Académie des Sciences [Academy of Sciences] - Académie nationale de Médecine
[National Academy of Medicine]
Dose-effect relationships and estimation of the carcinogenic effects
of low doses of ionizing radiation
http://www.radscihealth.org/rsh/Papers/FrenchAcadsFinal07_04_05.pdf
Epidemiological studies have been carried out to determine the possible carcinogenic risk of doses lower than 100 mSv, and they have not been able to detect statistically significant risks even on large cohorts or populations
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"La verdad absoluta no existe y esto es absolutamente cierto"
Les Luthiers.
Interesante informe del 2005.
Sin embargo no quedan claros los criterios de la revisión. No se relacionan y analizan los estudios revisados y sus características (tipo de exposición, por ejemplo) aunque si se habla (sólo he visto un párrafo) de que esto es válido para dosis internas (¡?) sin más explicación. No me es suficientemente clarificador.
Por otra parte, hay estudios más recientes que si detectan efectos nocivos de bajas dosis de radiación (médica, externa). En cualquier caso, mi posición actual, es que si bien puede haber una resistencia y adaptación a ciertos niveles bajos de radiación externa no lo creo, por no parecerme coherente, a la exposición interna por radionúclidos artificiales:
Int J Radiat Oncol Biol Phys. 2014 May 3. pii: S0360-3016(14)00335-6. doi: 10.1016/j.ijrobp.2014.03.019. [Epub ahead of print]
Neurochemical Evidence of Potential Neurotoxicity After Prophylactic Cranial Irradiation.
Kalm M1, Abel E2, Wasling P3, Nyman J2, Hietala MA4, Bremell D5, Hagberg L5, Elam M6, Blennow K7, Björk-Eriksson T2, Zetterberg H8.
Author information
• 1Department of Clinical Neuroscience and Rehabilitation, Insitute of Neuroscience and Physiology, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden. Electronic address:
marie.kalm@neuro.gu.se.
• 2Department of Oncology, Institute of Clinical Sciences, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.
• 3Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.
• 4Department of Neurology, Karolinska University Hospital, Stockholm, Sweden.
• 5Department of Infectious Diseases, Institute of Biomedicine, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.
• 6Department of Clinical Neuroscience and Rehabilitation, Insitute of Neuroscience and Physiology, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.
• 7Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden.
• 8Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden; UCL Institute of Neurology, London, United Kingdom.
Abstract
PURPOSE:
To examine whether cerebrospinal fluid biomarkers for neuroaxonal damage, neuroglial activation, and amyloid β-related processes could characterize the neurochemical response to cranial radiation.
METHODS AND MATERIALS:
Before prophylactic cranial irradiation (PCI) of patients with small cell lung cancer, each patient underwent magnetic resonance imaging of the brain, lumbar puncture, and Mini-Mental State Examination of cognitive function. These examinations were repeated at approximately 3 and 12 months after radiation.
RESULTS:
The major findings were as ***ows. (1) Cerebrospinal fluid markers for neuronal and neuroglial injury were elevated during the subacute phase after PCI. Neurofilament and T-tau increased 120% and 50%, respectively, after PCI (P<.05). The same was seen for the neuroglial markers YKL-40 and glial fibrillary acidic protein, which increased 144% and 106%, respectively, after PCI (P<.05). (2) The levels of secreted amyloid precursor protein-α and -β were reduced 44% and 46%, respectively, 3 months after PCI, and the levels continued to decrease as long as 1 year after treatment (P<.05). (3) Mini-Mental State Examination did not reveal any cognitive decline, indicating that a more sensitive test should be used in future studies.
CONCLUSION:
In conclusion, we were able to detect radiation therapy-induced changes in several markers reflecting neuronal injury, inflammatory/astroglial activation, and altered amyloid precursor protein/amyloid β metabolism, despite the low number of patients and quite moderate radiation doses (20-30 Gy). These changes are hypothesis generating and could potentially be used to assess the individual risk of developing long-term symptoms of chronic encephalopathy after PCI. This has to be evaluated in large studies with extended clinical ***ow-up and more detailed neurocognitive assessments.
Copyright © 2014 Elsevier Inc. All rights reserved.
Neurochemical Evidence of Poten... [Int J Radiat Oncol Biol Phys. 2014] - PubMed - NCBI
Aquat Toxicol. 2014 Jul;152:264-72. doi: 10.1016/j.aquatox.2014.04.005. Epub 2014 Apr 30.
Gamma rays induce DNA damage and oxidative stress associated with impaired growth and reproduction in the copepod Tigriopus japonicus.
Han J1, Won EJ1, Lee BY1, Hwang UK2, Kim IC3, Yim JH3, Leung KM4, Lee YS5, Lee JS6.
Author information
• 1Department of Biological Sciences, College of Science, Sungkyunkwan University, Suwon 440-746, South Korea.
• 2Marine Ecological Risk Assessment Center, West Sea Fisheries Research Institute, National Fisheries Research & Development Institute, Incheon 400-420, South Korea.
• 3Division of Life Sciences, Korea Polar Research Institute, Incheon 406-840, South Korea.
• 4School of Biological Sciences and the Swire Institute of Marine Science, The University of Hong Kong, Pokfulam Road, Hong Kong, China.
