on the basis of a constant multiplication of the background rate, and an absolute risk model was not compatible with the observed data. Overall, the excess relative risk per cGy for thyroid cancer development after childhood exposure is estimated as 0.3, and the absolute excess risk as 13 per 10(6) PY-cGy. For benign tumors the estimated excess relative risk was 0.1 per cGy and the absolute risk was 15 per 10(6) PY-cGy

  12. Application of low dose radiation for preservation of sea foods

    International Nuclear Information System (INIS)

    Venugopal, V.; Nair, P.M.

    1994-01-01

    Treatment of food with low doses of gamma radiation has been recognized to have two main advantages. These consist of: (1) improvement of food safety by elimination of pathogens and (2) reduction of microbial spoilage and extension of shelf life of perishable items by reducing the number of viable spoilage organisms. Studies during the last few decades have conclusively proved the beneficial effects of radiation with respect to fishery products. The three potential areas of application to fish products include: (i) radurization for shelf life extension (ii) radicidation to eliminate food borne pathogens in the products and (iii) radiation treatment to dried products to control insects

  13. Low-Dose Radiation Cataract and Genetic Determinants of Radiosensitivity

    Energy Technology Data Exchange (ETDEWEB)

    Kleiman, Norman Jay [Columbia University

    2013-11-30

    The lens of the eye is one of the most radiosensitive tissues in the body. Ocular ionizing radiation exposure results in characteristic, dose related, progressive lens changes leading to cataract formation. While initial, early stages of lens opacification may not cause visual disability, the severity of such changes progressively increases with dose until vision is impaired and cataract extraction surgery may be required. Because of the transparency of the eye, radiation induced lens changes can easily be followed non-invasively over time. Thus, the lens provides a unique model system in which to study the effects of low dose ionizing radiation exposure in a complex, highly organized tissue. Despite this observation, considerable uncertainties remain surrounding the relationship between dose and risk of developing radiation cataract. For example, a growing number of human epidemiological findings suggest significant risk among various groups of occupationally and accidentally exposed individuals and confidence intervals that include zero dose. Nevertheless, questions remain concerning the relationship between lens opacities, visual disability, clinical cataract, threshold dose and/or the role of genetics in determining radiosensitivity. Experimentally, the response of the rodent eye to radiation is quite similar to that in humans and thus animal studies are well suited to examine the relationship between radiation exposure, genetic determinants of radiosensitivity and cataractogenesis. The current work has expanded our knowledge of the low-dose effects of X-irradiation or high-LET heavy ion exposure on timing and progression of radiation cataract and has provided new information on the genetic, molecular, biochemical and cell biological features which contribute to this pathology. Furthermore, findings have indicated that single and/or multiple haploinsufficiency for various genes involved in DNA repair and cell cycle checkpoint control, such as Atm, Brca1 or Rad9, influence cataract development and thus radiosensitivity. These observations have direct applicability to various human populations including accidentally exposed individuals, interventional medical workers, astronauts and nuclear plant workers.

  14. Thymocyte apoptosis in response to low-dose radiation

    International Nuclear Information System (INIS)

    Shu-Zheng, Liu; Ying-Chun, Zhang; Ying, Mu; Xu, Su; Jian-Xiang, Liu

    1996-01-01

    Thymocyte apoptosis was assessed by counting apoptotic bodies with flow cytometry (FCM) and measuring DNA fragmentation with fluorescence spectrophotometry (FSP). J-shaped dose-response curves were obtained after both whole-body irradiation (WBI) of mice and in vitro irradiation of EL4 cells with doses ranging from 0.025 to 4 Gy X-rays. There was a significant reduction of apoptosis rate to below control level with doses within 0.2 Gy, and a dose-dependent increase in apoptosis with doses above 0.5 Gy. When thymocytes were cultured 24 h after WBI with 75 mGy X-rays in complete RPMI 1640 medium, a reduction in apoptosis was observed in the course of incubation for 72 h, and the presence of Con A in the medium accentuated this reduction in a dose- and time-dependent manner. The implications of these observations and the possible molecular mechanisms for future studies are proposed

  15. Low dose radiation damage effects in silicon strip detectors

    International Nuclear Information System (INIS)

    Wiącek, P.; Dąbrowski, W.

    2016-01-01

    The radiation damage effects in silicon segmented detectors caused by X-rays have become recently an important research topic driven mainly by development of new detectors for applications at the European X-ray Free Electron Laser (E-XFEL). However, radiation damage in silicon strip is observed not only after extreme doses up to 1 GGy expected at E-XFEL, but also at doses in the range of tens of Gy, to which the detectors in laboratory instruments like X-ray diffractometers or X-ray spectrometers can be exposed. In this paper we report on investigation of radiation damage effects in a custom developed silicon strip detector used in laboratory diffractometers equipped with X-ray tubes. Our results show that significant degradation of detector performance occurs at low doses, well below 200 Gy, which can be reached during normal operation of laboratory instruments. Degradation of the detector energy resolution can be explained by increasing leakage current and increasing interstrip capacitance of the sensor. Another observed effect caused by accumulation of charge trapped in the surface oxide layer is change of charge division between adjacent strips. In addition, we have observed unexpected anomalies in the annealing process.

  16. Low dose radiation damage effects in silicon strip detectors

    Science.gov (United States)

    Wiącek, P.; Dąbrowski, W.

    2016-11-01

    The radiation damage effects in silicon segmented detectors caused by X-rays have become recently an important research topic driven mainly by development of new detectors for applications at the European X-ray Free Electron Laser (E-XFEL). However, radiation damage in silicon strip is observed not only after extreme doses up to 1 GGy expected at E-XFEL, but also at doses in the range of tens of Gy, to which the detectors in laboratory instruments like X-ray diffractometers or X-ray spectrometers can be exposed. In this paper we report on investigation of radiation damage effects in a custom developed silicon strip detector used in laboratory diffractometers equipped with X-ray tubes. Our results show that significant degradation of detector performance occurs at low doses, well below 200 Gy, which can be reached during normal operation of laboratory instruments. Degradation of the detector energy resolution can be explained by increasing leakage current and increasing interstrip capacitance of the sensor. Another observed effect caused by accumulation of charge trapped in the surface oxide layer is change of charge division between adjacent strips. In addition, we have observed unexpected anomalies in the annealing process.

  17. IL-15 STIMULATED NATURAL KILLER CELLS CLEAR HIV-1 INFECTED CELLS FOLLOWING LATENCY REVERSAL EX VIVO.

    Science.gov (United States)

    Garrido, Carolina; Abad-Fernandez, Maria; Tuyishime, Marina; Pollara, Justin J; Ferrari, Guido; Soriano-Sarabia, Natalia; Margolis, David M

    2018-03-28

    Current efforts towards HIV eradication include approaches to augment immune recognition and elimination of persistently infected cells following latency reversal. Natural killer (NK) cells, the main effectors of the innate immune system, recognize and clear targets using different mechanisms than CD8 + T cells, offering an alternative or complementary approach for HIV clearance strategies. We assessed the impact of IL-15 treatment on NK cell function and the potential of stimulated NK cells to clear the HIV reservoir. We measured NK cell receptor expression, antibody-dependent cell-dependent cytotoxicity (ADCC), cytotoxicity, IFN-γ production and antiviral activity in autologous HIV replication systems. All NK cell functions were uniformly improved by IL-15, and more importantly, IL-15-treated NK cells were able to clear latently HIV infected cells after exposure to vorinostat, a clinically relevant latency reversing agent. We also demonstrate that NK cells from HIV infected individuals aviremic on antiretroviral therapy can be efficiently stimulated with IL-15. Our work opens a promising line of investigation towards future immunotherapies to clear persistent HIV infection using NK cells. IMPORTANCE In the search for an HIV cure, strategies to enhance immune function to allow recognition and clearance of HIV infected cells following latency reversal are being evaluated. Natural killer (NK) cells possess characteristics that can be exploited for immunotherapy against persistent HIV infection. We demonstrate that NK cells from HIV-positive donors can be strongly stimulated with IL-15, improving their antiviral and cytotoxic potential, and more importantly, clearing HIV infected cells after latency reversal with a clinically relevant drug. Our results encourage further investigation to design NK cell-based immunotherapies to achieve HIV eradication. Copyright © 2018 American Society for Microbiology.

  18. Reduced spread of Campylobacter jejuni in broiler chickens by stimulating the bird's natural barriers.

    Science.gov (United States)

    Moen, B; Rudi, K; Svihus, B; Skånseng, B

    2012-11-01

    We have tested the effect of feed structure and feeding regime to prevent the spread of the zoonotic pathogen Campylobacter jejuni in broiler chicken flocks. Birds were offered two types of feed, control diet and a diet supplemented with 15% oat/barley hulls for structure. In addition, the birds were either fed ad libitum or intermittent. One bird in each treatment group was infected with a three-strain-mix of Camp. jejuni, and the spread of Camp. jejuni within the group was investigated. Feed structure increased the gizzard weight, delayed the spread of Camp. jejuni within the group and reduced the relative amount of Camp. jejuni in the caecum compared with the control diet. Our results show that stimulating the bird's natural barriers is a novel and promising intervention strategy to reduce the spread of Camp. jejuni in chicken flocks. Preventing Camp. jejuni in broiler chicken flocks is essential to ensure food safety because this bacterium is transferred to chicken carcasses during the slaughter process and readily survive in unprocessed poultry products. We have evaluated a novel approach for stimulation of the bird's natural barriers in the upper digestive tract with promising results. © 2012 The Authors Journal of Applied Microbiology © 2012 The Society for Applied Microbiology.

  19. Early natural stimulation through environmental enrichment accelerates neuronal development in the mouse dentate gyrus.

    Directory of Open Access Journals (Sweden)

    Na Liu

    Full Text Available The dentate gyrus is the primary afferent into the hippocampal formation, with important functions in learning and memory. Granule cells, the principle neuronal type in the dentate gyrus, are mostly formed postnatally, in a process that continues into adulthood. External stimuli, including environmental enrichment, voluntary exercise and learning, have been shown to significantly accelerate the generation and maturation of dentate granule cells in adult rodents. Whether, and to what extent, such environmental stimuli regulate the development and maturation of dentate granule cells during early postnatal development is largely unknown. Furthermore, whether natural stimuli affect the synaptic properties of granule cells had been investigated neither in newborn neurons of the adult nor during early development. To examine the effect of natural sensory stimulation on the dentate gyrus, we reared newborn mice in an enriched environment (EE. Using immunohistochemistry, we showed that dentate granule cells from EE-reared mice exhibited earlier morphological maturation, manifested as faster peaking of doublecortin expression and elevated expression of mature neuronal markers (including NeuN, calbindin and MAP2 at the end of the second postnatal week. Also at the end of the second postnatal week, we found increased density of dendritic spines across the entire dentate gyrus, together with elevated levels of postsynaptic scaffold (post-synaptic density 95 and receptor proteins (GluR2 and GABA(ARγ2 of excitatory and inhibitory synapses. Furthermore, dentate granule cells of P14 EE-reared mice had lower input resistances and increased glutamatergic and GABAergic synaptic inputs. Together, our results demonstrate that EE-rearing promotes morphological and electrophysiological maturation of dentate granule cells, underscoring the importance of natural environmental stimulation on development of the dentate gyrus.

  20. Natural attenuation and biosurfactant-stimulated bioremediation of estuarine sediments contaminated with diesel oil.

    Science.gov (United States)

    Bayer, Débora M; Chagas-Spinelli, Alessandra C O; Gavazza, Sávia; Florencio, Lourdinha; Kato, Mario T

    2013-09-01

    We evaluated the bioremediation, by natural attenuation (NA) and by natural attenuation stimulated (SNA) using a rhamnolipid biosurfactant, of estuarine sediments contaminated with diesel oil. Sediment samples (30 cm) were put into 35 cm glass columns, and the concentrations of the 16 polycyclic aromatic hydrocarbons (PAHs) prioritized by the US Environmental Protection Agency were monitored for 111 days. Naphthalene percolated through the columns more than the other PAHs, and, in general, the concentrations of the lower molecular weight PAHs, consisting of two and three aromatic rings, changed during the first 45 days of treatment, whereas the concentrations of the higher molecular weight PAHs, consisting of four, five, and six rings, were more stable. The higher molecular weight PAHs became more available after 45 days, in the deeper parts of the columns (20-30 cm). Evidence of degradation was observed only for some compounds, such as pyrene, with a total removal efficiency of 82 and 78 % in the NA and SNA treatments, respectively, but without significant difference. In the case of total PAH removal, the efficiencies were significantly different of 82 and 67 %, respectively.

  1. Mixed Signals: Co-Stimulation in Invariant Natural Killer T Cell-Mediated Cancer Immunotherapy

    Directory of Open Access Journals (Sweden)

    Susannah C. Shissler

    2017-11-01

    Full Text Available Invariant natural killer T (iNKT cells are an integral component of the immune system and play an important role in antitumor immunity. Upon activation, iNKT cells can directly kill malignant cells as well as rapidly produce cytokines that stimulate other immune cells, making them a front line defense against tumorigenesis. Unfortunately, iNKT cell number and activity are reduced in multiple cancer types. This anergy is often associated with upregulation of co-inhibitory markers such as programmed death-1. Similar to conventional T cells, iNKT cells are influenced by the conditions of their activation. Conventional T cells receive signals through the following three types of receptors: (1 T cell receptor (TCR, (2 co-stimulation molecules, and (3 cytokine receptors. Unlike conventional T cells, which recognize peptide antigen presented by MHC class I or II, the TCRs of iNKT cells recognize lipid antigen in the context of the antigen presentation molecule CD1d (Signal 1. Co-stimulatory molecules can positively and negatively influence iNKT cell activation and function and skew the immune response (Signal 2. This study will review the background of iNKT cells and their co-stimulatory requirements for general function and in antitumor immunity. We will explore the impact of monoclonal antibody administration for both blocking inhibitory pathways and engaging stimulatory pathways on iNKT cell-mediated antitumor immunity. This review will highlight the incorporation of co-stimulatory molecules in antitumor dendritic cell vaccine strategies. The use of co-stimulatory intracellular signaling domains in chimeric antigen receptor-iNKT therapy will be assessed. Finally, we will explore the influence of innate-like receptors and modification of immunosuppressive cytokines (Signal 3 on cancer immunotherapy.

  2. Direct Imaging of Natural Fractures and Stress Compartments Stimulated by Hydraulic Fracturing

    Science.gov (United States)

    Lacazette, A.; Vermilye, J. M.

    2014-12-01

    This contribution will present results from passive seismic studies of hydraulic fracture treatments in North American and Asian basins. One of the key data types is a comparatively new surface-based seismic imaging product - "Tomographic Fracture Images®" (TFI®). The procedure is an extension of Seismic Emission Tomography (SET), which is well-established and widely used. Conventional microseismic results - microearthquake hypocenter locations, magnitudes, and focal mechanism solutions - are also obtained from the data via a branch of the processing workflow. TFI is accomplished by summing the individual time steps in a multidimensional SET hypervolume over extended periods of time, such as an entire frac stage. The dimensions of a SET hypervolume are the X, Y, and Z coordinates of the voxels, the time step (typically on the order of 100 milliseconds), and the seismic activity value. The resulting summed volume is skeletonized to produce images of the main fracture surfaces, which are known to occupy the maximum activity surfaces of the high activity clouds from theory, field studies, and experiments. The orientation vs. area of the resulting TFIs can be analyzed in detail and compared with independent data sets such as volumetric structural attributes from reflection seismic data and borehole fracture data. We find that the primary effect of hydraulic fracturing is to stimulate preexisting natural fracture networks and faults. The combination of TFIs with hypocenter distributions and microearthquake focal mechanisms provides detailed information on subsurface stress compartmentalization. Faults are directly imaged which allows discrimination of fault planes from auxiliary planes of focal mechanism solutions. Examples that will be shown include simultaneous movement on a thrust fault and tear fault and examples of radically different stress compartments (e.g. extensional vs. wrench faulting) stimulated during a single hydraulic fracture treatment. The figure

  3. Stimulating Interest in Natural Sciences and Training Observation Skills: The UAP Observations Reporting Scheme

    Science.gov (United States)

    Ailleris, P.

    2012-04-01

    For a number of reasons the general public and many young people are fascinated by the ideas of UFOs and extra-terrestrial life. As mysteries motivate to gain interest and knowledge, an opportunity exists, throughout these topics, to stimulate the people's interests to natural sciences and technology. A major problem however exists, concerning the fact that the general public generally associates any strange aerial sighting to something exotic, unknown, and to the possibility of extraterrestrial visitations. Rumours, irrational thinking and conspiracy theories prevail around these topics. Launched under the framework of the 2009 International Year of Astronomy, the Unidentified Aerospace Phenomena (UAP) Observations Reporting Scheme seeks to tackle this situation through approaching the topic from a professional and rational perspective, providing an opportunity to teach the public how to think more critically, demystifying UFO events, and ultimately attempting to stimulate the interest in natural sciences and technological disciplines. This is tentatively attempted through the following resources: Firstly, the project's website (1) provides an extensive resource for inquiry-based learning regarding the various natural or man-made phenomena that often give rise to false UAP sightings. It serves as a general forum for educating the public about human, atmospheric and astrophysical phenomena that could be observed in the sky. Secondly, the basic educational information provided on the web site allows potential UAP witnesses to critically evaluate the potential cause of their sightings. Visual descriptions, photos, video clips, tools, and links to relevant websites are provided for each category of phenomena, in order to assist the observer in his self-analysis. Amateur astronomers and societies who receive questions about UFOs can redirect queries to the website. Thirdly, the website provides novice observers viewing tips (e.g. elevation, azimuth, angular size) about

  4. Carbonate counter pump stimulated by natural iron fertilization in the Polar Frontal Zone

    Science.gov (United States)

    Salter, Ian; Schiebel, Ralf; Ziveri, Patrizia; Movellan, Aurore; Lampitt, Richard; Wolff, George A.

    2014-12-01

    The production of organic carbon in the ocean's surface and its subsequent downward export transfers carbon dioxide to the deep ocean. This CO2 drawdown is countered by the biological precipitation of carbonate, followed by sinking of particulate inorganic carbon, which is a source of carbon dioxide to the surface ocean, and hence the atmosphere over 100-1,000 year timescales. The net transfer of CO2 to the deep ocean is therefore dependent on the relative amount of organic and inorganic carbon in sinking particles. In the Southern Ocean, iron fertilization has been shown to increase the export of organic carbon, but it is unclear to what degree this effect is compensated by the export of inorganic carbon. Here we assess the composition of sinking particles collected from sediment traps located in the Polar Frontal Zone of the Southern Ocean. We find that in high-nutrient, low-chlorophyll regions that are characterized by naturally high iron concentrations, fluxes of both organic and inorganic carbon are higher than in regions with no iron fertilization. However, the excess flux of inorganic carbon is greater than that of organic carbon. We estimate that the production and flux of carbonate in naturally iron-fertilized waters reduces the overall amount of CO2 transferred to the deep ocean by 6-32%, compared to 1-4% at the non-fertilized site. We suggest that an increased export of organic carbon, stimulated by iron availability in the glacial sub-Antarctic oceans, may have been accompanied by a strengthened carbonate counter pump.

  5. A King Bolete, Boletus edulis (Agaricomycetes), RNA Fraction Stimulates Proliferation and Cytotoxicity of Natural Killer Cells Against Myelogenous Leukemia Cells.

    Science.gov (United States)

    Lemieszek, Marta Kinga; Nunes, Fernando Herminio Ferreira Milheiro; Sawa-Wejksza, Katarzyna; Rzeski, Wojciech

    2017-01-01

    Numerous studies indicate the crucial role of natural killer (NK) cells in the prevention of tumor growth and inhibition of their metastasis, which suggests the possibility of their use in cancer treatment. This therapeutic strategy required finding a selective NK cell stimulator that, upon administration, did not disturb organism homeostasis, unlike natural activators (interleukin-2 or interleukin-12). Because the majority of anticancer agents derived from Basidiomycetes are able to stimulate lymphocytes, we describe the influence of Boletus edulis RNA on a human NK cell line (NK92). Our studies showed that a B. edulis RNA fraction was not toxic against NK92 cells. Furthermore, the tested fraction significantly stimulated NK92 cell proliferation and their cytotoxicity against tumor cells. We demonstrate here, to our knowledge for the first time, that B. edulis RNA enhances NK cell activity and possesses immunomodulatory potential.

  6. Epidemiological studies on disturbances of human fetal development in areas with various doses of natural background radiation. I. Relationship between incidences of Down's syndrome or visible malformation and gonad dose equivalent rate of natural background radiation

    International Nuclear Information System (INIS)

    Ujeno, Y.

    1985-01-01

    The relationship between environmental radiation to the gonads and incidences of Down's syndrome and visible malformation was analyzed using Kendall's rank correlation method. The subjects, studied during a 3-yr period (1979-1981), were inhabitants of 46 prefectures in Japan that had various dose rates of natural background ionizing radiation. Results showed that the natural background very low-dose radiation rate was not a predominant factor responsible for inducing Down's syndrome or other visible malformations

  7. Hydromechanical and Thermomechanical Behaviour of Elastic Fractures during Thermal Stimulation of Naturally Fractured Reservoirs

    Science.gov (United States)

    Jalali, Mohammadreza; Valley, Benoît

    2015-04-01

    During the last two decades, incentives were put in place in order to feed our societies in energy with reduced CO2 emissions. Various policies have been considered to fulfill this strategy such as replacing coal by natural gas in power plants, producing electricity using CO2 free resources, and CO2 sequestration as a remediation for large point-source emitters (e.g. oil sands facilities, coal-fired power plants, and cement kilns). Naturally fractured reservoirs (NFRs) are among those geological structures which play a crucial role in the mentioned energy revolution. The behavior of fractured reservoirs during production processes is completely different than conventional reservoirs because of the dominant effects of fractures on fluid flux, with attendant issues of fracture fabric complexity and lithological heterogeneity. The level of complexity increases when thermal effects are taking place - as during the thermal stimulation of these stress-sensitive reservoirs in order to enhance the gas production in tight shales and/or increase the local conductivity of the fractures during the development of enhanced geothermal systems - where temperature is introduced as another degree of freedom in addition to pressure and displacement (or effective stress). Study of these stress-pressure-temperature effects requires a thermo-hydro-mechanical (THM) coupling approach, which considers the simultaneous variation of effective stress, pore pressure, and temperature and their interactions. In this study, thermal, hydraulic and mechanical behavior of partially open and elastic fractures in a homogeneous, isotropic and low permeable porous rock is studied. In order to compare the hydromechanical (HM) and thermomechanical (TM) characteristics of these fractures, three different injection scenarios, i.e. constant isothermal fluid injection rate, constant cooling without any fluid injection and constant cold fluid injection, are considered. Both thermomechanical and hydromechanical

  8. Interactive rhythmic auditory stimulation reinstates natural 1/f timing in gait of Parkinson's patients.

    Directory of Open Access Journals (Sweden)

    Michael J Hove

    Full Text Available Parkinson's disease (PD and basal ganglia dysfunction impair movement timing, which leads to gait instability and falls. Parkinsonian gait consists of random, disconnected stride times--rather than the 1/f structure observed in healthy gait--and this randomness of stride times (low fractal scaling predicts falling. Walking with fixed-tempo Rhythmic Auditory Stimulation (RAS can improve many aspects of gait timing; however, it lowers fractal scaling (away from healthy 1/f structure and requires attention. Here we show that interactive rhythmic auditory stimulation reestablishes healthy gait dynamics in PD patients. In the experiment, PD patients and healthy participants walked with a no auditory stimulation, b fixed-tempo RAS, and c interactive rhythmic auditory stimulation. The interactive system used foot sensors and nonlinear oscillators to track and mutually entrain with the human's step timing. Patients consistently synchronized with the interactive system, their fractal scaling returned to levels of healthy participants, and their gait felt more stable to them. Patients and healthy participants rarely synchronized with fixed-tempo RAS, and when they did synchronize their fractal scaling declined from healthy 1/f levels. Five minutes after removing the interactive rhythmic stimulation, the PD patients' gait retained high fractal scaling, suggesting that the interaction stabilized the internal rhythm generating system and reintegrated timing networks. The experiment demonstrates that complex interaction is important in the (reemergence of 1/f structure in human behavior and that interactive rhythmic auditory stimulation is a promising therapeutic tool for improving gait of PD patients.

  9. Effects of locus coeruleus stimulation on the responses of SI neurons of the rat to controlled natural and electrical stimulation of the skin.

    Science.gov (United States)

    Snow, P J; Andre, P; Pompeiano, O

    1999-02-01

    1. The effects of microstimulation of the locus coeruleus (LC) region on the spontaneous discharge and the response of SI neurons to natural and electrical stimulation of the skin have been investigated in 26 urethane anesthetized Sprague-Dawley rats. In particular, one or two air puffs, 5-10 msec in duration, 1-2 psi, usually separated by an interval of 40 msec, were applied on the hairy skin of the wrist or the forepaw at the presentation rate of 1/sec. For units unresponsive to air puffs, similar presentation of low intensity electrical stimuli (0.2-5.0 V, 0.2-0.4 msec pulses) were applied through two needles inserted on the most effective area of the skin. Both natural and electrical stimulations of the skin were applied under control conditions, as well as 50 msec after a 250 msec train of 0.3 msec pulses at 40 Hz. 20-30 microA applied stereotaxically to the LC complex through a tungsten microelectrode. 2. Not all cortical units exhibited spontaneous discharge. Most of the units, however, which were spontaneously active, were inhibited by electrical stimulation of the LC complex, while the remaining ones were excited. The sites of stimulation, which included either the LC proper or the locus subcoeruleus, were identified following both anatomical and physiological criteria. 3. SI neurons recorded at sites between 400 and 950 microns below the surface of the cortex, thus being most likely granule cells of layers III and IV, responded to cutaneous stimuli with spikes which occurred with a latency of 20-30 msec in response to single air puffs and a latency of 15-20 msec in response to single electrical pulses to the skin. In both instances the response to the second stimulus applied at the interstimulus interval of 40 msec was markedly reduced or abolished due to postexcitatory inhibition following the response to the first stimulus (in-field inhibition). In contrast, units particularly located at or below 1000 microns from the cortical surface, which were of

  10. A natural language-based presentation of cognitive stimulation to people with dementia in assistive technology: A pilot study.

    Science.gov (United States)

    Dethlefs, Nina; Milders, Maarten; Cuayáhuitl, Heriberto; Al-Salkini, Turkey; Douglas, Lorraine

    2017-12-01

    Currently, an estimated 36 million people worldwide are affected by Alzheimer's disease or related dementias. In the absence of a cure, non-pharmacological interventions, such as cognitive stimulation, which slow down the rate of deterioration can benefit people with dementia and their caregivers. Such interventions have shown to improve well-being and slow down the rate of cognitive decline. It has further been shown that cognitive stimulation in interaction with a computer is as effective as with a human. However, the need to operate a computer often represents a difficulty for the elderly and stands in the way of widespread adoption. A possible solution to this obstacle is to provide a spoken natural language interface that allows people with dementia to interact with the cognitive stimulation software in the same way as they would interact with a human caregiver. This makes the assistive technology accessible to users regardless of their technical skills and provides a fully intuitive user experience. This article describes a pilot study that evaluated the feasibility of computer-based cognitive stimulation through a spoken natural language interface. Prototype software was evaluated with 23 users, including healthy elderly people and people with dementia. Feedback was overwhelmingly positive.

  11. Nature of the concentration thresholds of europium atom yield from the oxidized tungsten surface under electron stimulated desorption

    CERN Document Server

    Davydov, S Y

    2002-01-01

    The nature of the electron-stimulated desorption (ESD) of the europium atoms by the E sub e irradiating electrons energies, equal to 50 and 80 eV, as well as peculiarities of the Eu atoms yield dependence on their concentration on the oxidized tungsten surface are discussed. It is shown, that the ESD originates by the electron transition from the interval 5p- or 5s shell of the tungsten surface atom onto the oxygen external unfilled 2p-level

  12. Study of nerve fibers nature reinforcing duodenal contractions by electrical stimulation of sympathetic nerve

    Directory of Open Access Journals (Sweden)

    Sveshnikov D.S.

    2011-09-01

    Full Text Available The subject of the article is to investigate the mechanism of increased reactions by electrical stimulation of the sympathetic nerve. Materials and methods: Experiments on dogs have shown that stimulant reactions during blockade of a-adrenergic by phentolamine and (3-adrenergic receptors with propranolol were completely eliminated by lizer-gol —the blocker of 5-HT12-receptors. Results: Infusion of lizergol did not influence on duodenal motor activity and the function of the vagus nerve. Conclusion: Effector neuron is found out to be serotonergic and its action is provided by 5-HT1 2 receptors

  13. Perinatal outcome in singletons after modified natural cycle IVF and standard IVF with ovarian stimulation

    NARCIS (Netherlands)

    Pelinck, Marie-Jose; Keizer, Marjan H.; Hoek, Annemieke; Simons, Arnold H. M.; Schelling, Karin; Middelburg, Karin; Heineman, Maas Jan

    Objective: Singletons born after IVF treatment are at risk for adverse pregnancy outcome, the cause of which is unknown. The aim of the present study was to investigate the influence of ovarian stimulation on perinatal outcome. Study design: In this single-centre retrospective study, perinatal

  14. Perinatal outcome in singletons after modified natural cycle IVF and standard IVF with ovarian stimulation

    NARCIS (Netherlands)

    Pelinck, Marie-José; Keizer, Marjan H.; Hoek, Annemieke; Simons, Arnold H. M.; Schelling, Karin; Middelburg, Karin; Heineman, Maas Jan

    2010-01-01

    Objective: Singletons born after IVF treatment are at risk for adverse pregnancy outcome, the cause of which is unknown. The aim of the present study was to investigate the influence of ovarian stimulation on perinatal outcome. Study design: In this single-centre retrospective study, perinatal

  15. Demonstration of a stimulating effect of natural ionizing radiation and of very low radiation doses on cell multiplication

    International Nuclear Information System (INIS)

    Planel, G.; Soleilhavoup, J.P.; Tixador, R.; Croute, F.; Richoilley, G.

    1976-01-01

    Experiments have been carried out to demonstrate a possible effect of natural ionizing radiation. Using lead shielding devices or an underground laboratory, it was shown that a decrease in background irradiation induces a decrease in cell growth rate (experiments carried out on Paramecia). On the other hand, the recovery of a normal irradiation level in shielding devices induces a quite normal cell proliferation. Moreover, small doses of γ rays from 60 Co exhibit a stimulating effect. Variations in cell radiosensitivity to these low doses are reported. Experiments carried out in the underground laboratory and at high altitude show that both telluric radioactivity and cosmic rays contribute to this stimulating effect on cell multiplication. (author)

  16. Acerogenin A, a natural compound isolated from Acer nikoense Maxim, stimulates osteoblast differentiation through bone morphogenetic protein action

    International Nuclear Information System (INIS)

    Kihara, Tasuku; Ichikawa, Saki; Yonezawa, Takayuki; Lee, Ji-Won; Akihisa, Toshihiro; Woo, Je Tae; Michi, Yasuyuki; Amagasa, Teruo; Yamaguchi, Akira

    2011-01-01

    Research highlights: → Acerogenin A stimulated osteoblast differentiation in osteogenic cells. → Acerogenin A-induced osteoblast differentiation was inhibited by noggin. → Acerogenin A increased Bmp-2, Bmp-4 and Bmp-7 mRNA expression in MC3T3-E1 cells. → Acerogenin A is a candidate agent for stimulating bone formation. -- Abstract: We investigated the effects of acerogenin A, a natural compound isolated from Acer nikoense Maxim, on osteoblast differentiation by using osteoblastic cells. Acerogenin A stimulated the cell proliferation of MC3T3-E1 osteoblastic cells and RD-C6 osteoblastic cells (Runx2-deficient cell line). It also increased alkaline phosphatase activity in MC3T3-E1 and RD-C6 cells and calvarial osteoblastic cells isolated from the calvariae of newborn mice. Acerogenin A also increased the expression of mRNAs related to osteoblast differentiation, including Osteocalcin, Osterix and Runx2 in MC3T3-E1 cells and primary osteoblasts: it also stimulated Osteocalcin and Osterix mRNA expression in RD-C6 cells. The acerogenin A treatment for 3 days increased Bmp-2, Bmp-4, and Bmp-7 mRNA expression levels in MC3T3-E1 cells. Adding noggin, a BMP specific-antagonist, inhibited the acerogenin A-induced increase in the Osteocalcin, Osterix and Runx2 mRNA expression levels. These results indicated that acerogenin A stimulates osteoblast differentiation through BMP action, which is mediated by Runx2-dependent and Runx2-independent pathways.

  17. Thermal and electron stimulated luminescence of natural bones, commercial hydroxyapatite and collagen.

    Science.gov (United States)

    Roman-Lopez, J; Correcher, V; Garcia-Guinea, J; Rivera, T; Lozano, I B

    2014-01-01

    The luminescence (cathodoluminescence and thermoluminescence) properties of natural bones (Siberian mammoth and adult elephant), commercial hydroxyapatite and collagen were analyzed. Chemical analyses of the natural bones were determined using by Electron Probe Micro-Analysis (EMPA). Structural, molecular and thermal characteristics were determined by X-ray Diffraction (XRD), Raman spectroscopy and Differential Thermal and Thermogravimetric analysis (DTA-TG). Cathodoluminescence (CL) spectra of natural bones and collagen showed similar intense broad bands at 440 and 490 nm related to luminescence of the tetrahedral anion [Formula: see text] or structural defects. A weaker luminescence exhibited at 310 nm could be attributed to small amount of rare earth elements (REEs). Four luminescent bands at 378, 424, 468 and 576 nm were observed in the commercial hydroxyapatite (HAP). Both natural bones and collagen samples exhibited natural thermoluminescence (NTL) with well-defined glow curves whereas that the induced thermoluminescence (ITL) only appears in the samples of commercial hydroxyapatite and collagen. Additional explanations for the TL anomalous fading of apatite, as a crucial difficulty performing dosimetry and dating, are also considered. Copyright © 2013 Elsevier B.V. All rights reserved.

  18. Possible techniques for decontamination of natural gas from gas wells stimulated by a nuclear explosion

    Energy Technology Data Exchange (ETDEWEB)

    Wethington, Jr, John A [Lawrence Radiation Laboratory, University of California, Livermore, CA (United States)

    1970-05-15

    Decontamination of the products from gas wells stimulated by nuclear explosions requires the removal of T, present as HT, CH{sub 3}T, C{sub 2}H{sub 5}T, etc., and {sup 85}Kr from the production stream. Flaring of large volumes of gas from the Gasbuggy well led to the replacement of radioactive cavity gas with inactive formation gas, but this would not be a satisfactory production procedure because it releases T and {sup 85}Kr into the atmosphere and wastes large amounts of product gas. Exchange reactions appear to offer promise for removing the tritium. For example, water or steam flowing countercurrent to tritiated gas in the presence of a suitable catalyst can participate in the exchange reactions CH{sub 3}T + H{sub 2}O {r_reversible} CH{sub 4} + HTO, HT + H{sub 2}O {r_reversible} H{sub 2} + HTO, resulting in the transfer of T from gas into water. Other possibilities for utilizing exchange reactions include exchange of the gas with ethylene glycol used in the gas dryer, with silicate rocks introduced into the gas stream, or with a countercurrent stream of NH{sub 3} or H{sub 2}S. As another approach, use of the contaminated gas for the manufacture of ammonia synthesis gas has potential for removal of both T and {sup 85}Kr. (author)

  19. Sound pressure distribution within natural and artificial human ear canals: forward stimulation.

    Science.gov (United States)

    Ravicz, Michael E; Tao Cheng, Jeffrey; Rosowski, John J

    2014-12-01

    This work is part of a study of the interaction of sound pressure in the ear canal (EC) with tympanic membrane (TM) surface displacement. Sound pressures were measured with 0.5-2 mm spacing at three locations within the shortened natural EC or an artificial EC in human temporal bones: near the TM surface, within the tympanic ring plane, and in a plane transverse to the long axis of the EC. Sound pressure was also measured at 2-mm intervals along the long EC axis. The sound field is described well by the size and direction of planar sound pressure gradients, the location and orientation of standing-wave nodal lines, and the location of longitudinal standing waves along the EC axis. Standing-wave nodal lines perpendicular to the long EC axis are present on the TM surface >11-16 kHz in the natural or artificial EC. The range of sound pressures was larger in the tympanic ring plane than at the TM surface or in the transverse EC plane. Longitudinal standing-wave patterns were stretched. The tympanic-ring sound field is a useful approximation of the TM sound field, and the artificial EC approximates the natural EC.

  20. Development of optically stimulated luminescence techniques using natural minerals and ceramics, and their application to retrospective dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Boetter-Jensen, L

    2000-09-01

    This thesis summarises research and development of optically stimulated luminescence (OSL) and its applications by the author at Risoe National Laboratory, up to 1999. These developments have been directed primarily at retrospective accident dosimetry and luminescence dating. Experimental investigations include the studies of OSL properties of the natural minerals quartz and feldspars and the artificial materials porcelain and aluminium oxide (Al{sub 2}O{sub 3}). Blue light emitting diodes and infrared laser diodes are shown to provide simple and practical alternatives to broad-band light and visible laser stimulation. The development of OSL apparatus designed for the rapid measurement of single grains of phosphors also opens up a new area of luminescence measurement, allowing the detailed examination of dose distributions within a multiple-grain sample. This is of particular importance to the studies of incompletely reset geological sediments, and to accident dosimetry measurements using unheated materials. Al{sub 2}O{sub 3}:C single crystals are tested as environmental OSL dosemeters for assessing both the natural background photon radiation dose rates in the field and the natural dose rates inside bricks collected for accident dose evaluation. Environmental doses of the order of few {mu}Gy are measured with high precision. UV photo-stimulated luminescence spectra obtained from porcelain samples are used to confirm that the main component responsible for the OSL signal from porcelain is Al{sub 2}O{sub 3}. OSL single-aliquot regenerative-dose (SAR) techniques are used with quartz extracted from Chernobyl bricks to determine the accrued dose after the accident. This has improved the measurement precision significantly, from about 5-6 % using traditional methods to now less than 2 %. Depth-dose profiles measured in Chernobyl bricks are compared with those obtained in the laboratory using different gamma sources and these comparisons show that the average energy of

  1. Development of optically stimulated luminescence techniques using natural minerals and ceramics, and their application to retrospective dosimetry

    International Nuclear Information System (INIS)

    Boetter-Jensen, L.

    2000-09-01

    This thesis summarises research and development of optically stimulated luminescence (OSL) and its applications by the author at Risoe National Laboratory, up to 1999. These developments have been directed primarily at retrospective accident dosimetry and luminescence dating. Experimental investigations include the studies of OSL properties of the natural minerals quartz and feldspars and the artificial materials porcelain and aluminium oxide (Al 2 O 3 ). Blue light emitting diodes and infrared laser diodes are shown to provide simple and practical alternatives to broad-band light and visible laser stimulation. The development of OSL apparatus designed for the rapid measurement of single grains of phosphors also opens up a new area of luminescence measurement, allowing the detailed examination of dose distributions within a multiple-grain sample. This is of particular importance to the studies of incompletely reset geological sediments, and to accident dosimetry measurements using unheated materials. Al 2 O 3 :C single crystals are tested as environmental OSL dosemeters for assessing both the natural background photon radiation dose rates in the field and the natural dose rates inside bricks collected for accident dose evaluation. Environmental doses of the order of few μGy are measured with high precision. UV photo-stimulated luminescence spectra obtained from porcelain samples are used to confirm that the main component responsible for the OSL signal from porcelain is Al 2 O 3 . OSL single-aliquot regenerative-dose (SAR) techniques are used with quartz extracted from Chernobyl bricks to determine the accrued dose after the accident. This has improved the measurement precision significantly, from about 5-6 % using traditional methods to now less than 2 %. Depth-dose profiles measured in Chernobyl bricks are compared with those obtained in the laboratory using different gamma sources and these comparisons show that the average energy of the accident radiation was

  2. Synthetic tactile perception induced by transcranial alternating-current stimulation can substitute for natural sensory stimulus in behaving rabbits.

    Science.gov (United States)

    Márquez-Ruiz, Javier; Ammann, Claudia; Leal-Campanario, Rocío; Ruffini, Giulio; Gruart, Agnès; Delgado-García, José M

    2016-01-21

    The use of brain-derived signals for controlling external devices has long attracted the attention from neuroscientists and engineers during last decades. Although much effort has been dedicated to establishing effective brain-to-computer communication, computer-to-brain communication feedback for "closing the loop" is now becoming a major research theme. While intracortical microstimulation of the sensory cortex has already been successfully used for this purpose, its future application in humans partly relies on the use of non-invasive brain stimulation technologies. In the present study, we explore the potential use of transcranial alternating-current stimulation (tACS) for synthetic tactile perception in alert behaving animals. More specifically, we determined the effects of tACS on sensory local field potentials (LFPs) and motor output and tested its capability for inducing tactile perception using classical eyeblink conditioning in the behaving animal. We demonstrated that tACS of the primary somatosensory cortex vibrissa area could indeed substitute natural stimuli during training in the associative learning paradigm.

  3. Natural Marine and Synthetic Xenobiotics Get on Nematode’s Nerves: Neuro-Stimulating and Neurotoxic Findings in Caenorhabditis elegans

    Directory of Open Access Journals (Sweden)

    Thora Lieke

    2015-05-01

    Full Text Available Marine algae release a plethora of organic halogenated compounds, many of them with unknown ecological impact if environmentally realistic concentrations are applied. One major compound is dibromoacetic acid (DBAA which was tested for neurotoxicity in the invertebrate model organism Caenorhabditis elegans (C. elegans. This natural compound was compared with the widespread synthetic xenobiotic tetrabromobisphenol-A (TBBP-A found in marine sediments and mussels. We found a neuro-stimulating effect for DBAA; this is contradictory to existing toxicological reports of mammals that applied comparatively high dosages. For TBBP-A, we found a hormetic concentration-effect relationship. As chemicals rarely occur isolated in the environment, a combination of both organobromines was also examined. Surprisingly, the presence of DBAA increased the toxicity of TBBP-A. Our results demonstrated that organohalogens have the potential to affect single organisms especially by altering the neurological processes, even with promoting effects on exposed organisms.

