Read Books Online and Download eBooks, EPub, PDF, Mobi, Kindle, Text Full Free.
Bystander Effects Due To Neutrons And Low Dose Hyperradiosensitivity To Gamma Rays In Human Cells Using Cytogenetics
Download Bystander Effects Due To Neutrons And Low Dose Hyperradiosensitivity To Gamma Rays In Human Cells Using Cytogenetics full books in PDF, epub, and Kindle. Read online Bystander Effects Due To Neutrons And Low Dose Hyperradiosensitivity To Gamma Rays In Human Cells Using Cytogenetics ebook anywhere anytime directly on your device. Fast Download speed and no annoying ads. We cannot guarantee that every ebooks is available!
Book Synopsis Bystander Effects Due to Neutrons, and Low-dose Hyperradiosensitivity to Gamma Rays in Human Cells Using Cytogenetics by : Isheeta Seth
Download or read book Bystander Effects Due to Neutrons, and Low-dose Hyperradiosensitivity to Gamma Rays in Human Cells Using Cytogenetics written by Isheeta Seth and published by . This book was released on 2014 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chapter 2: Micronuclei have been used extensively in studies as an easily-evaluated indicator of DNA damage but little is known about their association with other types of damage such as nucleoplasmic bridges and nuclear buds. Radiation-induced clastogenic events were evaluated via the cytokinesis-block micronucleus assay in two normal human lymphoblastoid cell lines exposed to neutrons or gamma radiation. Micronuclei, nucleoplasmic bridges and nuclear buds were enumerated by recording the coincident presence of these endpoints within individual cells, and the associations among these three endpoints were evaluated for all treatment conditions. The common odds ratios for micronuclei and nucleoplasmic bridges were found to be significantly larger than unity, indicating that the presence of one or more micronuclei in a cell imposes a significant risk for having one or more nucleoplasmic bridges in that same cell, and vice versa. The strength of this association did not change significantly with radiation dose. Common odds ratios for association between micronuclei and buds, and between bridges and buds were also found to be significantly higher than unity. However, associations between micronuclei and buds could not be calculated for some treatments due to heterogeneity in the odds ratios, and hence may depend on radiation dose. This study provides evidence for how paired analyses among genetic endpoints in the cytokinesis-block micronucleus assay can provide information concerning abnormalities of cell division and possibly about structural chromosomal rearrangements induced by radiation. Chapter 3: Bystander effects have been observed repeatedly in mammalian cells following photon and alpha particle irradiation. However, few studies have been performed to investigate bystander effects arising from neutron irradiation. Here we asked whether neutrons also induce a bystander effect in two normal human lymphoblastoid cell lines.
Book Synopsis Cytogenetic Evaluation of Low Dose Hyper-radiosensitivity in Human Lymphoblastoid Cell Lines Exposed to Cobalt-60 Gamma Radiation by : Gnanada S. Joshi
Download or read book Cytogenetic Evaluation of Low Dose Hyper-radiosensitivity in Human Lymphoblastoid Cell Lines Exposed to Cobalt-60 Gamma Radiation written by Gnanada S. Joshi and published by . This book was released on 2014 with total page 97 pages. Available in PDF, EPUB and Kindle. Book excerpt: For cells irradiated in an atmosphere of 5% O2, subsequent immediate re-oxygenation to ambient O2 levels restored the HRS effect, while cells cultured and irradiated at ambient O2 levels and then transferred to 5% O2 exhibited little or no HRS, indicating that ambient O2 levels after, but not before, radiation substantially affect the amounts of cytogenetic damage. HRS was not observed when cells were irradiated in G1. At doses of 40 - 400 cGy there was significantly less cytogenetic damage when cells were recovering from radiation at low O2 levels than at ambient O2 levels. Here we provide the first cytogenetic evidence for the loss of HRS at low O2 levels in G2-irradiated cells; these results suggest that at low O2 levels for all doses evaluated there is either less damage to DNA, perhaps due to lower amounts of reactive oxygen species, or that DNA damage repair pathways are activated more efficiently.