• 5Graduate School of Biomedical Science and Engineering, Hanyang University, Seoul 133-791, South Korea.
• 6Department of Biological Sciences, College of Science, Sungkyunkwan University, Suwon 440-746, South Korea. Electronic address:
jslee2@skku.edu.
Abstract
Nuclear radioisotope accidents are potentially ecologically devastating due to their impact on marine organisms. To examine the effects of exposure of a marine organism to radioisotopes, we irradiated the intertidal copepod Tigriopus japonicus with several doses of gamma radiation and analyzed the effects on mortality, fecundity, and molting by assessing antioxidant enzyme activities and gene expression patterns. No mortality was observed at 96h, even in response to exposure to a high dose (800Gy) of radiation, but mortality rate was significantly increased 120h (5 days) after exposure to 600 or 800Gy gamma ray radiation. We observed a dose-dependent reduction in fecundity of ovigerous females; even the group irradiated with 50Gy showed a significant reduction in fecundity, suggesting that gamma rays are likely to have a population level effect. In addition, we observed growth retardation, particularly at the nauplius stage, in individuals after gamma irradiation. In fact, nauplii irradiated with more than 200Gy, though able to molt to copepodite stage 1, did not develop into adults. Upon gamma radiation, T. japonicus showed a dose-dependent increase in reactive oxygen species (ROS) levels, the activities of several antioxidant enzymes, and expression of double-stranded DNA break damage genes (e.g. DNA-PK, Ku70, Ku80). At a low level (sub-lethal dose) of gamma irradiation, we found dose-dependent upregulation of p53, implying cellular damage in T. japonicus in response to sub-lethal doses of gamma irradiation, suggesting that T. japonicus is not susceptible to sub-lethal doses of gamma irradiation. Additionally, antioxidant genes, phase II enzyme (e.g. GSTs), and cellular cafrene genes (e.g. Hsps) that are involved in cellular defense mechanisms also showed the same expression patterns for sublethal doses of gamma irradiation (50-200Gy). These findings indicate that sublethal doses of gamma radiation can induce oxidative stress-mediated DNA damage and increase the expression of antioxidant enzymes and proteins with cafrene-related functions, thereby significantly affecting life history parameters such as fecundity and molting in the copepod T. japonicus.
Copyright © 2014 Elsevier B.V. All rights reserved.
Gamma rays induce DNA damage and oxidative str... [Aquat Toxicol. 2014] - PubMed - NCBI
En otro orden de cosas:
el aceite de lino (que debe ser de extracción en frío, no se puede calentar, exponer a la luz o al aíre)
parece tener un papel protector frente a diversos aspectos de la radiación a bajas dosis:
Asian Pac J Cancer Prev. 2014;15(6):2405-25.
Plant extracts and plant-derived compounds: promising players in a countermeasure strategy against radiological exposure.
Kma L.
Author information
• Cancer and Radiation Countermeasures Unit, Department of Biochemistry, North-Eastern Hill University, Meghalaya, India E-mail :
lakhonkma@gmail.com.
Abstract
Radiation exposure leads to several pathophysiological conditions, including oxidative damage, inflammation and fibrosis, thereby affecting the survival of organisms. This review explores the radiation countermeasure properties of fourteen (14) plant extracts or plant-derived compounds against these cellular manifestations. It was aimed at evaluating the possible role of plants or its constituents in radiation countermeasure strategy. All the 14 plant extracts or compounds derived from it and considered in this review have shown some radioprotection in different in vivo, ex-vivo and or in vitro models of radiological injury. However, few have demonstrated advantages over the others. C. majus possessing antioxidant, anti-inflammatory and immunomodulatory effects appears to be promising in radioprotection. Its crude extracts as well as various alkaloids and flavonoids derived from it, have shown to enhance survival rate in irradiated mice. Similarly, curcumin with its antioxidant and the ability to ameliorate late effect of radiation exposure, combined with improvement in survival in experimental animal ***owing irradiation, makes it another probable candidate against radiological injury. Furthermore, the extracts of P. hexandrum and P. kurroa in combine treatment regime, M. piperita, E. officinalis, A. sinensis, nutmeg, genistein and ginsan warrants further studies on their radioprotective potentials. However, one that has received a lot of attention is the dietary flaxseed. The scavenging ability against radiation-induced free radicals, prevention of radiation-induced lipid peroxidation, reduction in radiation cachexia, level of inflammatory cytokines and fibrosis, are some of the remarkable characteristics of flaxseed in animal models of radiation injury. While countering the harmful effects of radiation exposure, it has shown its ability to enhance survival rate in experimental animals. Further, flaxseed has been tested and found to be equally effective when administered before or after irradiation, and against low doses (≤ 5 Gy) to the whole body or high doses (12-13.5 Gy) to the whole thorax. This is particularly relevant since apart from the possibility of using it in pre-conditioning regime in radiotherapy, it could also be used during nuclear plant leakage/accidents and radiological terrorism, which are not pre-determined scenarios. However, considering the infancy of the field of plant-based radioprotectors, all the above-mentioned plant extracts/plant-derived compounds deserves further stringent study in different models of radiation injury.
PMID:
24761841
[PubMed - in process]
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Plant extracts and plant-derived com... [Asian Pac J Cancer Prev. 2014] - PubMed - NCBI