  4. Natural Marine and Synthetic Xenobiotics Get on Nematode's Nerves: Neuro-Stimulating and Neurotoxic Findings in Caenorhabditis elegans.

    Science.gov (United States)

    Lieke, Thora; Steinberg, Christian E W; Ju, Jingjuan; Saul, Nadine

    2015-05-06

    Marine algae release a plethora of organic halogenated compounds, many of them with unknown ecological impact if environmentally realistic concentrations are applied. One major compound is dibromoacetic acid (DBAA) which was tested for neurotoxicity in the invertebrate model organism Caenorhabditis elegans (C. elegans). This natural compound was compared with the widespread synthetic xenobiotic tetrabromobisphenol-A (TBBP-A) found in marine sediments and mussels. We found a neuro-stimulating effect for DBAA; this is contradictory to existing toxicological reports of mammals that applied comparatively high dosages. For TBBP-A, we found a hormetic concentration-effect relationship. As chemicals rarely occur isolated in the environment, a combination of both organobromines was also examined. Surprisingly, the presence of DBAA increased the toxicity of TBBP-A. Our results demonstrated that organohalogens have the potential to affect single organisms especially by altering the neurological processes, even with promoting effects on exposed organisms.

  5. ATR-101, a selective ACAT1 inhibitor, decreases ACTH-stimulated cortisol concentrations in dogs with naturally occurring Cushing's syndrome.

    Science.gov (United States)

    Langlois, Daniel K; Fritz, Michele C; Schall, William D; Bari Olivier, N; Smedley, Rebecca C; Pearson, Paul G; Bailie, Marc B; Hunt, Stephen W

    2018-05-02

    Cushing's syndrome in humans shares many similarities with its counterpart in dogs in terms of etiology (pituitary versus adrenal causes), clinical signs, and pathophysiologic sequelae. In both species, treatment of pituitary- and adrenal-dependent disease is met with limitations. ATR-101, a selective inhibitor of ACAT1 (acyl coenzyme A:cholesterol acyltransferase 1), is a novel small molecule therapeutic currently in clinical development for the treatment of adrenocortical carcinoma, congenital adrenal hyperplasia, and Cushing's syndrome in humans. Previous studies in healthy dogs have shown that ATR-101 treatment led to rapid, dose-dependent decreases in adrenocorticotropic hormone (ACTH) stimulated cortisol levels. The purpose of this clinical study was to investigate the effects of ATR-101 in dogs with Cushing's syndrome. ATR-101 pharmacokinetics and activity were assessed in 10 dogs with naturally-occurring Cushing's syndrome, including 7 dogs with pituitary-dependent disease and 3 dogs with adrenal-dependent disease. ATR-101 was administered at 3 mg/kg PO once daily for one week, followed by 30 mg/kg PO once daily for one (n = 4) or three (n = 6) weeks. Clinical, biochemical, adrenal hormonal, and pharmacokinetic data were obtained weekly for study duration. ATR-101 exposure increased with increasing dose. ACTH-stimulated cortisol concentrations, the primary endpoint for the study, were significantly decreased with responders (9 of 10 dogs) experiencing a mean ± standard deviation reduction in cortisol levels of 50 ± 17% at study completion. Decreases in pre-ACTH-stimulated cortisol concentrations were observed in some dogs although overall changes in pre-ACTH cortisol concentrations were not significant. The compound was well-tolerated and no serious drug-related adverse effects were reported. This study highlights the potential utility of naturally occurring canine Cushing's syndrome as a model for human disease and provides proof of

  6. A preliminary assessment of the radiological implications of commercial utilization of natural gas from a nuclearly stimulated well

    Energy Technology Data Exchange (ETDEWEB)

    Jacobs, D G; Struxness, E G [Health Physics Division, Oak Ridge National Laboratory, Oak Ridge, TN (United States); Bowman, C R [El Paso Natural Gas Company, El Paso, TX (United States)

    1970-05-01

    Widespread utilization of nuclear explosives, in conjunction with the natural gas industry, can result in radiation exposure of sizable population groups. It is prudent to make realistic assessments of such potential radiation exposures before they occur and, unless the expected exposures are clearly insignificant, to consider these exposures in evaluating the net benefit of this particular use of nuclear energy. All pertinent facts relating to such assessments should be made public and presented in such a way that those who are to assume the risks, if any, can make a reasonable judgment as to whether the risks are acceptable. Radioactivity in natural gas from the Gasbuggy cavity has been analyzed prior to and during flaring operations. None of this gas has entered the collection and distribution system, but a theoretical analysis has been made of the hypothetical impact on members of the public that would have occurred if the gas had been introduced into the commercial stream. Dose equivalents have been estimated for both workers and consumers. In this analysis, Gasbuggy gas has been traced through a real gas-collection system and processing plant, as represented by the present situation existing in the San Juan Production Division, El Paso Natural Gas Company. In addition, a number of considerations are presented which would apply to radiation exposure in metropolitan areas. Results of this analysis for the Gasbuggy well indicate hypothetical dose equivalents to various population groups to be well within the annual dose limits suggested by the International Commission on Radiological Protection. Projection to a steady-state situation involving extensive natural gas production from many producing wells also resulted in hypothetical dose equivalents within the annual dose limits. Simple extrapolation of the results from this analysis to potential exposures resulting from nuclear stimulation of other gas reservoirs cannot be made on a direct basis, but this method

  7. A preliminary assessment of the radiological implications of commercial utilization of natural gas from a nuclearly stimulated well

    International Nuclear Information System (INIS)

    Jacobs, D.G.; Struxness, E.G.; Bowman, C.R.

    1970-01-01

    Widespread utilization of nuclear explosives, in conjunction with the natural gas industry, can result in radiation exposure of sizable population groups. It is prudent to make realistic assessments of such potential radiation exposures before they occur and, unless the expected exposures are clearly insignificant, to consider these exposures in evaluating the net benefit of this particular use of nuclear energy. All pertinent facts relating to such assessments should be made public and presented in such a way that those who are to assume the risks, if any, can make a reasonable judgment as to whether the risks are acceptable. Radioactivity in natural gas from the Gasbuggy cavity has been analyzed prior to and during flaring operations. None of this gas has entered the collection and distribution system, but a theoretical analysis has been made of the hypothetical impact on members of the public that would have occurred if the gas had been introduced into the commercial stream. Dose equivalents have been estimated for both workers and consumers. In this analysis, Gasbuggy gas has been traced through a real gas-collection system and processing plant, as represented by the present situation existing in the San Juan Production Division, El Paso Natural Gas Company. In addition, a number of considerations are presented which would apply to radiation exposure in metropolitan areas. Results of this analysis for the Gasbuggy well indicate hypothetical dose equivalents to various population groups to be well within the annual dose limits suggested by the International Commission on Radiological Protection. Projection to a steady-state situation involving extensive natural gas production from many producing wells also resulted in hypothetical dose equivalents within the annual dose limits. Simple extrapolation of the results from this analysis to potential exposures resulting from nuclear stimulation of other gas reservoirs cannot be made on a direct basis, but this method

  8. Radionuclide Migration at the Rio Blanco Site, A Nuclear-stimulated Low-permeability Natural Gas Reservoir

    Energy Technology Data Exchange (ETDEWEB)

    Clay A. Cooper; Ming Ye; Jenny Chapman; Craig Shirley

    2005-10-01

    The U.S. Department of Energy and its predecessor agencies conducted a program in the 1960s and 1970s that evaluated technology for the nuclear stimulation of low-permeability gas reservoirs. The third and final project in the program, Project Rio Blanco, was conducted in Rio Blanco County, in northwestern Colorado. In this experiment, three 33-kiloton nuclear explosives were simultaneously detonated in a single emplacement well in the Mesaverde Group and Fort Union Formation, at depths of 1,780, 1,899, and 2,039 m below land surface on May 17, 1973. The objective of this work is to estimate lateral distances that tritium released from the detonations may have traveled in the subsurface and evaluate the possible effect of postulated natural-gas development on radionuclide migration. Other radionuclides were considered in the analysis, but the majority occur in relatively immobile forms (such as nuclear melt glass). Of the radionuclides present in the gas phase, tritium dominates in terms of quantity of radioactivity in the long term and contribution to possible whole body exposure. One simulation is performed for {sup 85}Kr, the second most abundant gaseous radionuclide produced after tritium.

  9. Naturally Induced Secretions of the Potato Cyst Nematode Co-stimulate the Proliferation of Both Tobacco Leaf Protoplasts and Human Peripheral Blood Mononuclear Cells

    NARCIS (Netherlands)

    Goverse, A.; Rouppe van der Voort, J.N.A.M.; Rouppe van der voort, C.; Kavelaars, A.; Smant, G.; Schots, A.; Bakker, J.; Helder, J.

    1999-01-01

    Naturally induced secretions from infective juveniles of the potato cyst nematode Globodera rostochiensis co-stimulate the proliferation of tobacco leaf protoplasts in the presence of the synthetic phytohormones α-naphthaleneacetic acid (NAA) and 6-benzylaminopurine (BAP). With the use of a

  10. Role of IL-2 and interferon in the generation of natural cytotoxic activity in influenza virus-stimulated PBL cultures: analysis with the use of prednisolone

    NARCIS (Netherlands)

    Braakman, E.; Treep-van Leeuwen, P.; ten Berge, R. J.; Schellekens, P. T.; Lucas, C. J.

    1988-01-01

    We have examined the role of interleukin 2, interferon-gamma and interferon-alpha in the generation of natural cytotoxic (NC) activity and cytotoxic T-lymphocyte (CTL) activity in peripheral blood lymphocyte cultures stimulated with influenza virus, using the immunosuppressive effects of

  11. Interleukin-15 stimulates natural killer cell-mediated killing of both human pancreatic cancer and stellate cells

    Science.gov (United States)

    Van Audenaerde, Jonas R.M.; De Waele, Jorrit; Marcq, Elly; Van Loenhout, Jinthe; Lion, Eva; Van den Bergh, Johan M.J.; Jesenofsky, Ralf; Masamune, Atsushi; Roeyen, Geert; Pauwels, Patrick; Lardon, Filip; Peeters, Marc; Smits, Evelien L.J.

    2017-01-01

    Pancreatic ductal adenocarcinoma (PDAC) is the 4th leading cause of cancer-related death in Western countries with a 5-year survival rate below 5%. One of the hallmarks of this cancer is the strong desmoplastic reaction within the tumor microenvironment (TME), orchestrated by activated pancreatic stellate cells (PSC). This results in a functional and mechanical shield which causes resistance to conventional therapies. Aiming to overcome this resistance by tackling the stromal shield, we assessed for the first time the capacity of IL-15 stimulated natural killer (NK) cells to kill PSC and pancreatic cancer cells (PCC). The potency of IL-15 to promote NK cell-mediated killing was evaluated phenotypically and functionally. In addition, NK cell and immune checkpoint ligands on PSC were charted. We demonstrate that IL-15 activated NK cells kill both PCC and PSC lines (range 9-35% and 20-50%, respectively) in a contact-dependent manner and significantly higher as compared to resting NK cells. Improved killing of these pancreatic cell lines is, at least partly, dependent on IL-15 induced upregulation of TIM-3 and NKG2D. Furthermore, we confirm significant killing of primary PSC by IL-15 activated NK cells in an ex vivo autologous system. Screening for potential targets for immunotherapeutic strategies, we demonstrate surface expression of both inhibitory (PD-L1, PD-L2) and activating (MICA/B, ULBPs and Galectin-9) ligands on primary PSC. These data underscore the therapeutic potential of IL-15 to promote NK cell-mediated cytotoxicity as a treatment of pancreatic cancer and provide promising future targets to tackle remaining PSC. PMID:28915646

  12. Spectral watermarking in femtosecond stimulated Raman spectroscopy: resolving the nature of the carotenoid S-star state

    NARCIS (Netherlands)

    Kloz, Miroslav; Weissenborn, J.; Polivka, T.; Frank, H.A.; Kennis, J.T.M.

    2016-01-01

    A new method for recording femtosecond stimulated Raman spectra was developed that dramatically improves and automatizes baseline problems. Instead of using a narrowband Raman source, the experiment is performed using shaping of a broadband source. This allows locking the signal into carefully

  13. Low-dose radiation potentiates the therapeutic efficacy of folate receptor-targeted hapten therapy.

    Science.gov (United States)

    Sega, Emanuela I; Lu, Yingjuan; Ringor, Michael; Leamon, Christopher P; Low, Philip S

    2008-06-01

    Human cancers frequently overexpress a high-affinity cell-surface receptor for the vitamin folic acid. Highly immunogenic haptens can be targeted to folate receptor-expressing cell surfaces by administration of folate-hapten conjugates, rendering the decorated tumor cell surfaces more recognizable by the immune system. Treatment of antihapten-immunized mice with folate-hapten constructs results in elimination of moderately sized tumors by the immune system. However, when subcutaneous tumors exceed 300 mm(3) before initiation of therapy, antitumor activity is significantly decreased. In an effort to enhance the efficacy of folate-targeted hapten immunotherapy (FTHI) against large tumors, we explored the combination of targeted hapten immunotherapy with low-dose radiotherapy. Mice bearing 300-mm(3) subcutaneous tumors were treated concurrently with FTHI (500 nmol/kg of folate conjugated to fluorescein isothiocyanate, 20,000 U/dose of interleukin 2, and 25,000 U/dose of interferon alpha) and low-dose radiotherapy (3 Gy/dose focused directly on the desired tumor mass). The efficacy of therapy was evaluated by measuring tumor volume. Tumor growth analyses show that radiotherapy synergizes with FTHI in antihapten-immunized mice, thereby allowing for cures of animals bearing tumors greater than 300 mm(3). More importantly, nonirradiated distal tumor masses in animals containing locally irradiated tumors also showed improved response to hapten immunotherapy, suggesting that not all tumor lesions must be identified and irradiated to benefit from the combination therapy. These results suggest that simultaneous treatment with FTHI and radiation therapy can enhance systemic antitumor activity in tumor-bearing mice.

  14. Low-dose radiation employed in diagnostic imaging causes genetic effects in cultured cells

    International Nuclear Information System (INIS)

    Ponzinibbio, Maria V.; Peral-Garcia, Pilar; Seoane, Analia; Crudeli, Cintia

    2010-01-01

    Background: Exposure to environmental, diagnostic, and occupational sources of radiation frequently involves low doses. Although these doses have no immediately noticeable impact on human health there is great interest in their long-term biological effects. Purpose: To assess immediate and time-delayed DNA damage in two cell lines exposed to low doses of ionizing radiation by using the comet assay and micronucleus test, and to compare these two techniques in the analysis of low-dose induced genotoxicity. Material and Methods: CHO and MRC-5 cells were exposed to 50 milliSievert (mSv) of ionizing radiation and assayed immediately after irradiation and at 16 or 12 passages post-irradiation, respectively. Comet assay and micronucleus test were employed. Results: The comet assay values observed in 50 mSv-treated cells were significantly higher than in the control group for both sample times and cell lines (P < 0.001). Micronuclei frequencies were higher in treated cells than in the control group (P < 0.01, CHO cells passage 16; P < 0.05, MRC-5 cells immediately after exposure; P < 0.01 MRC-5 cells passage 12). Correlation analysis between the two techniques was statistically significant (correlation coefficient 0.82, P < 0.05 and correlation coefficient 0.86, P < 0.05 for CHO and MRC-5 cells, respectively). Cells scored at passages 12 or 16 showed more damage than those scored immediately after exposure in both cell lines (no statistically significant differences). Conclusion: Cytomolecular and cytogenetic damage was observed in cells exposed to very low doses of X-rays and their progeny. A single low dose of ionizing radiation was sufficient to induce such response, indicating that mammalian cells are exquisitely sensitive to it. Comet and micronucleus assays are sensitive enough to assess this damage, although the former seems to be more efficient

  15. Significance of studies of low-dose radiation fallout in the western United States

    International Nuclear Information System (INIS)

    Rothman, K.J.

    1984-01-01

    The sum of evidence from these studies about the effects of nuclear testing is extremely modest. Lack of good dose information precluded any valuable scientific conclusions. The evidence indicating excesses of leukemia incidence beyond what would already be accepted as the leukemogenic effect of ionizing radiation is fragile. Similarly, the evidence presumed to indicate the absence of thyroid effects is unpersuasive, actually showing a weak but positive effect

  16. Low dose radiation and ALARA: the potential risks to patients and staff from alpha-therapy

    International Nuclear Information System (INIS)

    Priest, N.D.

    2014-01-01

    This year a new drug containing radium-223, an alpha-emitting radionuclide, was approved for use by the US Food and Drug Administration for the palliative treatment of advanced prostate cancer metastases. Other drugs containing short-lived alpha-emitters are on clinical trial in Europe. Commonly, these employ a radionuclide attached to an antibody that specifically targets tumor cells to produce a highly localized radio-therapeutic dose to the tumor. However, normal tissues within the body will also be irradiated, albeit sometimes at low dose, and the question arises as to whether this presents a significant additional risk to the patient. Similarly, medical staff that handle these radionuclides could receive intakes of the radionuclides. What is the risk to staff? To assess the risk resulting from small tissue alpha-doses the toxicological, both human and animal, database was re-examined. The results of 20 epidemiological and toxicological studies with alpha-emitting radionuclides were analysed. In all cases a polynomial function provided a better fit to the data than a linear, no thresholds function. Also, in 19 cases a threshold dose below which no cancer is seen was indicated. The position of this threshold varied according to cancer type, but was typically in the range 0.1 to 1.0Gy of tissue dose - with a mean of 0.5Gy. It is concluded that alpha-radiation induced tumorogenesis is a threshold response and that as long as tissue doses are kept below these thresholds no additional cancers would be seen in either patients receiving alpha-therapy or in staff exposed to 'spilt' radionuclide. The presence of thresholds questions the appropriateness of current ALARA practices that are mostly used to drive occupational alpha-radiation exposures to as close to zero as possible. (author)

  17. Reduction in flatulent factors in mung bean using low dose - radiation

    International Nuclear Information System (INIS)

    Machaiah, J.P.; Pednekar, M.D.; Thomas, Paul

    1997-01-01

    Mung beans, γ-irradiated at the disinfestation dose of 0.25 to 0.75 kGy and germinated (0-6 days), contained significantly lower levels of flatulence causing digosaccharides compared to the control, thus enhancing their nutritional quality and acceptability. (author). 2 refs., 3 figs

  18. Low-Dose Radiation Potentiates the Therapeutic Efficacy of Folate Receptor-Targeted Hapten Therapy

    International Nuclear Information System (INIS)

    Sega, Emanuela I.; Lu Yingjuan; Ringor, Michael; Leamon, Christopher P.; Low, Philip S.

    2008-01-01

    Purpose: Human cancers frequently overexpress a high-affinity cell-surface receptor for the vitamin folic acid. Highly immunogenic haptens can be targeted to folate receptor-expressing cell surfaces by administration of folate-hapten conjugates, rendering the decorated tumor cell surfaces more recognizable by the immune system. Treatment of antihapten-immunized mice with folate-hapten constructs results in elimination of moderately sized tumors by the immune system. However, when subcutaneous tumors exceed 300 mm 3 before initiation of therapy, antitumor activity is significantly decreased. In an effort to enhance the efficacy of folate-targeted hapten immunotherapy (FTHI) against large tumors, we explored the combination of targeted hapten immunotherapy with low-dose radiotherapy. Methods and Materials: Mice bearing 300-mm 3 subcutaneous tumors were treated concurrently with FTHI (500 nmol/kg of folate conjugated to fluorescein isothiocyanate, 20,000 U/dose of interleukin 2, and 25,000 U/dose of interferon α) and low-dose radiotherapy (3 Gy/dose focused directly on the desired tumor mass). The efficacy of therapy was evaluated by measuring tumor volume. Results: Tumor growth analyses show that radiotherapy synergizes with FTHI in antihapten-immunized mice, thereby allowing for cures of animals bearing tumors greater than 300 mm 3 . More importantly, nonirradiated distal tumor masses in animals containing locally irradiated tumors also showed improved response to hapten immunotherapy, suggesting that not all tumor lesions must be identified and irradiated to benefit from the combination therapy. Conclusions: These results suggest that simultaneous treatment with FTHI and radiation therapy can enhance systemic antitumor activity in tumor-bearing mice

  19. The philosophy of quarantine treatment as related to low-dose radiation

    International Nuclear Information System (INIS)

    Ouye, M.T.; Gilmore, J.E.

    1985-01-01

    The purpose for quarantine treatment is to prevent establishment of exotic pest populations from quarantined areas to nonquarantined areas through movement of host commodities. Quarantine treatment schedules approved by the Animal Plant Health Inspection Service (APHIS), U.S. Dept. of Agriculture (USDA), appear in its ''Plant Protection and Quarantine Programs Treatment Manual.'' These treatment schedules were developed through research demonstrating that when followed to the letter, quarantine security or negligible pest risk would be achieved. Negligible pest risk is currently synonymous with probit 9, the level of security at which no more than 3.2 pests per 100,000 treated will survive. Probits are based on mortality; therefore, relatively high dosages will be required and in some instances could damage the commodity at the dosage necessary to kill the pest. If the purpose of quarantine treatment is to prevent perpetuation of the pest species into nonquarantined areas, the criterion should be based on the ability of the treated pests to reproduce. The criteria currently being discussed by APHIS and the Agricultural Research Service are presented. Two key criteria are a redefinition of negligible pest risk and the concept of a two-stage quarantine treatment schedule

  20. Low-Dose Radiation Exposure and Atherosclerosis in ApoE(-/-) Mice

    NARCIS (Netherlands)

    Mitchel, R. E. J.; Hasu, M.; Bugden, M.; Wyatt, H.; Little, M. P.; Gola, A.; Hildebrandt, G.; Priest, N. D.; Whitman, S. C.

    The hypothesis that single low-dose exposures (0.025-0.5 Gy) to low-LET radiation given at either high (about 150 mGy/min) or low (1 mGy/min) dose rate would promote aortic atherosclerosis was tested in female C57BL/6J mice genetically predisposed to this disease (ApoE(-/-)). Mice were exposed

  1. ISD technology: a strategy for reduction of low-dose radiation exposure in human beings

    International Nuclear Information System (INIS)

    Hernandez, D.A.; Larsen, K.; Fertel, D.

    2000-01-01

    The primary purpose of this project is to refocus the current national health care debate. It is the first attempt to provide scientists, health care providers, health care policy makers, politicians, health care payers and public health advocates with a method to improve health care and cut costs through decision-making strategies based primarily on medical standards and secondarily on fiscal considerations. The method for decision-making described in this paper proves more cost-effective and medically sound than current practices. Illness Specific Diagnostic (ISD) tables are introduced as a method to reduce inappropriate use of ionizing radiation in medicine. The use of ISD tables destroys the myth of a single medical standard of care and focuses on the diagnostician as the individual most capable of diagnosing disease(s) in human beings. Additionally, ionizing radiation has been used routinely under the guise that the resulting benefits outweigh the risks involved in a procedure. This dubious tradition is questioned in this document. Attention is drawn to the inappropriate amount of radiation patients receive when ionizing diagnostic tests are performed with marginal or no diagnostic benefit. The results of a pilot study are presented that explicate the reduction of needless radiation to patients and associated reduction of costs that becomes possible in the presence of appropriate scientific medical standards. Ultimately, quality medicine is indeed the most cost-effective medicine possible. The current practice by which the United States Congress issues laws aimed at dictating quality medicine is both desperate and dangerous. Politicians and legislators would be wise to focus their efforts on methodologies that establish standards of care in a scientific manner that does not interfere with medical practice. ISD technology is precisely such a scientific method. It establishes the standard of medical care at the facility from which the ISD tables are generated. ISD tables bring much needed order to diagnostic testing and create a level playing field with which to evaluate medical centers' specificity, sensitivity, and ability to diagnose and treat diseases in humans. (author)

  2. Toxicity risk of non-target organs at risk receiving low-dose radiation: case report

    International Nuclear Information System (INIS)

    Shueng, Pei-Wei; Lin, Shih-Chiang; Chang, Hou-Tai; Chong, Ngot-Swan; Chen, Yu-Jen; Wang, Li-Ying; Hsieh, Yen-Ping; Hsieh, Chen-Hsi

    2009-01-01

    The spine is the most common site for bone metastases. Radiation therapy is a common treatment for palliation of pain and for prevention or treatment of spinal cord compression. Helical tomotherapy (HT), a new image-guided intensity modulated radiotherapy (IMRT), delivers highly conformal dose distributions and provides an impressive ability to spare adjacent organs at risk, thus increasing the local control of spinal column metastases and decreasing the potential risk of critical organs under treatment. However, there are a lot of non-target organs at risk (OARs) occupied by low dose with underestimate in this modern rotational IMRT treatment. Herein, we report a case of a pathologic compression fracture of the T9 vertebra in a 55-year-old patient with cholangiocarcinoma. The patient underwent HT at a dose of 30 Gy/10 fractions delivered to T8-T10 for symptom relief. Two weeks after the radiotherapy had been completed, the first course of chemotherapy comprising gemcitabine, fluorouracil, and leucovorin was administered. After two weeks of chemotherapy, however, the patient developed progressive dyspnea. A computed tomography scan of the chest revealed an interstitial pattern with traction bronchiectasis, diffuse ground-glass opacities, and cystic change with fibrosis. Acute radiation pneumonitis was diagnosed. Oncologists should be alert to the potential risk of radiation toxicities caused by low dose off-targets and abscopal effects even with highly conformal radiotherapy

  3. Low dose radiation exposure and atherosclerosis in ApoE{sup -/-} mice

    Energy Technology Data Exchange (ETDEWEB)

    Mitchel, R.E.J. [Atomic Energy of Canada Limited, Chalk River, ON (Canada); Hasu, M. [Univ. of Ottawa, Department of Pathology and Lab. Medicine, and Cellular and Molecular Medicine, Ottawa, ON (Canada); Univ. of Ottawa Heart Inst., Vascular Biology Group, Ottawa, ON (Canada); Bugden, M.; Wyatt, H. [Atomic Energy of Canada Limited, Chalk River, ON (Canada); Little, M. [Imperial Coll., Faculty of Medicine, St. Marys Campus, London (United Kingdom); Hildebrandt, G. [Univ. Hospital, Dept. of Radiotherapy, Rostock (Germany); Priest, N.D. [Atomic Energy of Canada Limited, Chalk River, ON (Canada); Whitman, S.C. [Univ. of Ottawa, Department of Pathology and Lab. Medicine, and Cellular and Molecular Medicine, Ottawa, ON (Canada); Univ. of Ottawa Heart Inst., Vascular Biology Group, Ottawa, ON (Canada)

    2010-07-01

    The hypothesis that single low dose exposures (0.025-0.5 Gy) to low LET radiation, given at either high (240 mGy/min) or low (1 mGy/min) dose rate, would promote aortic atherosclerosis was tested in female C57BI/6 mice genetically predisposed to this disease (ApoE-/-). Mice were exposed either at early stage disease (2 months of age) and examined 3 or 6 months later, or at late stage disease (8 months of age) and examined 2 or 4 months later. Compared to unexposed controls, all doses given at low or high dose rate at early stage disease had significant inhibitory effects on lesion growth and, at 25 or 50 mGy, on lesion frequency. No dose given at low dose rate had any effect on total serum cholesterol, but this was elevated by every dose given at high dose rate. Exposures at low dose rate had no effect on the percentage of lesion lipids contained within macrophages, and, at either high or low dose rate, had no significant effect on lesion severity. Exposure at late stage disease, to any dose at high dose rate, had no significant effect on lesion frequency, but at low dose rate some doses produced a small transient increase in this frequency. Exposure to low doses at low, but not high dose rate, significantly, but transiently reduced average lesion size, and at either dose rate transiently reduced lesion severity. Exposure to any dose at low dose rate (but not high dose rate) resulted in large and persistent decreases in serum cholesterol. These data indicate that a single low dose exposure, depending on dose and dose rate, generally protects against various measures of atherosclerosis in genetically susceptible mice. This result contrasts with the known, generally detrimental effects of high doses on this disease in the same mice, suggesting that a linear extrapolation of risk from high doses is not appropriate. (author)

  4. Perception of low dose radiation risks among radiation researchers in Korea.

    Science.gov (United States)

    Seong, Ki Moon; Kwon, TaeWoo; Seo, Songwon; Lee, Dalnim; Park, Sunhoo; Jin, Young Woo; Lee, Seung-Sook

    2017-01-01

    Expert's risk evaluation of radiation exposure strongly influences the public's risk perception. Experts can inform laypersons of significant radiation information including health knowledge based on experimental data. However, some experts' radiation risk perception is often based on non-conclusive scientific evidence (i.e., radiation levels below 100 millisievert), which is currently under debate. Examining perception levels among experts is important for communication with the public since these individual's opinions have often exacerbated the public's confusion. We conducted a survey of Korean radiation researchers to investigate their perceptions of the risks associated with radiation exposure below 100 millisievert. A linear regression analysis revealed that having ≥ 11 years' research experience was a critical factor associated with radiation risk perception, which was inversely correlated with each other. Increased opportunities to understand radiation effects at perception of radiation exposure. In addition, radiation researchers conceived that more scientific evidence reducing the uncertainty for radiation effects perception of radiation exposure.

  5. Molecular alterations in childhood thyroid cancer after Chernobyl accident and low-dose radiation risk

    International Nuclear Information System (INIS)

    Suzuki, Keiji; Mitsutake, Norisato; Yamashita, Shunichi

    2012-01-01

    The linear no-threshold (LNT) model of radiation carcinogenesis has been used for evaluating the risk from radiation exposure. While the epidemiological studies have supported the LNT model at doses above 100 mGy, more uncertainties are still existed in the LNT model at low doses below 100 mGy. Thus, it is urged to clarify the molecular mechanisms underlying radiation carcinogenesis. After the Chernobyl accident in 1986, significant amount of childhood thyroid cancer has emerged in the children living in the contaminated area. As the incidence of sporadic childhood thyroid cancer is very low, it is quite evident that those cancer cases have been induced by radiation exposure caused mainly by the intake of contaminated foods, such as milk. Because genetic alterations in childhood thyroid cancers have extensively been studied, it should provide a unique chance to understand the molecular mechanisms of radiation carcinogenesis. In a current review, molecular signatures obtained from the molecular studies of childhood thyroid cancer after Chernobyl accident have been overviewed, and new roles of radiation exposure in thyroid carcinogenesis will be discussed. (author)

  6. The special cell effects and somatic consequences of exposure to low dose radiation

    International Nuclear Information System (INIS)

    Regina Fedortseva; Sergei Aleksanin; Eugene Zheleznyakov; Irina Bychkovskaya

    2007-01-01

    Complete text of publication follows. Objective: The experimental data presented in the report put some clarity into the ongoing polemics about possibility of induction of harmful non-carcinogenic effects in human body as a result of exposure to low doses of radiation. The denial of this possibility is based on the fact that traditionally studied genotoxic effects cannot be the cause of this pathology: the incidence of these effects in exposure to low doses of radiation is fairly low; the effects are not overt in critical slowly regenerating tissues, since they can only be morphologically manifested in actively growing cell populations. Methods: Endothelium of myocardial and alveolar capillaries were studied ultra-structurally in 236 rats irradiated by a wide range of X-ray doses (0,25;0,5;2,25;4,5;9;30;48;100) and 28 intact control animals. Studies were conducted during 12-18 months. The material consisted of 2-3 portions from various parts of myocardium and lung. From each portion, sections were prepared, in which all capillary sections were analyzed and ultra-structure of all lining capillary endotheliocytes (their number most often was more than 100) was studied. In each animal the percentage of non-viable endotheliocytes with signs of generalized organoid destruction, damage of plasmalemma and nuclear structures was accounted. Results: Irradiation of rat to low and higher doses caused significant (up to 7 times) increase number of endothelial cells with various ultra-structural damages (from relatively light ones to in the cell death). Even the lowest dose - 0,25 Gy produce an increasing degeneration, intracellular lysis and defects of mitochondria. We found unusual features of postradiational endothelium changes: dose independence, necessity of revealing the long-term, non-mutational cellular effects, massive involvement of cells, early development of the maximum effect already after the low dose irradiation. These special somatic effects, unlike genotoxic effects, are not connected to cell division. They appear according to the principle 'all or nothing' in low doses of radiation (in mammals less than 1 Gy). In slowly regenerating tissues these effects (we called them 'alternative effects' result in various subcellular disorders (mostly cytoplasmic). An irreversible change of intracellular homeostasis and dystrophic processes occur within a few hours after exposure. This can result in morphological and functional changes in tissues (depopulation), thus providing for the development of non-carcinogenic somatic consequences of low-dose irradiation. Presumably the changes of this kind are responsible for pathogenesis of the remote somatic disorders following a moderate radiation exposure. The alternative effects are based on special hidden non-mutational alterations. Unlike the traditionally studied alterations they involve all cells of the population and can be inherited by all off-springs (at least in F1). This substantially broadens our notion of biological and applied significance of this phenomenon. Conclusion: The most typical manifestation of alternative effects is a persistently increasing predisposition of cells to damage and death. It is likely that other manifestations are also possible, including a non-specific increase of likelihood (due to impairment of reparation capability) of genome damage. This could give a better insight into the problem of biological risks of cancer transformation and occurrence of hereditary disorders after exposure to low-dose irradiation. It is essential that different biological organisms may develop alternative effects not only due to radiation but other kinds of exposure. This represents a substantial ecological importance of alternative effects and requires development of new methods of assessment of external factors.

  7. Low-dose radiation employed in diagnostic imaging causes genetic effects in cultured cells

    Energy Technology Data Exchange (ETDEWEB)

    Ponzinibbio, Maria V.; Peral-Garcia, Pilar; Seoane, Analia (Inst. de Genetica Veterinaria, Univ. Nacional de La Plata CONICET, La Plata (Argentina)), e-mail: aseoane@fcv.unlp.edu.ar; Crudeli, Cintia (Agencia Nacional de Promocion Cientifica y Tecnologica, La Plata (Argentina))

    2010-11-15

    Background: Exposure to environmental, diagnostic, and occupational sources of radiation frequently involves low doses. Although these doses have no immediately noticeable impact on human health there is great interest in their long-term biological effects. Purpose: To assess immediate and time-delayed DNA damage in two cell lines exposed to low doses of ionizing radiation by using the comet assay and micronucleus test, and to compare these two techniques in the analysis of low-dose induced genotoxicity. Material and Methods: CHO and MRC-5 cells were exposed to 50 milliSievert (mSv) of ionizing radiation and assayed immediately after irradiation and at 16 or 12 passages post-irradiation, respectively. Comet assay and micronucleus test were employed. Results: The comet assay values observed in 50 mSv-treated cells were significantly higher than in the control group for both sample times and cell lines (P < 0.001). Micronuclei frequencies were higher in treated cells than in the control group (P < 0.01, CHO cells passage 16; P < 0.05, MRC-5 cells immediately after exposure; P < 0.01 MRC-5 cells passage 12). Correlation analysis between the two techniques was statistically significant (correlation coefficient 0.82, P < 0.05 and correlation coefficient 0.86, P < 0.05 for CHO and MRC-5 cells, respectively). Cells scored at passages 12 or 16 showed more damage than those scored immediately after exposure in both cell lines (no statistically significant differences). Conclusion: Cytomolecular and cytogenetic damage was observed in cells exposed to very low doses of X-rays and their progeny. A single low dose of ionizing radiation was sufficient to induce such response, indicating that mammalian cells are exquisitely sensitive to it. Comet and micronucleus assays are sensitive enough to assess this damage, although the former seems to be more efficient

  8. High dose and low dose radiation exposure in the induction of breast cancer

    International Nuclear Information System (INIS)

    Fernandez-Vicioso, E.; Ruiz-Cruces, R.; Pastor Vega, Jose M.

    2001-01-01

    In today's modern practice of Radiation Oncology it is becoming increasingly common to follow many patients with breast cancer. There is a proven association between prior radiation and the development of breast cancer, although in many instances the available sources of data are confusing. Characteristic features of radiation induced breast cancer are the importance of age at first exposure to radiation and the long latency period. The risk of breast cancer is highest in women exposed in the first decade of life and lessens progressively with increased age at exposure. The latency period is typically 10 years or more; a time in which other age dependent factors may influence the expression of the malignant phenotype. Genetic factors may also (in theory) increase a particular patient's susceptibility. (author)

  9. Effects of cobalt-60 low doses radiation on beam, rice and radish seeds

    International Nuclear Information System (INIS)

    Kikuchi, O.K.

    1987-01-01

    The effects of cobalt-60 gamma radiation on seeds of bean (Phaseolus vulgaris L.), rice (Oryza sativa L.) and radish (Raphanus sativus L.) were studied. Bean and rice seeds were irradiated with 3.5 and 7.7 Gy (32 Gy/h). There was an apparent acceleration on rice seed germination with 3.5 Gy when they were stored for 6 days after irradiation, but the same dose caused a delay when the store time was 1 day. Bean seeds germination was not modified by 3.5 and 7.7 Gy, but the fresh and dry weight of young plants showed an increase, mainly due the major quantity of water in the embryonic axis. Bean seeds were irradiated with 0.5 and 2.0 Gy (30 Gy/h). Seeds germination showed a slight delay irradiating with 0.5 Gy, while height, fresh and dry weight and primary leaves area of the young plants as well as number of nodes, leaves, flowers, beans and seeds were not modified after irradiation with 0.5 and 2.0 Gy. Radish seeds irradiated with 10 and 30 Gy at dose rates of 4.5, 22.5 and 45.0 Gy/h showed a germination delay and fresh and dry weight values for young plants leaves lower than control. Roots of totally developed plants showed no modifications in weight, volume, mean diameter, lenght and in the amount of soluble reducing sugar. (author)

  10. Preliminary study for development of low dose radiation shielding material using liquid silicon and metallic compound

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Seo Goo; Lee, Sung Soo [Dept. of Medical Science, Graduate School of Soonchunhyang University, Asan (Korea, Republic of); Han, Su Chul [Div. of Medical Radiation Equipment, Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of); Kang, Sung Jin [SoonChunHyang University Hospital, Seoul (Korea, Republic of); Lim, Sung Wook [Graduate school of SeJong University, Seoul (Korea, Republic of)

    2017-09-15

    This study measured and compared the protective clothing using Pb used for shielding in a diagnostic X-ray energy range, and the shielding rates of X-ray fusion shielding materials using Si and TiO{sub 2}. For the experiment, a pad type shielding with a thickness of 1 mm was prepared by mixing Si-TiO{sub 2}, and the X-ray shielding rate was compared with 0.5 mmPb plate of The shielding rate of shielding of 0.5 mmPb plate 95.92%, 85.26 % based on the case of no shielding under each 60kVp, 100kVp tube voltage condition. When the shielding of Si-TiO{sub 2} pad was applied, the shielding rate equal to or greater than 0.5 mmPb plate was obtained at a thickness of 11 mm or more, and the shielding rate of 100% or more was confirmed at a thickness of 13 nn in 60kVp condition. When the shielding of Si-TiO{sub 2} pad was applied, the shielding rate equal to or greater than 0.5 mmPb plate was obtained at a thickness of 17 mm or more, and a shielding rate of 0.5 mmPb plate was observed at a thickness of 23 mm in 100kVp condition. Through the results of this study, We could confirm the possibility of manufacturing radiation protective materials that does not contain lead hazard using various metallic compound and liquid Si. This study shows that possibility of liquid Si and other metallic compound can harmonize easily. Beside, It is flexible and strong to physical stress than Pb obtained radiation protective clothes. But additional studies are needed to increase the shielding rate and reduce the weight.

  11. Low dose radiation and ALARA: the potential risks to patients and staff from alpha-therapy

    Energy Technology Data Exchange (ETDEWEB)

    Priest, N.D. [Atomic Energy of Canada Limited, Chalk River, ON (Canada)

    2014-07-01

    This year a new drug containing radium-223, an alpha-emitting radionuclide, was approved for use by the US Food and Drug Administration for the palliative treatment of advanced prostate cancer metastases. Other drugs containing short-lived alpha-emitters are on clinical trial in Europe. Commonly, these employ a radionuclide attached to an antibody that specifically targets tumor cells to produce a highly localized radio-therapeutic dose to the tumor. However, normal tissues within the body will also be irradiated, albeit sometimes at low dose, and the question arises as to whether this presents a significant additional risk to the patient. Similarly, medical staff that handle these radionuclides could receive intakes of the radionuclides. What is the risk to staff? To assess the risk resulting from small tissue alpha-doses the toxicological, both human and animal, database was re-examined. The results of 20 epidemiological and toxicological studies with alpha-emitting radionuclides were analysed. In all cases a polynomial function provided a better fit to the data than a linear, no thresholds function. Also, in 19 cases a threshold dose below which no cancer is seen was indicated. The position of this threshold varied according to cancer type, but was typically in the range 0.1 to 1.0Gy of tissue dose - with a mean of 0.5Gy. It is concluded that alpha-radiation induced tumorogenesis is a threshold response and that as long as tissue doses are kept below these thresholds no additional cancers would be seen in either patients receiving alpha-therapy or in staff exposed to 'spilt' radionuclide. The presence of thresholds questions the appropriateness of current ALARA practices that are mostly used to drive occupational alpha-radiation exposures to as close to zero as possible. (author)

  12. Effect of low dose radiation on somatic intrachromosomal recombination in vivo and in vitro

    International Nuclear Information System (INIS)

    Hooker, A.M.; Cormack, J.; Morley, A.A.; Sykes, P.J.; Bhat, M.