Book Synopsis Lack of Bystander Effects From High LET Radiation For Early Cytogenetic Endpoints by :
Download or read book Lack of Bystander Effects From High LET Radiation For Early Cytogenetic Endpoints written by and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The aim of this work was to study radiation-induced bystander effects for early cytogenetic end points in various cell lines using the medium transfer technique after exposure to high- and low-LET radiation. Cells were exposed to 20 MeV/ nucleon nitrogen ions, 968 MeV/nucleon iron ions, or 575 MeV/nucleon iron ions followed by transfer of the conditioned medium from the irradiated cells to unirradiated test cells. The effects studied included DNA double-strand break induction, [gamma]-H2AX focus formation, induction of chromatid breaks in prematurely condensed chromosomes, and micronucleus formation using DNA repair-proficient and -deficient hamster and human cell lines (xrs6, V79, SW48, MO59K and MO59J). Cell survival was also measured in SW48 bystander cells using X rays. Although it was occasionally possible to detect an increase in chromatid break levels using nitrogen ions and to see a higher number of [gamma]-H2AX foci using nitrogen and iron ions in xrs6 bystander cells in single experiments, the results were not reproducible. After we pooled all the data, we could not verify a significant bystander effect for any of these end points. Also, we did not detect a significant bystander effect for DSB induction or micronucleus formation in these cell lines or for clonogenic survival in SW48 cells. The data suggest that DNA damage and cytogenetic changes are not induced in bystander cells. In contrast, data in the literature show pronounced bystander effects in a variety of cell lines, including clonogenic survival in SW48 cells and induction of chromatid breaks and micronuclei in hamster cells. To reconcile these conflicting data, it is possible that the epigenetic status of the specific cell line or the precise culture conditions and medium supplements, such as serum, may be critical for inducing bystander effects.
Book Synopsis Biological Effects of Neutron Irradiation by : International Atomic Energy Agency
Download or read book Biological Effects of Neutron Irradiation written by International Atomic Energy Agency and published by . This book was released on 1974 with total page 506 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author :Committee to Assess Health Risks from Exposure to Low Levels of Ionizing Radiation Publisher :National Academies Press ISBN 13 :0309133343 Total Pages :422 pages Book Rating :4.3/5 (91 download)
Book Synopsis Health Risks from Exposure to Low Levels of Ionizing Radiation by : Committee to Assess Health Risks from Exposure to Low Levels of Ionizing Radiation
Download or read book Health Risks from Exposure to Low Levels of Ionizing Radiation written by Committee to Assess Health Risks from Exposure to Low Levels of Ionizing Radiation and published by National Academies Press. This book was released on 2006-03-23 with total page 422 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is the seventh in a series of titles from the National Research Council that addresses the effects of exposure to low dose LET (Linear Energy Transfer) ionizing radiation and human health. Updating information previously presented in the 1990 publication, Health Effects of Exposure to Low Levels of Ionizing Radiation: BEIR V, this book draws upon new data in both epidemiologic and experimental research. Ionizing radiation arises from both natural and man-made sources and at very high doses can produce damaging effects in human tissue that can be evident within days after exposure. However, it is the low-dose exposures that are the focus of this book. So-called “late” effects, such as cancer, are produced many years after the initial exposure. This book is among the first of its kind to include detailed risk estimates for cancer incidence in addition to cancer mortality. BEIR VII offers a full review of the available biological, biophysical, and epidemiological literature since the last BEIR report on the subject and develops the most up-to-date and comprehensive risk estimates for cancer and other health effects from exposure to low-level ionizing radiation.