    2003-01-01

    Full text: High doses of ionising radiation are mutagenic in a wide range of mutation assays. The majority of radiation exposure studies in in vivo mouse mutation assays have been performed at high doses, eg greater than 1 Gy. However, these doses are not relevant to the low doses of ionising radiation that the majority of the population might likely come into contact with. Radiation protection levels tend to be based on a simple linear no-threshold model which suggests that any radiation above zero is potentially harmful. The pKZ1 recombination mutagenesis mouse model has proven to be a sensitive assay for the detection of mutations caused by low doses of chemical agents. In pKZ1 mice, somatic intrachromosomal recombination (SICR) inversion events can be detected in cells using histochemistry for the E. coli LacZ transgene. We exposed pKZ1 mice to a single radiation dose ranging from 0.001 to 2 Gy. A significant increase in SICR was observed in spleen at the two highest doses of 0.1 and 2 Gy and a significant reduction in SICR below the endogenous frequency was observed at the two lowest doses of 0.01 and 0.001 Gy. After exposing a pKZ1 cell line to the same dose range, a similar J curve response was observed with significant increases in SICR observed at the 3 highest doses and a significant decrease below the endogenous frequency at the lowest dose (0.001 Gy). The next experiments will be to determine the dose where the SICR frequency returns to the endogenous level. The important question posed by these results is 'Is a reduction below the endogenous SICR level caused by low doses of ionising radiation anti-mutagenic?' Studies now need to be performed to investigate the effect of low doses of radiation on other mutation end-points, and the mechanism for the reduction in SICR

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

    International Nuclear Information System (INIS)

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

    1996-01-01

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

  14. MPGD for breast cancer prevention: a high resolution and low dose radiation medical imaging

    Science.gov (United States)

    Gutierrez, R. M.; Cerquera, E. A.; Mañana, G.

    2012-07-01

    Early detection of small calcifications in mammograms is considered the best preventive tool of breast cancer. However, existing digital mammography with relatively low radiation skin exposure has limited accessibility and insufficient spatial resolution for small calcification detection. Micro Pattern Gaseous Detectors (MPGD) and associated technologies, increasingly provide new information useful to generate images of microscopic structures and make more accessible cutting edge technology for medical imaging and many other applications. In this work we foresee and develop an application for the new information provided by a MPGD camera in the form of highly controlled images with high dynamical resolution. We present a new Super Detail Image (S-DI) that efficiently profits of this new information provided by the MPGD camera to obtain very high spatial resolution images. Therefore, the method presented in this work shows that the MPGD camera with SD-I, can produce mammograms with the necessary spatial resolution to detect microcalcifications. It would substantially increase efficiency and accessibility of screening mammography to highly improve breast cancer prevention.

  15. Study on mechanism of decreased lipid peroxide by low dose radiation

    International Nuclear Information System (INIS)

    Yamaoka, Kiyonori; Okazoe, Yoko; Akimaru, Kunihiro; Sato, E.F.; Utsumi, Kozo.

    1991-01-01

    We examined the effect of SOD on lipid peroxidation in biomembrane from V.E-deficient rats, in order to study the mechanism of increased SOD activities and decreased lipid peroxide by low dose irradiation. The following results were obtained. i. Active oxygen (O 2 - ) strongly enhances lipid peroxidations in biomembrane with the Fe 3+ as catalyst. ii. SOD evidently inhibits lipid peroxidations under above conditions. iii. We suggested that the effect of SOD enhanced by low dose irradiation results in inhibition of lipid peroxidation. (author)

  16. Targeted computerised tomography scanning of the ankle syndesmosis with low dose radiation exposure

    Energy Technology Data Exchange (ETDEWEB)

    Kotwal, Rahul [Princess of Wales Hospital, Bridgend (United Kingdom); Rath, Narendra [Royal Gwent Hospital, Newport (United Kingdom); Paringe, Vishal; Hemmadi, Sandeep; Thomas, Rhys; Lyons, Kath [University Hospital of Wales, Cardiff (United Kingdom)

    2016-03-15

    To devise a new protocol for targeted CT scanning of the distal tibiofibular syndesmosis with minimal radiation exposure to patients. We also aimed to correlate the reduction of the syndesmosis as seen on CT scans with the functional outcome of patients. Prospective study. Forty adults undergoing surgical stabilisation of an acute distal tibiofibular syndesmosis injury were recruited. A targeted five-cut computerised tomography scan protocol was developed. The radiation exposure to the patient with this protocol was only 0.002 mSv. Scans were performed 12 weeks after surgery. The contralateral ankle of every patient was used as a control to determine the accuracy of the reduction of the syndesmosis for that individual patient. American Orthopaedic Foot and Ankle Society (AOFAS) scores were obtained at a minimum of 1 year after surgery. After considering the exclusions, 36 patients formed the study group. A wide variation was observed in the anatomy of the normal syndesmosis. If we considered a difference of more than 2 mm between the normal and injured syndesmosis relationship as significant, 15 (41.6 %) of our patients had a significant difference between the injured and normal sides. AOFAS scores were available for 13 of these patients and were good to excellent in 11(84.6 %). Our study describes a reliable new CT scanning technique for the distal tibiofibular syndesmosis using only five cuts and a low-radiation-dose protocol. Clinical correlation of the findings on the scan with functional outcomes suggests that routine post-operative CT of the syndesmosis is probably not justified. (orig.)

  17. Modulation of low dose radiation effect on pentose phosphate pathway enzymes by B-multivitamin deficiency

    International Nuclear Information System (INIS)

    Zimatkina, T.I.; Lashak, L.K.; Moiseenok, A.G.

    1997-01-01

    Blood, liver, thymus and spleen of albino rats injected subcutaneously with antivitamins (othythiamine and methotrexate) and subjected to prolonger γ-irradiation in the overall dose of 0.75 Gy were assayed for transketolase and glucose-6-phosphate dehydrogenase after 12h, 1, 2, 5 and 40 days from the last radiation dose. High transketolase sensitivity was found both to radiation (activation) and the combined effects of vitamin deficiency and radiation (potentiation of antivitamin inhibitory action) in all the tissues studied. The activity of glucose-6-phosphate dehydrogenase was little changed under the given experimental manipulations, but the combined effect of the factors considerably inhibited the enzyme activities in the organs of the immune system. Consequently, in B-multivitamin deficiency the effect of low radiation doses was subjected to a considerable modulation resulting in profound inhibition of the oxidation and nonoxidative branches of the pentose phosphate pathway. (author). 9 refs, 2 tabs

  18. Low Dose Radiation Cancer Risks: Epidemiological and Toxicological Models. Final Technical Report

    International Nuclear Information System (INIS)

    Hoel, David G.

    2012-01-01

    The basic purpose of this one year research grant was to extend the two stage clonal expansion model (TSCE) of carcinogenesis to exposures other than the usual single acute exposure. The two-stage clonal expansion model of carcinogenesis incorporates the biological process of carcinogenesis, which involves two mutations and the clonal proliferation of the intermediate cells, in a stochastic, mathematical way. The current TSCE model serves a general purpose of acute exposure models but requires numerical computation of both the survival and hazard functions. The primary objective of this research project was to develop the analytical expressions for the survival function and the hazard function of the occurrence of the first cancer cell for acute, continuous and multiple exposure cases within the framework of the piece-wise constant parameter two-stage clonal expansion model of carcinogenesis. For acute exposure and multiple exposures of acute series, it is either only allowed to have the first mutation rate vary with the dose, or to have all the parameters be dose dependent; for multiple exposures of continuous exposures, all the parameters are allowed to vary with the dose. With these analytical functions, it becomes easy to evaluate the risks of cancer and allows one to deal with the various exposure patterns in cancer risk assessment. A second objective was to apply the TSCE model with varing continuous exposures from the cancer studies of inhaled plutonium in beagle dogs. Using step functions to estimate the retention functions of the pulmonary exposure of plutonium the multiple exposure versions of the TSCE model was to be used to estimate the beagle dog lung cancer risks. The mathematical equations of the multiple exposure versions of the TSCE model were developed. A draft manuscript which is attached provides the results of this mathematical work. The application work using the beagle dog data from plutonium exposure has not been completed due to the fact that the research project did not continue beyond its first year.

  19. Public education on the health effects of low dose radiation. Why the government underestimated the risks?

    International Nuclear Information System (INIS)

    Sakiyama, Hisako

    2012-01-01

    Here the education on the health effects of radiation, which has not been taken up in the report of the National Diet of Japan Fukushima Nuclear Accident Independent Investigation Commission (NAIIC), is mentioned: The atomic power policy for the education on the health effects of radiation, the correspondence of the Ministry of Education, Culture, Sports, Science and Technology after the Fukushima accident, the side readers on the radiation, Is there the clear evidence on the correlation of dose rate under 100 mSv to diseases?, the ploblem of dose and dose-rate effectiveness factor, the fluctuation range of the death rate 0.5% from cancer, the influence and assistance of the electric enterprise union to ICRP members, etc. (M.H.)

  20. Extracting Gene Networks for Low-Dose Radiation Using Graph Theoretical Algorithms

    Energy Technology Data Exchange (ETDEWEB)

    Voy, Brynn H [ORNL; Scharff, Jon [University of Tennessee, Knoxville (UTK); Perkins, Andy [University of Tennessee, Knoxville (UTK); Saxton, Arnold [University of Tennessee, Knoxville (UTK); Borate, Bhavesh [University of Tennessee, Knoxville (UTK); Chesler, Elissa J [ORNL; Branstetter, Lisa R [ORNL; Langston, Michael A [University of Tennessee, Knoxville (UTK)

    2006-01-01

    Genes with common functions often exhibit correlated expression levels, which can be used to identify sets of interacting genes from microarray data. Microarrays typically measure expression across genomic space, creating a massive matrix of co-expression that must be mined to extract only the most relevant gene interactions. We describe a graph theoretical approach to extracting co-expressed sets of genes, based on the computation of cliques. Unlike the results of traditional clustering algorithms, cliques are not disjoint and allow genes to be assigned to multiple sets of interacting partners, consistent with biological reality. A graph is created by thresholding the correlation matrix to include only the correlations most likely to signify functional relationships. Cliques computed from the graph correspond to sets of genes for which significant edges are present between all members of the set, representing potential members of common or interacting pathways. Clique membership can be used to infer function about poorly annotated genes, based on the known functions of better-annotated genes with which they share clique membership (i.e., ''guilt-by-association''). We illustrate our method by applying it to microarray data collected from the spleens of mice exposed to low-dose ionizing radiation. Differential analysis is used to identify sets of genes whose interactions are impacted by radiation exposure. The correlation graph is also queried independently of clique to extract edges that are impacted by radiation. We present several examples of multiple gene interactions that are altered by radiation exposure and thus represent potential molecular pathways that mediate the radiation response.

  1. Alterations of proteins in murine splenic cells after low dose radiation

    International Nuclear Information System (INIS)

    Chen Shali; Meng Qingyong; Liu Shuzheng

    1997-01-01

    Alterations of proteins in the nuclear and cytoplasmic fractions of splenocytes were investigated in mice 4 hours after whole body irradiation with 75 mGy X-rays by 2D-electrophoresis. It was found that alterations of 6 proteins ranging in size from 12 to 43 kD with their pI distribution from 5.6 to 6.6 were displayed in the nuclear fraction of splenocytes in irradiated mice, of which there were 4 novel proteins and 2 up-regulated proteins and at the same time alterations of 10 proteins ranging in size from 10 to 69 kD with their pI distribution from 5.3 to 8.2 were displayed in the cytoplasmic fraction of splenocytes in irradiated mice, of which there were 6 novel proteins, 1 up-regulated proteins and 3 down-regulated proteins, and 3 proteins ranging in size from 24 to 32 kD with their pI distribution from 5.2 to 6.5 disappeared after radiation. It was shown that a 32000/5.2 (MW/pI) protein molecule in the sham-irradiated cytosol of splenocytes appeared in the nuclei after radiation and a 43000/6.3 protein molecule in the sham-irradiated cytosol decreased and appeared in the nuclei after radiation. The results suggest that exchanges of protein molecules occurred between nuclear and cytoplasmic compartments after radiation

  2. Effect of low dose radiation (LDR) on biological activity of NK cell

    International Nuclear Information System (INIS)

    Yang Liyun; Lin Meixiong; Luo Min; Ran Min; Liang Xuefei

    2006-01-01

    Objective: To study the in vitro and in vivo effect of LDR on the proliferation and killing activity of mouse NK cells with exploitation of the related mechanism of signal transduction. The effect of infused NK cells on inhibiton of oncogenesis and tumor burden regression was also studied. Methods: Mononuclear cells extracted from mouse spleen were treated with immunomagnetic bead for the isolation of CD3 - /CD16 + , CD56 + cells. After verified with flowcytometry, these NK cells were cultured with mice splenic cells (irradiated with 20Gy 60 Co gamma ray) as feeder cells and rhIL-2 as induction factor for 3 rounds (5 days each round). Specimens of cultured NK cells were treated with different doses of radiation (25mGy, 75mGy, 200mGy, 500mGy), the proliferation index (PI) with tumoreidal activity on K562 cells (with 3 H-TdR) incorporation was examined at 4h, 24h, 48h, 72h after irradiation respectively. The role of P38MAPK signal pathway in the LDR effect was examined with adding either inhibitor (SB203580) or activator (P79350) of P38MAPK into the culture and measuring the PI, Killing activity (as expression of the related factors IFN-gamma, FasL, perforin) of NK cells thereafter. The in vivo test involved exposing mice to whole body 25mGy irradiation, harvesting splenic NK cells at 4h, 24h, 48h, 72h later respectively and performing the above-described in vitro procedures. Inhibition of oncogenesis was examined in vivo with infusion of cultured NK cells (LDR treated vs LDR non-treated) 10 days after infusion of K562 cells into mice and examination of hepatic/splenic CD 13+ , S-stage cells and peripheral blood tumor cells in the sacrificed animal another 10 days later. Also, K562 cells were innoculated subcutaneously into mice. After tumor nodule formation (2.0 x 2.0 mm), NK cells (LDR treated vs non-treated) were infused and regression of the tumor nodule with the weight of hepatic tumor mass was noticed in sacrificed animals on d 8 and the survival rate on d 40 recorded. Results: With the above methods, CD3 - /CD16 + , CD56 + NK cell were successfully cultured. The PI and killing activity were highest at 24h after 75mGy LDR in vitro, but at 48h in vivo. Both PI and killing activity demonstrated as expression of IFN-gamma, FasL, perforin were significantly increased after LDR (vs without LDR, P + , S-stage cells and peripheral blood abnormal (tumor) cell percentages (vs without LDR, P<0.05). The same was true for tumor bearing mouse models (with K562 cells subcutaneous inoculation and tumor nodule formation) i.e. more tumor nodule regression and less hepatic tumor weight with prolonged survival (vs without LDR, P<0.05). Conclusion: Both in vitro and in vivo, LDR could promote the PI and killing activity of NK cells the through P38MAPK signal pathway augmentation. Better inhibition of oncogenesis and decrease of tumor burden were clearly demonstrated with infusion of LDR treated NK cells into mouse models (prepared with K562 cells). (authors)

  3. Perception of low dose radiation risks among radiation researchers in Korea

    Science.gov (United States)

    Seo, Songwon; Lee, Dalnim; Park, Sunhoo; Jin, Young Woo; Lee, Seung-Sook

    2017-01-01

    Expert’s risk evaluation of radiation exposure strongly influences the public’s risk perception. Experts can inform laypersons of significant radiation information including health knowledge based on experimental data. However, some experts’ radiation risk perception is often based on non-conclusive scientific evidence (i.e., radiation levels below 100 millisievert), which is currently under debate. Examining perception levels among experts is important for communication with the public since these individual’s opinions have often exacerbated the public’s confusion. We conducted a survey of Korean radiation researchers to investigate their perceptions of the risks associated with radiation exposure below 100 millisievert. A linear regression analysis revealed that having ≥ 11 years’ research experience was a critical factor associated with radiation risk perception, which was inversely correlated with each other. Increased opportunities to understand radiation effects at risk perception of radiation exposure. In addition, radiation researchers conceived that more scientific evidence reducing the uncertainty for radiation effects risk perception of radiation exposure. PMID:28166286

  4. Immunological effects of low dose radiation. Absent or minor effects of Chernobyl fallout in Norway?

    International Nuclear Information System (INIS)

    Reitan, J.B.; Bergan, T.D.; Strand, P.; Melbye, O.J.

    1998-01-01

    In this pilot study of those Norwegian individuals most heavily exposed to the Chernobyl Fallout, immunological parameters generally stayed within normal limits. However, some parameter, apparently within the assumed normal range did, in fact correlate to the estimated individual dose as assessed by wholebody counting of radiocaesium content. The small possible effects revealed in this study may represent real biological effects, but do not necessarily represent a health detriment. 43 refs., 4 figs., 6 tabs

  5. Multidisciplinary European Low Dose Initiative (MELODI). Strategic research agenda for low dose radiation risk research

    Energy Technology Data Exchange (ETDEWEB)

    Kreuzer, M. [Federal Office for Radiation Protection, BfS, Department of Radiation Protection and Health, Neuherberg (Germany); Auvinen, A. [University of Tampere, Tampere (Finland); STUK, Helsinki (Finland); Cardis, E. [ISGlobal, Barcelona Institute for Global Health, Barcelona (Spain); Durante, M. [Institute for Fundamental Physics and Applications, TIFPA, Trento (Italy); Harms-Ringdahl, M. [Stockholm University, Centre for Radiation Protection Research, Stockholm (Sweden); Jourdain, J.R. [Institute for Radiological Protection and Nuclear Safety, IRSN, Fontenay-aux-roses (France); Madas, B.G. [MTA Centre for Energy Research, Environmental Physics Department, Budapest (Hungary); Ottolenghi, A. [University of Pavia, Physics Department, Pavia (Italy); Pazzaglia, S. [Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA), Rome (Italy); Prise, K.M. [Queens University Belfast, Belfast (United Kingdom); Quintens, R. [Belgian Nuclear Research Centre, SCK-CEN, Mol (Belgium); Sabatier, L. [French Atomic Energy Commission, CEA, Paris (France); Bouffler, S. [Public Health England, PHE, Chilton (United Kingdom)

    2018-03-15

    MELODI (Multidisciplinary European Low Dose Initiative) is a European radiation protection research platform with focus on research on health risks after exposure to low-dose ionising radiation. It was founded in 2010 and currently includes 44 members from 18 countries. A major activity of MELODI is the continuous development of a long-term European Strategic Research Agenda (SRA) on low-dose risk for radiation protection. The SRA is intended to identify priorities for national and European radiation protection research programs as a basis for the preparation of competitive calls at the European level. Among those key priorities is the improvement of health risk estimates for exposures close to the dose limits for workers and to reference levels for the population in emergency situations. Another activity of MELODI is to ensure the availability of European key infrastructures for research activities, and the long-term maintenance of competences in radiation research via an integrated European approach for training and education. The MELODI SRA identifies three key research topics in low dose or low dose-rate radiation risk research: (1) dose and dose rate dependence of cancer risk, (2) radiation-induced non-cancer effects and (3) individual radiation sensitivity. The research required to improve the evidence base for each of the three key topics relates to three research lines: (1) research to improve understanding of the mechanisms contributing to radiogenic diseases, (2) epidemiological research to improve health risk evaluation of radiation exposure and (3) research to address the effects and risks associated with internal exposures, differing radiation qualities and inhomogeneous exposures. The full SRA and associated documents can be downloaded from the MELODI website (http://www.melodi-online.eu/sra.html). (orig.)

  6. Community Surveys Low Dose Radiation. Fernald, Ohio and Rocky Flats, Colorado

    CERN Document Server

    Mertz, C K; Johnson, S; MacGregor, D G; Satterfield, T

    2002-01-01

    This report is intended to present a basic description of the data from the two community surveys and to document the text of the questions; the methods used for the survey data collection; and a brief overview of the results. Completed surveys were conducted at local communities near the Rocky Flats, Colorado and the Fernald, Ohio sites; no survey was conducted for the Brookhaven, New York site. Fernald. The Fernald sample was randomly selected from 98% of all potential residential telephones in the townships of Ross, Morgan, and Crosby. The only telephone exchanges not used for the Fernald study had 4%, or fewer, of the holders of the telephone numbers actually living in either of the three target townships. Surveying started on July 24, 2001 and finished on August 30, 2001. A total of 399 completed interviews were obtained resulting in a CASRO response rate of 41.8%. The average length of an interview was 16.5 minutes. Rocky Flats. The sample was randomly selected from all potential residential telephones ...

  7. Extracting gene networks for low-dose radiation using graph theoretical algorithms.

    Directory of Open Access Journals (Sweden)

    Brynn H Voy

    2006-07-01

    Full Text Available Genes with common functions often exhibit correlated expression levels, which can be used to identify sets of interacting genes from microarray data. Microarrays typically measure expression across genomic space, creating a massive matrix of co-expression that must be mined to extract only the most relevant gene interactions. We describe a graph theoretical approach to extracting co-expressed sets of genes, based on the computation of cliques. Unlike the results of traditional clustering algorithms, cliques are not disjoint and allow genes to be assigned to multiple sets of interacting partners, consistent with biological reality. A graph is created by thresholding the correlation matrix to include only the correlations most likely to signify functional relationships. Cliques computed from the graph correspond to sets of genes for which significant edges are present between all members of the set, representing potential members of common or interacting pathways. Clique membership can be used to infer function about poorly annotated genes, based on the known functions of better-annotated genes with which they share clique membership (i.e., "guilt-by-association". We illustrate our method by applying it to microarray data collected from the spleens of mice exposed to low-dose ionizing radiation. Differential analysis is used to identify sets of genes whose interactions are impacted by radiation exposure. The correlation graph is also queried independently of clique to extract edges that are impacted by radiation. We present several examples of multiple gene interactions that are altered by radiation exposure and thus represent potential molecular pathways that mediate the radiation response.

  8. Community Surveys: Low Dose Radiation. Fernald, Ohio and Rocky Flats, Colorado

    Energy Technology Data Exchange (ETDEWEB)

    C. K. Mertz; James Flynn; Donald G. MacGregor; Theresa Satterfield; Stephen M. Johnson; Seth Tuler; Thomas Webler

    2002-10-16

    This report is intended to present a basic description of the data from the two community surveys and to document the text of the questions; the methods used for the survey data collection; and a brief overview of the results. Completed surveys were conducted at local communities near the Rocky Flats, Colorado and the Fernald, Ohio sites; no survey was conducted for the Brookhaven, New York site. Fernald. The Fernald sample was randomly selected from 98% of all potential residential telephones in the townships of Ross, Morgan, and Crosby. The only telephone exchanges not used for the Fernald study had 4%, or fewer, of the holders of the telephone numbers actually living in either of the three target townships. Surveying started on July 24, 2001 and finished on August 30, 2001. A total of 399 completed interviews were obtained resulting in a CASRO response rate of 41.8%. The average length of an interview was 16.5 minutes. Rocky Flats. The sample was randomly selected from all potential residential telephones in Arvada and from 99% of the potential telephones in Westminster. Surveying started on August 10, 2001 and finished on September 25, 2001. A total of 401 completed interviews were obtained with a CASRO response rate of 32.5%. The average length of an interview was 15.7 minutes. Overall, respondents hold favorable views of science. They indicate an interest in developments in science and technology, feel that the world is better off because of science, and that science makes our lives healthier, easier, and more comfortable. However, respondents are divided on whether science should decide what is safe or not safe for themselves and their families. The majority of the respondents think that standards for exposure to radiation should be based on what science knows about health effects of radiation and on what is possible with today's technology. Although few respondents had visited the sites, most had heard or read something about Fernald or Rocky Flat s in the media. Impressions of the sites tend to be negative. Most respondents feel that overall their community would be better off without the site. However, when asked about the economic future of their community after cleanup and closure of the site, only 31-43% thought that it will be better, 47-56% thought their local economy will be about the same.

  9. Effect of Whole Body Low Dose Radiation (WB-LDR) on diabetic rats

    International Nuclear Information System (INIS)

    Roy, B.G.

    2014-01-01

    Exposure of type II diabetic mice to LDR has been shown to significantly up regulate pancreatic antioxidants along with reduction of glucose levels. Present study was aimed to evaluate the effects of WB-LDR on type II diabetic rats. Sprague-Dawley male rats (n=18) were pre-treated with Alloxan Monohydrate (150 mg/kg body weight, IP) to induce hyperglycemia. Elevated level of blood glucose was monitored for consecutive 10 days by Glucometer (Accu-Chek, Active) before irradiation. Two group of rats (n=12) were exposed to single dose of 0.25 Gy and 0.5 Gy of gamma radiation at the rate of 1.02 Gy/minute. Blood glucose level, feed, water intake and body weight was monitored for 10 days post irradiation. Results revealed weight loss, polydipsia, polyphagia and elevated blood glucose level up to 10th day in diabetic control, whereas; reverse trend was observed from 7th day post irradiation in two treated groups. However, no significant difference was found between two treated groups. The results indicate that treatment with WB-LDR reduces the blood-glucose level and so its complications in diabetic rats. (author)

  10. Low-dose radiation-induced adaptive response in bone marrow cells of mice

    International Nuclear Information System (INIS)

    Farooqi, Zeba; Kesavan, P.C.

    1993-01-01

    Using bone marrow cells of whole body irradiated mice, the cytogenetic adaptive response induced by low conditioning doses of gamma-rays was investigated. The conditioning doses (0.025 and 0.05 Gy) were given at a dose-rate of 1.67 Gy/min. The challenging dose of 1 Gy was given at a dose-rate of 0.045 Gy/s. The challenging dose was given at different time intervals after the conditioning dose. The time intervals between the conditioning dose and challenging dose were 2, 7.5, 13, 18.5 and 24 h. When the time interval between the conditioning dose and the challenging dose was 2 h, both conditioning doses (0.025 and 0.05 Gy) reduced the frequency of MNPCEs and chromosomal aberrations in the bone marrow cells. The data collected at different time intervals (7.5, 13, 18.5 h) reveal that the radioadaptive response persisted for a longer time when the lower conditioning dose (0.025 Gy) was given. With the higher conditioning dose (0.05 Gy), the radioadaptive response disappeared after a time interval of 13 h. When the time interval between the conditioning dose and the challenging doses was 18.5 or 24 h, only the lower conditioning dose appeared effective in inducing the radioadaptive response

  11. We can do better than effective dose for estimating or comparing low-dose radiation risks

    International Nuclear Information System (INIS)

    Brenner, D.J.

    2012-01-01

    The effective dose concept was designed to compare the generic risks of exposure to different radiation fields. More commonly these days, it is used to estimate or compare radiation-induced cancer risks. For various reasons, effective dose represents flawed science: for instance, the tissue-specific weighting factors used to calculate effective dose are a subjective mix of different endpoints; and the marked and differing age and gender dependencies for different health detriment endpoints are not taken into account. This paper suggests that effective dose could be replaced with a new quantity, ‘effective risk’, which, like effective dose, is a weighted sum of equivalent doses to different tissues. Unlike effective dose, where the tissue-dependent weighting factors are a set of generic, subjective committee-defined numbers, the weighting factors for effective risk are simply evaluated tissue-specific lifetime cancer risks per unit equivalent dose. Effective risk, which has the potential to be age and gender specific if desired, would perform the same comparative role as effective dose, be just as easy to estimate, be less prone to misuse, be more directly understandable, and would be based on solid science. An added major advantage is that it gives the users some feel for the actual numerical values of the radiation risks they are trying to control.

  12. New approach to explain results of the low dose radiation on the Raphanus sativus

    Energy Technology Data Exchange (ETDEWEB)

    Kurisu, Y.; Yoshioka, K.; Yoshida, S.; Murata, I.; Takahashi, A. [Osaka University, Graduate School of Engineering, Department of Nuclear Engineering, Suita, Osaka (Japan)

    2002-01-01

    Recently, the researches on radiation hormesis toward the animals and plants are made abundantly. The radiation hormesis effect is that subharmful doses of radiation may evoke a stimulatory response in any organism. We did irradiation experiments of fusion (DD and DT) neutron, thermal and fast neutron, and 60-cobalt gamma-ray to the dry seeds of Raphanus stivus, and examined whether radiation hormesis effects appeared by measuring germination rate, the length of a hypocotyl and a root and the total weight on the 7th day from starring cultivation. The evaluation of radiation hormesis effects was done by using relative effectiveness which is the ratio of the mean of the measurement objects of the irradiation group to that of non-irradiation group. In the Raphanus stivus the radiation hormesis effects of the measured objects were only turned up in seed groups irradiated by the fusion (D-T) neutron. We have confirmed that absorbed dose range where the effects are revealed is from 1 cGy to 10 Gy and there the relative effectiveness is from 1.05 to 1.25. In this research the model about radiation hormesis effect on Raphanus sativus confirmed in irradiation of D-T neutrons is proposed. And it is apparent that radiation from radio activated seeds influences hormesis effect on Raphanus sativus. (author)

  13. Is There a Dose-Response Relationship for Heart Disease With Low-Dose Radiation Therapy?

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Eugene [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Corbett, James R. [Division of Nuclear Medicine, Department of Radiology, University of Michigan, Ann Arbor, Michigan (United States); Moran, Jean M. [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Griffith, Kent A. [Department of Biostatistics, University of Michigan, Ann Arbor, Michigan (United States); Marsh, Robin B.; Feng, Mary; Jagsi, Reshma; Kessler, Marc L. [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Ficaro, Edward C. [Division of Nuclear Medicine, Department of Radiology, University of Michigan, Ann Arbor, Michigan (United States); Pierce, Lori J., E-mail: ljpierce@umich.edu [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States)

    2013-03-15

    Purpose: To quantify cardiac radiation therapy (RT) exposure using sensitive measures of cardiac dysfunction; and to correlate dysfunction with heart doses, in the setting of adjuvant RT for left-sided breast cancer. Methods and Materials: On a randomized trial, 32 women with node-positive left-sided breast cancer underwent pre-RT stress single photon emission computed tomography (SPECT-CT) myocardial perfusion scans. Patients received RT to the breast/chest wall and regional lymph nodes to doses of 50 to 52.2 Gy. Repeat SPECT-CT scans were performed 1 year after RT. Perfusion defects (PD), summed stress defects scores (SSS), and ejection fractions (EF) were evaluated. Doses to the heart and coronary arteries were quantified. Results: The mean difference in pre- and post-RT PD was −0.38% ± 3.20% (P=.68), with no clinically significant defects. To assess for subclinical effects, PD were also examined using a 1.5-SD below the normal mean threshold, with a mean difference of 2.53% ± 12.57% (P=.38). The mean differences in SSS and EF before and after RT were 0.78% ± 2.50% (P=.08) and 1.75% ± 7.29% (P=.39), respectively. The average heart Dmean and D95 were 2.82 Gy (range, 1.11-6.06 Gy) and 0.90 Gy (range, 0.13-2.17 Gy), respectively. The average Dmean and D95 to the left anterior descending artery were 7.22 Gy (range, 2.58-18.05 Gy) and 3.22 Gy (range, 1.23-6.86 Gy), respectively. No correlations were found between cardiac doses and changes in PD, SSS, and EF. Conclusions: Using sensitive measures of cardiac function, no clinically significant defects were found after RT, with the average heart Dmean <5 Gy. Although a dose response may exist for measures of cardiac dysfunction at higher doses, no correlation was found in the present study for low doses delivered to cardiac structures and perfusion, SSS, or EF.

  14. Targeted computerised tomography scanning of the ankle syndesmosis with low dose radiation exposure

    International Nuclear Information System (INIS)

    Kotwal, Rahul; Rath, Narendra; Paringe, Vishal; Hemmadi, Sandeep; Thomas, Rhys; Lyons, Kath

    2016-01-01

    To devise a new protocol for targeted CT scanning of the distal tibiofibular syndesmosis with minimal radiation exposure to patients. We also aimed to correlate the reduction of the syndesmosis as seen on CT scans with the functional outcome of patients. Prospective study. Forty adults undergoing surgical stabilisation of an acute distal tibiofibular syndesmosis injury were recruited. A targeted five-cut computerised tomography scan protocol was developed. The radiation exposure to the patient with this protocol was only 0.002 mSv. Scans were performed 12 weeks after surgery. The contralateral ankle of every patient was used as a control to determine the accuracy of the reduction of the syndesmosis for that individual patient. American Orthopaedic Foot and Ankle Society (AOFAS) scores were obtained at a minimum of 1 year after surgery. After considering the exclusions, 36 patients formed the study group. A wide variation was observed in the anatomy of the normal syndesmosis. If we considered a difference of more than 2 mm between the normal and injured syndesmosis relationship as significant, 15 (41.6 %) of our patients had a significant difference between the injured and normal sides. AOFAS scores were available for 13 of these patients and were good to excellent in 11(84.6 %). Our study describes a reliable new CT scanning technique for the distal tibiofibular syndesmosis using only five cuts and a low-radiation-dose protocol. Clinical correlation of the findings on the scan with functional outcomes suggests that routine post-operative CT of the syndesmosis is probably not justified. (orig.)

  15. Effect of low dose radiation on the odontogenesis of mice foetus

    International Nuclear Information System (INIS)

    Osman, M.; Al-Achkar, W.

    1998-09-01

    Mice foetuses were irradiated in utero by gamma rays (0,2, 4,6 Gy) at 10, 12, 14, 16, 18 days of gestation. Histological study was carried out on the first premandibular tooth after 2,4,6,8 days of irradiation, to investigate the effect of irradiation on different steps of tooth development. It appeared that the irradiation induced a delay in the tooth development depending on the time of irradiation and period of gestation. The 2 Gy irradiation effect was small. The 4 Gy dose induced a delay of the cytodifferentiation of the odontoblasts and the ameloblasts. These effects were associated with a morphological retardation in the coronal and the tooth root. More pronounced effects after 6 Gy irradiation for all aspects of the odontogenesis were observed. It caused a strong decrease in the tooth development of the anlages (irradiation of day 12 of the gestation), blocked the morphogenesis (irradiation of day 14), and delayed the cytodifferentiation of the odontoblasts and the amelobasts (irradiation of day 16). Whereas the irradiation at the day 18 had no effects on the functional differentiation of the odontoblasts, but a delay in the functional differentiation of the ameloblasts was observed. Our results show, in our experimental conditions, that irradiation effect the processes prior to the cytodifferentiation of the ameloblasts and the odontoblasts and there are no effects to be observed on the cyto and functional differentiation of these two blasts when their cells achieved its final differentiation. (author)

  16. Epidemiologic study on respiratory cancer among miners with low dose radiation exposures

    International Nuclear Information System (INIS)

    Comba, P.

    1993-01-01

    The aim of the project is the study of specific mortality causes among Italian miners, with special reference to respiratory malignancies. The contrast between observed and expected mortality rates for lung cancer of miners exposed to different levels of radiation provide figures for estimating the number of extra cases of lung cancer per working level month and person years of exposure. The study included 1357 subjects, 60 of whom were lost to follow-up. The total number of deceased subjects was 527; for 30 of them it was not possible to ascertain the cause of death. (R.P.) 2 refs., 3 tabs

  17. The effect of lysate of spleen cells after low dose radiation (LDR) on NK activity

    International Nuclear Information System (INIS)

    Lu Duicai; Su Liaoyuan

    2003-01-01

    To find effect of lysate of spleen cells after LDR on NK activity of CD 57 cells or non-CD 57 cells, lysate of spleen cells after LDR were extracted. McAb (anti CD 57 cells) was used to separate CD 57 cells from human peripheral blood by Panning direct method. The CD 57 cells and non-CD 57 cells were used as effective cells. K 562 cells labelled by 3 H-TdR were used as target cells. The ratio of effect cells to target cells was 10:1. NK activity of CD 57 cells or non-CD 5 -7 cells with the lysate of spleen cells after LDR was reflected by the efficiency of anti tumor cells. The 3 H-TdR incorporation in K 562 cells cultured with non-CD 57 cells was significantly lower than that with CD 57 cells. After use of the lysate of spleen cells after LDR, NK activities of CD 57 cells and non-CD 57 cells were 1.24 and 1.58 respectively. They were both increased obviously compared with control groups. The effect of anti K 562 cells of non-CD 57 cells is even greater than that of CD 57 cells. The lysate of spleen cells after LDR can enhance the effect of both non-CD 57 cells and CD 57 cells

  18. Community Surveys: Low Dose Radiation. Fernald, Ohio and Rocky Flats, Colorado

    International Nuclear Information System (INIS)

    C. K. Mertz; James Flynn; Donald G. MacGregor; Theresa Satterfield; Stephen M. Johnson; Seth Tuler; Thomas Webler email ckmertz@decisionresearch.org

    2002-01-01

    This report is intended to present a basic description of the data from the two community surveys and to document the text of the questions; the methods used for the survey data collection; and a brief overview of the results. Completed surveys were conducted at local communities near the Rocky Flats, Colorado and the Fernald, Ohio sites; no survey was conducted for the Brookhaven, New York site. Fernald. The Fernald sample was randomly selected from 98% of all potential residential telephones in the townships of Ross, Morgan, and Crosby. The only telephone exchanges not used for the Fernald study had 4%, or fewer, of the holders of the telephone numbers actually living in either of the three target townships. Surveying started on July 24, 2001 and finished on August 30, 2001. A total of 399 completed interviews were obtained resulting in a CASRO response rate of 41.8%. The average length of an interview was 16.5 minutes. Rocky Flats. The sample was randomly selected from all potential residential telephones in Arvada and from 99% of the potential telephones in Westminster. Surveying started on August 10, 2001 and finished on September 25, 2001. A total of 401 completed interviews were obtained with a CASRO response rate of 32.5%. The average length of an interview was 15.7 minutes. Overall, respondents hold favorable views of science. They indicate an interest in developments in science and technology, feel that the world is better off because of science, and that science makes our lives healthier, easier, and more comfortable. However, respondents are divided on whether science should decide what is safe or not safe for themselves and their families. The majority of the respondents think that standards for exposure to radiation should be based on what science knows about health effects of radiation and on what is possible with today's technology. Although few respondents had visited the sites, most had heard or read something about Fernald or Rocky Flat s in the media. Impressions of the sites tend to be negative. Most respondents feel that overall their community would be better off without the site. However, when asked about the economic future of their community after cleanup and closure of the site, only 31-43% thought that it will be better, 47-56% thought their local economy will be about the same

  19. Pretreatment of low dose radiation reduces radiation-induced apoptosis in mouse lymphoma (EL4) cells.

    Science.gov (United States)

    Kim, J H; Hyun, S J; Yoon, M Y; Ji, Y H; Cho, C K; Yoo, S Y

    1997-06-01

    Induction of an adaptive response to ionizing radiation in mouse lymphoma (EL4) cells was studied by using cell survival fraction and apoptotic nucleosomal DNA fragmentation as biological end points. Cells in early log phase were pre-exposed to low dose of gamma-rays (0.01 Gy) 4 or 20 hrs prior to high dose gamma-ray (4, 8 and 12 Gy for cell survival fraction analysis; 8 Gy for DNA fragmentation analysis) irradiation. Then cell survival fractions and the extent of DNA fragmentation were measured. Significant adaptive response, increase in cell survival fraction and decrease in the extent of DNA fragmentation were induced when low and high dose gamma-ray irradiation time interval was 4 hr. Addition of protein or RNA synthesis inhibitor, cycloheximide or 5,6-dichloro-1-beta-d-ribofuranosylbenzimidazole (DRFB), respectively during adaptation period, the period from low dose gamma-ray irradiation to high dose gamma-ray irradiation, was able to inhibit the induction of adaptive response, which is the reduction of the extent DNA fragmentation in irradiated EL4 cells. These data suggest that the induction of adaptive response to ionizing radiation in EL4 cells required both protein and RNA synthesis.

  20. Immunological effects of low dose radiation. Absent or minor effects of Chernobyl fallout in Norway?

    Energy Technology Data Exchange (ETDEWEB)

    Reitan, J.B.; Bergan, T.D.; Strand, P. [Statens Straalevern, Oesteraas (Norway); Melbye, O.J. [Rikshospitalet, Oslo (Norway)

    1998-01-01

    In this pilot study of those Norwegian individuals most heavily exposed to the Chernobyl Fallout, immunological parameters generally stayed within normal limits. However, some parameter, apparently within the assumed normal range did, in fact correlate to the estimated individual dose as assessed by wholebody counting of radiocaesium content. The small possible effects revealed in this study may represent real biological effects, but do not necessarily represent a health detriment. 43 refs., 4 figs., 6 tabs.

  1. Low dose radiation exposure and atherosclerosis in ApoE-/- mice

    International Nuclear Information System (INIS)

    Mitchel, R.E.J.; Hasu, M.; Bugden, M.; Wyatt, H.; Little, M.; Hildebrandt, G.; Priest, N.D.; Whitman, S.C.

    2010-01-01

    The hypothesis that single low dose exposures (0.025-0.5 Gy) to low LET radiation, given at either high (240 mGy/min) or low (1 mGy/min) dose rate, would promote aortic atherosclerosis was tested in female C57BI/6 mice genetically predisposed to this disease (ApoE-/-). Mice were exposed either at early stage disease (2 months of age) and examined 3 or 6 months later, or at late stage disease (8 months of age) and examined 2 or 4 months later. Compared to unexposed controls, all doses given at low or high dose rate at early stage disease had significant inhibitory effects on lesion growth and, at 25 or 50 mGy, on lesion frequency. No dose given at low dose rate had any effect on total serum cholesterol, but this was elevated by every dose given at high dose rate. Exposures at low dose rate had no effect on the percentage of lesion lipids contained within macrophages, and, at either high or low dose rate, had no significant effect on lesion severity. Exposure at late stage disease, to any dose at high dose rate, had no significant effect on lesion frequency, but at low dose rate some doses produced a small transient increase in this frequency. Exposure to low doses at low, but not high dose rate, significantly, but transiently reduced average lesion size, and at either dose rate transiently reduced lesion severity. Exposure to any dose at low dose rate (but not high dose rate) resulted in large and persistent decreases in serum cholesterol. These data indicate that a single low dose exposure, depending on dose and dose rate, generally protects against various measures of atherosclerosis in genetically susceptible mice. This result contrasts with the known, generally detrimental effects of high doses on this disease in the same mice, suggesting that a linear extrapolation of risk from high doses is not appropriate. (author)

  2. The role of natural growth stimulators in regulation of regeneration processes in small intestinal epithelium after irradiation

    International Nuclear Information System (INIS)

    Dziekiewicz, M.

    1996-01-01

    In this paper, basing on recently published data, the influence of growth factors on small intestine epithelium regeneration after irradiation is presented. Our knowledge of growth control in the small intestine mucosa may become an accepted mode of radio-, chemotherapy and the treatment of acute radiation sickness in the future. Results of recent studies suggest that there are different factors which can modulate the process of epithelium regeneration. Some of them such as gastrin, enteroglucagon, CCK, EGF, FGF, TGF and IL-11 are able to enhance this process. In addition, other factor-PGE-2 is responsible for not only stimulation of small intestine epithelium growth but radioprotection as well. (author)

  3. A high-resolution 7-Tesla fMRI dataset from complex natural stimulation with an audio movie.

    Science.gov (United States)

    Hanke, Michael; Baumgartner, Florian J; Ibe, Pierre; Kaule, Falko R; Pollmann, Stefan; Speck, Oliver; Zinke, Wolf; Stadler, Jörg

    2014-01-01

    Here we present a high-resolution functional magnetic resonance (fMRI) dataset - 20 participants recorded at high field strength (7 Tesla) during prolonged stimulation with an auditory feature film ("Forrest Gump"). In addition, a comprehensive set of auxiliary data (T1w, T2w, DTI, susceptibility-weighted image, angiography) as well as measurements to assess technical and physiological noise components have been acquired. An initial analysis confirms that these data can be used to study common and idiosyncratic brain response patterns to complex auditory stimulation. Among the potential uses of this dataset are the study of auditory attention and cognition, language and music perception, and social perception. The auxiliary measurements enable a large variety of additional analysis strategies that relate functional response patterns to structural properties of the brain. Alongside the acquired data, we provide source code and detailed information on all employed procedures - from stimulus creation to data analysis. In order to facilitate replicative and derived works, only free and open-source software was utilized.

  4. Naturally induced secretions of the potato cyst nematode co-stimulate the proliferation of both tobacco leaf protoplasts and human peripheral blood mononuclear cells.

    Science.gov (United States)

    Goverse, A; Rouppe van der Voort, J; Roppe van der Voort, C; Kavelaars, A; Smant, G; Schots, A; Bakker, J; Helder, J

    1999-10-01

    Naturally induced secretions from infective juveniles of the potato cyst nematode Globodera rostochiensis co-stimulate the proliferation of tobacco leaf protoplasts in the presence of the synthetic phytohormones alpha-naphthaleneacetic acid (NAA) and 6-benzylaminopurine (BAP). With the use of a protoplast-based bioassay, a low-molecular-weight peptide(s) (cyst nematode secretions also co-stimulated mitogenesis in human peripheral blood mononuclear cells (PBMC). The stimulation of plant cells isolated from nontarget tissue--these nematodes normally invade the roots of potato plants--suggests the activation of a general signal transduction mechanism(s) by an oligopeptide(s) secreted by the nematode. Whether a similar oligopeptide-induced mechanism underlies human PBMC activation remains to be investigated. Reactivation of the cell cycle is a crucial event in feeding cell formation by cyst nematodes. The secretion of a mitogenic low-molecular-weight peptide(s) by infective juveniles of the potato cyst nematode could contribute to the redifferentiation of plant cells into such a feeding cell.

  5. Cumulative pregnancy rates after sequential treatment with modified natural cycle IVF followed by IVF with controlled ovarian stimulation

    NARCIS (Netherlands)

    Pelinck, M. J.; Knol, H. M.; Vogel, N. E. A.; Arts, E. G. J. M.; Simons, A. H. M.; Heineman, M. J.; Hoek, A.

    BACKGROUND: In modified natural cycle IVF (MNC-IVF), treatment is aimed at using the one follicle that spontaneously develops to dominance, using a GnRH-antagonist together with gonadotrophins in the late follicular phase only. The MNC-IVF is of interest because of its low-risk and patient-friendly

  6. Cumulative pregnancy rates after sequential treatment with modified natural cycle IVF followed by IVF with controlled ovarian stimulation

    NARCIS (Netherlands)

    Pelinck, M. J.; Knol, H. M.; Vogel, N. E. A.; Arts, E. G. J. M.; Simons, A. H. M.; Heineman, M. J.; Hoek, A.

    2008-01-01

    BACKGROUND: In modified natural cycle IVF (MNC-IVF), treatment is aimed at using the one follicle that spontaneously develops to dominance, using a GnRH-antagonist together with gonadotrophins in the late follicular phase only. The MNC-IVF is of interest because of its low-risk and patient-friendly

  7. Frozen-thawed embryo transfer in a natural or mildly hormonally stimulated cycle in women with regular ovulatory cycles: a RCT.

    Science.gov (United States)

    Peeraer, Karen; Couck, Isabelle; Debrock, Sophie; De Neubourg, Diane; De Loecker, Peter; Tomassetti, Carla; Laenen, Annouschka; Welkenhuysen, Myriam; Meeuwis, Luc; Pelckmans, Sofie; Meuleman, Christel; D'Hooghe, Thomas

    2015-11-01

    Can ovarian stimulation with low dose hMG improve the implantation rate (IR) per frozen-thawed embryo transferred (FET) when compared with natural cycle in an FET programme in women with a regular ovulatory cycle? Both IR and live birth rate (LBR) per FET were similar in the group with mild ovarian stimulation and the natural cycle group. Different cycle regimens for endometrial preparation are used prior to FET: spontaneous ovulatory cycles, cycles with artificial endometrial preparation using estrogen and progesterone hormones, and cycles stimulated with gonadotrophins or clomiphene citrate. At present, it is not clear which regimen results in the highest IR or LBR. More specifically, there are no RCTs in ovulatory women comparing reproductive outcome after FET during a natural cycle and during a hormonally stimulated cycle. A total of 410 women scheduled for FET during 579 cycles (December 2003-September 2013) were enrolled in an open-label RCT to natural cycle (NC FET group, n = 291) or to a cycle hormonally stimulated with s.c. gonadotrophins (hMG FET group, 37.5-75 IU per day, n = 288). A total of 672 embryos were transferred during 434 cycles (332 embryos and 213 cycles in the NC FET group; 340 embryos and 221 cycles in the hMG FET group). Assuming a = 0.05 and 80% power, it was calculated that 219 frozen-thawed embryos were required for transfer in each group to demonstrate a difference of 10% in IR. Women were eligible according to the following inclusion criteria: regular ovulatory cycle, female age ≥21 years and ≤45 years, informed consent. FET cycles with preimplantation genetic screening were excluded. The primary outcome was IR per embryo transferred. Secondary outcomes included IR with fetal heart beat (FHB), LBR per embryo transferred and endometrial thickness on the day of hCG administration. Statistical analysis was by intention to treat and controlled for the presence of multiple measures, as eligible women could be randomized in more than

  8. Changing the Metacognitive Orientation of a Classroom Environment to Stimulate Metacognitive Reflection Regarding the Nature of Physics Learning

    Science.gov (United States)

    Thomas, Gregory P.

    2013-05-01

    Problems persist with physics learning in relation to students' understanding and use of representations for making sense of physics concepts. Further, students' views of physics learning and their physics learning processes have been predominantly found to reflect a 'surface' approach to learning that focuses on mathematical aspects of physics learning that are often passed on via textbooks and lecture-style teaching. This paper reports on a teacher's effort to stimulate students' metacognitive reflection regarding their views of physics learning and their physics learning processes via a pedagogical change that incorporated the use of a representational framework and metaphors. As a consequence of the teacher's pedagogical change, students metacognitively reflected on their views of physics and their learning processes and some reported changes in their views of what it meant to understand physics and how they might learn and understand physics concepts. The findings provide a basis for further explicit teaching of representational frameworks to students in physics education as a potential means of addressing issues with their physics learning.

  9. Radiation, hypoxia and genetic stimulation: implications for future therapies

    International Nuclear Information System (INIS)

    Adams, Gerald E.; Hasan, Na'il M.; Joiner, Michael C.

    1997-01-01

    The cellular stress response, whereby very low doses of cytotoxic agents induce resistance to much higher doses, is an evolutionary defence mechanism and is stimulated following challenges by numerous chemical, biological and physical agents including particularly radiation, drugs, heat and hypoxia. There is much homology in the effects of these agents which are manifest through the up-regulation of various genetic pathways. Low-dose radiation stress influences processes involved in cell-cycle control, signal transduction pathways, radiation sensitivity, changes in cell adhesion and cell growth. There is also homology between radiation and other cellular stress agents, particularly hypoxia. Whereas traditionally, hypoxia was regarded mainly as an agent conferring resistance to radiation, there is now much evidence illustrating the cytokine-like properties of hypoxia as well as radiation. Stress phenomena are likely to be important in risks arising from low doses of radiation. Conversely, exploitation of the stress response in settings appropriate to therapy can be particularly beneficial not only in regard to radiation alone but in combinations of radiation and drugs. Similarly, tissue hypoxia can be exploited in novel ways of enhancing therapeutic efficacy. Bioreductive drugs, which are cytotoxically activated in hypoxic regions of tissue, can be rendered even more effective by hypoxia-induced increased expression of enzyme reductases. Nitric oxide pathways are influenced by hypoxia thereby offering possibilities for novel vascular based therapies. Other approaches are discussed

  10. Combining natural language processing and network analysis to examine how advocacy organizations stimulate conversation on social media.

    Science.gov (United States)

    Bail, Christopher Andrew

    2016-10-18

    Social media sites are rapidly becoming one of the most important forums for public deliberation about advocacy issues. However, social scientists have not explained why some advocacy organizations produce social media messages that inspire far-ranging conversation among social media users, whereas the vast majority of them receive little or no attention. I argue that advocacy organizations are more likely to inspire comments from new social media audiences if they create "cultural bridges," or produce messages that combine conversational themes within an advocacy field that are seldom discussed together. I use natural language processing, network analysis, and a social media application to analyze how cultural bridges shaped public discourse about autism spectrum disorders on Facebook over the course of 1.5 years, controlling for various characteristics of advocacy organizations, their social media audiences, and the broader social context in which they interact. I show that organizations that create substantial cultural bridges provoke 2.52 times more comments about their messages from new social media users than those that do not, controlling for these factors. This study thus offers a theory of cultural messaging and public deliberation and computational techniques for text analysis and application-based survey research.

  11. Efficacy of polyethylene glycol-conjugated bovine granulocyte colony-stimulating factor for reducing the incidence of naturally occurring clinical mastitis in periparturient dairy cows and heifers.

    Science.gov (United States)

    Hassfurther, Renee L; TerHune, Terry N; Canning, Peter C

    2015-03-01

    To evaluate effects of various doses of polyethylene glycol (PEG)-conjugated bovine granulocyte colony-stimulating factor (bG-CSF) on the incidence of naturally occurring clinical mastitis in periparturient dairy cattle. 211 periparturient Holstein cows and heifers. Approximately 7 days before the anticipated date of parturition (day of parturition = day 0), healthy cattle received SC injections of sterile saline (0.9% NaCl) solution (control treatment) or PEG-bG-CSF at 5, 10, or 20 μg/kg. Cattle were commingled and housed in a pen with dirt flooring, which was kept wet to maximize the incidence of naturally occurring clinical mastitis. Within 24 hours after parturition, each animal again received the assigned treatment. Mammary glands and milk were visually scored for abnormalities twice daily for 28 days after parturition. Milk samples were aseptically collected from mammary glands with an abnormal appearance or abnormal milk and submitted for microbial culture. Daily milk production was recorded, and milk composition was assessed on days 3, 5, 7, and 10. Cattle treated with PEG-bG-CSF at 10 and 20 μg/kg had significantly fewer cases of clinical mastitis (9/54 and 5/53, respectively), compared with control cattle (18/53). Administration of PEG -bG-CSF did not significantly affect daily milk production or milk composition. Results suggested that PEG-bG-CSF was effective for reducing the incidence of naturally occurring clinical mastitis in periparturient dairy cattle. Further investigations of the use of PEG-bG-CSF as a potential preventative intervention should be conducted.

  12. natural

    Directory of Open Access Journals (Sweden)

    Elías Gómez Macías

    2006-01-01

    Full Text Available Partiendo de óxido de magnesio comercial se preparó una suspensión acuosa, la cual se secó y calcinó para conferirle estabilidad térmica. El material, tanto fresco como usado, se caracterizó mediante DRX, área superficial BET y SEM-EPMA. El catalizador mostró una matriz de MgO tipo periclasa con CaO en la superficie. Las pruebas de actividad catalítica se efectuaron en lecho fijo empacado con partículas obtenidas mediante prensado, trituración y clasificación del material. El flujo de reactivos consistió en mezclas gas natural-aire por debajo del límite inferior de inflamabilidad. Para diferentes flujos y temperaturas de entrada de la mezcla reactiva, se midieron las concentraciones de CH4, CO2 y CO en los gases de combustión con un analizador de gases tipo infrarrojo no dispersivo (NDIR. Para alcanzar conversión total de metano se requirió aumentar la temperatura de entrada al lecho a medida que se incrementó el flujo de gases reaccionantes. Los resultados obtenidos permiten desarrollar un sistema de combustión catalítica de bajo costo con un material térmicamente estable, que promueva la alta eficiencia en la combustión de gas natural y elimine los problemas de estabilidad, seguridad y de impacto ambiental negativo inherentes a los procesos de combustión térmica convencional.

  13. WC1+ γδ T cells from cattle naturally infected with Mycobacterium avium subsp. paratuberculosis respond differentially to stimulation with PPD-J.

    Science.gov (United States)

    Albarrak, S M; Waters, W R; Stabel, J R; Hostetter, J M

    2017-08-01

    A role for γδ T cells in protection against mycobacterial infections including Johne's disease (JD) has been suggested. In neonatal calves where the risk to infection with Mycobacterium avium subsp. paratuberculosis (MAP) is high, the majority of circulating CD3 + lymphocytes are γδ TCR + . Bovine γδ T cells are divided into two major subsets based on the surface expression of workshop cluster 1 (WC1). The WC1 + subset, the predominant subset in periphery, is further divided into WC1.1 + and WC1.2 + subpopulations. The ability of γδ T cells to produce IFN-γ prior to CD4 + αβ T cell activation could be crucial to the outcome of MAP infection. In the current study, cattle were naturally infected with MAP and were classified as either in the subclinical or clinical stage of infection. Compared to the control non-infected group, γδ T cell frequency in circulating lymphocytes was significantly lower in the clinical group. The observed decline in frequency was restricted to the WC1.2 + subset, and was not associated with preferential migration to infection sites (distal-ileum). γδ T cells proliferated significantly in recall responses to stimulation with purified protein derivative from MAP (PPD-J) only in subclinically infected cattle. These responses were a heterogeneous mixture of WC1.1 and WC1.2 subsets. Proliferation and IFN-γ production by the WC1.1 + γδ T cell subset was significantly higher in the subclinical group compared to the control and clinical groups. Our data indicates differences in MAP-specific ex-vivo responses of peripheral WC1 + γδ T cells of cattle with the subclinical or clinical form of JD. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Differential stimulation of antioxidant defense in various organs of mice after whole body exposure to low-dose gamma radiation

    International Nuclear Information System (INIS)

    Pathak, C.M.; Avti, P.K.; Khanduja, K.L.; Sharma, S.C.

    2007-01-01

    It has been generally considered that any dose of ionizing radiation is detrimental to the living organisms, however low the radiation dose may be. The much relied upon 'Linear-No-Threshold' (LNT) hypothesis dose not have any convincing experimental evidence regarding the damaging effects at very low-doses and low-dose rates. Generally, the deleterious biological effects have been inferred theoretically by extrapolating the known effects of high radiation dose to low-dose range. Recently, it has been reported that the living organisms do not respond to ionizing radiations in a linear manner in the low-dose range 0.01-0.50 Gy and rather restore the homeostasis both in-vivo and in-vitro by normal physiological mechanisms such as, cellular and DNA repair processes, immune reactions, antioxidant defense, adaptive responses, activation of immune functions; stimulation of growth etc. In this study, we have attempted to find: (i) the critical radiation dose range and the post irradiation period during which the antioxidant defense systems in the lungs, liver and kidneys remain stimulated; and (ii) to evaluate the degree to which these defense mechanisms remain stimulated in these organs after whole body exposure of the animal to low-dose radiation

  15. Exploring the Role of Piwi/piRNA Pathway in Epigenetic Dysregulation in Low Dose Radiation Induced Cardiovascular Disease

    Science.gov (United States)

    Jejelowo, O. A.; Tariq, M. A.

    2018-02-01

    We will utilize multi-omics to identify robust biomarkers and to understand radiation effects and develop countermeasures. Information obtained will enhance development of capabilities to monitor health in real time and for mitigation of risks.

  16. DNA mismatch repair protein MSH2 dictates cellular survival in response to low dose radiation in endometrial carcinoma cells.

    LENUS (Irish Health Repository)

    Martin, Lynn M

    2013-07-10

    DNA repair and G2-phase cell cycle checkpoint responses are involved in the manifestation of hyper-radiosensitivity (HRS). The low-dose radioresponse of MSH2 isogenic endometrial carcinoma cell lines was examined. Defects in cell cycle checkpoint activation and the DNA damage response in irradiated cells (0.2 Gy) were evaluated. HRS was expressed solely in MSH2+ cells and was associated with efficient activation of the early G2-phase cell cycle checkpoint. Maintenance of the arrest was associated with persistent MRE11, γH2AX, RAD51 foci at 2 h after irradiation. Persistent MRE11 and RAD51 foci were also evident 24 h after 0.2 Gy. MSH2 significantly enhances cell radiosensitivity to low dose IR.

  17. TU-C-18A-01: Models of Risk From Low-Dose Radiation Exposures: What Does the Evidence Say?

    International Nuclear Information System (INIS)

    Bushberg, J; Boreham, D; Ulsh, B

    2014-01-01

    At dose levels of (approximately) 500 mSv or more, increased cancer incidence and mortality have been clearly demonstrated. However, at the low doses of radiation used in medical imaging, the relationship between dose and cancer risk is not well established. As such, assumptions about the shape of the dose-response curve are made. These assumptions, or risk models, are used to estimate potential long term effects. Common models include 1) the linear non-threshold (LNT) model, 2) threshold models with either a linear or curvilinear dose response above the threshold, and 3) a hormetic model, where the risk is initially decreased below background levels before increasing. The choice of model used when making radiation risk or protection calculations and decisions can have significant implications on public policy and health care decisions. However, the ongoing debate about which risk model best describes the dose-response relationship at low doses of radiation makes informed decision making difficult. This symposium will review the two fundamental approaches to determining the risk associated with low doses of ionizing radiation, namely radiation epidemiology and radiation biology. The strengths and limitations of each approach will be reviewed, the results of recent studies presented, and the appropriateness of different risk models for various real world scenarios discussed. Examples of well-designed and poorly-designed studies will be provided to assist medical physicists in 1) critically evaluating publications in the field and 2) communicating accurate information to medical professionals, patients, and members of the general public. Equipped with the best information that radiation epidemiology and radiation biology can currently provide, and an understanding of the limitations of such information, individuals and organizations will be able to make more informed decisions regarding questions such as 1) how much shielding to install at medical facilities, 2) at what dose level are risk vs. benefit discussions with patients appropriate, 3) at what dose level should we tell a pregnant woman that the baby’s health risk from a prenatal radiation exposure is “significant”, 4) is informed consent needed for patients undergoing medical imaging, and 5) at what dose level is evacuation appropriate after a radiological accident. Examples of the tremendous impact that choosing different risks models can have on the answers to these types of questions will be given.A moderated panel discussion will allow audience members to pose questions to the faculty members, each of whom is an established expert in his respective discipline. Learning Objectives: Understand the fundamental principles, strengths and limitations of radiation epidemiology and radiation biology for determining the risk from exposures to low doses of ionizing radiation Become familiar with common models of risk used to describe the dose-response relationship at low dose levels Learn to identify strengths and weaknesses in studies designed to measure the effect of low doses of ionizing radiation Understand the implications of different risk models on public policy and health care decisions

  18. Low-Dose Radiation-Induced Adaptive Response in Polychromatic Mice Erythrocyte as Measured by Acridine Orange Stained Micronuleus Assay

    International Nuclear Information System (INIS)

    Hee-Sun, K.; Kwang-Hee, Y.; Cha-Soom, K.; Jung-Mi, C.; Gu-Choul, S.; Suk-Young, P.; Kyoung-H, C.; Chong-Soom, K.; Young-Khi, L.; Jae-Ho, W.

    2004-01-01

    The effect of conditioning pretreatment with 0.01Gy of gamma rays on micronucleated polychromatic erythrocyte (MN-PCE) induction by 2Gy of g-rays was determined in peripheral blood of C3H/He mice. The timing of their administration of challenge doses was 6hr. The response was determined by scoring of Acridine orange dye stained MN-PCEs. The results indicate that low dose gamma ray pretreatment does protect against MN-PCE induction by the challenge g-ray dose. Introduction: An adaptive response induced by low doses of ionizing radiation in vivo reported. Some research team reports that a reduction on MN-PCE of mice caused by the pretreatment was observed [1- 4]. However, there was variability in the amount of the response depending on the time and adaptive dose [3]. This is important because the variation of MN-PCE frequency with time could lead to differences in the interpretation. In this study, differences in the biological effects within the priming dose ranges are discussed. Materials and Methods: Specific pathogen free 5-week-old C3H/He mice, purchased from Shizuoka Laboratory Center (Japan), were kept in clean and conventional environment. When 6 weeks old, the animal were whole body irradiated using irradiator of IBL-437 (137Cs, 0.8Gy/min). After various time intervals, the two groups were administrated to adaptation dose and challenge dose of 0.01Gy and 2Gy, respectively. For experiments, sham-irradiated, only adaptive and challenge dose irradiated groups were run concurrently. Smears were stained and scored using Acridine orange dye method [2]. Statistically significant differences in MN-PCE frequency were determined by comparing tie individual values at each group with the respective control values (challenge dose irradiated group) by using the paired ttest. Results and Discussions: Induced MN by the challenge dose (2Gy) after the pretreatment with 0.01Gy is low to the one induced by the challenge dose alone. In the present study, this estimation for the experiment with a challenge dose of 2Gy suggests a response of nearly 15%. These results agree with some studies in which the induction of the adaptive response by g-rays was observed made in vivo in mice [1]. However, these results disagree with some studies using BALB/c mice. It is possible that genetic differences between C3H/He mice used in the present study and the BALB/c mice used in the previous one [3] could be explain the differential conditions. Moreover, the doses (0.025Gy) and the timing (2hr) of radiation exposures in previous study were different compared to presented here. These results indicate that low dose g-ray pretreatment doses protect against MN-PCE induction by the challenge g-ray dose depend on priming dose, adaptation time and mice strain. (Author)

  19. Effects of long-term low dose radiation. Epstein-Barr virus-specific antibodies in radiological technologists

    Energy Technology Data Exchange (ETDEWEB)

    Kumagai, Etsuko; Higashida, Yoshiharu; Onomichi, Mitsukazu; Nakamura, Ikuo; Tanoue, Shozo; Tanaka, Ryuji; Kumagai, Takashi; Katsuki, Takato; Sawada, Shozo.

    1988-09-01

    To clarify the long-term effects of occupational exposure to low doses of radiation, Epstein-Barr virus (EBV)-specific antibody titers in sera from 104 radiological technologists (R.T.) and 118 controls in Kumamoto prefecture were measured by the immunofluorescence method. Antibody titers to viral capsid antigen (VCA)-IgG increased with the years of experience as R.T., and the prevalence of abnormal antibody titers to both VCA-IgG and early antigen (EA)-IgG were significantly higher in R.T. with over 15 years of experience or 30 rads of cumulative radiation dose than in the controls. However, there was no correlation between exposure and the frequency of abnormal EBV-associated nuclear antigen (EBNA) antibody titers. The EBV-specific antibody titers of 24 Hiroshima atomic-bomb survivors were also measured. They were similar to those of the R.T. with over 30 years of experience. The EBV-specific antibody titers of R.T. suggest that there may be an impairment of immunologic competence after continuous long-term exposure to low doses of radiation. Also, the correlation of EBV-specific antibody titers and frequency of cells with chromosome aberrations in 53 R.T. was studied. Some correlations were found between the antibody titers to both of the VCA-IgG and EBNA and the frequency of cells with chromosome aberrations.

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

    International Nuclear Information System (INIS)

    Ohnishi, Takeo

    1997-01-01

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

  1. TU-C-18A-01: Models of Risk From Low-Dose Radiation Exposures: What Does the Evidence Say?

    Energy Technology Data Exchange (ETDEWEB)

    Bushberg, J [UC Davis Medical Center, Sacramento, CA (United States); Boreham, D [McMaster University, Ontario, CA (Canada); Ulsh, B

    2014-06-15

    At dose levels of (approximately) 500 mSv or more, increased cancer incidence and mortality have been clearly demonstrated. However, at the low doses of radiation used in medical imaging, the relationship between dose and cancer risk is not well established. As such, assumptions about the shape of the dose-response curve are made. These assumptions, or risk models, are used to estimate potential long term effects. Common models include 1) the linear non-threshold (LNT) model, 2) threshold models with either a linear or curvilinear dose response above the threshold, and 3) a hormetic model, where the risk is initially decreased below background levels before increasing. The choice of model used when making radiation risk or protection calculations and decisions can have significant implications on public policy and health care decisions. However, the ongoing debate about which risk model best describes the dose-response relationship at low doses of radiation makes informed decision making difficult. This symposium will review the two fundamental approaches to determining the risk associated with low doses of ionizing radiation, namely radiation epidemiology and radiation biology. The strengths and limitations of each approach will be reviewed, the results of recent studies presented, and the appropriateness of different risk models for various real world scenarios discussed. Examples of well-designed and poorly-designed studies will be provided to assist medical physicists in 1) critically evaluating publications in the field and 2) communicating accurate information to medical professionals, patients, and members of the general public. Equipped with the best information that radiation epidemiology and radiation biology can currently provide, and an understanding of the limitations of such information, individuals and organizations will be able to make more informed decisions regarding questions such as 1) how much shielding to install at medical facilities, 2) at what dose level are risk vs. benefit discussions with patients appropriate, 3) at what dose level should we tell a pregnant woman that the baby’s health risk from a prenatal radiation exposure is “significant”, 4) is informed consent needed for patients undergoing medical imaging, and 5) at what dose level is evacuation appropriate after a radiological accident. Examples of the tremendous impact that choosing different risks models can have on the answers to these types of questions will be given.A moderated panel discussion will allow audience members to pose questions to the faculty members, each of whom is an established expert in his respective discipline. Learning Objectives: Understand the fundamental principles, strengths and limitations of radiation epidemiology and radiation biology for determining the risk from exposures to low doses of ionizing radiation Become familiar with common models of risk used to describe the dose-response relationship at low dose levels Learn to identify strengths and weaknesses in studies designed to measure the effect of low doses of ionizing radiation Understand the implications of different risk models on public policy and health care decisions.

  2. Regulation Of Nf=kb And Mnsod In Low Dose Radiation Induced Adaptive Protection Of Mouse And Human Skin Cells

    Energy Technology Data Exchange (ETDEWEB)

    Jian Li

    2012-11-07

    A sampling of publications resulting from this grant is provided. One is on the subject of NF-κB-Mediated HER2 Overexpression in Radiation-Adaptive Resistance. Another is on NF-κB-mediated adaptive resistance to ionizing radiation.

  3. Adaptive response of apoptosis in EL-4 lymphoma cells induced by low dose radiation and its mechanism

    International Nuclear Information System (INIS)

    Liu Shuchun; Gong Pingsheng; Wang Zhicheng; Sun Liguang; Gong Shouliang

    2008-01-01

    EL-4 lymphoma cells were irradiated with the inductive doses (D1: 25-200 mGy, dose rate: 12.5mGy/min) and the challenging dose (D2:0.5-3.0 Gy, dose rate: 287 mGy/min), and the time interval between D1 and D2 was 6 h. The percentage of cell apoptosis and the expressive levels of cell apoptosis-associated gene pro- reins were measured with flow cytometry. The percentages of cell apoptosis in the D1 + D2 group with 25-100 mGy (D1) and 1.5 Gy (D2) or 75 mGy (D1) and 25-200 mGy (D2) were significantly lower than those in the D2 group. As compared with the D2 group, the positive percentage of cell Bcl-2 protein expression increased somewhat, and Bax decreased significantly, meanwhile the ratio of Bcl-2/Bax increased significantly and p53 decreased somewhat in D1 + D2 group with 25-100 mGy (D1) and 1.5 Gy (D2). The adaptive response of EL-4 lymphoma cell apoptosis could be induced by pre-irradiation with 25-100 mGy. Meantime, the expressive levels of cell apoptosis-associated gene Bcl-2, Bax and p53 proteins could change accordingly with cell apoptosis. These gene protein changes may play an important role in the mechanism of the adaptive response. (authors)

  4. U.S.Department of energy low dose radiation research program: potential impact on Human health risk from Chornobyl

    International Nuclear Information System (INIS)

    Brooks, A.

    2002-01-01

    Radiation risks from low levels of radiation exposure, cannot be predicted with epidemiological studies alone. Combining advances in technology with those in cell and molecular biology make it possible to detect biological changes after low doses and dose-rates of radiation exposure, such as Chornobyl. Understanding the role of these biological changes in cancer risk may or may not impact radiation protection standards. However, they will help ensure that the standards are both adequate and appropriate

  5. Cytogenetic Effects of Low Dose Radiation in Mammalian Cells Analysis of the Phenomenon Hypersensitivity and Induced Radioresistence

    CERN Document Server

    Shmakova, N L; Nasonova, E A; Krasavin, E A; Rsjanina, A V

    2001-01-01

    The induction of cytogenetic damage after irradiation of chinese hamster cells and human melanoma cells within dose range 1-200 cGy was studied. The anaphase and metaphase analysis of chromosome damage and micronuclei test were applied. The hypersensitivity (HRS) at doses below 20 cGy and the increased radioresistence at higher doses (IR) were shown with all cytogenetic criteria for both cell lines. The phenomenon of HRS/IR was reproduced in synchronic as well as in asynchronic population of chinese hamster cells. This fact shows that HRS was caused by high radiosensitivity of all cells and can not be explained by any differential sensitivity of cells in different phases of the cell cycle. So it was supposed that the increasing radioresistence is determined by the inclusion of the inducible repair processes in all cells. This conclusion agress with the fact that there was no evidence of HRS on dose-effect curves and that some part of pre-existent damage was repaired after preliminary irradiation with low dose...

  6. Long term control of a maxillary sinus mucoepidermoid carcinoma with low dose radiation therapy: a case report

    International Nuclear Information System (INIS)

    Vulpe, Horia; Giuliani, Meredith; Goldstein, David; Perez-Ordonez, Bayardo; Dawson, Laura A; Hope, Andrew

    2013-01-01

    Mucoepidermoid carcinoma of the maxillary sinus is a rare malignancy of the head and neck. The location of this tumour near vital structures and its large size at presentation makes surgical resection with negative margins challenging. In incurable cases, relief from symptoms such as epistaxis may be achieved with radiation therapy. We present a case of mucoepidermoid carcinoma of the maxillary sinus that was effectively palliated with a short course of radiation therapy, achieving complete cessation of bleeding, decrease in tumour size, and long term control. We surveyed the literature on mucoepidermoid carcinomas and propose that some tumours may be particularly radiosensitive, benefiting from even short courses of radiation therapy

  7. Viability of Vibrio cholerae 01 on frog legs under frozen and refrigerated conditions and low dose radiation treatment

    International Nuclear Information System (INIS)

    Sang, F.C.; Hugh-Jones, M.E.; Hagstad, H.V.

    1987-01-01

    Frog legs were contaminated with Vibrio cholerae 01, Inaba serotype, EITor biotype. The organism remained viable for more than 28 and 2 d when stored at -20°C and 4°C, respectively. Exposure to a multicuries 60 Cobalt source of 50 and 100 kilorads eliminated V. cholerae from both the frozen and fresh frog legs

  8. Examination of gene expression in mice exposed to low dose radiation using affymetrix cDNA microarrays

    Energy Technology Data Exchange (ETDEWEB)

    Morris, D.; Knox, D.; Lavoie, J.; Lemon, J.; Boreham, D. [McMaster Univ., Hamilton, Ontario (Canada)

    2005-07-01

    'Full text:' Gamma radiation acts via the indirect effect to damage cells by producing reactive oxygen species (ROS). These ROS are capable damaging macromolecules and, altering signal pathways and gene transcription. Cells have evolved enzymes and mechanisms to scavenge ROS and repair oxidative damage. Microarrays allow the survey of the gene transcription activity of thousands of genes simultaneously. Messenger RNA is extracted from cells, hybridized with the complementary DNA (cDNA) of a microarray chip, and examined with a chip reader. Affymetrix microarray chips have been produced by the CSCHAH in Winnipeg containing 26000 murine genes. Groups of female mice have been exposed to low dose whole body chronic gamma radiation exposures of 0,50,100, and 120 mGy, corresponding to 15,30,60, and 75 weeks, respectively. MRNA from mice brain tissue has been extracted, isolated, converted to cDNA and labeled. Gene expression in each irradiated mouse was compared to the pooled expression of the control mice. Analysis of gene expression levels are performed with microarray analytical software, Array Pro by Media Cybernetics, and powerful statistical software, BRB microarray tools. Differences in gene expressions, focusing on genes for cytokines, DNA repair mechanisms, immuno-modulators, apoptosis pathways, and enzymatic anti-oxidant systems, are being examined and will be reported. (author)

  9. Immunological low-dose radiation modulates the pediatric medulloblastoma antigens and enhances antibody-dependent cellular cytotoxicity.

    Science.gov (United States)

    Das, Arabinda; McDonald, Daniel; Lowe, Stephen; Bredlau, Amy-Lee; Vanek, Kenneth; Patel, Sunil J; Cheshier, Samuel; Eskandari, Ramin

    2017-03-01

    Immunotherapy can be an effective treatment for pediatric medulloblastoma (MB) patients. However, major subpopulations do not respond to immunotherapy, due to the lack of antigenic mutations or the immune-evasive properties of MB cells. Clinical observations suggest that radiation therapy (RT) may expand the therapeutic reach of immunotherapy. The aim of the present investigation is to study the effect of low-dose X-ray radiation (LDXR, 1 Gy) on the functional immunological responses of MB cells (DAOY, D283, and D341). Induction of MB cell death was examined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Production of reactive oxygen species (ROS) was measured by fluorescent probes. Changes in the expression of  human leukocyte antigen (HLA) molecules and caspase-3 activities during treatment were analyzed using Western blotting and caspase-3 assay. Western blot analysis demonstrated that LDXR upregulated the expression of HLA class I and HLA II molecules by more than 20% compared with control and high-dose (12 Gy) groups in vitro. Several of these HLA subtypes, such as MAGE C1, CD137, and ICAM-1, have demonstrated upregulation. In addition, LDXR increases ROS production in association with phosphorylation of NF-κB and cell surface expression of mAb target molecules (HER2 and VEGF). These data suggest that a combined LDXR and mAb therapy can create a synergistic effect in vitro. These results suggest that LDXR modulates HLA molecules, leading to alterations in T-cell/tumor-cell interaction and enhancement of T-cell-mediated MB cell death. Also, low-dose radiotherapy combined with monoclonal antibody therapy may one day augment the standard treatment for MB, but more investigation is needed to prove its utility as a new therapeutic combination for MB patients.

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

    International Nuclear Information System (INIS)

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

    2001-01-01

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

  11. growth stimulant

    African Journals Online (AJOL)

    Effects of timing and duration of supplementation of LIVFIT VET ® (growth stimulant) as substitute for fish meal on the growth performance, haematology and clinical enzymes concentration of growing pigs.

  12. Brain Stimulation Therapies

    Science.gov (United States)

    ... Magnetic Seizure Therapy Deep Brain Stimulation Additional Resources Brain Stimulation Therapies Overview Brain stimulation therapies can play ... for a shorter recovery time than ECT Deep Brain Stimulation Deep brain stimulation (DBS) was first developed ...

  13. Rapid and preferential distribution of blood-borne αCD3εAb to the liver is followed by local stimulation of T cells and natural killer T cells

    Science.gov (United States)

    Wingender, Gerhard; Schumak, Beatrix; Schurich, Anna; Gessner, J Engelbert; Endl, Elmar; Limmer, Andreas; Knolle, Percy A

    2006-01-01

    Dissemination of soluble molecules or antigens via the blood stream is considered to lead to a uniform distribution in the various organs of the body, but organ-specific microarchitecture and vascularization may influence this. Following intravenous injection of αCD3ε antibody (αCD3εAb) we observed clear differences in antibody binding to Fcγ receptor (FcγR)+ antigen-presenting cells (APCs) or T lymphocytes in different organs. Significant binding of blood-borne αCD3εAb was only detected in the spleen and liver and not in the thymus or lymph node. In the spleen, only 10% of dendritic cells/macrophages and 40% of T-cell receptor (TCR)-β+ cells were positive for αCD3εAb, and, dependent on FcγR-mediated cross-linking of αCD3εAb, a similar percentage of splenic TCR-β+ cells were stimulated and became CD69+. Stimulation of TCR-β+ cells in the liver was at least as efficient as in the spleen, but almost all T cells and all scavenger liver sinusoidal endothelial cells bound αCD3εAb. In contrast to CD69 up-regulation, only CD4+ natural killer T (NKT) cells and CD11ahigh CD8+ T cells were activated by αCD3εAb and expressed interferon (IFN)-γ. Again, IFN-γ release from NKT/T cells was at least as efficient in the liver as in the spleen. Taken together, our results support the notion that the combination of extensive hepatic vascularization and very high scavenger activity allows the liver to fulfill its metabolic tasks and to promote stimulation of the large but widely distributed hepatic population of NKT/T cells. PMID:16423047

  14. NK-cell-dependent killing of colon carcinoma cells is mediated by natural cytotoxicity receptors (NCRs) and stimulated by parvovirus infection of target cells

    International Nuclear Information System (INIS)

    Bhat, Rauf; Rommelaere, Jean

    2013-01-01

    Investigating how the immune system functions during malignancies is crucial to developing novel therapeutic strategies. Natural killer (NK) cells, an important component of the innate immune system, play a vital role in immune defense against tumors and virus-infected cells. The poor survival rate in colon cancer makes it particularly important to develop novel therapeutic strategies. Oncolytic viruses, in addition to lysing tumor cells, may have the potential to augment antitumor immune responses. In the present study, we investigate the role of NK cells and how parvovirus H-1PV can modulate NK-cell mediated immune responses against colon carcinoma. Human NK cells were isolated from the blood of healthy donors. The cytotoxicity and antibody-mediated inhibition of NK cells were measured in chromium release assays. Phenotypic assessment of colon cancer and dendritic cells was done by FACS. The statistical significance of the results was calculated with Student’s t test (*p <0.05; **, p < 0.01; ***, p < 0.001). We show that IL-2-activated human NK cells can effectively kill colon carcinoma cells. Killing of colon carcinoma cells by NK cells was further enhanced upon infection of the former cells with parvovirus H-1PV. H-1PV has potent oncolytic activity against various tumors, yet its direct killing effect on colon carcinoma cells is limited. The cytotoxicity of NK cells towards colon carcinoma cells, both mock- and H-1PV-infected, was found to be mostly mediated by a combination of natural cytotoxicity receptors (NCRs), namely NKp30, 44, and 46. Colon carcinoma cells displayed low to moderate expression of NK cell ligands, and this expression was modulated upon H-1PV infection. Lysates of H-1PV-infected colon carcinoma cells were found to increase MHC class II expression on dendritic cells. Altogether, these data suggest that IL-2-activated NK cells actively kill colon carcinoma cells and that this killing is mediated by several natural cytotoxicity receptors

  15. A Successful Pregnancy by Utilization of Gradually Increasing Low Dose Gonadotrophin Stimulation in a Modified Natural Cycle in Vitro Fertilization Procedure: Case Report

    Directory of Open Access Journals (Sweden)

    Serkan Kahyaoğlu

    2016-05-01

    Full Text Available The modified natural cycle in vitro fertilization (MNC-IVF treatment can be a promising method for poor responder patients especially in young patients with poor ovarian reserve. A 34-year-old primary infertile woman presented with a history of poor ovarian response and cycle cancellation following controlled ovarian hyperstimulation during an IVF-ET procedure two months ago. During MNC-IVF treatment with intracytoplasmic sperm injection (ICSI, gradually increasing doses of hMG for three days (totally 675 IU have been administered accompanied by daily 0,25 mg cetrorelix. Following ovulation triggering, one oocyte was picked up and a good quality (grade 1 embryo was transferred on day 2. A clinical pregnancy was established with ultrasonography on sixth weeks of gestation. Acceptable pregnancy rates per embryo transfer, low medication cost, relatively low risk of complications and higher patient acceptability are the main advantages of MNC-IVF treatment as a feasible treatment option especially for poor responder patients.

  16. Possible Protective Effect of Low-dose Gamma Irradiation and Certain Natural Products on Chemically Induced Hepatotoxicity in Rats

    International Nuclear Information System (INIS)

    Rashed, R.R.A.