Book Synopsis Radiation-induced Bystander Effects in HT-29 Cell Culture by : Jennifer Bain Pafford
Download or read book Radiation-induced Bystander Effects in HT-29 Cell Culture written by Jennifer Bain Pafford and published by . This book was released on 2012 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Effects of Low-dose Radiation on Gene Expression in Syrian Hamster Embryo Cells by :
Download or read book Effects of Low-dose Radiation on Gene Expression in Syrian Hamster Embryo Cells written by and published by . This book was released on 1992 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: Past work by or group and others has shown the modulation of specific genes following exposure of cells to ionizing radiation. Many classes of genes have been found to be modulated in response to ionizing radiation, including those encoding cytoskeletal elements, cell growth arresting proteins, cytokines, and cellular oncogenes. The functions of this specific modulation of gene expression are currently being investigated by several groups: it has been suggested that gene modulation in response to radiation plays a role in the cellular repair of DNA damage, cell survival, or cellular transformation. Several groups have examined induction of nuclear proto-oncogenes following exposure to DNA-damaging agents. In all experiments, we examined modulation of gene expression by ionizing radiations in Syrian hamster embryo (SHE) fibroblasts, which are normal diploid cells that can be neoplastically transformed by low doses of ionizing radiations. Cells plated in 100-mm Petri plates containing 10 ml of medium were irradiated with 6°C?-rays or fission-spectrum neutrons (0.85 MeV) from the JANUS reactor. All irradiations were performed at 37°C on cycling cells; equitoxic doses of neutrons and?-rays were selected on the basis of survival data.
Book Synopsis Radiation Induced Bystander Effects in Human Lymphoblastoid Cells by : Defence R & D Canada - Ottawa
Download or read book Radiation Induced Bystander Effects in Human Lymphoblastoid Cells written by Defence R & D Canada - Ottawa and published by Defence R&D Canada - Ottawa. This book was released on 2003 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Studies of Bystander Effects in 3-D Tissue Systems Using a Low-LET Microbeam by :
Download or read book Studies of Bystander Effects in 3-D Tissue Systems Using a Low-LET Microbeam written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: It is now accepted that biological effects may occur in cells that were not themselves traversed by ionizing radiation but are close to those that were. Little is known about the mechanism underlying such a bystander effect, although cell-to-cell communication is thought to be important. Previous work demonstrated a significant bystander effect for clonogenic survival and oncogenic transformation in C3H 10T1/2 cells. Additional studies were undertaken to assess the importance of the degree of cell-to-cell contact at the time of irradiation on the magnitude of this bystander effect by varying the cell density. When 10% of cells were exposed to a range of 2-12 alpha particles, a significantly greater number of cells were inactivated when cells were irradiated at high density than at low density. In addition, the oncogenic transformation frequency was significantly higher in high-density cultures. These results suggest that when a cell is hit by radiation, the transmission of the bystander signal through cell-to-cell contact is an important mediator of the effect, implicating the involvement of intracellular communication through gap junctions. Additional studies to address the relationship between the bystander effect and the adaptive response were undertaken. A novel apparatus, where targeted and non-targeted cells were grown in close proximity, was used to investigate these. It was further examined whether a bystander effect or an adaptive response could be induced by a factor(s) present in the supernatants of cells exposed to a high or low dose of X-rays, respectively. When non-hit cells were co-cultured for 24 h with cells irradiated with 5 Gy alpha-particles, a significant increase in both cell killing and oncogenic transformation frequency was observed. If these cells were treated with 2 cGy X-rays 5 h before co-culture with irradiated cells, approximately 95% of the bystander effect was cancelled out. A 2.5-fold decrease in the oncogenic transformation frequency was also observed. When cells were cultured in medium donated from cells exposed to 5 Gy X-rays, a significant bystander effect was observed for clonogenic survival. When cells were cultured for 5 h with supernatant from donor cells exposed to 2 cGy and were then irradiated with 4 Gy X-rays, they failed to show an increase in survival compared with cells directly irradiated with 4 Gy. However, a twofold reduction in the oncogenic transformation frequency was seen. An adaptive dose of X-rays cancelled out the majority of the bystander effect produced by alpha-particles. For oncogenic transformation, but not cell survival, radioadaption can occur in unirradiated cells via a transmissible