    2015-01-01

    Liver, the largest organ in the human body, is a vital organ that performs more than 500 vital metabolic functions. More than a 1000 drugs of the modern pharmacopoeia can induce liver injury with different clinical presentations. In the most severe cases, drug-induced liver injury may require liver transplantation or lead to death of the patient. Acetaminophen (acetyl-para-amino-phenol, paracetamol, APAP) is safe at therapeutic doses, but accidental or intentional overdose can induce severe hepatotoxicity in both humans and experimental animals. APAP-induced hepatotoxicity is dose related and reproducible in animals, and is thus widely used as a model for experimentally induced hepatotoxicity. Many herbs have been used as natural remedies for the prevention and/or treatment of liver diseases. Herbal drugs gained importance and popularity in recent years because of their safety, efficacy and cost effectiveness. Interestingly, exposure to a small dose or dose rate of radiation was reported to induce stress, perturbing homeostasis. Organisms respond adaptively to such disturbances. The mechanisms by which low-dose radiation (LDR) protects the cells or tissue against subsequent radiation- or drug-induced toxicities have been attributed to its stimulation of various protective molecules such as antioxidants and anti apoptotic. In the light of the above mentioned information, this study was constructed in order to investigate the mechanism(s) of the hepato protective effects offered by each of garlic oil (GO), black seed oil (BO) and sesame oil (SO) each alone or combined with low dose total body gamma (γ)-irradiation against APAP-induced hepatotoxicity in male albino Wistar rats. Preliminary pilot studies were performed prior to the main experimental work; in order to select the effective irradiation dose, the hepato protective natural products and the duration of their administration to be used in the main study. To carry out the main study, 96 rats were randomly

  17. Optically stimulated luminescence from quartz measured using the linear modulation technique

    DEFF Research Database (Denmark)

    Bulur, E.; Bøtter-Jensen, L.; Murray, A.S.

    2000-01-01

    The optically stimulated luminescence (OSL) from heated natural quartz has been investigated using the linear modulation technique (LMT), in which the excitation light intensity is increased linearly during stimulation. In contrast to conventional stimulation, which usually produces a monotonical...

  18. Evaluation of the potential immunotoxicity of 3-monochloro-1,2-propanediol in Balb/c mice I. Effect on antibody forming cell, mitogen-stimulated lymphocyte proliferation, splenic subset, and natural killer cell activity

    International Nuclear Information System (INIS)

    Lee, Jong Kwon; Byun, Jung A.; Park, Seung Hee; Kim, Hyung Soo; Park, Jae Hyun; Eom, Juno H.; Oh, Hye Young

    2004-01-01

    3-Monochloro-1,2-propanediol (MCPD) is a well-known by-product of acid-hydrolyzed soy sauce during its manufacturing process. MCPD has been reported genotoxic in vitro, and reproductive toxicity and carcinogenicity in rats. However, no previous studies have investigated MCPD-induced alterations in the immune system. In the present study, MCPD was administered by gavage for 14 days at 0, 25, 50, and 100 mg/kg per day to female Balb/c mice. The antibody-mediated immune response to sheep red blood cells (SRBC) was assessed using the antibody-forming cell (AFC) assay, and splenic cell phenotypes were quantified by flow cytometry. Hematological and histopathological changes were assessed. Mitogen-stimulated spleen lymphocyte proliferation and natural killer (NK) cell activity were evaluated. The T-lymphocyte blastogenesis by concanavalin A (Con A) or anti-CD3 and B-lymphocyte blastogenesis by lipopolysaccharide (LPS) were not significantly changed. There were no significant changes in the hematological and histopathological findings of MCPD-treated mice. However, the significant decrease in thymus weight was observed in 100 mg dose group, even though that did not change body weight gain. The cellularities of spleen and thymus were significantly reduced in high-dose group. Exposure to high dose of MCPD decreased the AFC response to SRBC in mice. There was a significant decrease in NK cell activity of mice treated with high dose of MCPD. These results indicate that MCPD could modulate the immune function in Balb/c mice

  19. Addictive drugs and brain stimulation reward.

    Science.gov (United States)

    Wise, R A

    1996-01-01

    Direct electrical or chemical stimulation of specific brain regions can establish response habits similar to those established by natural rewards such as food or sexual contact. Cocaine, mu and delta opiates, nicotine, phencyclidine, and cannabis each have actions that summate with rewarding electrical stimulation of the medial forebrain bundle (MFB). The reward-potentiating effects of amphetamine and opiates are associated with central sites of action where these drugs also have their direct rewarding effects, suggesting common mechanisms for drug reward per se and for drug potentiation of brain stimulation reward. The central sites at which these and perhaps other drugs of abuse potentiate brain stimulation reward and are rewarding in their own right are consistent with the hypothesis that the laboratory reward of brain stimulation and the pharmacological rewards of addictive drugs are habit forming because they act in the brain circuits that subserve more natural and biologically significant rewards.

  20. Spinal cord stimulation

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/007560.htm Spinal cord stimulation To use the sharing features on this page, please enable JavaScript. Spinal cord stimulation is a treatment for pain that uses ...

  1. Feldspar, Infrared Stimulated Luminescence

    DEFF Research Database (Denmark)

    Jain, Mayank

    2014-01-01

    This entry primarily concerns the characteristics and the origins of infrared-stimulated luminescence in feldspars.......This entry primarily concerns the characteristics and the origins of infrared-stimulated luminescence in feldspars....

  2. Growth hormone stimulation test

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/003377.htm Growth hormone stimulation test To use the sharing features on this page, please enable JavaScript. The growth hormone (GH) stimulation test measures the ability of ...

  3. Early brain response to low-dose radiation exposure involves molecular networks and pathways associated with cognitive functions, advanced aging and Alzheimer's disease.

    Science.gov (United States)

    Lowe, Xiu R; Bhattacharya, Sanchita; Marchetti, Francesco; Wyrobek, Andrew J

    2009-01-01

    Understanding the cognitive and behavioral consequences of brain exposures to low-dose ionizing radiation has broad relevance for health risks from medical radiation diagnostic procedures, radiotherapy and environmental nuclear contamination as well as for Earth-orbit and space missions. Analyses of transcriptome profiles of mouse brain tissue after whole-body irradiation showed that low-dose exposures (10 cGy) induced genes not affected by high-dose radiation (2 Gy) and that low-dose genes were associated with unique pathways and functions. The low-dose response had two major components: pathways that are consistently seen across tissues and pathways that were specific for brain tissue. Low-dose genes clustered into a saturated network (P < 10(-53)) containing mostly down-regulated genes involving ion channels, long-term potentiation and depression, vascular damage, etc. We identified nine neural signaling pathways that showed a high degree of concordance in their transcriptional response in mouse brain tissue after low-dose irradiation, in the aging human brain (unirradiated), and in brain tissue from patients with Alzheimer's disease. Mice exposed to high-dose radiation did not show these effects and associations. Our findings indicate that the molecular response of the mouse brain within a few hours after low-dose irradiation involves the down-regulation of neural pathways associated with cognitive dysfunctions that are also down-regulated in normal human aging and Alzheimer's disease.

  4. Hemo rheological Changes Associated with Occupational Exposure to Low Doses Radiation from X-Ray Inspection Machines Influenced by Smoking Habits

    International Nuclear Information System (INIS)

    Ahmed, M.A.M.; El-khatib, A.M.; Naim, M.A.; Ali, F.M.

    2011-01-01

    The effects of low dose x-ray radiation on some rheological parameters of blood were investigated in 30 male x-ray workers and 20 healthy volunteers not occupationally exposed to any type of radiation and match in age. Each group was classified according to smoking habits. The analysis of the flow curve of all subjects was performed by applying power-law model and Bingham plastic model. The results indicated elevates in whole blood viscosity and yield stress in smoker subjects as compared with non-smoker subjects and also showed that the elevation of blood viscosity of smoker radiation workers are related to work duration in the radiation field.We have observed that cigarette smoking increases the hazardous effects of radiation through the increase of blood viscosity, which excess the risk of cardiovascular disease. So it is recommended to consider blood viscosity measurements to be included in routine medical investigation for occupational workers and rheological

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

    International Nuclear Information System (INIS)

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

    2008-01-01

    Full text: As a result of the Mayak PA activities, radioactive wastes were discharged into the Techa River over the period 1949-1956. Data on eye pathology among Techa riverside residents chronically exposed to radiation (external and internal) have been collected and analyzed. The cohort which includes persons of the two genders born before 1950 gives one of the rare opportunities to assess the risk of late effects on human health associated with small-dose radiation exposure. Currently, the cohort numbers 29,749 individuals. In terms of ethnicity, 80 % of the cohort members are Slavs, and 20 % are Tartars and Bashkirs. The first study and analyses of eye pathology were conducted for this cohort during the period from 2001 through 2004. It was established that the cumulative rate of eye disease incidence increased with age and exposure dose. The relative risk value for development of ophthalmopathy among members of the study group was estimated taking into account the potential effects of gender, ethnicity and attained age. The relative risk value was 2.42 per 1 Gy of absorbed dose to soft tissues (95 % CI: 1.94; 3.03). With increase in attained age by 10 years an 8 % increase in the incidence of eye pathology was registered (p<0.001). The rate of eye disease incidence estimated for women was significantly higher than that for men (p<0.05 %). No significant differences were noted in the coefficient of eye disease incidence calculated for different ethnic groups. The structure of ophthalmopathy registered in residents of the Techa riverside villages chronically exposed in the dose range from 0 to 1,180 mGy is characterized by prevalence of cataracts, retinal and chorioid disorders. The rates of eye disease incidence were found to be dependent on external exposure dose; the highest doses were observed in the dose groups with doses 25 mGy. A statistically significant increase in the incidence of retinal angiosklerosis and a manifest tendency to develop cataracts was noted to be associated with increased dose. A direct dependence of the cataract incidence on hypertensive disease and diabetes mellitus (p<0.001) was revealed. At late time, the followed-up individuals chronically exposed at highest doses (with a mean dose of 800 mGy) manifested a statistically significant reduction in electrophysiological parameters of the retina and the visual nerve (the A-wave of the total electroretinogram and lability of the visual nerve) as compared to members of the control group, and in relation to the age-specific norm. (author)

  6. The use of the mouse chimera assay to detect early embryonic damage from male mice exposed to low-dose radiation

    International Nuclear Information System (INIS)

    Oudiz, D.; Warner, P.; Walsh, K.J.; Wiley, L.

    1990-01-01

    Mouse chimeras are in vitro aggregations of two 4-cell embryos and are used to detect subtle, nonlethal changes, which are expressed as a proliferative disadvantage in exposed embryos. One of the embryos is labeled with a viable dye (FITC) in order to determine the relative cellular contribution of each embryo when the chimera is dissociated 40 hours later. This proliferative disadvantage has been seen at doses which do not produce an effect on cell number when the embryos are cultured singly. Previously, the assay has detected a decrease in cellular proliferation in embryos from male mice exposed to a single dose of x-radiation as low as 0.05 Gy. In the current study, male mice were irradiated with a single dose of 0, 0.001, 0.01, or 0.05 Gy, and then serially mated for the next 8 weeks to unexposed females. Chimeras were constructed from control and treated embryos. Embryos from males treated with 0.05 Gy exhibited a significant decrease in cellular proliferation during weeks 6 and 7 post-irradiation. A similar decrease was seen in the males treated with 0.01 Gy. No reductions were observed from embryos cultured singly in any of the treatment groups

  7. Using low-dose radiation to potentiate the effect of induction chemotherapy in head and neck cancer: Results of a prospective phase 2 trial

    Directory of Open Access Journals (Sweden)

    Susanne M. Arnold, MD

    2016-10-01

    Conclusion: Chemopotentiating LDFRT combined with paclitaxel and carboplatin is effective in SCCHN and provided an excellent median overall survival of 107.2 months, with median PFS not yet reached in this locally advanced SCCHN cohort. This compares favorably to prior investigations and caused fewer grade 3 and 4 toxicities than more intensive, 3-drug induction regimens. This trial demonstrates the innovative use of LDFRT as a potentiator of chemotherapy.

  8. Low-Dose Radiation Treatment in Pulmonary Mucosa-Associated Lymphoid Tissue Lymphoma: A Plausible Approach? A Single-Institution Experience in 10 Patients

    Energy Technology Data Exchange (ETDEWEB)

    Girinsky, Theodore, E-mail: girinsky@igr.fr [Department of Radiation Oncology, Institut Gustave Roussy, Villejuif (France); Paumier, Amaury [Department of Radiation Oncology, Institut Gustave Roussy, Villejuif (France); Ferme, Christophe; Hanna, Colette; Ribrag, Vincent [Department of Hematology, Institut Gustave Roussy, Villejuif (France); Leroy-Ladurie, Francois [Department of Thoracic Surgery, Centre Chirurgical Marie Lannelongue, Le Plessis Robinson (France); Ghalibafian, Mithra [Department of Radiation Oncology, Institut Gustave Roussy, Villejuif (France)

    2012-07-01

    Purpose: To propose an alternative approach for treatment of pulmonary marginal zone lymphoma, using a very small radiation dose (2 Multiplication-Sign 2 Gy) delivered exclusively to tumor sites. Methods and Materials: Patients had localized pulmonary mucosa-associated lymphoid tissue (MALT) lymphoma according to the World Health Organization classification. The 6-MV radiation treatments were delivered using tumor-limited fields, except in cases of diffuse bilateral involvement. Two daily fractions of 2 Gy were delivered to tumor-limited fields using a 6-MV linear accelerator. Results: Ten patients with pulmonary MALT lymphoma entered the study. All but 1 had localized tumor masses. The median follow-up was 56 months (range, 2-103 months). Complete remission or an unconfirmed complete remission was obtained in 60% of patients within the first 2 months, and two additional partial responses were converted into a long-term unconfirmed complete remission. All patients are well and alive, no local progression was observed, and the 5-year progression-free survival rate was 87.5% (95% confidence interval 49%-97%). Conclusions: Our results suggest that extremely low radiation doses delivered exclusively to tumor sites might be a treatment option in pulmonary MALT lymphoma.

  9. Low-Dose Radiation Treatment in Pulmonary Mucosa-Associated Lymphoid Tissue Lymphoma: A Plausible Approach? A Single-Institution Experience in 10 Patients

    International Nuclear Information System (INIS)

    Girinsky, Theodore; Paumier, Amaury; Ferme, Christophe; Hanna, Colette; Ribrag, Vincent; Leroy-Ladurie, François; Ghalibafian, Mithra

    2012-01-01

    Purpose: To propose an alternative approach for treatment of pulmonary marginal zone lymphoma, using a very small radiation dose (2 × 2 Gy) delivered exclusively to tumor sites. Methods and Materials: Patients had localized pulmonary mucosa-associated lymphoid tissue (MALT) lymphoma according to the World Health Organization classification. The 6-MV radiation treatments were delivered using tumor-limited fields, except in cases of diffuse bilateral involvement. Two daily fractions of 2 Gy were delivered to tumor-limited fields using a 6-MV linear accelerator. Results: Ten patients with pulmonary MALT lymphoma entered the study. All but 1 had localized tumor masses. The median follow-up was 56 months (range, 2–103 months). Complete remission or an unconfirmed complete remission was obtained in 60% of patients within the first 2 months, and two additional partial responses were converted into a long-term unconfirmed complete remission. All patients are well and alive, no local progression was observed, and the 5-year progression-free survival rate was 87.5% (95% confidence interval 49%–97%). Conclusions: Our results suggest that extremely low radiation doses delivered exclusively to tumor sites might be a treatment option in pulmonary MALT lymphoma.

  10. Biological dosimetry - a Bayesian approach in the presentation of the uncertainty of the estimated dose in cases of exposure to low dose radiation

    International Nuclear Information System (INIS)

    Di Giorgio, Marina; Zaretzky, A.

    2010-01-01

    Biodosimetry laboratory experience has shown that there are limitations in the existing statistical methodology. Statistical difficulties generally occur due to the low number of aberrations leading to large uncertainties for dose estimation. Some problems derived from limitations of the classical statistical methodology, which requires that chromosome aberration yields be considered as something fixed and consequently provides a deterministic dose estimation and associated confidence limits. On the other hand, recipients of biological dosimetry reports, including medical doctors, regulators and the patients themselves may have a limited comprehension of statistics and of informed reports. Thus, the objective of the present paper is to use a Bayesian approach to present the uncertainty on the estimated dose to which a person could be exposed, in the case of low dose (occupational doses) radiation exposure. Such methodology will allow the biodosimetrists to adopt a probabilistic approach for the cytogenetic data analysis. At present, classical statistics allows to produce a confidence interval to report such dose, with a lower limit that could not detach from zero. In this situation it becomes difficult to make decisions as they could impact on the labor activities of the worker if an exposure exceeding the occupational dose limits is inferred. The proposed Bayesian approach is applied to occupational exposure scenario to contribute to take the appropriate radiation protection measures. (authors) [es

  11. Exposure to low-dose radiation and the risk of breast cancer among women with a familial or genetic predisposition : a meta-analysis

    NARCIS (Netherlands)

    Jansen-van der Weide, Marijke C.; Greuter, Marcel J. W.; Jansen, Liesbeth; Oosterwijk, Jan C.; Pijnappel, Ruud M.; de Bock, Geertruida H.

    Women with familial or genetic aggregation of breast cancer are offered screening outside the population screening programme. However, the possible benefit of mammography screening could be reduced due to the risk of radiation-induced tumours. A systematic search was conducted addressing the

  12. Effect of low dose radiation in lymphocytes from children exposed to ionizing radiation after the Chernobyl accident. Cytogenetic, chromosome painting, GPA and adaptive response studies

    International Nuclear Information System (INIS)

    Padovani, L.; Appolloni, M.; Anzidei, P.; Spano, M.; Stronati, L.; Testa, A.; Mauro, F.

    1997-01-01

    The present study concerns the monitoring of some children coming from Byelorussian, Ukrainian and Russian republics, exposed to the fall-out, or to the initial acute dose of radiation with the aim of assessing the effects of ionizing radiation on human health and of verifying the persisting of chromosomal damage several years after the accident. Both structural chromosomes damage (conventional cytogenetic and chromosome painting) and molecular mutation (GPA) have been investigated, moreover the possible induction of an adaptive response has been tested. (author)

  13. Exposure to low-dose radiation and the risk of breast cancer among women with a familial or genetic predisposition : a meta-analysis

    NARCIS (Netherlands)

    Jansen-van der Weide, Marijke C.; Greuter, Marcel J. W.; Jansen, Liesbeth; Oosterwijk, Jan C.; Pijnappel, Ruud M.; de Bock, Geertruida H.

    2010-01-01

    Women with familial or genetic aggregation of breast cancer are offered screening outside the population screening programme. However, the possible benefit of mammography screening could be reduced due to the risk of radiation-induced tumours. A systematic search was conducted addressing the

  14. Study of feasibility of detecting effects of low-dose radiation in shipyard workers. Final report, May 15-August 15, 1978

    International Nuclear Information System (INIS)

    Matanoski, G.M.

    1982-12-01

    There is very little information available on the chronic health effects from repeated low-level doses of radiation. This study examines the adequacy of determining radiation exposure doses in shipyard workers, the procedures used in the radiation control programs, and the feasibility of establishing an appropriate population of nuclear and non-nuclear shipyard workers for long-term studies of low-level radiation. The availability of records and the methods of population identification and of measurement of radiation dose were determined during initial visits to the yards. Personnel, industrial hygiene, radiation and medical records were examined for suitability, completeness and accuracy. It was necessary to assure that no possible errors or omissions in personnel and radiation records existed in order that the final data will have validity. Preliminary investigations on the methods of follow-up in the Portsmouth population and the time required for each procedure were also undertaken in order to have a better estimate of the total cost for a long term study

  15. The anti-inflammatory effect of low-dose radiation therapy involves a diminished CCL20 chemokine expression and granulocyte/endothelial cell adhesion

    Energy Technology Data Exchange (ETDEWEB)

    Roedel, F. [Dept. of Radiotherapy and Oncology, Univ. of Frankfurt/Main (Germany); Hofmann, D.; Auer, J.; Roellinghoff, M.; Beuscher, H.U. [Inst. of Microbiology and Immunology, Univ. of Erlangen-Nuremberg, Erlangen (Germany); Keilholz, L. [Dept. of Radiotherapy, Clinical Center Bayreuth (Germany); Sauer, R. [Dept. of Radiooncology, Univ. of Erlangen-Nuremberg, Erlangen (Germany)

    2008-01-15

    Background and purpose: low-dose radiotherapy (LD-RT) is known to exert an anti-inflammatory effect, however, the underlying molecular mechanisms are not fully understood. The manipulation of polymorphonuclear neutrophil (PMN) function and/or recruitment may be one mechanism. Chemokines contribute to this process by creating a chemotactic gradient and by activating integrins. This study aimed to characterize the effect of LD-RT on CCL20 chemokine production and PMN/endothelial cell (EC) adhesion. Material and methods: the EC line EA.hy.926 was irradiated with doses ranging from 0 to 3 Gy and was co-cultured with PMNs from healthy donors either by direct cell contact or separated by transwell membrane chambers. CXCL8, CCL18, CCL20 chemokine and tumor necrosis factor-(TNF-){alpha} cytokine levels in supernatants were determined by ELISA and adhesion assays were performed. The functional impact of the cytokines transforming growth factor-(TGF-){beta}{sub 1} and TNF-{alpha} and of the intercellular adhesion molecule-(ICAM-)1 on CCL20 expression was analyzed by using neutralizing antibodies. Results: as compared to CXCL8 and CCL18, CCL20 chemokine secretion was found to be exclusively induced by a direct cell-cell contact between PMNs and EA.hy.926 ECs in a TNF-{alpha}-dependent, but ICAM-1-independent manner. Furthermore, irradiation with doses between 0.5 and 1 Gy resulted in a significant reduction of CCL20 release which was dependent on TGF-{beta}{sub 1} (p < 0.01). The decrease of CCL20 paralleled with a significant reduction in PMN/EA.hy.926 EC adhesion (p < 0.001). Conclusion: the modulation of CCL20 chemokine expression and PMN/EC adhesion adds a further facet to the plethora of mechanisms contributing to the anti-inflammatory efficacy of LD-RT. (orig.)

  16. Effects of reduced natural background radiation on Drosophila melanogaster growth and development as revealed by the FLYINGLOW program.

    Science.gov (United States)

    Morciano, Patrizia; Iorio, Roberto; Iovino, Daniela; Cipressa, Francesca; Esposito, Giuseppe; Porrazzo, Antonella; Satta, Luigi; Alesse, Edoardo; Tabocchini, Maria Antonella; Cenci, Giovanni

    2018-01-01

    Natural background radiation of Earth and cosmic rays played a relevant role during the evolution of living organisms. However, how chronic low doses of radiation can affect biological processes is still unclear. Previous data have indicated that cells grown at the Gran Sasso Underground Laboratory (LNGS, L'Aquila) of National Institute of Nuclear Physics (INFN) of Italy, where the dose rate of cosmic rays and neutrons is significantly reduced with respect to the external environment, elicited an impaired response against endogenous damage as compared to cells grown outside LNGS. This suggests that environmental radiation contributes to the development of defense mechanisms at cellular level. To further understand how environmental radiation affects metabolism of living organisms, we have recently launched the FLYINGLOW program that aims at exploiting Drosophila melanogaster as a model for evaluating the effects of low doses/dose rates of radiation at the organismal level. Here, we will present a comparative data set on lifespan, motility and fertility from different Drosophila strains grown in parallel at LNGS and in a reference laboratory at the University of L'Aquila. Our data suggest the reduced radiation environment can influence Drosophila development and, depending on the genetic background, may affect viability for several generations even when flies are moved back to normal background radiation. As flies are considered a valuable model for human biology, our results might shed some light on understanding the effect of low dose radiation also in humans. © 2017 Wiley Periodicals, Inc.

  17. [Transcranial magnetic stimulation].

    Science.gov (United States)

    Tormos, J M; Catalá, M D; Pascual-Leone, A

    Transcranial magnetic stimulation (TMS) permits stimulation of the cerebral cortex in humans without requiring open access to the brain and is one of the newest tools available in neuroscience. There are two main types of application: single-pulse TMS and repetitive TMS. The magnetic stimulator is composed of a series of capacitors that store the voltage necessary to generate a stimulus of the sufficient intensity of generate an electric field in the stimulation coil. The safety of TMS is supported by the considerable experience derived from studies involving electrical stimulation of the cortex in animals and humans, and also specific studies on the safety of TMS in humans. In this article we review historical and technical aspects of TMS, describe its adverse effects and how to avoid them, summarize the applications of TMS in the investigation of different cerebral functions, and discuss the possibility of using TMS for the treatment of neuropsychiatric disorders.

  18. Music acupuncture stimulation method.

    Science.gov (United States)

    Brătilă, F; Moldovan, C

    2007-01-01

    Harmonic Medicine is the model using the theory that the body rhythms synchronize to an outer rhythm applied for therapeutic purpose, can restores the energy balance in acupuncture channels and organs and the condition of well-being. The purpose of this scientific work was to demonstrate the role played by harmonic sounds in the stimulation of the Lung (LU) Meridian (Shoutaiyin Feijing) and of the Kidney (KI) Meridian (Zushaoyin Shenjing). It was used an original method that included: measurement and electronic sound stimulation of the Meridian Entry Point, measurement of Meridian Exit Point, computer data processing, bio feed-back adjustment of the music stimulation parameters. After data processing, it was found that the sound stimulation of the Lung Meridian Frequency is optimal between 122 Hz and 128 Hz, with an average of 124 Hz (87% of the subjects) and for Kidney Meridian from 118 Hz to 121 Hz, with an average of 120 Hz (67% of the subjects). The acupuncture stimulation was more intense for female subjects (> 7%) than for the male ones. We preliminarily consider that an informational resonance phenomenon can be developed between the acupuncture music stimulation frequency and the cellular dipole frequency, being a really "resonant frequency signature" of an acupoint. The harmonic generation and the electronic excitation or low-excitation status of an acupuncture point may be considered as a resonance mechanism. By this kind of acupunctural stimulation, a symphony may act and play a healer role.

  19. The ISMAAR proposal on terminology for ovarian stimulation for IVF

    NARCIS (Netherlands)

    Nargund, G.; Fauser, B. C. J. M.; Macklon, N. S.; Ombelet, W.; Nygren, K.; Frydman, R.

    IVF is performed with oocytes collected in natural and stimulated cycles. Different approaches to ovarian stimulation have been employed worldwide. Following the introduction of GnRH antagonists and strategies to reduce multiple births such as single embryo transfer, there is a genuine scientific

  20. The ISMAAR proposal on terminology for ovarian stimulation for IVF

    NARCIS (Netherlands)

    Nargund, G.; Fauser, B. C. J. M.; Macklon, N. S.; Ombelet, W.; Nygren, K.; Frydman, R.

    2007-01-01

    IVF is performed with oocytes collected in natural and stimulated cycles. Different approaches to ovarian stimulation have been employed worldwide. Following the introduction of GnRH antagonists and strategies to reduce multiple births such as single embryo transfer, there is a genuine scientific

  1. New York Canyon Stimulation

    Energy Technology Data Exchange (ETDEWEB)

    Raemy, Bernard

    2012-06-21

    The New York Canyon Stimulation Project was to demonstrate the commercial application of Enhanced Geothermal System techniques in Buena Vista Valley area of Pershing County, Nevada. From October 2009 to early 2012, TGP Development Company aggressively implemented Phase I of Pre-Stimulation and Site/Wellbore readiness. This included: geological studies; water studies and analyses and procurement of initial permits for drilling. Oversubscription of water rights and lack of water needed for implementation of EGS were identified and remained primary obstacles. Despite extended efforts to find alternative solutions, the water supply circumstances could not be overcome and led TGP to determine a "No Go" decision and initiate project termination in April 2012.

  2. IDEA: Stimulating Oral Production.

    Science.gov (United States)

    Easley, Jacob J.

    1995-01-01

    Presents daily activities that facilitate complete sentence response, promote oral production, and aid the learning of vocabulary in foreign-language classes. Because speech is the primary form of communication in the foreign-language classroom, it is important to stimulate students to converse as soon as possible. (Author/CK)

  3. stimulated BV2 Microglial

    African Journals Online (AJOL)

    2012-03-26

    Mar 26, 2012 ... 2), in LPS-stimulated BV2 microglial cells. The level of NO production was analyzed using Griess reaction. The release of PGE2 was determined using sandwich enzyme-linked immunosorbent assay. The DNA-binding activity of nuclear factor-κB (NF-κB) was measured by electrophoretic mobility shift assay ...

  4. Brain stimulation in migraine.

    Science.gov (United States)

    Brighina, Filippo; Cosentino, Giuseppe; Fierro, Brigida

    2013-01-01

    Migraine is a very prevalent disease with great individual disability and socioeconomic burden. Despite intensive research effort in recent years, the etiopathogenesis of the disease remains to be elucidated. Recently, much importance has been given to mechanisms underlying the cortical excitability that has been suggested to be dysfunctional in migraine. In recent years, noninvasive brain stimulation techniques based on magnetic fields (transcranial magnetic stimulation, TMS) and on direct electrical currents (transcranial direct current stimulation, tDCS) have been shown to be safe and effective tools to explore the issue of cortical excitability, activation, and plasticity in migraine. Moreover, TMS, repetitive TMS (rTMS), and tDCS, thanks to their ability to interfere with and/or modulate cortical activity inducing plastic, persistent effects, have been also explored as potential therapeutic approaches, opening an interesting perspective for noninvasive neurostimulation for both symptomatic and preventive treatment of migraine and other types of headache. In this chapter we critically review evidence regarding the role of noninvasive brain stimulation in the pathophysiology and treatment of migraine, delineating the advantages and limits of these techniques together with potential development and future application. © 2013 Elsevier B.V. All rights reserved.

  5. Biological effects of high level natural background radiation on human population residing in Kerala coast, South West India

    International Nuclear Information System (INIS)

    Seshadri, M.

    2010-01-01

    The populations residing in Kerala coast are exposed to elevated natural background radiation since many generations. Extensive studies conducted by Bio-Medical group, Bhabha Atomic Research Center have generated wealth of data from this area dealing with epidemiology, monitoring the newborns for malformations, Health Audit Survey, Dosimetry and biological studies using cytogenetic and molecular biology techniques. Our studies on congenital malformations and chromosomal anomalies in children born to parents residing in High Level Natural Radiation Areas in Kerala have not shown any significant difference from normal radiation areas. Screening of over 1,25,000 consecutively born children showed an incidence rate which is comparable in both areas. Other factors such as consanguinity, maternal age and gravida status are more significant contributors than radiation dose to the risk for having malformation in child. Radiation prevalent in the HLNRA is in the dose range of above 1.5 to about 50 mGy per year which translates to doses in the range of nGy per hour. This clearly indicate the number of cells exposed to radiations will be one in few thousand or ten thousands. This throws up challenges in our capability to investigate the effects of radiation on cells. It has become imperative to develop and exploit techniques which will detect responses in single cells and would be able screen large number of cells at a time. Developments in cell biology and molecular biology are now giving us these capabilities. Use of flowcytometer and next generation sequencing would enable us to address many of these questions and provide meaningful approaches to understand the effects of such low dose radiation

  6. [Transcranial magnetic stimulation and motor cortex stimulation in neuropathic pain].

    Science.gov (United States)

    Mylius, V; Ayache, S S; Teepker, M; Kappus, C; Kolodziej, M; Rosenow, F; Nimsky, C; Oertel, W H; Lefaucheur, J P

    2012-12-01

    Non-invasive and invasive cortical stimulation allows the modulation of therapy-refractory neuropathic pain. High-frequency repetitive transcranial magnetic stimulation (rTMS) of the contralateral motor cortex yields therapeutic effects at short-term and predicts the benefits of epidural motor cortex stimulation (MCS). The present article summarizes the findings on application, mechanisms and therapeutic effects of cortical stimulation in neuropathic pain.

  7. Sensory adaptation to electrical stimulation of the somatosensory nerves.

    Science.gov (United States)

    Graczyk, Emily Lauren; Delhaye, Benoit; Schiefer, Matthew A; Bensmaia, Sliman J; Tyler, Dustin J

    2018-03-19

    Sensory systems adapt their sensitivity to ambient stimulation levels to improve their responsiveness to changes in stimulation. The sense of touch is also subject to adaptation, as evidenced by the desensitization produced by prolonged vibratory stimulation of the skin. Electrical stimulation of nerves elicits tactile sensations that can convey feedback for bionic limbs. In this study, we investigate whether artificial touch is also subject to adaptation, despite the fact that the peripheral mechanotransducers are bypassed. Approach: Using well-established psychophysical paradigms, we characterize the time course and magnitude of sensory adaptation caused by extended electrical stimulation of the residual somatosensory nerves in three human amputees implanted with cuff electrodes. Main results: We find that electrical stimulation of the nerve also induces perceptual adaptation that recovers after cessation of the stimulus. The time course and magnitude of electrically-induced adaptation are equivalent to their mechanically-induced counterparts. Significance: We conclude that, in natural touch, the process of mechanotransduction is not required for adaptation, and artificial touch naturally experiences adaptation-induced adjustments of the dynamic range of sensations. Further, as it does for native hands, adaptation confers to bionic hands enhanced sensitivity to changes in stimulation and thus a more natural sensory experience. . Creative Commons Attribution license.

  8. Grating stimulated echo

    International Nuclear Information System (INIS)

    Dubetsky, B.; Berman, P.R.; Sleator, T.

    1992-01-01

    A theory of a grating simulated echo (GTE) is developed. The GSE involves the sequential excitation of atoms by two counterpropagating traveling waves, a standing wave, and a third traveling wave. It is shown that the echo signal is very sensitive to small changes in atomic velocity, much more sensitive than the normal stimulated echo. Use of the GSE as a collisional probe or accelerometer is discussed

  9. Thyroid Stimulating Hormone Receptor

    Directory of Open Access Journals (Sweden)

    Murat Tuncel

    2017-02-01

    Full Text Available Thyroid stimulating hormone receptor (TSHR plays a pivotal role in thyroid hormone metabolism. It is a major controller of thyroid cell function and growth. Mutations in TSHR may lead to several thyroid diseases, most commonly hyperthyroidism. Although its genetic and epigenetic alterations do not directly lead to carcinogenesis, it has a crucial role in tumor growth, which is initiated by several oncogenes. This article will provide a brief review of TSHR and related diseases.

  10. Training and natural immunity

    DEFF Research Database (Denmark)

    Pedersen, Bente Klarlund; Helge, Jørn Wulff; Richter, Erik

    2000-01-01

    these subjects were used to eliminate day-to-day variation in the immunological tests. Independently of diet, training increased the percentage of CD3-CD16+ CD56+ natural killer (NK) cells from [mean (SEM)] 14 (1) % to 20 (3) % (P = 0.05), whereas the NK-cell activity, either unstimulated or stimulated...... influence natural immunity, and suggest that ingestion of a fat-rich diet during training is detrimental to the immune system compared to the effect of a carbohydrate-rich diet....

  11. Low intensity transcranial electric stimulation

    DEFF Research Database (Denmark)

    Antal, Andrea; Alekseichuk, I; Bikson, M

    2017-01-01

    Low intensity transcranial electrical stimulation (TES) in humans, encompassing transcranial direct current (tDCS), transcutaneous spinal Direct Current Stimulation (tsDCS), transcranial alternating current (tACS), and transcranial random noise (tRNS) stimulation or their combinations, appears...

  12. Spinal Cord Stimulation

    DEFF Research Database (Denmark)

    Meier, Kaare

    2014-01-01

    Spinal cord stimulation (SCS) is a surgical treatment for chronic neuropathic pain that is refractory to other treatment. Originally described by Shealy et al. in 1967(1), it is used to treat a range of conditions such as complex regional pain syndrome (CRPS I)(2), angina pectoris(3), radicular...... pain after failed back surgery syndrome (FBSS)(4), pain due to peripheral nerve injury, stump pain(5), peripheral vascular disease(6) and diabetic neuropathy(7,8); whereas phantom pain(9), postherpetic neuralgia(10), chronic visceral pain(11), and pain after partial spinal cord injury(12) remain more...

  13. Metallic taste from electrical and chemical stimulation.

    Science.gov (United States)

    Lawless, Harry T; Stevens, David A; Chapman, Kathryn W; Kurtz, Anne

    2005-03-01

    A series of three experiments investigated the nature of metallic taste reports after stimulation with solutions of metal salts and after stimulation with metals and electric currents. To stimulate with electricity, a device was fabricated consisting of a small battery affixed to a plastic handle with the anode side exposed for placement on the tongue or oral tissues. Intensity of taste from metals and batteries was dependent upon the voltage and was more robust in areas dense in fungiform papillae. Metallic taste was reported from stimulation with ferrous sulfate solutions, from metals and from electric stimuli. However, reports of metallic taste were more frequent when the word 'metallic' was presented embedded in a list of choices, as opposed to simple free-choice labeling. Intensity decreased for ferrous sulfate when the nose was occluded, consistent with a decrease in retronasal smell, as previously reported. Intensity of taste evoked by copper metal, bimetallic stimuli (zinc/copper) or small batteries (1.5-3 V) was not affected by nasal occlusion. This difference suggests two distinct mechanisms for evocation of metallic taste reports, one dependent upon retronasal smell and a second mediated by oral chemoreceptors.

  14. A distributed current stimulator ASIC for high density neural stimulation.

    Science.gov (United States)

    Jeong Hoan Park; Chaebin Kim; Seung-Hee Ahn; Tae Mok Gwon; Joonsoo Jeong; Sang Beom Jun; Sung June Kim

    2016-08-01

    This paper presents a novel distributed neural stimulator scheme. Instead of a single stimulator ASIC in the package, multiple ASICs are embedded at each electrode site for stimulation with a high density electrode array. This distributed architecture enables the simplification of wiring between electrodes and stimulator ASIC that otherwise could become too complex as the number of electrode increases. The individual ASIC chip is designed to have a shared data bus that independently controls multiple stimulating channels. Therefore, the number of metal lines is determined by the distributed ASICs, not by the channel number. The function of current steering is also implemented within each ASIC in order to increase the effective number of channels via pseudo channel stimulation. Therefore, the chip area can be used more efficiently. The designed chip was fabricated with area of 0.3 mm2 using 0.18 μm BCDMOS process, and the bench-top test was also conducted to validate chip performance.

  15. Computationally Developed Sham Stimulation Protocol for Multichannel Desynchronizing Stimulation

    Directory of Open Access Journals (Sweden)

    Magteld Zeitler

    2018-05-01

    Full Text Available A characteristic pattern of abnormal brain activity is abnormally strong neuronal synchronization, as found in several brain disorders, such as tinnitus, Parkinson's disease, and epilepsy. As observed in several diseases, different therapeutic interventions may induce a placebo effect that may be strong and hinder reliable clinical evaluations. Hence, to distinguish between specific, neuromodulation-induced effects and unspecific, placebo effects, it is important to mimic the therapeutic procedure as precisely as possibly, thereby providing controls that actually lack specific effects. Coordinated Reset (CR stimulation has been developed to specifically counteract abnormally strong synchronization by desynchronization. CR is a spatio-temporally patterned multichannel stimulation which reduces the extent of coincident neuronal activity and aims at an anti-kindling, i.e., an unlearning of both synaptic connectivity and neuronal synchrony. Apart from acute desynchronizing effects, CR may cause sustained, long-lasting desynchronizing effects, as already demonstrated in pre-clinical and clinical proof of concept studies. In this computational study, we set out to computationally develop a sham stimulation protocol for multichannel desynchronizing stimulation. To this end, we compare acute effects and long-lasting effects of six different spatio-temporally patterned stimulation protocols, including three variants of CR, using a no-stimulation condition as additional control. This is to provide an inventory of different stimulation algorithms with similar fundamental stimulation parameters (e.g., mean stimulation rates but qualitatively different acute and/or long-lasting effects. Stimulation protocols sharing basic parameters, but inducing nevertheless completely different or even no acute effects and/or after-effects, might serve as controls to validate the specific effects of particular desynchronizing protocols such as CR. In particular, based on

  16. Transcranial magnetic stimulation in children.

    Science.gov (United States)

    Garvey, Marjorie A; Mall, Volker

    2008-05-01

    Developmental disabilities (e.g. attention deficit disorder; cerebral palsy) are frequently associated with deviations of the typical pattern of motor skill maturation. Neurophysiologic tools, such as transcranial magnetic stimulation (TMS), which probe motor cortex function, can potentially provide insights into both typical neuromotor maturation and the mechanisms underlying the motor skill deficits in children with developmental disabilities. These insights may set the stage for finding effective interventions for these disorders. We review the literature pertaining to the use of TMS in pediatrics. Most TMS-evoked parameters show age-related changes in typically developing children and some of these are abnormal in a number of childhood-onset neurological disorders. Although no TMS-evoked parameters are diagnostic for any disorder, changes in certain parameters appear to reflect disease burden or may provide a measure of treatment-related improvement. Furthermore, TMS may be especially useful when combined with other neurophysiologic modalities (e.g. fMRI). However, much work remains to be done to determine if TMS-evoked parameters can be used as valid and reliable biomarkers for disease burden, the natural history of neurological injury and repair, and the efficacy of pharmacological and rehabilitation interventions.

  17. Correlation of maternal age, gravida status, major malformations, stillbirth and sex ratio in high level natural radiation areas of Kerala coast

    International Nuclear Information System (INIS)

    Sudheer, K.R.; Koya, P.K.M.; Jaikrishan, G.; Das, Birajalaxmi

    2016-01-01

    As a part of the ongoing study on biological and health effects of chronic low dose and/or dose rate on human population, consecutive births were monitored in selected Govt. hospitals located in normal and high level natural radiation areas (HLNRA) of Kerala coast. This area is unique because of its vast population size and varied range of background radiation level due to natural deposit of monazite containing thorium. The objective is to elucidate the role of chronic low dose radiation, if any, on the adverse pregnancy outcome. Since 1995, ∼1,70,000 newborns were monitored in this area, of which 74,238 singleton first births were monitored. Of these, 634 (0.85%) cases were observed with detectable major congenital malformations (that include serious structural, functional or cosmetic disability requiring surgical or medical management) and 240 (0.32%) cases were stillborn. Sex ratio at first birth was observed in the ratio of 1050 males to 1000 females. The distribution of age at marriage of the mothers was stratified into the following groups: d"18 years (15.5%), 19 20 years (25.9%), 21 22 years (25.6%), 23 24 years (17.2%) and >25 years (15.8%). It was observed that about 78.9% mothers had their first birth within one year of marriage, 13.7% had their first birth within 1.1 2 years and 5.2% within 2.1 4 years. About 2.2% (1613) mothers had their first child after 4 years or more. Individual, combined and interactive effects of age at marriage, first birth interval (first gravida status), background radiation levels and gender of the newborn on major congenital malformation and stillbirth will be discussed. (author)

  18. Stimulated Thomson scattering

    International Nuclear Information System (INIS)

    Spencer, R.L.

    1979-03-01

    The theory of stimulated Thomson scattering is investigated both quantum mechanically and classically. Two monochromatic electromagnetic waves of like polarization travelling in opposite directions are allowed to interact for a time tau with the electrons in a collisionless plasma. The electromagnetic waves have frequencies well above the plasma frequency, and their difference frequency is allowed to range upward from the plasma frequency. With the difference frequency well above the plasma frequency, the rate at which energy is transferred from one wave to the other is calculated quantum mechanically, classically from a fluid theory, and classically from an independent electron theory. The rate is calculated in both the homogeneously broadened limit, and in the inhomogeneously broadened limit

  19. Engagement sensitive visual stimulation

    Directory of Open Access Journals (Sweden)

    Deepesh Kumar

    2016-06-01

    Full Text Available Stroke is one of leading cause of death and disability worldwide. Early detection during golden hour and treatment of individual neurological dysfunction in stroke using easy-to-access biomarkers based on a simple-to-use, cost-effective, clinically-valid screening tool can bring a paradigm shift in healthcare, both urban and rural. In our research we have designed a quantitative automatic home-based oculomotor assessment tool that can play an important complementary role in prognosis of neurological disorders like stroke for the neurologist. Once the patient has been screened for stroke, the next step is to design proper rehabilitation platform to alleviate the disability. In addition to the screening platform, in our research, we work in designing virtual reality based rehabilitation exercise platform that has the potential to deliver visual stimulation and in turn contribute to improving one’s performance.

  20. Stimulated coherent transition radiation

    International Nuclear Information System (INIS)

    Hung-chi Lihn.

    1996-03-01

    Coherent radiation emitted from a relativistic electron bunch consists of wavelengths longer than or comparable to the bunch length. The intensity of this radiation out-numbers that of its incoherent counterpart, which extends to wavelengths shorter than the bunch length, by a factor equal to the number of electrons in the bunch. In typical accelerators, this factor is about 8 to 11 orders of magnitude. The spectrum of the coherent radiation is determined by the Fourier transform of the electron bunch distribution and, therefore, contains information of the bunch distribution. Coherent transition radiation emitted from subpicosecond electron bunches at the Stanford SUNSHINE facility is observed in the far-infrared regime through a room-temperature pyroelectric bolometer and characterized through the electron bunch-length study. To measure the bunch length, a new frequency-resolved subpicosecond bunch-length measuring system is developed. This system uses a far-infrared Michelson interferometer to measure the spectrum of coherent transition radiation through optical autocorrelation with resolution far better than existing time-resolved methods. Hence, the radiation spectrum and the bunch length are deduced from the autocorrelation measurement. To study the stimulation of coherent transition radiation, a special cavity named BRAICER is invented. Far-infrared light pulses of coherent transition radiation emitted from electron bunches are delayed and circulated in the cavity to coincide with subsequent incoming electron bunches. This coincidence of light pulses with electron bunches enables the light to do work on electrons, and thus stimulates more radiated energy. The possibilities of extending the bunch-length measuring system to measure the three-dimensional bunch distribution and making the BRAICER cavity a broadband, high-intensity, coherent, far-infrared light source are also discussed

  1. Lipopolysaccharide (LPS) stimulation of fungal secondary metabolism

    Science.gov (United States)

    Khalil, Zeinab G.; Kalansuriya, Pabasara; Capon, Robert J.

    2014-01-01

    We report on a preliminary investigation of the use the Gram-negative bacterial cell wall constituent lipopolysaccharide (LPS) as a natural chemical cue to stimulate and alter the expression of fungal secondary metabolism. Integrated high-throughput micro-cultivation and micro-analysis methods determined that 6 of 40 (15%) of fungi tested responded to an optimal exposure to LPS (0.6 ng/mL) by activating, enhancing or accelerating secondary metabolite production. To explore the possible mechanisms behind this effect, we employed light and fluorescent microscopy in conjunction with a nitric oxide (NO)-sensitive fluorescent dye and an NO scavenger to provide evidence that LPS stimulation of fungal secondary metabolism coincided with LPS activation of NO. Several case studies demonstrated that LPS stimulation can be scaled from single microplate well (1.5 mL) to preparative (>400 mL) scale cultures. For example, LPS treatment of Penicillium sp. (ACM-4616) enhanced pseurotin A and activated pseurotin A1 and pseurotin A2 biosynthesis, whereas LPS treatment of Aspergillus sp. (CMB-M81F) substantially accelerated and enhanced the biosynthesis of shornephine A and a series of biosynthetically related ardeemins and activated production of neoasterriquinone. As an indication of broader potential, we provide evidence that cultures of Penicillium sp. (CMB-TF0411), Aspergillus niger (ACM-4993F), Rhizopus oryzae (ACM-165F) and Thanatephorus cucumeris (ACM-194F) were responsive to LPS stimulation, the latter two examples being particular noteworthy as neither are known to produce secondary metabolites. Our results encourage the view that LPS stimulation can be used as a valuable tool to expand the molecular discovery potential of fungal strains that either have been exhaustively studied by or are unresponsive to traditional culture methodology. PMID:25379339

  2. Natural gas in developing countries

    International Nuclear Information System (INIS)

    Holwerda, B.

    1998-01-01

    Everywhere in the world plans are being made to stimulate the natural gas industry in developing countries. High investment costs are the biggest problem almost everywhere. Even countries with a closed economy realize that they do not get far without foreign capital. Cases are presented for Africa, Pakistan, and Indonesia

  3. Fascinating Organic Molecules from Nature

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 18; Issue 7. Fascinating Organic Molecules from Nature - Sweet Stimulants of ... Road Banashankari 2nd Stage Bangalore 560 070, India. Department of Chemistry Sri Sathya Sai Institute of Higher Learning Brindavan Campus Bangalore 560 067, India.

  4. Natural gas

    Energy Technology Data Exchange (ETDEWEB)

    Fraser, J W

    1967-08-01

    This report on the natural gas industry of Canada includes: composition and uses of natural gas, production statistics, exploration and development, reserve estimates, natural gas processing, transportation, and marketing. For the Canadian natural gas industry, 1966 was a year of moderate expansion in all phases, with a strong demand continuing for sulfur and liquid hydrocarbons produced as by-products of gas processing. Value of natural gas production increased to $199 million and ranked sixth in terms of value of mineral ouput in Canada. Currently, natural gas provides over 70% of Canada's energy requirements. Proved remaining marketable reserves are estimated to be in excess of a 29-yr supply.

  5. Ultrasound stimulation on bone healing. The optimization of stimulation time

    International Nuclear Information System (INIS)

    Rosim, R.C.; Paulin, J.B.P.; Goncalves, R.P.

    1990-01-01

    Previous works in ultrasonic simulation of bone healing dealt with parameters optimization. Albertin (1983) studied the stimulation time and found forty minutes as ideal. However, this stimulation time was the largest one employed and remained some doubt about the most appropriated value. 30, 40, 50 and 60 minutes of stimulation time were selected, while others parameters were held constant with: pulse width in 200 μs, repetition rate in 1000 pulses per second and amplitude in 30 V. Partial incomplete transverse osteotomies were done in the middle third of radio in the right forearm of rabbits. Twenty four animals divided in four subgroups, with 6 animals each were stimulated. The daily stimulation time for each subgroup was 30, 40, 50 and minutes respectively, during 15 consecutive days. The stimulation procedure started 24 hours after surgery. After the stimulation period, radiological, histological and morphometric evaluations were done and greater bone healing was found for the 50 minutes stimulation subgroup, in them new bone was also prominent. (author)

  6. Transcranial brain stimulation: closing the loop between brain and stimulation

    DEFF Research Database (Denmark)

    Karabanov, Anke; Thielscher, Axel; Siebner, Hartwig Roman

    2016-01-01

    -related and state-related variability. Fluctuations in brain-states can be traced online with functional brain imaging and inform the timing or other settings of transcranial brain stimulation. State-informed open-loop stimulation is aligned to the expression of a predefined brain state, according to prespecified......PURPOSE OF REVIEW: To discuss recent strategies for boosting the efficacy of noninvasive transcranial brain stimulation to improve human brain function. RECENT FINDINGS: Recent research exposed substantial intra- and inter-individual variability in response to plasticity-inducing transcranial brain...... stimulation. Trait-related and state-related determinants contribute to this variability, challenging the standard approach to apply stimulation in a rigid, one-size-fits-all fashion. Several strategies have been identified to reduce variability and maximize the plasticity-inducing effects of noninvasive...

  7. Natural Gas

    OpenAIRE

    Bakar, Wan Azelee Wan Abu; Ali, Rusmidah

    2010-01-01

    Natural gas fuel is a green fuel and becoming very demanding because it is environmental safe and clean. Furthermore, this fuel emits lower levels of potentially harmful by-products into the atmosphere. Most of the explored crude natural gas is of sour gas and yet, very viable and cost effective technology is still need to be developed. Above all, methanation technology is considered a future potential treatment method for converting the sour natural gas to sweet natural gas.

  8. Biological Bases for Radiation Adaptive Responses in the Lung

    Energy Technology Data Exchange (ETDEWEB)

    Scott, Bobby R. [Lovelace Biomedical and Environmental Research Inst., Albuquerque, NM (United States); Lin, Yong [Lovelace Biomedical and Environmental Research Inst., Albuquerque, NM (United States); Wilder, Julie [Lovelace Biomedical and Environmental Research Inst., Albuquerque, NM (United States); Belinsky, Steven [Lovelace Biomedical and Environmental Research Inst., Albuquerque, NM (United States)

    2015-03-01

    Our main research objective was to determine the biological bases for low-dose, radiation-induced adaptive responses in the lung, and use the knowledge gained to produce an improved risk model for radiation-induced lung cancer that accounts for activated natural protection, genetic influences, and the role of epigenetic regulation (epiregulation). Currently, low-dose radiation risk assessment is based on the linear-no-threshold hypothesis, which now is known to be unsupported by a large volume of data.

  9. The analysis of thermally stimulated processes

    CERN Document Server

    Chen, R; Pamplin, Brian

    1981-01-01

    Thermally stimulated processes include a number of phenomena - either physical or chemical in nature - in which a certain property of a substance is measured during controlled heating from a 'low' temperature. Workers and graduate students in a wide spectrum of fields require an introduction to methods of extracting information from such measurements. This book gives an interdisciplinary approach to various methods which may be applied to analytical chemistry including radiation dosimetry and determination of archaeological and geological ages. In addition, recent advances are included, such

  10. Natural gas technology

    International Nuclear Information System (INIS)

    Todaro, J.M.; Herbert, J.H.

    1997-01-01

    This presentation is devoted to a discussion regarding current and planned US fossil energy research and development for fiscal years 1996, 1997 and 1998. The principal focus of research in the immediate future will be: clean coal fuels, natural gas and oil exploration and production, especially reservoir life extension, advanced drilling completion and stimulation systems, advanced diagnostics and imaging systems, environmental compliance in technology development, regulatory streamlining and risk assessment. Program goals to 2010 were summarized as: increasing domestic oil and gas recovery; increasing recoverable reserves; decreasing cumulative industry environmental compliance costs; increasing revenues to the federal government; saving jobs in the U.S

  11. EOR by stimulated microflora

    Energy Technology Data Exchange (ETDEWEB)

    Svarovskaya, L.I.; Altunina, L.K.; Rozhenkova, Z.A.; Bulavin, V.D. [Institute of Petroleum Chemistry, Tomsk (Russian Federation)

    1995-12-31

    A combined microbiological and physico-chemical method for EOR has been developed for flooded West Siberia oil fields with formation temperature of 45{degrees}-95{degrees}C (318-365K). Formation water includes rich and various biocenoses numbering up to 2 x 10{sup 7} cells per ml. Representatives of genera, i.e, Pseudomonas, Bacillus, Actinomyces, Micrococcus, Mycobacterium, Sarcina, etc. were found to be the most widely distributed microorganisms. The method is based on injection of systems exhibiting high oil displacing capacity and at the same time being an additional nitrous nutrient for endemic populations of microorganisms. Their injection into formation water favors biomass growth by 4-6 orders and promotes syntheses of biosurfactants, biopolymers, acids, etc., and gaseous products. The features of residual oil displacement have been studied on laboratory models using a combined microbiological and physico-chemical method. A curve for the yield of residual oil is presented by two peaks. The first peak is stipulated by the washing action of oil displacement system, and the second one by the effect of metabolites produced at stimulation of biogenic processes. Oil displacement index increases by 15%-30%.

  12. Subliminal Stimulation: Hoax or Reality?

    Science.gov (United States)

    Trank, Douglas M.

    Subliminal stimulation is defined as that which is perceived by an individual below the threshold of awareness or cognizance. This article traces the history of research in subliminal stimulation to illustrate that under certain circumstances and conditions, this behavioral phenomenon does occur. Although subliminal stimuli do affect human…

  13. Stimulating Language: Insights from TMS

    Science.gov (United States)

    Devlin, Joseph T.; Watkins, Kate E.

    2007-01-01

    Fifteen years ago, Pascual-Leone and colleagues used transcranial magnetic stimulation (TMS) to investigate speech production in pre-surgical epilepsy patients and in doing so, introduced a novel tool into language research. TMS can be used to non-invasively stimulate a specific cortical region and transiently disrupt information processing. These…

  14. Electrical Stimulation of Coleopteran Muscle for Initiating Flight.

    Directory of Open Access Journals (Sweden)

    Hao Yu Choo

    Full Text Available Some researchers have long been interested in reconstructing natural insects into steerable robots or vehicles. However, until recently, these so-called cyborg insects, biobots, or living machines existed only in science fiction. Owing to recent advances in nano/micro manufacturing, data processing, and anatomical and physiological biology, we can now stimulate living insects to induce user-desired motor actions and behaviors. To improve the practicality and applicability of airborne cyborg insects, a reliable and controllable flight initiation protocol is required. This study demonstrates an electrical stimulation protocol that initiates flight in a beetle (Mecynorrhina torquata, Coleoptera. A reliable stimulation protocol was determined by analyzing a pair of dorsal longitudinal muscles (DLMs, flight muscles that oscillate the wings. DLM stimulation has achieved with a high success rate (> 90%, rapid response time (< 1.0 s, and small variation (< 0.33 s; indicating little habituation. Notably, the stimulation of DLMs caused no crucial damage to the free flight ability. In contrast, stimulation of optic lobes, which was earlier demonstrated as a successful flight initiation protocol, destabilized the beetle in flight. Thus, DLM stimulation is a promising secure protocol for inducing flight in cyborg insects or biobots.

  15. Electrical stimulation of the dorsolateral prefrontal cortex improves memory monitoring.

    Science.gov (United States)

    Chua, Elizabeth F; Ahmed, Rifat

    2016-05-01

    The ability to accurately monitor one's own memory is an important feature of normal memory function. Converging evidence from neuroimaging and lesion studies have implicated the dorsolateral prefrontal cortex (DLPFC) in memory monitoring. Here we used high definition transcranial direct stimulation (HD-tDCS), a non-invasive form of brain stimulation, to test whether the DLPFC has a causal role in memory monitoring, and the nature of that role. We used a metamemory monitoring task, in which participants first attempted to recall the answer to a general knowledge question, then gave a feeling-of-knowing (FOK) judgment, followed by a forced choice recognition task. When participants received DLPFC stimulation, their feeling-of-knowing judgments were better predictors of memory performance, i.e., they had better memory monitoring accuracy, compared to stimulation of a control site, the anterior temporal lobe (ATL). Effects of DLPFC stimulation were specific to monitoring accuracy, as there was no significant increase in memory performance, and if anything, there was poorer memory performance with DLPFC stimulation. Thus we have demonstrated a causal role for the DLPFC in memory monitoring, and showed that electrically stimulating the left DLPFC led people to more accurately monitor and judge their own memory. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Electrical Stimulation of Coleopteran Muscle for Initiating Flight.

    Science.gov (United States)

    Choo, Hao Yu; Li, Yao; Cao, Feng; Sato, Hirotaka

    2016-01-01

    Some researchers have long been interested in reconstructing natural insects into steerable robots or vehicles. However, until recently, these so-called cyborg insects, biobots, or living machines existed only in science fiction. Owing to recent advances in nano/micro manufacturing, data processing, and anatomical and physiological biology, we can now stimulate living insects to induce user-desired motor actions and behaviors. To improve the practicality and applicability of airborne cyborg insects, a reliable and controllable flight initiation protocol is required. This study demonstrates an electrical stimulation protocol that initiates flight in a beetle (Mecynorrhina torquata, Coleoptera). A reliable stimulation protocol was determined by analyzing a pair of dorsal longitudinal muscles (DLMs), flight muscles that oscillate the wings. DLM stimulation has achieved with a high success rate (> 90%), rapid response time (cyborg insects or biobots.

  17. Evaluation of focused multipolar stimulation for cochlear implants: a preclinical safety study

    Science.gov (United States)

    Shepherd, Robert K.; Wise, Andrew K.; Enke, Ya Lang; Carter, Paul M.; Fallon, James B.

    2017-08-01

    Objective. Cochlear implants (CIs) have a limited number of independent stimulation channels due to the highly conductive nature of the fluid-filled cochlea. Attempts to develop highly focused stimulation to improve speech perception in CI users includes the use of simultaneous stimulation via multiple current sources. Focused multipolar (FMP) stimulation is an example of this approach and has been shown to reduce interaction between stimulating channels. However, compared with conventional biphasic current pulses generated from a single current source, FMP is a complex stimulus that includes extended periods of stimulation before charge recovery is achieved, raising questions on whether chronic stimulation with this strategy is safe. The present study evaluated the long-term safety of intracochlear stimulation using FMP in a preclinical animal model of profound deafness. Approach. Six cats were bilaterally implanted with scala tympani electrode arrays two months after deafening, and received continuous unilateral FMP stimulation at levels that evoked a behavioural response for periods of up to 182 d. Electrode impedance, electrically-evoked compound action potentials (ECAPs) and auditory brainstem responses (EABRs) were monitored periodically over the course of the stimulation program from both the stimulated and contralateral control cochleae. On completion of the stimulation program cochleae were examined histologically and the electrode arrays were evaluated for evidence of platinum (Pt) corrosion. Main results. There was no significant difference in electrode impedance between control and chronically stimulated electrodes following long-term FMP stimulation. Moreover, there was no significant difference between ECAP and EABR thresholds evoked from control or stimulated cochleae at either the onset of stimulation or at completion of the stimulation program. Chronic FMP stimulation had no effect on spiral ganglion neuron (SGN) survival when compared with

  18. Bubble nonlinear dynamics and stimulated scattering process

    Science.gov (United States)

    Jie, Shi; De-Sen, Yang; Sheng-Guo, Shi; Bo, Hu; Hao-Yang, Zhang; Shi-Yong, Hu

    2016-02-01

    A complete understanding of the bubble dynamics is deemed necessary in order to achieve their full potential applications in industry and medicine. For this purpose it is first needed to expand our knowledge of a single bubble behavior under different possible conditions including the frequency and pressure variations of the sound field. In addition, stimulated scattering of sound on a bubble is a special effect in sound field, and its characteristics are associated with bubble oscillation mode. A bubble in liquid can be considered as a representative example of nonlinear dynamical system theory with its resonance, and its dynamics characteristics can be described by the Keller-Miksis equation. The nonlinear dynamics of an acoustically excited gas bubble in water is investigated by using theoretical and numerical analysis methods. Our results show its strongly nonlinear behavior with respect to the pressure amplitude and excitation frequency as the control parameters, and give an intuitive insight into stimulated sound scattering on a bubble. It is seen that the stimulated sound scattering is different from common dynamical behaviors, such as bifurcation and chaos, which is the result of the nonlinear resonance of a bubble under the excitation of a high amplitude acoustic sound wave essentially. The numerical analysis results show that the threshold of stimulated sound scattering is smaller than those of bifurcation and chaos in the common condition. Project supported by the Program for Changjiang Scholars and Innovative Research Team in University, China (Grant No. IRT1228) and the Young Scientists Fund of the National Natural Science Foundation of China (Grant Nos. 11204050 and 11204049).

  19. PLURALIZING NATURE

    DEFF Research Database (Denmark)

    Clemmensen, Thomas Juel

    2014-01-01

    Denmark is widely recognised for its democratic approach to planning and the idea of planning for the common good. This interest in the common good and common values seems also to be reflected in the way which nature restoration is planned and managed – one common nature directed by the public...... authorities. But nature restoration is far from being a neural undertaking. Just like any other type of heritage production it can be the source of dissonance – ‘our’ nature is not necessary ‘their’ nature. Often this dissonance is managed in ways, which are not particular sensitive to site......-specificity. As exemplified by the Skjern River Restoration Project (1999-2003), one interpretation of the landscape sometimes suppresses other valid interpretations neglecting its diverse history. However, evidence from Switzerland suggests that planning for the common good, in the case of nature restoration, does...

  20. Vagal nerve stimulation therapy: what is being stimulated?

    Science.gov (United States)

    Kember, Guy; Ardell, Jeffrey L; Armour, John A; Zamir, Mair

    2014-01-01

    Vagal nerve stimulation in cardiac therapy involves delivering electrical current to the vagal sympathetic complex in patients experiencing heart failure. The therapy has shown promise but the mechanisms by which any benefit accrues is not understood. In this paper we model the response to increased levels of stimulation of individual components of the vagal sympathetic complex as a differential activation of each component in the control of heart rate. The model provides insight beyond what is available in the animal experiment in as much as allowing the simultaneous assessment of neuronal activity throughout the cardiac neural axis. The results indicate that there is sensitivity of the neural network to low level subthreshold stimulation. This leads us to propose that the chronic effects of vagal nerve stimulation therapy lie within the indirect pathways that target intrinsic cardiac local circuit neurons because they have the capacity for plasticity.

  1. Vagal nerve stimulation therapy: what is being stimulated?

    Directory of Open Access Journals (Sweden)

    Guy Kember

    Full Text Available Vagal nerve stimulation in cardiac therapy involves delivering electrical current to the vagal sympathetic complex in patients experiencing heart failure. The therapy has shown promise but the mechanisms by which any benefit accrues is not understood. In this paper we model the response to increased levels of stimulation of individual components of the vagal sympathetic complex as a differential activation of each component in the control of heart rate. The model provides insight beyond what is available in the animal experiment in as much as allowing the simultaneous assessment of neuronal activity throughout the cardiac neural axis. The results indicate that there is sensitivity of the neural network to low level subthreshold stimulation. This leads us to propose that the chronic effects of vagal nerve stimulation therapy lie within the indirect pathways that target intrinsic cardiac local circuit neurons because they have the capacity for plasticity.

  2. Natural Philosophy

    OpenAIRE

    Blair, Ann M.

    2006-01-01

    Natural philosophy” is often used by European historians as an umbrella term to designate the study of nature before it can easily be identified with what we call “science” today, to avoid the modern and potentially anachronistic connotations of that term. But “natural philosophy” (and its equivalents in different languages) was also an actor's category, a term commonly used throughout the early modern period and typically defined quite broadly as the study of natural bodies. As the central ...

  3. Dissonant Nature

    DEFF Research Database (Denmark)

    Clemmensen, Thomas Juel

    2013-01-01

    Nature restoration is far from being a neural undertaking. Just like any other type of heritage production it can be the source of dissonance – ‘our’ nature is not necessary ‘their’ nature. Often this dissonance is managed in ways, which are not particular sensitive to site-specificity. As exempl...... and allows for multiple interpretations to coexist. Evidence can be found in the Re-naturalization of River Aire (2002-2015), a restoration project, which reveals approaches that could be labelled landscape architecture specific....

  4. Temporal naturalism

    Science.gov (United States)

    Smolin, Lee

    2015-11-01

    Two people may claim both to be naturalists, but have divergent conceptions of basic elements of the natural world which lead them to mean different things when they talk about laws of nature, or states, or the role of mathematics in physics. These disagreements do not much affect the ordinary practice of science which is about small subsystems of the universe, described or explained against a background, idealized to be fixed. But these issues become crucial when we consider including the whole universe within our system, for then there is no fixed background to reference observables to. I argue here that the key issue responsible for divergent versions of naturalism and divergent approaches to cosmology is the conception of time. One version, which I call temporal naturalism, holds that time, in the sense of the succession of present moments, is real, and that laws of nature evolve in that time. This is contrasted with timeless naturalism, which holds that laws are immutable and the present moment and its passage are illusions. I argue that temporal naturalism is empirically more adequate than the alternatives, because it offers testable explanations for puzzles its rivals cannot address, and is likely a better basis for solving major puzzles that presently face cosmology and physics. This essay also addresses the problem of qualia and experience within naturalism and argues that only temporal naturalism can make a place for qualia as intrinsic qualities of matter.

  5. Electrical stimulation in exercise training

    Science.gov (United States)

    Kroll, Walter

    1994-01-01

    Electrical stimulation has a long history of use in medicine dating back to 46 A.D. when the Roman physician Largus found the electrical discharge of torpedo fishes useful in the treatment of pain produced by headache and gout. A rival Greek physician, Dioscorides, discounted the value of the torpedo fish for headache relief but did recommend its use in the treatment of hemorrhoids. In 1745, the Leyden jar and various sized electrostatic generators were used to treat angina pectoris, epilepsy, hemiplegia, kidney stones, and sciatica. Benjamin Franklin used an electrical device to treat successfully a young woman suffering from convulsive fits. In the late 1800's battery powered hydroelectric baths were used to treat chronic inflammation of the uterus while electrified athletic supporters were advertised for the treatment of male problems. Fortunately, such an amusing early history of the simple beginnings of electrical stimulation did not prevent eventual development of a variety of useful therapeutic and rehabilitative applications of electrical stimulation. Over the centuries electrical stimulation has survived as a modality in the treatment of various medical disorders with its primary application being in the rehabilitation area. Recently, a surge of new interest in electrical stimulation has been kindled by the work of a Russian sport scientist who reported remarkable muscle strength and endurance improvements in elite athletes. Yakov Kots reported his research on electric stimulation and strength improvements in 1977 at a Canadian-Soviet Exchange Symposium held at Concordia University in Montreal. Since then an explosion of new studies has been seen in both sport science and in medicine. Based upon the reported works of Kots and the present surge of new investigations, one could be misled as to the origin of electrical stimulation as a technique to increase muscle strength. As a matter of fact, electric stimulation has been used as a technique to improve

  6. COMMUNICATION Designing a somatosensory neural prosthesis: percepts evoked by different patterns of thalamic stimulation

    Science.gov (United States)

    Heming, Ethan; Sanden, Andrew; Kiss, Zelma H. T.

    2010-12-01

    Although major advances have been made in the development of motor prostheses, fine motor control requires intuitive somatosensory feedback. Here we explored whether a thalamic site for a somatosensory neural prosthetic could provide natural somatic sensation to humans. Different patterns of electrical stimulation (obtained from thalamic spike trains) were applied in patients undergoing deep brain stimulation surgery. Changes in pattern produced different sensations, while preserving somatotopic representation. While most percepts were reported as 'unnatural', some stimulations produced more 'natural' sensations than others. However, the additional patterns did not elicit more 'natural' percepts than high-frequency (333 Hz) electrical stimulation. These features suggest that despite some limitations, the thalamus may be a feasible site for a somatosensory neural prosthesis and different stimulation patterns may be useful in its development.

  7. Stimulating endogenous cardiac regeneration

    Directory of Open Access Journals (Sweden)

    Amanda eFinan

    2015-09-01

    Full Text Available The healthy adult heart has a low turnover of cardiac myocytes. The renewal capacity, however, is augmented after cardiac injury. Participants in cardiac regeneration include cardiac myocytes themselves, cardiac progenitor cells, and peripheral stem cells, particularly from the bone marrow compartment. Cardiac progenitor cells and bone marrow stem cells are augmented after cardiac injury, migrate to the myocardium, and support regeneration. Depletion studies of these populations have demonstrated their necessary role in cardiac repair. However, the potential of these cells to completely regenerate the heart is limited. Efforts are now being focused on ways to augment these natural pathways to improve cardiac healing, primarily after ischemic injury but in other cardiac pathologies as well. Cell and gene therapy or pharmacological interventions are proposed mechanisms. Cell therapy has demonstrated modest results and has passed into clinical trials. However, the beneficial effects of cell therapy have primarily been their ability to produce paracrine effects on the cardiac tissue and recruit endogenous stem cell populations as opposed to direct cardiac regeneration. Gene therapy efforts have focused on prolonging or reactivating natural signaling pathways. Positive results have been demonstrated to activate the endogenous stem cell populations and are currently being tested in clinical trials. A potential new avenue may be to refine pharmacological treatments that are currently in place in the clinic. Evidence is mounting that drugs such as statins or beta blockers may alter endogenous stem cell activity. Understanding the effects of these drugs on stem cell repair while keeping in mind their primary function may strike a balance in myocardial healing. To maximize endogenous cardiac regeneration,a combination of these approaches couldameliorate the overall repair process to incorporate the participation ofmultiple cell players.

  8. Matematica Natural.

    Science.gov (United States)

    Lozano, Patricia; Medearis, Linda

    Matematica Natural (Natural Mathematics) is a mathematics curriculum for young children based on the assumption that they learn mathematics through concrete, real life, relevant experiences and that educational differences rather than cultural differences influence math achievement. The curriculum uses hands-on materials and activities to teach…

  9. Natural radiation

    International Nuclear Information System (INIS)

    Feliciano, Vanusa Maria Delage

    2016-01-01

    Cosmic radiation, as well as cosmogenic radiation, terrestrial radiation, radon and thorium are introduced in this chapter 3. The distribution of natural radiation sources is treated, where the percentage distribution of the contribution relative to exposure to radiation from natural and artificial sources is also included

  10. Framing nature

    NARCIS (Netherlands)

    Jansen, Peter

    2017-01-01

    This PhD thesis is about communication concerning nature in the Netherlands. The purpose of this exploratory study is to take both a theoretical and an empirical look at whether (implicit) religious elements play a role in this communication about nature in the Netherlands.

    In this PhD

  11. Natur formet

    DEFF Research Database (Denmark)

    Søberg, Martin

    2011-01-01

    Anmeldelse af Malene Hauxner, "Fra naturlig natur til SUPERNATUR – Europæisk landskabsarkitektur 1967-2007 set fra Danmark", Risskov: Ikaros Press, 2011.......Anmeldelse af Malene Hauxner, "Fra naturlig natur til SUPERNATUR – Europæisk landskabsarkitektur 1967-2007 set fra Danmark", Risskov: Ikaros Press, 2011....

  12. Multielectrode intrafascicular and extraneural stimulation

    NARCIS (Netherlands)

    Veltink, Petrus H.; van Alste, Jan A.; Boom, H.B.K.

    1989-01-01

    The relationship between nerve stimulation, pulse amplitude and isometric muscle force was measured to investigate recruitment of motor units. Force addition experiments were performed to obtain insight in the intersection of motor unit groups recruited by different electrodes. Intrafascicular and

  13. Noninvasive Stimulation of the Human Brain

    DEFF Research Database (Denmark)

    Di Lazzaro, Vincenzo; Rothwell, John; Capogna, Marco

    2017-01-01

    Noninvasive brain stimulation methods, such as transcranial electric stimulation and transcranial magnetic stimulation are widely used tools for both basic research and clinical applications. However, the cortical circuits underlying their effects are poorly defined. Here we review the current...

  14. Economics of nuclear gas stimulation

    Energy Technology Data Exchange (ETDEWEB)

    Frank, G W [Austral Oil Company Incorporated, Houston, TX (United States); Coffer, H F; Luetkehans, G R [CER Geonuclear Corporation, Las Vegas, NV (United States)

    1970-05-01

    Nuclear stimulation of the Mesaverde Formation in the Piceance Basin appears to be the only available method that can release the contained gas economically. In the Rulison Field alone estimates show six to eight trillion cubic feet of gas may be made available by nuclear means, and possibly one hundred trillion cubic feet could be released in the Piceance Basin. Several problems remain to be solved before this tremendous gas reserve can be tapped. Among these are (1) rates of production following nuclear stimulation; (2) costs of nuclear stimulation; (3) radioactivity of the chimney gas; and (4) development of the ideal type of device to carry out the stimulations. Each of these problems is discussed in detail with possible solutions suggested. First and foremost is the rate at which gas can be delivered following nuclear stimulation. Calculations have been made for expected production behavior following a 5-kiloton device and a 40-kiloton device with different permeabilities. These are shown, along with conventional production history. The calculations show that rates of production will be sufficient if costs can be controlled. Costs of nuclear stimulation must be drastically reduced for a commercial process. Project Rulison will cost approximately $3.7 million, excluding lease costs, preliminary tests, and well costs. At such prices, nothing can possibly be commercial; however, these costs can come down in a logical step-wise fashion. Radiation contamination of the gas remains a problem. Three possible solutions to this problem are included. (author)

  15. Economics of nuclear gas stimulation

    International Nuclear Information System (INIS)

    Frank, G.W.; Coffer, H.F.; Luetkehans, G.R.

    1970-01-01

    Nuclear stimulation of the Mesaverde Formation in the Piceance Basin appears to be the only available method that can release the contained gas economically. In the Rulison Field alone estimates show six to eight trillion cubic feet of gas may be made available by nuclear means, and possibly one hundred trillion cubic feet could be released in the Piceance Basin. Several problems remain to be solved before this tremendous gas reserve can be tapped. Among these are (1) rates of production following nuclear stimulation; (2) costs of nuclear stimulation; (3) radioactivity of the chimney gas; and (4) development of the ideal type of device to carry out the stimulations. Each of these problems is discussed in detail with possible solutions suggested. First and foremost is the rate at which gas can be delivered following nuclear stimulation. Calculations have been made for expected production behavior following a 5-kiloton device and a 40-kiloton device with different permeabilities. These are shown, along with conventional production history. The calculations show that rates of production will be sufficient if costs can be controlled. Costs of nuclear stimulation must be drastically reduced for a commercial process. Project Rulison will cost approximately $3.7 million, excluding lease costs, preliminary tests, and well costs. At such prices, nothing can possibly be commercial; however, these costs can come down in a logical step-wise fashion. Radiation contamination of the gas remains a problem. Three possible solutions to this problem are included. (author)

  16. Biomarkers and Stimulation Algorithms for Adaptive Brain Stimulation

    Directory of Open Access Journals (Sweden)

    Kimberly B. Hoang

    2017-10-01

    Full Text Available The goal of this review is to describe in what ways feedback or adaptive stimulation may be delivered and adjusted based on relevant biomarkers. Specific treatment mechanisms underlying therapeutic brain stimulation remain unclear, in spite of the demonstrated efficacy in a number of nervous system diseases. Brain stimulation appears to exert widespread influence over specific neural networks that are relevant to specific disease entities. In awake patients, activation or suppression of these neural networks can be assessed by either symptom alleviation (i.e., tremor, rigidity, seizures or physiological criteria, which may be predictive of expected symptomatic treatment. Secondary verification of network activation through specific biomarkers that are linked to symptomatic disease improvement may be useful for several reasons. For example, these biomarkers could aid optimal intraoperative localization, possibly improve efficacy or efficiency (i.e., reduced power needs, and provide long-term adaptive automatic adjustment of stimulation parameters. Possible biomarkers for use in portable or implanted devices span from ongoing physiological brain activity, evoked local field potentials (LFPs, and intermittent pathological activity, to wearable devices, biochemical, blood flow, optical, or magnetic resonance imaging (MRI changes, temperature changes, or optogenetic signals. First, however, potential biomarkers must be correlated directly with symptom or disease treatment and network activation. Although numerous biomarkers are under consideration for a variety of stimulation indications the feasibility of these approaches has yet to be fully determined. Particularly, there are critical questions whether the use of adaptive systems can improve efficacy over continuous stimulation, facilitate adjustment of stimulation interventions and improve our understanding of the role of abnormal network function in disease mechanisms.

  17. Natural radiation; A radiacao natural

    Energy Technology Data Exchange (ETDEWEB)

    Feliciano, Vanusa Maria Delage

    2016-07-01

    Cosmic radiation, as well as cosmogenic radiation, terrestrial radiation, radon and thorium are introduced in this chapter 3. The distribution of natural radiation sources is treated, where the percentage distribution of the contribution relative to exposure to radiation from natural and artificial sources is also included.

  18. Improved discrimination of visual stimuli following repetitive transcranial magnetic stimulation.

    Directory of Open Access Journals (Sweden)

    Michael L Waterston

    Full Text Available BACKGROUND: Repetitive transcranial magnetic stimulation (rTMS at certain frequencies increases thresholds for motor-evoked potentials and phosphenes following stimulation of cortex. Consequently rTMS is often assumed to introduce a "virtual lesion" in stimulated brain regions, with correspondingly diminished behavioral performance. METHODOLOGY/PRINCIPAL FINDINGS: Here we investigated the effects of rTMS to visual cortex on subjects' ability to perform visual psychophysical tasks. Contrary to expectations of a visual deficit, we find that rTMS often improves the discrimination of visual features. For coarse orientation tasks, discrimination of a static stimulus improved consistently following theta-burst stimulation of the occipital lobe. Using a reaction-time task, we found that these improvements occurred throughout the visual field and lasted beyond one hour post-rTMS. Low-frequency (1 Hz stimulation yielded similar improvements. In contrast, we did not find consistent effects of rTMS on performance in a fine orientation discrimination task. CONCLUSIONS/SIGNIFICANCE: Overall our results suggest that rTMS generally improves or has no effect on visual acuity, with the nature of the effect depending on the type of stimulation and the task. We interpret our results in the context of an ideal-observer model of visual perception.

  19. Natural Communities

    Data.gov (United States)

    Kansas Data Access and Support Center — This dataset shows the locations of known tracts of high quality natural communities in Kansas, generalized to the PLSS section. It is not a compehensive dataset of...

  20. Sciences & Nature

    African Journals Online (AJOL)

    AFRICAN JOURNALS ONLINE (AJOL) · Journals · Advanced Search · USING AJOL ... Sciences & Nature, the Scientific Journal edited by the University of ... Subjects covered include agronomy, sciences of the earth, environment, biological, ...

  1. Pluralising Nature

    DEFF Research Database (Denmark)

    Clemmensen, Thomas Juel

    2017-01-01

    suppress other valid perceptions, in conflict with the need for different groups of people to be able to identify with the same territory. However, planning for the common good, in the case of nature restoration, does not necessarily mean planning for one common nature. Understanding and working......Denmark is recognised for its democratic approach to planning, and for the idea of planning for the common good. This interest in the common good and in common values also seems to be reflected in the way that the restoration of nature is planned and managed, suggesting that there is one common...... “nature” that everyone can agree on. But nature restoration is far from being an unproblematic undertaking. As with any other type of heritage production, it can be the source of dissonance. As exemplified by the Skjern River Restoration Project, one perception of a landscape and its value as “nature” can...

  2. Writing Nature

    Directory of Open Access Journals (Sweden)

    Kristin Asdal

    2014-06-01

    Full Text Available This special issue of the Nordic Journal of Science and Technology Studies is interested in how nature, in different versions and forms, is invited into our studies, analyses, and stories. How is it that we “write nature”? How is it that we provide space for, and actually describe the actors, agents, or surroundings, in our stories and analyses? The articles in the issue each deal with different understandings of both the practices of writing and the introduction of various natures into these. In this introduction to the issue the editors engage with actor-network theory as a material semiotic resource for writing nature. We propose to foreground actor-network theory as a writing tool, at the expense of actor-network theory as a distinct vocabulary. In doing this and pointing out the semiotic origins to material-semiotics we also want to problematize a clear-cut material approach to writing nature.

  3. Electrical stimulation and motor recovery.

    Science.gov (United States)

    Young, Wise

    2015-01-01

    In recent years, several investigators have successfully regenerated axons in animal spinal cords without locomotor recovery. One explanation is that the animals were not trained to use the regenerated connections. Intensive locomotor training improves walking recovery after spinal cord injury (SCI) in people, and >90% of people with incomplete SCI recover walking with training. Although the optimal timing, duration, intensity, and type of locomotor training are still controversial, many investigators have reported beneficial effects of training on locomotor function. The mechanisms by which training improves recovery are not clear, but an attractive theory is available. In 1949, Donald Hebb proposed a famous rule that has been paraphrased as "neurons that fire together, wire together." This rule provided a theoretical basis for a widely accepted theory that homosynaptic and heterosynaptic activity facilitate synaptic formation and consolidation. In addition, the lumbar spinal cord has a locomotor center, called the central pattern generator (CPG), which can be activated nonspecifically with electrical stimulation or neurotransmitters to produce walking. The CPG is an obvious target to reconnect after SCI. Stimulating motor cortex, spinal cord, or peripheral nerves can modulate lumbar spinal cord excitability. Motor cortex stimulation causes long-term changes in spinal reflexes and synapses, increases sprouting of the corticospinal tract, and restores skilled forelimb function in rats. Long used to treat chronic pain, motor cortex stimuli modify lumbar spinal network excitability and improve lower extremity motor scores in humans. Similarly, epidural spinal cord stimulation has long been used to treat pain and spasticity. Subthreshold epidural stimulation reduces the threshold for locomotor activity. In 2011, Harkema et al. reported lumbosacral epidural stimulation restores motor control in chronic motor complete patients. Peripheral nerve or functional electrical

  4. Natural aphrodisiacs.

    Science.gov (United States)

    Shamloul, Rany

    2010-01-01

    The search for a remedy or a prescription that can enhance sexual function and/or treat male erectile dysfunction has been an obsession throughout known history. Whether it was an Eastern civilization or a Western one, religious or atheist, man's aspiration for a better or best "manhood" has been a history-time goal. This review will discuss the current research done on the most popular natural aphrodisiacs and examine the weight of evidence to support or discourage the use of any of these substances to enhance sexual desire and/or function. Review of the current evidence on the use of natural substances as aphrodisiacs. Efficacy of natural aphrodisiacs in enhancing sexual function in men and women. There is little evidence from literature to recommend the usage of natural aphrodisiacs for the enhancement of sexual desire and/or performance. Data on yohimbine's efficacy does not support the wide use of the drug, which has only mild effects in the treatment of psychogenic ED. Although there's a positive trend towards recommending ginseng as an effective aphrodisiac, however, more in depth studies involving large number of subjects and its mechanism of action are needed before definite conclusions could be reached. Data on the use of natural aphrodisiacs in women is limited. The current body of objective evidence does not support the use of any natural aphrodisiac as an effective treatment for male or female sexual dysfunctions. Potent men and men with ED will continue the search for natural aphrodisiacs despite the current disappointing data on their effectiveness. Care should be taken regarding the fraud addition of sildenafil analogues to natural aphrodisiacs.