factor(s). A pilot study was undertaken to observe the bystander effect in a realistic multicellular three-dimensional morphology. We found bystander responses in a three-dimensional, normal human-tissue system. Endpoints were induction of micronucleated and apoptotic cells. A charged-particle microbeam was used, allowing irradiation of cells in defined locations in the tissue yet guaranteeing that no cells located more than a few micrometers away receive any radiation exposure. Unirradiated cells up to 1 mm distant from irradiated cells showed a significant enhancement in effect over background, with an average increase in effect of 1.7-fold for micronuclei and 2.8-fold for apoptosis. The surprisingly long range of bystander signals in human tissue suggests that bystander responses may be important in extrapolating radiation risk estimates from epidemiologically accessible doses down to very low doses where nonhit bystander cells will predominate. Finally, it would be of great benefit to develop a reproducible tissue system suitable for critical radiobiological assays. We have developed a reliable protocol to harvest cells from tissue samples and to investigate the damage induced on a single cell basis. In order to result in a valid tool for bystander experiments, the method focuses on processing and analyzing radiation damage in individual cells as a function of their relative position in the tissue. We have investigated the micronucleus formation following partial irradiation with 3.5 MeV protons in an artificial human skin construct. Following the optimization of the Cytochalasin-B concentration and incubation time necessary to obtain a reproducible and suitable number of binucleated cells, the induction of micronuclei across the samples is assessed for 3 dose. The reproducible and low background frequency of micronuclei measured in this system allowed us to detect small increases following the irradiation exposure. The effect is statistically significant at doses as low as 0.1 Gy and it shows evidence of a spatial dependency as it decreases in the cells further away from the directly exposed area. This experimental protocol represents the initial steps in the development of an in vivo-like assay for complex radiation damage in human tissues.
Book Synopsis Analysis of Cancer Risks in Populations Near Nuclear Facilities by : National Research Council
Download or read book Analysis of Cancer Risks in Populations Near Nuclear Facilities written by National Research Council and published by National Academies Press. This book was released on 2012-06-29 with total page 424 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the late 1980s, the National Cancer Institute initiated an investigation of cancer risks in populations near 52 commercial nuclear power plants and 10 Department of Energy nuclear facilities (including research and nuclear weapons production facilities and one reprocessing plant) in the United States. The results of the NCI investigation were used a primary resource for communicating with the public about the cancer risks near the nuclear facilities. However, this study is now over 20 years old. The U.S. Nuclear Regulatory Commission requested that the National Academy of Sciences provide an updated assessment of cancer risks in populations near USNRC-licensed nuclear facilities that utilize or process uranium for the production of electricity. Analysis of Cancer Risks in Populations near Nuclear Facilities: Phase 1 focuses on identifying scientifically sound approaches for carrying out an assessment of cancer risks associated with living near a nuclear facility, judgments about the strengths and weaknesses of various statistical power, ability to assess potential confounding factors, possible biases, and required effort. The results from this Phase 1 study will be used to inform the design of cancer risk assessment, which will be carried out in Phase 2. This report is beneficial for the general public, communities near nuclear facilities, stakeholders, healthcare providers, policy makers, state and local officials, community leaders, and the media.
Book Synopsis Health Effects of Exposure to Low Levels of Ionizing Radiation by : National Research Council
Download or read book Health Effects of Exposure to Low Levels of Ionizing Radiation written by National Research Council and published by National Academies. This book was released on 1990-02-01 with total page 436 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book reevaluates the health risks of ionizing radiation in light of data that have become available since the 1980 report on this subject was published. The data include new, much more reliable dose estimates for the A-bomb survivors, the results of an additional 14 years of follow-up of the survivors for cancer mortality, recent results of follow-up studies of persons irradiated for medical purposes, and results of relevant experiments with laboratory animals and cultured cells. It analyzes the data in terms of risk estimates for specific organs in relation to dose and time after exposure, and compares radiation effects between Japanese and Western populations.
Book Synopsis Multiple Stressors: A Challenge for the Future by : Carmel Mothersill
Download or read book Multiple Stressors: A Challenge for the Future written by Carmel Mothersill and published by Springer Science & Business Media. This book was released on 2007-08-20 with total page 483 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ecotoxiclogical risk from multiple stressors covers any situation where org- isms are exposed to a combination of environmental stressors. These include physical and chemical pollutants as well as other stressors such as parasites and environmental impact (e. g. , climate change or habitat loss). The combi- tion of stressors can result in increased risk to organisms (either additive or synergistic effects) or decreased effects (protective or antagonistic effects). The multiple stressor challenge is an international, multi-disciplinary problem requiring an international, multi-disciplinary approach. The c- rent approach to multiple stressors is to examine one stressor at a time and assume additivity. Little work has been done on combinations of stressors such that potential interactions can be determined. The problem is very complex. Multiple stressors pose a whole spectrum of challenges that range from basic science to regulation, policy and gove- ance. The challenges raise fundamental questions about our understanding of the basic biological response to stressors, as well as the implications of those uncertainties in environmental risk assessment and management. In addition to the great breadth, there is also great depth in the research ch- lenges, largely due to the complexity of the issues. From a basic science point of view, many of the mechanisms and processes under investigation are at the cutting edge of science — involving new paradigms such as genomic ins- bility and bystander effects.
Book Synopsis Principles of Clinical Medicine for Space Flight by : Michael R. Barratt
Download or read book Principles of Clinical Medicine for Space Flight written by Michael R. Barratt and published by Springer Science & Business Media. This book was released on 2008-03-20 with total page 592 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the years, a large body of knowledge has developed regarding the ways in which space flight affects the health of the personnel involved. Now, for the first time, this clinical knowledge on how to diagnose and treat conditions that either develop during a mission or because of a mission has been compiled by Drs. Michael Barratt and Sam L. Pool of the NASA/Johnson Space Center. Complete with detailed information on the physiological and psychological affects of space flight as well as how to diagnose and treat everything from dental concerns to decompression to dermatological problems encountered, this text is a must have for all those associated with aerospace medicine.
Author :IARC Working Group on the Evaluation of Carcinogenic Risks to Humans Publisher : ISBN 13 : Total Pages :620 pages Book Rating :4.3/5 (91 download)
Book Synopsis Ionizing Radiation, Part 2 by : IARC Working Group on the Evaluation of Carcinogenic Risks to Humans
Download or read book Ionizing Radiation, Part 2 written by IARC Working Group on the Evaluation of Carcinogenic Risks to Humans and published by . This book was released on 2001 with total page 620 pages. Available in PDF, EPUB and Kindle. Book excerpt: Evaluates the evidence for carcinogenicity of ionizing radiation from internally deposited radionuclides. The radionuclides considered belong to two broad categories, those that emit a-particles (helium nuclei) and those that emit b-particles (electrons).
Download or read book Cumulated Index Medicus written by and published by . This book was released on 2000 with total page 1844 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Report of the Committee Examining Radiation Risks of Internal Emitters (CERRIE). by : Great Britain. Committee Examining Radiation Risks of Internal Emitters
Download or read book Report of the Committee Examining Radiation Risks of Internal Emitters (CERRIE). written by Great Britain. Committee Examining Radiation Risks of Internal Emitters and published by . This book was released on 2004 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Oncology written by Alfred E. Chang and published by Springer Science & Business Media. This book was released on 2007-12-08 with total page 2040 pages. Available in PDF, EPUB and Kindle. Book excerpt: Title consistently uses the evidence-based approach Evidence-based tables make documentation of care plan easy Interdisciplinary orientation – all aspects of patient care are covered Only book that involves experts from the entire range of cancer treatment in the fields of medical, surgical and radiation oncology Includes hot topics such as prevention and breast cancer Offers ground-breaking sections on the latest research and clinical applications in cancer survivorship Chapter on PET addresses imaging issues and how to get the best results Most comprehensive sections on the biology and epidemiology of cancer as compared to competitors