  5. Visualization of recognition on the biological effects of low-dose radiation through a survey of the scientists. Taking an accident at Fukushima Daiichi Nuclear Power Plant as an example

    International Nuclear Information System (INIS)

    Takayasu, Kenta; Onoue, Yousuke; Koyamada, Kouji; Konami, Hideo; Manabe, Yuichirou; Bando, Masako

    2017-01-01

    Since Fukushima Daiichi Nuclear Accident caused by the Great East Japan Earthquake, radiation exposure problem has been discussed among government agencies, medical personnels, scientists, and so on. At that time, people were confused by pendulumlike instructions of the Japanese government and scientists. It is said that there are multiple academic fields which related to radiation exposure problem and they need to be interdisciplinary. We think that the confusion is due to lack of mutual understanding among various academic fields and insufficiency of interdisciplinary communication. In this work, we investigated the current situation of interdisciplinary communication among these fields through the radiation exposure problem by our questionnaire survey and researched what problem is attributed to. From the result, character of each academic field and their communality are clarified. We believe this result leads us to propose the true way of interdisciplinary research and communication of different academic fields. (author)

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

    Science.gov (United States)

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

    2017-02-01

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

  7. Biologically based analysis of lung cancer incidence in a large Canadian occupational cohort with low-LET low-dose radiation exposure, and comparison with Japanese atomic bomb survivors

    International Nuclear Information System (INIS)

    Hazelton, W.D.; Curtis, S.B.; Moolgavkar, S.H.; Hutchinson, F.; Krewski, D.

    2003-01-01

    Lung cancer incidence is analyzed in a large Canadian National Dose Registry (CNDR) cohort with individual annual dosimetry for low-dose occupational exposure to gamma and tritium radiation using several types of multistage models. The primary analysis utilizes the two-stage clonal expansion model (TSCE), with sensitivity analyses using extensions of this model incorporating additional stages. Characteristic and distinct temporal patterns of risk are found for dose-response affecting early, middle, or late stages of carcinogenesis, e.g. initiation with one or more stages, clonal expansion, or malignant conversion. Fixed lag or lag distributions are used to model time from first malignant cell to incidence. Background rates are analyzed by gender, job classification and birth cohort. Lacking individual smoking data, surrogate doses based on US annual per capita cigarette consumption appear to account for much of the birth cohort effect. Males, with mean cumulative exposure for gamma and tritium of 11.5 mSv and 322 incident lung cancer cases have a significant dose-response with 33 cases attributable to radiation. Female dose-response, with mean cumulative exposure of 1.7 mSv and 78 incident cases, appears similar but is not statistically significant. Findings for males include an inverse-dose-rate effect (increased risk with protraction of a given dose) and dose-response effects on initiation, promotion and malignant conversion, although the effect on initiation is not statistically significant. The excess relative risk (ERR) and excess absolute risk (EAR) depend on age at exposure, duration, dose, and age at follow-up. The ERR increases with dose, tapering off at higher doses, making a plot of ERR against dose concave-downward, similar to apparent low-dose results seen below 1 Sv for solid tumor mortality of atomic bomb survivors. The concave-downward trend of ERR and the inverse-dose-rate effect are both counter to prevailing beliefs about effects of low-LET ionizing radiation. The dose-response estimated from the Canadian data is consistent with the dose-response seen in the A-bomb survivors' data when account is taken of the virtually instantaneous exposure in the latter cohort

  8. Hippocampal volumes in patients exposed to low-dose radiation to the basal brain. A case–control study in long-term survivors from cancer in the head and neck region

    International Nuclear Information System (INIS)

    Olsson, Erik; Löfdahl, Elisabet; Malmgren, Helge; Eckerström, Carl; Berg, Gertrud; Borga, Magnus; Ekholm, Sven; Johannsson, Gudmundur; Ribbelin, Susanne; Starck, Göran; Wysocka, Anna

    2012-01-01

    An earlier study from our group of long time survivors of head and neck cancer who had received a low radiation dose to the hypothalamic-pituitary region, with no signs of recurrence or pituitary dysfunction, had their quality of life (QoL) compromised as compared with matched healthy controls. Hippocampal changes have been shown to accompany several psychiatric conditions and the aim of the present study was to test whether the patients’ lowered QoL was coupled to a reduction in hippocampal volume. Patients (11 men and 4 women, age 31–65) treated for head and neck cancer 4–10 years earlier and with no sign of recurrence or pituitary dysfunction, and 15 matched controls were included. The estimated radiation doses to the basal brain including the hippocampus (1.5 – 9.3 Gy) had been calculated in the earlier study. The hippocampal volumetry was done on coronal sections from a 1.5 T MRI scanner. Measurements were done by two independent raters, blinded to patients and controls, using a custom method for computer assisted manual segmentation. The volumes were normalized for intracranial volume which was also measured manually. The paired t test and Wilcoxon’s signed rank test were used for the main statistical analysis. There was no significant difference with respect to left, right or total hippocampal volume between patients and controls. All mean differences were close to zero, and the two-tailed 95% confidence interval for the difference in total, normalized volume does not include a larger than 8% deficit in the patients. The study gives solid evidence against the hypothesis that the patients’ lowered quality of life was due to a major reduction of hippocampal volume

  9. Evoked Electromyographically Controlled Electrical Stimulation

    Directory of Open Access Journals (Sweden)

    Mitsuhiro Hayashibe

    2016-07-01

    Full Text Available Time-variant muscle responses under electrical stimulation (ES are often problematic for all the applications of neuroprosthetic muscle control. This situation limits the range of ES usage in relevant areas, mainly due to muscle fatigue and also to changes in stimulation electrode contact conditions, especially in transcutaneous ES. Surface electrodes are still the most widely used in noninvasive applications.Electrical field variations caused by changes in the stimulation contact condition markedly affect the resulting total muscle activation levels. Fatigue phenomena under functional electrical stimulation (FES are also well known source of time-varying characteristics coming from muscle response under ES. Therefore it is essential to monitor the actual muscle state and assess the expected muscle response by ES so as to improve the current ES system in favour of adaptive muscle-response-aware FES control. To deal with this issue, we have been studying a novel control technique using evoked electromyography (eEMG signals to compensate for these muscle time-variances under ES for stable neuroprosthetic muscle control. In this perspective article, I overview the background of this topic and highlight important points to be aware of when using ES to induce the desired muscle activation regardless of the time-variance. I also demonstrate how to deal with the common critical problem of ES to move toward robust neuroprosthetic muscle control with the Evoked Electromyographically Controlled Electrical Stimulation paradigm.

  10. Electrical stimulation superimposed onto voluntary muscular contraction.

    Science.gov (United States)

    Paillard, Thierry; Noé, Frédéric; Passelergue, Philippe; Dupui, Philippe

    2005-01-01

    Electrical stimulation (ES) reverses the order of recruitment of motor units (MU) observed with voluntary muscular contraction (VOL) since under ES, large MU are recruited before small MU. The superimposition of ES onto VOL (superimposed technique: application of an electrical stimulus during a voluntary muscle action) can theoretically activate more motor units than VOL performed alone, which can engender an increase of the contraction force. Two superimposed techniques can be used: (i) the twitch interpolation technique (ITT), which consists of interjecting an electrical stimulus onto the muscle nerve; and (ii) the percutaneous superimposed electrical stimulation technique (PST), where the stimulation is applied to the muscle belly. These two superimposed techniques can be used to evaluate the ability to fully activate a muscle. They can thus be employed to distinguish the central or peripheral nature of fatigue after exhausting exercise. In general, whatever the technique employed, the superimposition of ES onto volitional exercise does not recruit more MU than VOL, except with eccentric actions. Nevertheless, the neuromuscular response associated with the use of the superimposed technique (ITT and PST) depends on the parameter of the superimposed current. The sex and the training level of the subjects can also modify the physiological impact of the superimposed technique. Although the motor control differs drastically between training with ES and VOL, the integration of the superimposed technique in training programmes with healthy subjects does not reveal significant benefits compared with programmes performed only with voluntary exercises. Nevertheless, in a therapeutic context, training programmes using ES superimposition compensate volume and muscle strength deficit with more efficiency than programmes using VOL or ES separately.

  11. Emancipating Nature

    DEFF Research Database (Denmark)

    Munk, Anders Kristian

    2012-01-01

    The issue of riverine flooding in the UK is closely tied up with computer simulations. Arguably, these modelling practices are ripe with the anticipation of nature. They aspire to pre-empt it, hence expect it to be ‘out there’, and ultimately work through formalized distillations of it – hydrodyn......The issue of riverine flooding in the UK is closely tied up with computer simulations. Arguably, these modelling practices are ripe with the anticipation of nature. They aspire to pre-empt it, hence expect it to be ‘out there’, and ultimately work through formalized distillations...... of it – hydrodynamic equations – which have their own anticipations and place their own demands on their modellers. Through the experience of a flood modelling apprenticeship I argue that the taking-place of such anticipations paradoxically relies on the birth of a hybrid, the model-modeller, and thus on a nature...

  12. Surface electrical stimulation to evoke referred sensation.

    Science.gov (United States)

    Forst, Johanna C; Blok, Derek C; Slopsema, Julia P; Boss, John M; Heyboer, Lane A; Tobias, Carson M; Polasek, Katharine H

    2015-01-01

    Surface electrical stimulation (SES) is being investigated as a noninvasive method to evoke natural sensations distal to electrode location. This may improve treatment for phantom limb pain as well as provide an alternative method to deliver sensory feedback. The median and/or ulnar nerves of 35 subjects were stimulated at the elbow using surface electrodes. Strength-duration curves of hand sensation were found for each subject. All subjects experienced sensation in their hand, which was mostly described as a paresthesia-like sensation. The rheobase and chronaxie values were found to be lower for the median nerve than the ulnar nerve, with no significant difference between sexes. Repeated sessions with the same subject resulted in sufficient variability to suggest that recalculating the strength-duration curve for each electrode placement is necessary. Most of the recruitment curves in this study were generated with 28 to 36 data points. To quickly reproduce these curves with limited increase in error, we recommend 10 data points. Future studies will focus on obtaining different sensations using SES with the strength-duration curve defining the threshold of the effective parameter space.

  13. Natural aerodynamics

    CERN Document Server

    Scorer, R S

    1958-01-01

    Natural Aerodynamics focuses on the mathematics of any problem in air motion.This book discusses the general form of the law of fluid motion, relationship between pressure and wind, production of vortex filaments, and conduction of vorticity by viscosity. The flow at moderate Reynolds numbers, turbulence in a stably stratified fluid, natural exploitation of atmospheric thermals, and plumes in turbulent crosswinds are also elaborated. This text likewise considers the waves produced by thermals, transformation of thin layer clouds, method of small perturbations, and dangers of extra-polation.Thi

  14. Provincialising Nature

    DEFF Research Database (Denmark)

    Provincialising Nature: Multidisciplinary Approaches to the Politics of the Environment in Latin America offers a timely analysis of some of the crucial challenges, contradictions and promises within current environmental discourses and practices in the region. This book shows both challenging...... scenarios and original perspectives that have emerged in Latin America in relation to the globally urgent issues of climate change and the environmental crisis. Two interconnected analytical frameworks guide the discussions in the book: the relationship between nature, knowledge and identity and their role...

  15. Optically stimulated luminescence dosimetry with gypsum wallboard (drywall)

    International Nuclear Information System (INIS)

    Thompson, J. W.; Burdette, K. E.; Inrig, E. L.; Dewitt, R.; Mistry, R.; Rink, W. J.; Boreham, D. R.

    2010-01-01

    Gypsum wallboard (drywall) represents an attractive target for retrospective dosimetry by optically stimulated luminescence (OSL) in the event of a radiological accident or malicious use of nuclear material. In this study, wallboard is shown to display a radiation-induced luminescence signal (RIS) as well as a natural background signal (NS), which is comparable in intensity to the RIS. Excitation and emission spectra show that maximum luminescence intensity is obtained for stimulation with blue light-emitting diodes (470 nm) and for detection in the ultraviolet region (290-370 nm). It is necessary to decrease the optical stimulation power dramatically in order to adequately separate the RIS from the interfering background signal. The necessary protocols are developed for accurately measuring the absorbed dose as low as 500 mGy and demonstrate that the RIS decays logarithmically with storage time, with complete erasure expected within 1-4 d. (authors)

  16. Noninvasive Transcranial Brain Stimulation and Pain

    OpenAIRE

    Rosen, Allyson C.; Ramkumar, Mukund; Nguyen, Tam; Hoeft, Fumiko

    2009-01-01

    Transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) are two noninvasive brain stimulation techniques that can modulate activity in specific regions of the cortex. At this point, their use in brain stimulation is primarily investigational; however, there is clear evidence that these tools can reduce pain and modify neurophysiologic correlates of the pain experience. TMS has also been used to predict response to surgically implanted stimulation for the tre...

  17. Natural Attenuation of Hydrocarbon and Trichloroethylene Vapors in the Subsurface Environment at Plattsburgh Air Force Base

    National Research Council Canada - National Science Library

    Ostendorf, David

    1997-01-01

    .... UMASS tested the hypothesis that natural attenuation processes, stimulated by injected air, reduce emissions of hydrocarbons and trichloroethylene vapors to acceptable air quality standards at the site. Drs...

  18. Nature Watch

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 1; Issue 3. Nature Watch Diversity of Bats. G Marimuthu. Feature Article Volume 1 Issue 3 March 1996 pp 103-110. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/001/03/0103-0110. Author Affiliations.

  19. Nature's Palette

    Science.gov (United States)

    McBride, Brooke B.; Brewer, Carol A.

    2010-01-01

    Flower petals, acorn hats, exoskeletons of beetles, and lichens are just a few of the objects students may find in a surprising array of vivid colors. These tiny examples from nature's palette can be discovered in a school yard, a park, or even along the edges of a paved sidewalk...it simply takes careful observation! This article describes a…

  20. Nature Watch

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 9; Issue 9. Nature Watch - Coral Reefs and their Fauna: An Underwater Fantasyland. Anuradha Bhat. Feature Article Volume 9 Issue 9 September 2004 pp 62-73. Fulltext. Click here to view fulltext PDF. Permanent link:

  1. Nature Watch

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 20; Issue 3. Nature Watch: Symbiosis in Coastal Marine Communities. Neelam Pereira. Feature Article Volume 20 Issue 3 March 2015 pp 245-253. Fulltext. Click here to view fulltext PDF. Permanent link:

  2. Nature Watch

    Indian Academy of Sciences (India)

    ... Lecture Workshops · Refresher Courses · Symposia · Live Streaming. Home; Journals; Resonance – Journal of Science Education; Volume 3; Issue 5. Nature Watch - Thinking Like a Tahr: When Males and Females go their Separate Ways. M D Madhusudan. Feature Article Volume 3 Issue 5 May 1998 pp 43-47 ...

  3. Natural Propositions

    DEFF Research Database (Denmark)

    Stjernfelt, Frederik

    Preface -- Introduction -- The generality of signs -- Dicisigns -- Some consequences of the dicisign doctrine -- Dicisigns and cognition -- Natural propositions--the evolution of semiotic self-control -- Dicisigns beyond language -- Operational and optimal iconicity in Peirce's diagrammatology...... -- Cows, red cows, and red herrings -- Corollarial and theorematic experiments with diagrams -- Strategies of research: Peirce's enlightenment maxims -- Perspective -- References -- Index....

  4. Nature Watch

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 6; Issue 7. Nature Watch - Singapore's Jurong BirdPark: A Study Model. Abraham Verghese. Feature Article Volume 6 Issue 7 July 2001 pp 74-88. Fulltext. Click here to view fulltext PDF. Permanent link:

  5. Kritikkens natur

    DEFF Research Database (Denmark)

    Schatz-Jakobsen, Claus

    1999-01-01

    Artiklen introducerer det nye forskningsfelt inden for samtænkning af litteratur, kultur og natur, den såkaldt økologiske kritik, og kaster et kritisk blik på  dens brug af romantisk litteratur som proto-økologisk kanon....

  6. Nature Watch

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 4; Issue 7. Nature Watch - The Odyssey of the Olive Ridley. Kartik Shanker. Feature Article Volume 4 Issue 7 July 1999 pp 68-78. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/004/07/0068-0078 ...

  7. Nature Watch

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 1; Issue 8. Nature Watch - Secrets of the Shieldtails. Kartik Shanker. Feature Article Volume 1 Issue 8 August 1996 pp 64-70. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/001/08/0064-0070 ...

  8. Nature Watch

    Indian Academy of Sciences (India)

    2016-08-26

    Aug 26, 2016 ... ... 20; Issue 1. Nature Watch: A Tale of Two Turtles. V Deepak. Feature Article Volume 20 Issue 1 January 2015 pp 47-54. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/020/01/0047-0054. Keywords. Ecology; endemic; India; turtles; tortoises; Western Ghats.

  9. Stimulating effects of ionizing radiation

    International Nuclear Information System (INIS)

    Jaworowski, Z.

    1995-01-01

    The influence of low doses on human organism is not definite known up to now. The worldwide discussion on this topic has been presented. A lot of analysed statistical data proved that the stimulating effect of low doses of ionizing radiation really exists and can have a beneficial influence on human health. 43 refs, 4 figs, 6 tabs

  10. Ovarian stimulation and embryo quality

    NARCIS (Netherlands)

    Baart, Esther; Macklon, Nick S.; Fauser, Bart J. C. M.

    To Study the effects of different ovarian stimulation approaches on oocyte and embryo quality, it is imperative to assess embryo quality with a reliable and objective method. Embryos rated as high quality by standardized morphological assessment are associated with higher implantation and pregnancy

  11. Enteral feeding without pancreatic stimulation

    DEFF Research Database (Denmark)

    Kaushik, Neeraj; Pietraszewski, Marie; Holst, Jens Juul

    2005-01-01

    OBJECTIVE: All forms of commonly practiced enteral feeding techniques stimulate pancreatic secretion, and only intravenous feeding avoids it. In this study, we explored the possibility of more distal enteral infusions of tube feeds to see whether activation of the ileal brake mechanism can result...

  12. Transcranial magnetic stimulation in schizophrenia.

    Science.gov (United States)

    Zaman, Rashid; Thind, Dilraj; Kocmur, Marga

    2008-11-01

    Transcranial magnetic stimulation (TMS) is a non-invasive and painless way of stimulating the neural tissue (cerebral cortex, spinal roots, and cranial and peripheral nerves). The first attempts at stimulating the neural tissue date back to 1896 by d'Arsonval; however, it was successfully carried out by Barker and colleagues in Sheffield, UK, in 1985. It soon became a useful tool in neuroscience for neurophysiologists and neurologists and psychiatrists. The original single-pulse TMS, largely used as an investigative tool, was further refined and developed in the early 1990s into what is known as repetitive TMS (rTMS), having a frequency range of 1-60 Hz. The stimulation by both TMS and rTMS of various cortical regions displayed alteration of movement, mood, and behavior, leading researchers to investigate a number of psychiatric and neuropsychiatric disorders, as well as to explore its therapeutic potential. There is now a large amount of literature on the use of TMS/rTMS in depression; however, its use in schizophrenia, both as an investigative and certainly as a therapeutic tool is relatively recent with a limited but increasing number of publications. In this article, we will outline the principles of TMS/rTMS and critically review their use in schizophrenia both as investigative and potential therapeutic tools.

  13. Aversive Stimulation -- Criteria for Application.

    Science.gov (United States)

    O'Donnell, Patrick A.; Ohlson, Glenn A.

    Criteria for applying aversive stimulation with severely handicapped children are examined, and practical and ethical issues are considered. Factors seen to influence punishment outcomes include timing, intensity, and schedule of reinforcement. Suggested is the need for further research on the comparative effectiveness of positive and negative…

  14. Thalamic stimulation in absence epilepsy

    NARCIS (Netherlands)

    Luttjohann, A.K.; Luijtelaar, E.L.J.M. van

    2013-01-01

    Purpose The site specific effects of two different types of electrical stimulation of the thalamus on electroencephalic epileptic activity as generated in the cortico-thalamo-cortical system were investigated in genetic epileptic WAG/Rij rats, a well characterized and validated absence

  15. FROM THE CONVENTIONAL TO THE MILDER APPROACHES TO OVARIAN STIMULATION FOR IN VITRO FERTILIZATION

    Directory of Open Access Journals (Sweden)

    Eda Vrtačnik-Bokal

    2018-02-01

    Full Text Available Background: In-vitro fertilization (IVF is performed with oocytes collected in natural and stimulated cycles. Different approaches to ovarian stimulation have been employed worldwide. Fol- lowing the introduction of gonadotrophin realising hormone (GnRH antagonists and strategies to reduce multiple birth such as single embryo transfer, there is an interest in the revival of natural and mild approaches to ovarian stimulation in IVF. Particulary mild ovarian stimulation aims to achieve cost-effective, patient-friendly regimens which optimize the balance between outcomes and risks of treatment. Methods: Pubmed was searched up to 2009 for papers on natural, modified natural, mild and con- ventional IVF cycles. Results: Data discussed in this review do not allow any conclusions to be drawn regarding the most optimal mild ovarian stimulation protocol. However, it is absolutelly clear that introduction of GnRH antagonists into clinical practice has allowed for the introduction of milder stimulation approaches for IVF treatment because of preventing premature luteinising hor- mone (LH rise by competitive blockade of the GnRH receptors. Studies also show that mild exogenous gonadotrophins interference with the decrease in follicle-stimulating hormone ((FSH levels in the mid-folicular phase was sufficient to override the selection of a single dominant follicle and enhance the most mature follicles to growth due to their increased sensitivity for FSH and acquired responsiveness to LH. Conclusions: The implementation of mild stimulation and modified natural cycle into standard clinical practise appears to be justified, although more prospective studies are needed to find the most appropriate mild stimulation approaches.

  16. Stimulation of phagocytosis by sulforaphane

    International Nuclear Information System (INIS)

    Suganuma, Hiroyuki; Fahey, Jed W.; Bryan, Kelley E.; Healy, Zachary R.; Talalay, Paul

    2011-01-01

    Research highlights: → Sulforaphane stimulates the phagocytosis of RAW 264.7 macrophages under conditions of serum deprivation. → This effect does not require Nrf2-dependent induction of phase 2 genes. → Inactivation of macrophage migration inhibitory factor (MIF) by sulforaphane may be involved in stimulation of phagocytosis by sulforaphane. -- Abstract: Sulforaphane, a major isothiocyanate derived from cruciferous vegetables, protects living systems against electrophile toxicity, oxidative stress, inflammation, and radiation. A major protective mechanism is the induction of a network of endogenous cytoprotective (phase 2) genes that are regulated by transcription factor Nrf2. To obtain a more detailed understanding of the anti-inflammatory and immunomodulatory effects of sulforaphane, we evaluated its effect on the phagocytosis activity of RAW 264.7 murine macrophage-like cells by measuring the uptake of 2-μm diameter polystyrene beads. Sulforaphane raised the phagocytosis activity of RAW 264.7 cells but only in the absence or presence of low concentrations (1%) of fetal bovine serum. Higher serum concentrations depressed phagocytosis and abolished its stimulation by sulforaphane. This stimulation did not depend on the induction of Nrf2-regulated genes since it occurred in peritoneal macrophages of nrf2 -/- mice. Moreover, a potent triterpenoid inducer of Nrf2-dependent genes did not stimulate phagocytosis, whereas sulforaphane and another isothiocyanate (benzyl isothiocyanate) had comparable inducer potencies. It has been shown recently that sulforaphane is a potent and direct inactivator of macrophage migration inhibitory factor (MIF), an inflammatory cytokine. Moreover, the addition of recombinant MIF to RAW 264.7 cells attenuated phagocytosis, but sulforaphane-inactivated MIF did not affect phagocytosis. The inactivation of MIF may therefore be involved in the phagocytosis-enhancing activity of sulforaphane.

  17. Stimulation of phagocytosis by sulforaphane

    Energy Technology Data Exchange (ETDEWEB)

    Suganuma, Hiroyuki, E-mail: hsuganu1@jhmi.edu [Lewis B. and Dorothy Cullman Cancer Chemoprotection Center, Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD 21205 (United States); Fahey, Jed W., E-mail: jfahey@jhmi.edu [Lewis B. and Dorothy Cullman Cancer Chemoprotection Center, Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD 21205 (United States); Bryan, Kelley E., E-mail: kbryanm1@jhmi.edu [Lewis B. and Dorothy Cullman Cancer Chemoprotection Center, Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD 21205 (United States); Healy, Zachary R., E-mail: zhealy1@jhmi.edu [Lewis B. and Dorothy Cullman Cancer Chemoprotection Center, Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD 21205 (United States); Talalay, Paul, E-mail: ptalalay@jhmi.edu [Lewis B. and Dorothy Cullman Cancer Chemoprotection Center, Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD 21205 (United States)

    2011-02-04

    Research highlights: {yields} Sulforaphane stimulates the phagocytosis of RAW 264.7 macrophages under conditions of serum deprivation. {yields} This effect does not require Nrf2-dependent induction of phase 2 genes. {yields} Inactivation of macrophage migration inhibitory factor (MIF) by sulforaphane may be involved in stimulation of phagocytosis by sulforaphane. -- Abstract: Sulforaphane, a major isothiocyanate derived from cruciferous vegetables, protects living systems against electrophile toxicity, oxidative stress, inflammation, and radiation. A major protective mechanism is the induction of a network of endogenous cytoprotective (phase 2) genes that are regulated by transcription factor Nrf2. To obtain a more detailed understanding of the anti-inflammatory and immunomodulatory effects of sulforaphane, we evaluated its effect on the phagocytosis activity of RAW 264.7 murine macrophage-like cells by measuring the uptake of 2-{mu}m diameter polystyrene beads. Sulforaphane raised the phagocytosis activity of RAW 264.7 cells but only in the absence or presence of low concentrations (1%) of fetal bovine serum. Higher serum concentrations depressed phagocytosis and abolished its stimulation by sulforaphane. This stimulation did not depend on the induction of Nrf2-regulated genes since it occurred in peritoneal macrophages of nrf2{sup -/-} mice. Moreover, a potent triterpenoid inducer of Nrf2-dependent genes did not stimulate phagocytosis, whereas sulforaphane and another isothiocyanate (benzyl isothiocyanate) had comparable inducer potencies. It has been shown recently that sulforaphane is a potent and direct inactivator of macrophage migration inhibitory factor (MIF), an inflammatory cytokine. Moreover, the addition of recombinant MIF to RAW 264.7 cells attenuated phagocytosis, but sulforaphane-inactivated MIF did not affect phagocytosis. The inactivation of MIF may therefore be involved in the phagocytosis-enhancing activity of sulforaphane.

  18. Physiological recruitment of motor units by high-frequency electrical stimulation of afferent pathways.

    Science.gov (United States)

    Dideriksen, Jakob L; Muceli, Silvia; Dosen, Strahinja; Laine, Christopher M; Farina, Dario

    2015-02-01

    Neuromuscular electrical stimulation (NMES) is commonly used in rehabilitation, but electrically evoked muscle activation is in several ways different from voluntary muscle contractions. These differences lead to challenges in the use of NMES for restoring muscle function. We investigated the use of low-current, high-frequency nerve stimulation to activate the muscle via the spinal motoneuron (MN) pool to achieve more natural activation patterns. Using a novel stimulation protocol, the H-reflex responses to individual stimuli in a train of stimulation pulses at 100 Hz were reliably estimated with surface EMG during low-level contractions. Furthermore, single motor unit recruitment by afferent stimulation was analyzed with intramuscular EMG. The results showed that substantially elevated H-reflex responses were obtained during 100-Hz stimulation with respect to a lower stimulation frequency. Furthermore, motor unit recruitment using 100-Hz stimulation was not fully synchronized, as it occurs in classic NMES, and the discharge rates differed among motor units because each unit was activated only after a specific number of stimuli. The most likely mechanism behind these observations is the temporal summation of subthreshold excitatory postsynaptic potentials from Ia fibers to the MNs. These findings and their interpretation were also verified by a realistic simulation model of afferent stimulation of a MN population. These results suggest that the proposed stimulation strategy may allow generation of considerable levels of muscle activation by motor unit recruitment that resembles the physiological conditions. Copyright © 2015 the American Physiological Society.

  19. The Use of Brain Stimulation in Dysphagia Management.

    Science.gov (United States)

    Simons, Andre; Hamdy, Shaheen

    2017-04-01

    Dysphagia is common sequela of brain injury with as many as 50% of patients suffering from dysphagia following stroke. Currently, the majority of guidelines for clinical practice in the management of dysphagia focus on the prevention of complications while any natural recovery takes place. Recently, however, non-invasive brain stimulation (NIBS) techniques like transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) have started to attract attention and are applied to investigate both the physiology of swallowing and influences on dysphagia. TMS allows for painless stimulation of the brain through an intact skull-an effect which would normally be impossible with electrical currents due to the high resistance of the skull. By comparison, tDCS involves passing a small electric current (usually under 2 mA) produced by a current generator over the scalp and cranium external to the brain. Initial studies used these techniques to better understand the physiological mechanisms of swallowing in healthy subjects. More recently, a number of studies have investigated the efficacy of these techniques in the management of neurogenic dysphagia with mixed results. Controversy still exists as to which site, strength and duration of stimulation yields the greatest improvement in dysphagia. And while multiple studies have suggested promising effects of NIBS, more randomised control trials with larger sample sizes are needed to investigate the short- and long-term effects of NIBS in neurogenic dysphagia.

  20. Provincialising Nature

    DEFF Research Database (Denmark)

    Provincialising Nature: Multidisciplinary Approaches to the Politics of the Environment in Latin America offers a timely analysis of some of the crucial challenges, contradictions and promises within current environmental discourses and practices in the region. This book shows both challenging...... scenarios and original perspectives that have emerged in Latin America in relation to the globally urgent issues of climate change and the environmental crisis. Two interconnected analytical frameworks guide the discussions in the book: the relationship between nature, knowledge and identity and their role...... in understanding recent and current practices of climate change and environmental policy. The different chapters in this volume contribute to this debate by offering multidisciplinary perspectives on particular aspects of these two frameworks and through a multidirectional outlook that links the local, national...

  1. Unbounded Naturalism

    Directory of Open Access Journals (Sweden)

    Andrew Taggart

    2008-10-01

    Full Text Available nbsp;font face="Times, serif"font size="3"In the Anglo-American reception of John McDowellrsquo;s /font/fontfont face="Times, serif"font size="3"emMind and World/em/font/fontfont face="Times, serif"font size="3", there has been little attention paid to the developmental aspect of his lsquo;partially re-enchantedrsquo; naturalism. In lsquo;Naturalism Unboundedrsquo;, I argue that McDowellrsquo;s story of our normal upbringing (/font/fontfont face="Times, serif"font size="3"emBildung/em/font/fontfont face="Times, serif"font size="3" presents problems for his claim that we have a lsquo;standing obligationrsquo; to reflect on our perceptual experiences. I follow this critique up with a Hegelian-inspired attempt to retain and revise the vital points he makes about experience./font/font

  2. Stimulated transitions in resonant atom Majorana mixing

    Science.gov (United States)

    Bernabéu, José; Segarra, Alejandro

    2018-02-01

    Massive neutrinos demand to ask whether they are Dirac or Majorana particles. Majorana neutrinos are an irrefutable proof of physics beyond the Standard Model. Neutrinoless double electron capture is not a process but a virtual Δ L = 2 mixing between a parent A Z atom and a daughter A ( Z - 2) excited atom with two electron holes. As a mixing between two neutral atoms and the observable signal in terms of emitted two-hole X-rays, the strategy, experimental signature and background are different from neutrinoless double beta decay. The mixing is resonantly enhanced for almost degeneracy and, under these conditions, there is no irreducible background from the standard two-neutrino channel. We reconstruct the natural time history of a nominally stable parent atom since its production either by nature or in the laboratory. After the time periods of atom oscillations and the decay of the short-lived daughter atom, at observable times the relevant "stationary" states are the mixed metastable long-lived state and the non-orthogonal short-lived excited state, as well as the ground state of the daughter atom. We find that they have a natural population inversion which is most appropriate for exploiting the bosonic nature of the observed atomic transitions radiation. Among different observables of the atom Majorana mixing, we include the enhanced rate of stimulated X-ray emission from the long-lived metastable state by a high-intensity X-ray beam: a gain factor of 100 can be envisaged at current XFEL facilities. On the other hand, the historical population of the daughter atom ground state can be probed by exciting it with a current pulsed optical laser, showing the characteristic absorption lines: the whole population can be excited in a shorter time than typical pulse duration.

  3. Natural games

    International Nuclear Information System (INIS)

    Anttila, Jani; Annila, Arto

    2011-01-01

    A course of a game is formulated as a physical process that will consume free energy in the least time. Accordingly, the rate of entropy increase is the payoff function that will subsume all forms of free energy that motivate diverse decisions. Also other concepts of game theory are related to their profound physical counterparts. When the physical portrayal of behavior is mathematically analyzed, the course of a game is found to be inherently unpredictable because each move affects motives in the future. Despite the non-holonomic character of the natural process, the objective of consuming free energy in the least time will direct an extensive-form game toward a Lyapunov-stable point that satisfies the minimax theorem. -- Highlights: → Behavior in the context of game theory is described as a natural process. → The rate of entropy increase, derived from statistical physics of open systems, is identified as the payoff function. → Entropy as the payoff function also clarifies motives of collaboration and subjective nature of decision making. → Evolutionary equation of motion that accounts for the course of a game is inherently unpredictable.

  4. Somato stimulation and acupuncture therapy.

    Science.gov (United States)

    Zhao, Jing-Jun; Rong, Pei-Jing; Shi, Li; Ben, Hui; Zhu, Bing

    2016-05-01

    Acupuncture is an oldest somato stimulus medical technique. As the most representative peripheral nerve stimulation therapy, it has a complete system of theory and application and is applicable to a large population. This paper expounds the bionic origins of acupuncture and analyzes the physiological mechanism by which acupuncture works. For living creatures, functionally sound viscera and effective endurance of pain are essential for survival. This paper discusses the way in which acupuncture increases the pain threshold of living creatures and the underlying mechanism from the perspective of bionics. Acupuncture can also help to adjust visceral functions and works most effectively in facilitating the process of digestion and restraining visceral pain. This paper makes an in-depth overview of peripheral nerve stimulation therapy represented by acupuncture. We look forward to the revival of acupuncture, a long-standing somato stimulus medicine, in the modern medical systems.

  5. Femtosecond Broadband Stimulated Raman Spectroscopy

    International Nuclear Information System (INIS)

    Lee, Soo-Y; Yoon, Sagwoon; Mathies, Richard A

    2006-01-01

    Femtosecond broadband stimulated Raman spectroscopy (FSRS) is a new technique where a narrow bandwidth picosecond Raman pump pulse and a red-shifted broadband femtosecond Stokes probe pulse (with or without time delay between the pulses) act on a sample to produce a high resolution Raman gain spectrum with high efficiency and speed, free from fluorescence background interference. It can reveal vibrational structural information and dynamics of stationary or transient states. Here, the quantum picture for femtosecond broadband stimulated Raman spectroscopy (FSRS) is used to develop the semiclassical coupled wave theory of the phenomenon and to derive an expression for the measurable Raman gain in FSRS. The semiclassical theory is applied to study the dependence of lineshapes in FSRS on the pump-probe time delay and to deduce vibrational dephasing times in cyclohexane in the ground state

  6. Vagal stimulation in heart failure.

    Science.gov (United States)

    De Ferrari, Gaetano M

    2014-04-01

    Heart failure (HF) is accompanied by an autonomic imbalance that is almost always characterized by both increased sympathetic activity and withdrawal of vagal activity. Experimentally, vagal stimulation has been shown to exert profound antiarrhythmic activity and to improve cardiac function and survival in HF models. A open-label pilot clinical study in 32 patients with chronic HF has shown safety and tolerability of chronic vagal stimulation associated with subjective (improved quality of life and 6-min walk test) and objective improvements (reduced left ventricular systolic volumes and improved left ventricular ejection fraction). Three larger clinical studies, including a phase III trial are currently ongoing and will evaluate the clinical role of this new approach.

  7. Tactile Stimulation and Consumer Response.

    OpenAIRE

    Hornik, Jacob

    1992-01-01

    Tactile behavior is a basic communication form as well as an expression of interpersonal involvement. This article presents three studies offering evidence for the positive role of casual interpersonal touch on consumer behavior. More specifically, it provides initial support for the view that tactile stimulation in various consumer behavior situations enhances the positive feeling for and evaluation of both the external stimuli and the touching source. Further, customers touched by a request...

  8. Resonant Impulsive Stimulated Raman Scattering

    Energy Technology Data Exchange (ETDEWEB)

    Mokhtari, A; Chesnoy, J

    1988-03-15

    Using a femtosecond dye laser, we observe in real-time vibrational oscillations excited by impulsive stimulated Raman scattering (ISRS) close to an electronic resonance. We perform single-beam Raman excitation and probe the driven coherence by a polarization-sensitive detection. We demonstrate for the first time impulsively Raman-induced dichroism, birefringence as well as frequency and time delay shifts. We analyse the characteristics of resonant ISRS on a vibrational mode of a dye molecule (malachite green) in solution.

  9. Transcranial Magnetic Stimulation in Children

    OpenAIRE

    Garvey, Marjorie A.; Mall, Volker

    2008-01-01

    Developmental disabilities (e.g. attention deficit disorder; cerebral palsy) are frequently associated with deviations of the typical pattern of motor skill maturation. Neurophysiologic tools, such as transcranial magnetic stimulation (TMS), which probe motor cortex function, can potentially provide insights into both typical neuromotor maturation and the mechanisms underlying the motor skill deficits in children with developmental disabilities. These insights may set the stage for finding ef...

  10. Resonant Impulsive Stimulated Raman Scattering

    International Nuclear Information System (INIS)

    Mokhtari, A.; Chesnoy, J.

    1988-01-01

    Using a femtosecond dye laser, we observe in real-time vibrational oscillations excited by impulsive stimulated Raman scattering (ISRS) close to an electronic resonance. We perform single-beam Raman excitation and probe the driven coherence by a polarization-sensitive detection. We demonstrate for the first time impulsively Raman-induced dichroism, birefringence as well as frequency and time delay shifts. We analyse the characteristics of resonant ISRS on a vibrational mode of a dye molecule (malachite green) in solution

  11. Optical stimulated luminescence (OSL) dating

    International Nuclear Information System (INIS)

    Banerjee, D.

    1999-01-01

    Since the pioneering work by Huntley et al. (1985), optical dating is being increasingly recognised as an important technique for establishing a time frame of deposition of sediments (Aitken, 1998). Optical dating differs from thermoluminescence (TL) dating in that visible/infrared light from lasers or LEDs (light-emitting-diodes) is used as a means of stimulation, in contrast to thermal stimulation. It has several advantages over TL dating: (i) the resetting of the OSL (optically stimulated luminescence) clock is more effective than that of TL clock; for sediments transported under water or in other situations where the sediment grains have undergone inhomogeneous bleaching, this property ensures that ages based on optical dating are generally more reliable than TL ages, (ii) the optical dating technique is non-destructive, and multiple readouts of the optical signal is possible; this feature has resulted in the development of single-aliquot and single-grain protocols (Murray and Wintle, 1999; Banerjee et al. 1999), (iii) the sample is not heated as in TL; thus, spurious luminescence is avoided and there is a significant reduction in blackbody radiation. Dating of materials which change phase on heating is also practical, and finally, (iv) thermal quenching of luminescence is negligible, allowing accurate estimation of kinetic parameters using standard techniques and providing access to deep OSL traps. This characteristic may be helpful in extending the limits of optical dating beyond the last 150 ka from a global point of view

  12. Performance Enhancement by Brain Stimulation

    Directory of Open Access Journals (Sweden)

    Parisa Gazerani

    2017-09-01

    Full Text Available Number of substances and strategies are available to increase performance in sport (Catlin and Murray, 1996. Since 2004, the World Anti-Doping Agency (WADA posts an updated list of substances and methods prohibited to athletes. Drugs (e.g., steroids, stimulants are a major part of this list; however, technologies and methods (e.g., gene doping are increasingly being identified and added (WADA, 2017. Among technologies and methods that might exert a potential effect on athletic performance, brain stimulation has recently been subjected to extensive discussion. Neuro-enhancement for doping purposes has been termed “neurodoping” in the literature (Davis, 2013; however, this concept needs further documentation before the term “neurodoping” can be used properly. Two major non-invasive techniques of brain stimulations are transcranial magnetic stimulation (TMS (Hallett, 2007; Rossi et al., 2009, and transcranial direct current stimulation (tDCS (Stagg and Nitsche, 2011. In TMS, an electric coil held over the head applies magnetic pulses to create currents in the brain. In tDCS, a low, continuous electrical current is delivered to the brain by using surface electrodes attached on the scalp. TMS and tDCS have been used in both research and clinic (Shin and Pelled, 2017 for example to examine alterations in cognitive function or motor skills or to assist in recovering motor function after a stroke (Gomez Palacio Schjetnan et al., 2013 or reducing fatigue in patients with multiple sclerosis (Saiote et al., 2014. In an opinion paper, it was proposed that use of emerging brain stimulation techniques might also enhance physical and mental performance in sports (Davis, 2013. The assumption was based on several reports. For example some studies have shown that TMS could shorten reaction times to visual, auditory and touch stimuli, reduce tremor, and enhance the acquisition of complex motor skills. Based on the current evidence, a recent review (Colzato

  13. Cortical stimulation and neuropathic pain

    Directory of Open Access Journals (Sweden)

    Cristiane Cagnoni Ramos

    2015-02-01

    Full Text Available http://dx.doi.org/10.5007/2175-7925.2015v28n2p1 This paper is a review of physiological and behavioral data on motor cortex stimulation (MCS and its role in persistent neuropathic pain. MCS has been widely used in clinical medicine as a tool for the management of pain that does not respond satisfactorily to any kind of conventional analgesia. Some important mechanisms involved in nociceptive modulation still remains unclear. The aim of this study was to describe the mechanisms involved in neuropathic pain and introduce the effectiveness of electrical stimulation of the motor cortex used in the treatment of this disease. The ascending pain pathways are activated by peripheral receptors, in which there is the transduction of a chemical, physical or mechanical stimulus as a nerve impulse, where this impulse is transmitted to the dorsal horn of the spinal cord, which connects with second-order neurons and ascends to different locations in the central nervous system where the stimulus is perceived as pain. Because MCS has been proved to modulate this pathway in the motor cortex, it has been studied to mimic its effects in clinical practice and improve the treatments used for chronic pain. MCS has gained much attention in recent years due to its action in reversing chronic neuropathic pain, this being more effective than electrical stimulation at different locations and related pain nuclei.

  14. Cortical stimulation and neuropathic pain

    Directory of Open Access Journals (Sweden)

    Cristiane Cagnoni Ramos

    2015-05-01

    Full Text Available This paper is a review of physiological and behavioral data on motor cortex stimulation (MCS and its role in persistent neuropathic pain. MCS has been widely used in clinical medicine as a tool for the management of pain that does not respond satisfactorily to any kind of conventional analgesia. Some important mechanisms involved in nociceptive modulation still remains unclear. The aim of this study was to describe the mechanisms involved in neuropathic pain and introduce the effectiveness of electrical stimulation of the motor cortex used in the treatment of this disease. The ascending pain pathways are activated by peripheral receptors, in which there is the transduction of a chemical, physical or mechanical stimulus as a nerve impulse, where this impulse is transmitted to the dorsal horn of the spinal cord, which connects with second-order neurons and ascends to different locations in the central nervous system where the stimulus is perceived as pain. Because MCS has been proved to modulate this pathway in the motor cortex, it has been studied to mimic its effects in clinical practice and improve the treatments used for chronic pain. MCS has gained much attention in recent years due to its action in reversing chronic neuropathic pain, this being more effective than electrical stimulation at different locations and related pain nuclei.

  15. Follicle-stimulating hormone (FSH) blood test

    Science.gov (United States)

    ... ency/article/003710.htm Follicle-stimulating hormone (FSH) blood test To use the sharing features on this page, please enable JavaScript. The follicle stimulating hormone (FSH) blood test measures the level of FSH in blood. FSH ...

  16. Vagus Nerve Stimulation for Treating Epilepsy

    Science.gov (United States)

    ... and their FAMILIES VAGUS NERVE STIMULATION FOR TREATING EPILEPSY This information sheet is provided to help you ... how vagus nerve stimulation (VNS) may help treat epilepsy. The American Academy of Neurology (AAN) is the ...

  17. Wireless distributed functional electrical stimulation system

    Directory of Open Access Journals (Sweden)

    Jovičić Nenad S

    2012-08-01

    Full Text Available Abstract Background The control of movement in humans is hierarchical and distributed and uses feedback. An assistive system could be best integrated into the therapy of a human with a central nervous system lesion if the system is controlled in a similar manner. Here, we present a novel wireless architecture and routing protocol for a distributed functional electrical stimulation system that enables control of movement. Methods The new system comprises a set of miniature battery-powered devices with stimulating and sensing functionality mounted on the body of the subject. The devices communicate wirelessly with one coordinator device, which is connected to a host computer. The control algorithm runs on the computer in open- or closed-loop form. A prototype of the system was designed using commercial, off-the-shelf components. The propagation characteristics of electromagnetic waves and the distributed nature of the system were considered during the development of a two-hop routing protocol, which was implemented in the prototype’s software. Results The outcomes of this research include a novel system architecture and routing protocol and a functional prototype based on commercial, off-the-shelf components. A proof-of-concept study was performed on a hemiplegic subject with paresis of the right arm. The subject was tasked with generating a fully functional palmar grasp (closing of the fingers. One node was used to provide this movement, while a second node controlled the activation of extensor muscles to eliminate undesired wrist flexion. The system was tested with the open- and closed-loop control algorithms. Conclusions The system fulfilled technical and application requirements. The novel communication protocol enabled reliable real-time use of the system in both closed- and open-loop forms. The testing on a patient showed that the multi-node system could operate effectively to generate functional movement.

  18. Wireless distributed functional electrical stimulation system.

    Science.gov (United States)

    Jovičić, Nenad S; Saranovac, Lazar V; Popović, Dejan B

    2012-08-09

    The control of movement in humans is hierarchical and distributed and uses feedback. An assistive system could be best integrated into the therapy of a human with a central nervous system lesion if the system is controlled in a similar manner. Here, we present a novel wireless architecture and routing protocol for a distributed functional electrical stimulation system that enables control of movement. The new system comprises a set of miniature battery-powered devices with stimulating and sensing functionality mounted on the body of the subject. The devices communicate wirelessly with one coordinator device, which is connected to a host computer. The control algorithm runs on the computer in open- or closed-loop form. A prototype of the system was designed using commercial, off-the-shelf components. The propagation characteristics of electromagnetic waves and the distributed nature of the system were considered during the development of a two-hop routing protocol, which was implemented in the prototype's software. The outcomes of this research include a novel system architecture and routing protocol and a functional prototype based on commercial, off-the-shelf components. A proof-of-concept study was performed on a hemiplegic subject with paresis of the right arm. The subject was tasked with generating a fully functional palmar grasp (closing of the fingers). One node was used to provide this movement, while a second node controlled the activation of extensor muscles to eliminate undesired wrist flexion. The system was tested with the open- and closed-loop control algorithms. The system fulfilled technical and application requirements. The novel communication protocol enabled reliable real-time use of the system in both closed- and open-loop forms. The testing on a patient showed that the multi-node system could operate effectively to generate functional movement.

  19. A Chip for an Implantable Neural Stimulator

    DEFF Research Database (Denmark)

    Gudnason, Gunnar; Bruun, Erik; Haugland, Morten

    2000-01-01

    This paper describes a chip for a multichannel neural stimulator for functional electrical stimulation (FES). The purpose of FES is to restore muscular control in disabled patients. The chip performs all the signal processing required in an implanted neural stimulator. The power and digital data...

  20. Frequency shifts in stimulated Raman scattering

    International Nuclear Information System (INIS)

    Zinth, W.; Kaiser, W.

    1980-01-01

    The nonresonant contributions to the nonlinear susceptibility chisup(()3) produce a frequency chirp during stimulated Raman scattering. In the case of transient stimulated Raman scattering, the spectrum of the generated Stokes pulse is found at higher frequencies than expected from spontaneous Raman data. The frequency difference can be calculated from the theory of stimulated Raman scattering. (orig.)

  1. Geothermal Reservoir Well Stimulation Program: technology transfer

    Energy Technology Data Exchange (ETDEWEB)

    1980-05-01

    Each of the following types of well stimulation techniques are summarized and explained: hydraulic fracturing; thermal; mechanical, jetting, and drainhole drilling; explosive and implosive; and injection methods. Current stimulation techniques, stimulation techniques for geothermal wells, areas of needed investigation, and engineering calculations for various techniques. (MHR)

  2. Optical stimulator for vision-based sensors

    DEFF Research Database (Denmark)

    Rössler, Dirk; Pedersen, David Arge Klevang; Benn, Mathias

    2014-01-01

    We have developed an optical stimulator system for vision-based sensors. The stimulator is an efficient tool for stimulating a camera during on-ground testing with scenes representative of spacecraft flights. Such scenes include starry sky, planetary objects, and other spacecraft. The optical...

  3. Natural games

    Science.gov (United States)

    Anttila, Jani; Annila, Arto

    2011-10-01

    A course of a game is formulated as a physical process that will consume free energy in the least time. Accordingly, the rate of entropy increase is the payoff function that will subsume all forms of free energy that motivate diverse decisions. Also other concepts of game theory are related to their profound physical counterparts. When the physical portrayal of behavior is mathematically analyzed, the course of a game is found to be inherently unpredictable because each move affects motives in the future. Despite the non-holonomic character of the natural process, the objective of consuming free energy in the least time will direct an extensive-form game toward a Lyapunov-stable point that satisfies the minimax theorem.

  4. Natural uranium

    International Nuclear Information System (INIS)

    Ammerich, Marc; Frot, Patricia; Gambini, Denis-Jean; Gauron, Christine; Moureaux, Patrick; Herbelet, Gilbert; Lahaye, Thierry; Pihet, Pascal; Rannou, Alain

    2014-08-01

    This sheet belongs to a collection which relates to the use of radionuclides essentially in unsealed sources. Its goal is to gather on a single document the most relevant information as well as the best prevention practices to be implemented. These sheets are made for the persons in charge of radiation protection: users, radioprotection-skill persons, labor physicians. Each sheet treats of: 1 - the radio-physical and biological properties; 2 - the main uses; 3 - the dosimetric parameters; 4 - the measurement; 5 - the protection means; 6 - the areas delimitation and monitoring; 7 - the personnel classification, training and monitoring; 8 - the effluents and wastes; 9 - the authorization and declaration administrative procedures; 10 - the transport; and 11 - the right conduct to adopt in case of incident or accident. This sheet deals specifically with natural uranium

  5. Next nature : nature changes along with us

    NARCIS (Netherlands)

    Mensvoort, van K.M.; Grievink, H.J.

    2011-01-01

    We debate saving nature, we dream about escaping to nature, but rarely do we ask "What is nature?". The Next Nature book radically shifts your notion of nature. Where technology and nature are traditionally seen as opposed, they now appear to merge or even trade places. With our urge to design our

  6. Natural isotopes

    International Nuclear Information System (INIS)

    Vogel, J.C.

    1986-01-01

    14 C dates between 600 and 900 AD were obtained for early Iron Age sites in Natal, and from 1300 to 1450 AD for rock engraving sites in Bushmanland. Palaeoenvironmental data derived from the dating of samples related to sedimentary and geomorphic features in the central and northern Namib Desert enabled the production of a tentative graph for the changes in humidity in the region over the past 40000 years. These results suggest that relatively humid conditions came to an end in the Namib at ±25000 BP (before present). The increased precision of the SIRA mass spectrometer enabled the remeasurement of 13 C and 18 O in the Cango stalagmite. This data confirmed that the environmental temperatures in the Southern Cape remained constant to within ±1 o C during the past 5500 years. Techniques and applications for environmental isotopes in hydrology were developed to determine the origin and movement of ground water. Isotopic fractionation effects in light elements in nature were investigated. The 15 N/ 14 N ratio in bones of animals and humans increases in proportion to the aridity of the environment. This suggests that 15 N in bone from dated archaeological sites could be used to detect changes in past climatic conditions as naturally formed nitrate minerals are higly soluble and are only preserved in special, very dry environments. The sources and sinks of CO 2 on the South African subcontinent were also determined. The 13 C/ 12 C ratios of air CO 2 obtained suggest that the vegetation provides the major proportion of respired CO 2 . 9 refs., 1 fig

  7. Stimulation of hair cells with ultraviolet light

    Science.gov (United States)

    Azimzadeh, Julien B.; Fabella, Brian A.; Hudspeth, A. J.

    2018-05-01

    Hair bundles are specialized organelles that transduce mechanical inputs into electrical outputs. To activate hair cells, physiologists have resorted to mechanical methods of hair-bundle stimulation. Here we describe a new method of hair-bundle stimulation, irradiation with ultraviolet light. A hair bundle illuminated by ultraviolet light rapidly moves towards its tall edge, a motion typically associated with excitatory stimulation. The motion disappears upon tip-link rupture and is associated with the opening of mechanotransduction channels. Hair bundles can be induced to move sinusoidally with oscillatory modulation of the stimulation power. We discuss the implications of ultraviolet stimulation as a novel hair-bundle stimulus.

  8. Dose-response of seeds of the parasitic weeds Striga and Orobanche toward the synthetic germination stimulants GR24.

    NARCIS (Netherlands)

    Wigchert, S.C.M.; Kuiper, E.; Boelhouwer, G.J.; Nefkens, G.H.L.; Verkley, J.A.C.; Zwanenburg, B.

    1999-01-01

    Striga and Orobanche seeds germinate in response to a host-derived germination stimulant. Dose-response curves of the synthetic strigolactone analogues GR 24 and Nijmegen 1 were determined, and their activities were compared to that of the naturally occurring stimulant sorgolactone. Typical

  9. Direct electrical stimulation of human cortex evokes high gamma activity that predicts conscious somatosensory perception

    Science.gov (United States)

    Muller, Leah; Rolston, John D.; Fox, Neal P.; Knowlton, Robert; Rao, Vikram R.; Chang, Edward F.

    2018-04-01

    Objective. Direct electrical stimulation (DES) is a clinical gold standard for human brain mapping and readily evokes conscious percepts, yet the neurophysiological changes underlying these percepts are not well understood. Approach. To determine the neural correlates of DES, we stimulated the somatosensory cortex of ten human participants at frequency-amplitude combinations that both elicited and failed to elicit conscious percepts, meanwhile recording neural activity directly surrounding the stimulation site. We then compared the neural activity of perceived trials to that of non-perceived trials. Main results. We found that stimulation evokes distributed high gamma activity, which correlates with conscious perception better than stimulation parameters themselves. Significance. Our findings suggest that high gamma activity is a reliable biomarker for perception evoked by both natural and electrical stimuli.

  10. Thermally stimulated scattering in plasmas

    DEFF Research Database (Denmark)

    Dysthe, K. B.; Mjølhus, E.; Pécseli, H. L.

    1985-01-01

    this experiment local heat conduction is of little importance and the dynamic evolution for the electron temperature is dominated by heating and energy exchange with the ion component. These features are incorporated in the analysis. The resulting set of equations gives a growth rate and characteristic scale size......A theory for stimulated scattering of a laser beam is formulated where the dominant nonlinearity is the ohmic heating of the plasma. The analysis is carried out with particular reference to experimental investigations of CO2 laser heating of linear discharge plasma. In the conditions characterizing...

  11. Natural killer cells in leukemogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Seidel, H.J.; Stolz, W.; Sutter, H.; Kreja, L.

    1986-01-01

    In order to relate a reduced natural killer (NK) cell function to leukemogenesis, NK cells in the spleen and peritoneal exudate cells, with and without stimulation by Corynebacterium parvum, were tested in mice of various strains after split dose irradiation and after leukemogenic treatment with butyl- and methylnitrosourea. The investigations included also mice submitted to non-leukemogenic irradiation (1 x 1.5 and 1 x 4.5 Gy) and mice submitted to an additional treatment with hydrocortisone, which delays leukemia development after methylnitrosourea. There was, indeed, a NK-cell depression, but no major differences were seen between mice prone to leukemia development and those after cytotoxic, but nonleukemogenic, treatment.

  12. Evaluation of different types of rooting stimulators

    Directory of Open Access Journals (Sweden)

    Petr Salaš

    2012-01-01

    Full Text Available This paper focuses on the assessment of selected stimulators, especially from Rhizopon product line, which are used for rooting and root system enhancement in various ornamental woody species. Two available methods of cuttings stimulation were selected from the available range of rooting stimulators: stimulation by long-term immersion in solutions or treatment of cuttings with powder stimulators. The experiment involved stimulators with two active components, currently the most commonly used phytohormones for this purpose – IBA and NAA – that were applied in different concentrations. The experiment took place in three propagation terms with twelve coniferous and deciduous shrub varieties. The results of the experiment show the different reactions of the individual species as well as varieties on the respective term of propagation and used form of stimulator.

  13. Natural Nanoparticles: A Particular Matter Inspired by Nature

    Directory of Open Access Journals (Sweden)

    Sharoon Griffin

    2017-12-01

    Full Text Available During the last couple of decades, the rapidly advancing field of nanotechnology has produced a wide palette of nanomaterials, most of which are considered as “synthetic” and, among the wider public, are often met with a certain suspicion. Despite the technological sophistication behind many of these materials, “nano” does not always equate with “artificial”. Indeed, nature itself is an excellent nanotechnologist. It provides us with a range of fine particles, from inorganic ash, soot, sulfur and mineral particles found in the air or in wells, to sulfur and selenium nanoparticles produced by many bacteria and yeasts. These nanomaterials are entirely natural, and, not surprisingly, there is a growing interest in the development of natural nanoproducts, for instance in the emerging fields of phyto- and phyco-nanotechnology. This review will highlight some of the most recent—and sometimes unexpected—advances in this exciting and diverse field of research and development. Naturally occurring nanomaterials, artificially produced nanomaterials of natural products as well as naturally occurring or produced nanomaterials of natural products all show their own, particular chemical and physical properties, biological activities and promise for applications, especially in the fields of medicine, nutrition, cosmetics and agriculture. In the future, such natural nanoparticles will not only stimulate research and add a greener outlook to a traditionally high-tech field, they will also provide solutions—pardon—suspensions for a range of problems. Here, we may anticipate specific biogenic factories, valuable new materials based on waste, the effective removal of contaminants as part of nano-bioremediation, and the conversion of poorly soluble substances and materials to biologically available forms for practical uses.

  14. Stimulation of collateral artery growth: travelling further down the road to clinical application

    OpenAIRE

    Schirmer, S.H.; van Nooijen, F.C.; Piek, J.J.; van Royen, N.

    2009-01-01

    Collateral artery growth is a potent natural defence mechanism to prevent death and myocardial infarction in occlusive artery disease. Given the high prevalence of arterial obstructive disease, a therapeutic compound stimulating collateral vessel growth could have a major impact on morbidity and mortality world wide. Although experimental studies on the stimulation of arteriogenesis have been promising, not a single drug has been proved to be applicable in clinical practice, either because of...

  15. Braille line using electrical stimulation

    International Nuclear Information System (INIS)

    Puertas, A; Pures, P; Echenique, A M; Ensinck, J P Graffigna y G

    2007-01-01

    Conceived within the field of Rehabilitation Technologies for visually impaired persons, the present work aims at enabling the blind user to read written material by means of a tactile display. Once he is familiarized to operate this system, the user will be able to achieve greater performance in study, academic and job activities, thus achieving a rapid and easier social inclusion. The devise accepts any kind of text that is computer-loadable (documents, books, Internet information, and the like) which, through digital means, can be read as Braille text on the pad. This tactile display is composed of an electrodes platform that simulate, through stimulation the writing/reading Braille characters. In order to perceive said characters in similar way to the tactile feeling from paper material, the skin receptor of fingers are stimulated electrically so as to simulate the same pressure and depressions as those of the paper-based counterpart information. Once designed and developed, the display was tested with blind subjects, with relatively satisfactory results. As a continuing project, this prototype is currently being improved as regards

  16. Braille line using electrical stimulation

    Science.gov (United States)

    Puertas, A.; Purés, P.; Echenique, A. M.; Ensinck, J. P. Graffigna y. G.

    2007-11-01

    Conceived within the field of Rehabilitation Technologies for visually impaired persons, the present work aims at enabling the blind user to read written material by means of a tactile display. Once he is familiarized to operate this system, the user will be able to achieve greater performance in study, academic and job activities, thus achieving a rapid and easier social inclusion. The devise accepts any kind of text that is computer-loadable (documents, books, Internet information, and the like) which, through digital means, can be read as Braille text on the pad. This tactile display is composed of an electrodes platform that simulate, through stimulation the writing/reading Braille characters. In order to perceive said characters in similar way to the tactile feeling from paper material, the skin receptor of fingers are stimulated electrically so as to simulate the same pressure and depressions as those of the paper-based counterpart information. Once designed and developed, the display was tested with blind subjects, with relatively satisfactory results. As a continuing project, this prototype is currently being improved as regards.

  17. Transcranial magnetic stimulation: language function.

    Science.gov (United States)

    Epstein, C M

    1998-07-01

    Studies of language using transcranial magnetic stimulation (TMS) have focused both on identification of language areas and on elucidation of function. TMS may result in either inhibition or facilitation of language processes and may operate directly at a presumptive site of language cortex or indirectly through intracortical networks. TMS has been used to create reversible "temporary lesions," similar to those produced by Wada tests and direct cortical electrical stimulation, in cerebral cortical areas subserving language function. Rapid-rate TMS over the left inferior frontal region blocks speech output in most subjects. However, the results are not those predicted from classic models of language organization. Speech arrest is obtained most easily over facial motor cortex, and true aphasia is rare, whereas right hemisphere or bilateral lateralization is unexpectedly prominent. A clinical role for these techniques is not yet fully established. Interfering with language comprehension and verbal memory is currently more difficult than blocking speech output, but numerous TMS studies have demonstrated facilitation of language-related tasks, including oral word association, story recall, digit span, and picture naming. Conversely, speech output also facilitates motor responses to TMS in the dominant hemisphere. Such new and often-unexpected findings may provide important insights into the organization of language.

  18. Braille line using electrical stimulation

    Energy Technology Data Exchange (ETDEWEB)

    Puertas, A; Pures, P; Echenique, A M; Ensinck, J P Graffigna y G [Gabinete de TecnologIa Medica. Universidad N. de San Juan (Argentina)

    2007-11-15

    Conceived within the field of Rehabilitation Technologies for visually impaired persons, the present work aims at enabling the blind user to read written material by means of a tactile display. Once he is familiarized to operate this system, the user will be able to achieve greater performance in study, academic and job activities, thus achieving a rapid and easier social inclusion. The devise accepts any kind of text that is computer-loadable (documents, books, Internet information, and the like) which, through digital means, can be read as Braille text on the pad. This tactile display is composed of an electrodes platform that simulate, through stimulation the writing/reading Braille characters. In order to perceive said characters in similar way to the tactile feeling from paper material, the skin receptor of fingers are stimulated electrically so as to simulate the same pressure and depressions as those of the paper-based counterpart information. Once designed and developed, the display was tested with blind subjects, with relatively satisfactory results. As a continuing project, this prototype is currently being improved as regards.

  19. Statistics of natural binaural sounds.

    Directory of Open Access Journals (Sweden)

    Wiktor Młynarski

    Full Text Available Binaural sound localization is usually considered a discrimination task, where interaural phase (IPD and level (ILD disparities at narrowly tuned frequency channels are utilized to identify a position of a sound source. In natural conditions however, binaural circuits are exposed to a stimulation by sound waves originating from multiple, often moving and overlapping sources. Therefore statistics of binaural cues depend on acoustic properties and the spatial configuration of the environment. Distribution of cues encountered naturally and their dependence on physical properties of an auditory scene have not been studied before. In the present work we analyzed statistics of naturally encountered binaural sounds. We performed binaural recordings of three auditory scenes with varying spatial configuration and analyzed empirical cue distributions from each scene. We have found that certain properties such as the spread of IPD distributions as well as an overall shape of ILD distributions do not vary strongly between different auditory scenes. Moreover, we found that ILD distributions vary much weaker across frequency channels and IPDs often attain much higher values, than can be predicted from head filtering properties. In order to understand the complexity of the binaural hearing task in the natural environment, sound waveforms were analyzed by performing Independent Component Analysis (ICA. Properties of learned basis functions indicate that in natural conditions soundwaves in each ear are predominantly generated by independent sources. This implies that the real-world sound localization must rely on mechanisms more complex than a mere cue extraction.

  20. Statistics of natural binaural sounds.

    Science.gov (United States)

    Młynarski, Wiktor; Jost, Jürgen

    2014-01-01

    Binaural sound localization is usually considered a discrimination task, where interaural phase (IPD) and level (ILD) disparities at narrowly tuned frequency channels are utilized to identify a position of a sound source. In natural conditions however, binaural circuits are exposed to a stimulation by sound waves originating from multiple, often moving and overlapping sources. Therefore statistics of binaural cues depend on acoustic properties and the spatial configuration of the environment. Distribution of cues encountered naturally and their dependence on physical properties of an auditory scene have not been studied before. In the present work we analyzed statistics of naturally encountered binaural sounds. We performed binaural recordings of three auditory scenes with varying spatial configuration and analyzed empirical cue distributions from each scene. We have found that certain properties such as the spread of IPD distributions as well as an overall shape of ILD distributions do not vary strongly between different auditory scenes. Moreover, we found that ILD distributions vary much weaker across frequency channels and IPDs often attain much higher values, than can be predicted from head filtering properties. In order to understand the complexity of the binaural hearing task in the natural environment, sound waveforms were analyzed by performing Independent Component Analysis (ICA). Properties of learned basis functions indicate that in natural conditions soundwaves in each ear are predominantly generated by independent sources. This implies that the real-world sound localization must rely on mechanisms more complex than a mere cue extraction.

  1. Stimulation of demand response through evaluation and training

    International Nuclear Information System (INIS)

    Encinas, N.; Alfonso, D.; Alvarez, C.; Mendez, C.; Rodriguez, J.; Perez-Navarro, A.; Gabaldon, A.

    2004-01-01

    The objective of Demand Response is to enhance customer choice opportunities by means of price-responsive mechanisms in contrast to direct load control practices and associated revenues based on fixed incentives. In this way, the new approach complements the traditional concept of Demand Side Management by including the voluntary nature to customer participation. This voluntary feature implies a change in customers' traditional behaviour and therefore stimulation and training is needed to achieve an optimal participation. This paper presents a methodology developed to stimulate and train customers for Demand Response practices as well as to identify the suitable products for different customers. Finally, the paper includes an example of the methodology considering a university as a customer. (au)

  2. Nature and nature values in organic agriculture

    DEFF Research Database (Denmark)

    Hansen, Lene; Noe, Egon; Højring, Katrine

    2006-01-01

    The relationship between agriculture and nature is a centra issue in the current agricultural debate. Organic farming has ambitions and a special potential in relation to nature. Consideration for nature is part of the guiding principals of organic farming and many organic farmers are committed...... to protecting natural qualities. However, the issue of nature, landscape, and land use is not straightforward. Nature is an ambiguous concept that involves multiple interests and actors reaching far beyond farmers. The Danish research project ......

  3. Multisensory stimulation in stroke rehabilitation

    Directory of Open Access Journals (Sweden)

    Barbro Birgitta Johansson

    2012-04-01

    Full Text Available The brain has a large capacity for automatic simultaneous processing and integration of sensory information. Combining information from different sensory modalities facilitates our ability to detect, discriminate, and recognize sensory stimuli, and learning is often optimal in a multisensory environment. Currently used multisensory stimulation methods in stroke rehabilitation include motor imagery, action observation, training with a mirror or in a virtual environment, or various kinds of music therapy. Several studies have shown positive effects been reported but to give general recommendation more studies are needed. Patient heterogeneity and the interactions of age, gender, genes and environment are discussed. Randomized controlled longitudinal trials starting earlier post stroke are needed. The advance in brain network science and neuroimaging enabling longitudinal studies of structural and functional networks are likely to have an important impact on patient selection for specific interventions in future stroke rehabilitation.

  4. Efficacy of natural cycle IVF: a review of the literature

    NARCIS (Netherlands)

    Pelinck, M. J.; Hoek, A.; Simons, A. H. M.; Heineman, M. J.

    2002-01-01

    Since the introduction of IVF treatments, natural cycle IVF has been largely replaced by IVF with ovarian stimulation. However, natural cycle IVF has several advantages. It is associated with a close to zero multiple pregnancy rate, and a zero risk of ovarian hyperstimulation syndrome. Per cycle,

  5. Efficacy of natural cycle IVF : a review of the literature

    NARCIS (Netherlands)

    Pelinck, MJ; Hoek, A; Simons, AHM; Heineman, MJ

    2002-01-01

    Since the introduction of IVF treatments, natural cycle IVF has been largely replaced by IVF with ovarian stimulation. However, natural cycle IVF has several advantages. It is associated with a close to zero multiple pregnancy rate, and a zero risk of ovarian hyperstimulation syndrome. Per cycle,

  6. Non-invasive neural stimulation

    Science.gov (United States)

    Tyler, William J.; Sanguinetti, Joseph L.; Fini, Maria; Hool, Nicholas

    2017-05-01

    Neurotechnologies for non-invasively interfacing with neural circuits have been evolving from those capable of sensing neural activity to those capable of restoring and enhancing human brain function. Generally referred to as non-invasive neural stimulation (NINS) methods, these neuromodulation approaches rely on electrical, magnetic, photonic, and acoustic or ultrasonic energy to influence nervous system activity, brain function, and behavior. Evidence that has been surmounting for decades shows that advanced neural engineering of NINS technologies will indeed transform the way humans treat diseases, interact with information, communicate, and learn. The physics underlying the ability of various NINS methods to modulate nervous system activity can be quite different from one another depending on the energy modality used as we briefly discuss. For members of commercial and defense industry sectors that have not traditionally engaged in neuroscience research and development, the science, engineering and technology required to advance NINS methods beyond the state-of-the-art presents tremendous opportunities. Within the past few years alone there have been large increases in global investments made by federal agencies, foundations, private investors and multinational corporations to develop advanced applications of NINS technologies. Driven by these efforts NINS methods and devices have recently been introduced to mass markets via the consumer electronics industry. Further, NINS continues to be explored in a growing number of defense applications focused on enhancing human dimensions. The present paper provides a brief introduction to the field of non-invasive neural stimulation by highlighting some of the more common methods in use or under current development today.

  7. Technical review of the high energy gas stimulation technique

    Energy Technology Data Exchange (ETDEWEB)

    Haney, B.; Cuthill, D. [Computalog Ltd., Calgary, AB (Canada)

    1997-08-01

    High Energy Gas Stimulation (HEGS) or propellant stimulation is a process that enhances production of oil wells by decreasing wellbore damage and increasing near wellbore permeability. The technique has been used on about 7,000 wells with varying results. The HEGS tool is a cast cylinder of solid rocket propellant with a central ignition system. The propellant is fired and as it burns it produces a pressure load on the formation, increasing fracture volume which enhances the flow channels. Background information on the development and application of this stimulation technique was provided. The introduction of fractures around a wellbore is dependent on the pressure loading rate and the dynamic response of the rock. Propellant stimulation relies on controlling the pressure-time behaviour to maximize fracture growth by fluid pressurization. The process is composed of 3 sequential phases: (1) wellbore pressurization, (2) fracture initiation, and (3) fracture extension. A full description of each of these phases was provided. Geologic and well-tool factors that have a significant influence on the fracturing process such as in-situ stress, natural fractures and flaws, formation mechanical properties, formation fluid and flow properties, formation thermal properties, and wellbore, tool, and tamp configuration, were also reviewed. The many applications for HEGS were presented. It was emphasized that the success of HEGS is dependent on pre-stimulation problem evaluation and on proper charge design. Since HEGS will decrease near-wellbore restrictions and initiate formation breakdown, it should only be used in cases where this will be beneficial to the well. Careful attention to engineering will optimize results. 21 refs., 13 figs.

  8. Consensus paper: combining transcranial stimulation with neuroimaging

    DEFF Research Database (Denmark)

    Siebner, Hartwig R; Bergmann, Til O; Bestmann, Sven

    2009-01-01

    neuroimaging (online approach), TMS can be used to test how focal cortex stimulation acutely modifies the activity and connectivity in the stimulated neuronal circuits. TMS and neuroimaging can also be separated in time (offline approach). A conditioning session of repetitive TMS (rTMS) may be used to induce...... information obtained by neuroimaging can be used to define the optimal site and time point of stimulation in a subsequent experiment in which TMS is used to probe the functional contribution of the stimulated area to a specific task. In this review, we first address some general methodologic issues that need......In the last decade, combined transcranial magnetic stimulation (TMS)-neuroimaging studies have greatly stimulated research in the field of TMS and neuroimaging. Here, we review how TMS can be combined with various neuroimaging techniques to investigate human brain function. When applied during...

  9. Bursting behaviours in cascaded stimulated Brillouin scattering

    International Nuclear Information System (INIS)

    Liu Zhan-Jun; He Xian-Tu; Zheng Chun-Yang; Wang Yu-Gang

    2012-01-01

    Stimulated Brillouin scattering is studied by numerically solving the Vlasov—Maxwell system. A cascade of stimulated Brillouin scattering can occur when a linearly polarized laser pulse propagates in a plasma. It is found that a stimulated Brillouin scattering cascade can reduce the scattering and increase the transmission of light, as well as introduce a bursting behaviour in the evolution of the laser-plasma interaction. The bursting time in the reflectivity is found to be less than half the ion acoustic period. The ion temperature can affect the stimulated Brillouin scattering cascade, which can repeat several times at low ion temperatures and can be completely eliminated at high ion temperatures. For stimulated Brillouin scattering saturation, higher-harmonic generation and wave—wave interaction of the excited ion acoustic waves can restrict the amplitude of the latter. In addition, stimulated Brillouin scattering cascade can restrict the amplitude of the scattered light. (physics of gases, plasmas, and electric discharges)

  10. Mimicking muscle activity with electrical stimulation

    Science.gov (United States)

    Johnson, Lise A.; Fuglevand, Andrew J.

    2011-02-01

    Functional electrical stimulation is a rehabilitation technology that can restore some degree of motor function in individuals who have sustained a spinal cord injury or stroke. One way to identify the spatio-temporal patterns of muscle stimulation needed to elicit complex upper limb movements is to use electromyographic (EMG) activity recorded from able-bodied subjects as a template for electrical stimulation. However, this requires a transfer function to convert the recorded (or predicted) EMG signals into an appropriate pattern of electrical stimulation. Here we develop a generalized transfer function that maps EMG activity into a stimulation pattern that modulates muscle output by varying both the pulse frequency and the pulse amplitude. We show that the stimulation patterns produced by this transfer function mimic the active state measured by EMG insofar as they reproduce with good fidelity the complex patterns of joint torque and joint displacement.

  11. Noninvasive transcranial brain stimulation and pain.

    Science.gov (United States)

    Rosen, Allyson C; Ramkumar, Mukund; Nguyen, Tam; Hoeft, Fumiko

    2009-02-01

    Transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) are two noninvasive brain stimulation techniques that can modulate activity in specific regions of the cortex. At this point, their use in brain stimulation is primarily investigational; however, there is clear evidence that these tools can reduce pain and modify neurophysiologic correlates of the pain experience. TMS has also been used to predict response to surgically implanted stimulation for the treatment of chronic pain. Furthermore, TMS and tDCS can be applied with other techniques, such as event-related potentials and pharmacologic manipulation, to illuminate the underlying physiologic mechanisms of normal and pathological pain. This review presents a description and overview of the uses of two major brain stimulation techniques and a listing of useful references for further study.

  12. Transcranial electrical stimulation accelerates human sleep homeostasis.

    Directory of Open Access Journals (Sweden)

    Davide Reato

    Full Text Available The sleeping brain exhibits characteristic slow-wave activity which decays over the course of the night. This decay is thought to result from homeostatic synaptic downscaling. Transcranial electrical stimulation can entrain slow-wave oscillations (SWO in the human electro-encephalogram (EEG. A computational model of the underlying mechanism predicts that firing rates are predominantly increased during stimulation. Assuming that synaptic homeostasis is driven by average firing rates, we expected an acceleration of synaptic downscaling during stimulation, which is compensated by a reduced drive after stimulation. We show that 25 minutes of transcranial electrical stimulation, as predicted, reduced the decay of SWO in the remainder of the night. Anatomically accurate simulations of the field intensities on human cortex precisely matched the effect size in different EEG electrodes. Together these results suggest a mechanistic link between electrical stimulation and accelerated synaptic homeostasis in human sleep.

  13. Understanding the True Stimulated Reservoir Volume in Shale Reservoirs

    KAUST Repository

    Hussain, Maaruf

    2017-06-06

    Successful exploitation of shale reservoirs largely depends on the effectiveness of hydraulic fracturing stimulation program. Favorable results have been attributed to intersection and reactivation of pre-existing fractures by hydraulically-induced fractures that connect the wellbore to a larger fracture surface area within the reservoir rock volume. Thus, accurate estimation of the stimulated reservoir volume (SRV) becomes critical for the reservoir performance simulation and production analysis. Micro-seismic events (MS) have been commonly used as a proxy to map out the SRV geometry, which could be erroneous because not all MS events are related to hydraulic fracture propagation. The case studies discussed here utilized a fully 3-D simulation approach to estimate the SRV. The simulation approach presented in this paper takes into account the real-time changes in the reservoir\\'s geomechanics as a function of fluid pressures. It is consisted of four separate coupled modules: geomechanics, hydrodynamics, a geomechanical joint model for interfacial resolution, and an adaptive re-meshing. Reservoir stress condition, rock mechanical properties, and injected fluid pressure dictate how fracture elements could open or slide. Critical stress intensity factor was used as a fracture criterion governing the generation of new fractures or propagation of existing fractures and their directions. Our simulations were run on a Cray XC-40 HPC system. The studies outcomes proved the approach of using MS data as a proxy for SRV to be significantly flawed. Many of the observed stimulated natural fractures are stress related and very few that are closer to the injection field are connected. The situation is worsened in a highly laminated shale reservoir as the hydraulic fracture propagation is significantly hampered. High contrast in the in-situ stresses related strike-slip developed thereby shortens the extent of SRV. However, far field nature fractures that were not connected to

  14. Particle trapping in stimulated scattering processes

    International Nuclear Information System (INIS)

    Karttunen, S.J.; Heikkinen, J.A.

    1981-01-01

    Particle trapping effects on stimulated Brillouin and Raman scattering are investigated. A time and space dependent model assumes a Maxwellian plasma which is taken to be homogeneous in the interaction region. Ion trapping has a rather weak effect on stimulated Brillouin scattering and large reflectivities are obtained even in strong trapping regime. Stimulated Raman scattering is considerably reduced by electron trapping. Typically 15-20 times larger laser intensities are required to obtain same reflectivity levels than without trapping. (author)

  15. Step-wise stimulated martensitic transformations

    International Nuclear Information System (INIS)

    Airoldi, G.; Riva, G.

    1991-01-01

    NiTi alloys, widely known both for their shape memory properties and for unusual pseudoelastic behaviour, are now on the forefront attention for step-wise induced memory processes, thermal or stress stimulated. Literature results related to step-wise stimulated martensite (direct transformation) are examined and contrasted with step-wise thermal stimulated parent phase (reverse transformation). Hypothesis are given to explain the key characters of both transformations, a thermodynamic model from first principles being till now lacking

  16. Analysis of Facial Expression by Taste Stimulation

    Science.gov (United States)

    Tobitani, Kensuke; Kato, Kunihito; Yamamoto, Kazuhiko

    In this study, we focused on the basic taste stimulation for the analysis of real facial expressions. We considered that the expressions caused by taste stimulation were unaffected by individuality or emotion, that is, such expressions were involuntary. We analyzed the movement of facial muscles by taste stimulation and compared real expressions with artificial expressions. From the result, we identified an obvious difference between real and artificial expressions. Thus, our method would be a new approach for facial expression recognition.

  17. Geothermal Reservoir Well Stimulation Program: technology transfer

    Energy Technology Data Exchange (ETDEWEB)

    1980-05-01

    A literature search on reservoir and/or well stimulation techniques suitable for application in geothermal fields is presented. The literature on stimulation techniques in oil and gas field applications was also searched and evaluated as to its relevancy to geothermal operations. The equivalent low-temperature work documented in the open literature is cited, and an attempt is made to evaluate the relevance of this information as far as high-temperature stimulation work is concerned. Clays play an important role in any stimulation work. Therefore, special emphasis has been placed on clay behavior anticipated in geothermal operations. (MHR)

  18. Studies in dosimetry using stimulated exoelectron emission

    International Nuclear Information System (INIS)

    Petel, Maurice.

    1976-06-01

    Some applications of the stimulated exoelectron emission in radiation dosimetry are discussed. The principles which govern the phenomenon are presented. The apparatus, in particular the counter, used to monitor the emission is discussed with reference to both optical and thermal stimulation. The correlation existing between thermoluminescence and thermally stimulated exoelectron emission were studied in both lithium fluoride and aluminium oxide. Furthermore, aluminium oxides from different sources were examined, and one of these, chosen to investigate the dosimetric properties of this material using both methods of stimulation [fr

  19. Optical stimulation of peripheral nerves in vivo

    Science.gov (United States)

    Wells, Jonathon D.

    This dissertation documents the emergence and validation of a new clinical tool that bridges the fields of biomedical optics and neuroscience. The research herein describes an innovative method for direct neurostimulation with pulsed infrared laser light. Safety and effectiveness of this technique are first demonstrated through functional stimulation of the rat sciatic nerve in vivo. The Holmium:YAG laser (lambda = 2.12 mum) is shown to operate at an optimal wavelength for peripheral nerve stimulation with advantages over standard electrical neural stimulation; including contact-free stimulation, high spatial selectivity, and lack of a stimulation artifact. The underlying biophysical mechanism responsible for transient optical nerve stimulation appears to be a small, absorption driven thermal gradient sustained at the axonal layer of nerve. Results explicitly prove that low frequency optical stimulation can reliably stimulate without resulting in tissue thermal damage. Based on the positive results from animal studies, these optimal laser parameters were utilized to move this research into the clinic with a combined safety and efficacy study in human subjects undergoing selective dorsal rhizotomy. The clinical Holmium:YAG laser was used to effectively stimulate human dorsal spinal roots and elicit functional muscle responses recorded during surgery without evidence of nerve damage. Overall these results predict that this technology can be a valuable clinical tool in various neurosurgical applications.

  20. Thermally stimulated luminescence and photoluminescence ...

    Indian Academy of Sciences (India)

    2012-01-13

    Jan 13, 2012 ... red to ultraviolet, which depends on the crystal structure of host materials ..... to strong anisotropic nature of the fine structure (fs) transi- tion(s), other .... 39 2065. Pan Shilie, Wu Yicheng, Fu Peizhen, Zhang Guochun, Li Zhihua,.