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Biological Effects of Ionizing Radiation on Fukushima Wildlife

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Relatively little research has been conducted on animal life in Japan and its coastal waters after the Fukushima Daiichi disaster but anomalies have already been identified.

One study found a marked decline in bird abundance in Fukushima.[i]

Spiders, grasshoppers, dragonflies, butterflies, bumblebees and cicadas also suffered population declines since the accident.[ii]

Another study found cesium contamination in Japanese macaques, ranging across time from a high of 25,000 Becquerels per kilogram in 2011 to 2,000 in 2012.[iii]

Yet another study published in 2015 found chromosomal malformations in wild mice caught in Fukushima Prefecture, with young mice more adversely impacted than older mice.[iv]

Research conducted by Japan’s National Institute of Radiological Sciences on fir trees near the Fukushima Daiichi plant found significant increases in morphological defects corresponding to radiation exposure doses.[v]

Taken together, these studies point to increased biological risks for flora and fauna living in radiation contaminated zones.

REFERENCES

[i] A. Moller, A. Hagiwara, S. Matsui, S. Kasahara, K. Kawatsu, I. Nishiumi, H. Suzuki, K. Ueda, T. and A. Mousseau (2012) ‘Abundance of Birds in Fukushima as Judged from Chernobyl’, Environmental Pollution, 164, 36–39.

[ii] A. Moller, I. Nishiumi, H. Suzuki, K. Ueda, T. A. Mousseau (2013) ‘Differences in Effects of Radiation of Animals in Fukushima and Chernobyl’, Ecological Indicators, 24, 75–81.

[iii] S. Kimura and A. Hatano (4 October 2012) ‘Scientists in Groundbreaking Study on Effects of Radiation in Fukushima’, The Asahi Shimbun, http://ajw.asahi.com/article/0311disaster/fukushima/AJ201210040003, date accessed 6 October 2012.

[iv] Yoshihisa Kubota, Hideo Tsuji, Taiki Kawagoshi, Naoko Shiomi, Hiroyuki Takahashi, Yoshito Watanabe, Shoichi Fuma, Kazutaka Doi, Isao Kawaguchi, Masanari Aoki, Masahide Kubota, Yoshiaki Furuhata, Yusaku Shigemura, Masahiko Mizoguchi, Fumio Yamada, Morihiko Tomozawa, Shinsuke H. Sakamoto, and Satoshi Yoshida Chromosomal Aberrations in Wild Mice Captured in Areas Differentially Contaminated by the Fukushima Dai-ichi Nuclear Power Plant Accident. Environ. Sci. Technol., 2015, 49 (16), pp 10074–10083. DOI: 10.1021/acs.est.5b01554.

[v] Watanabe, Yoshito, San’ei Ichikawa, Masahide Kubota, Junko Hoshino, Yoshihisa Kubota, Kouichi Maruyama, Shoichi Fuma, Isao Kawaguchi, Vasyl Yoschenko, Satoshi Yoshida, “Morphological defects in native Japanese fir trees around the Fukushima Daiichi Nuclear Power Plant,” Scientific Reports 5.13232 (2015): doi:10.1038/srep13232.

http://majiasblog.blogspot.fr/2017/01/biological-effects-of-ionizing.html

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January 24, 2017 Posted by | Fukushima 2017 | , , , | Leave a comment

Ionizing radiation May Contribute to Development of Alzheimer’s

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University of Southern Denmark

More humans than ever are exposed to higher levels of ionizing radiation from medical equipment, airplanes, etc. A new study suggests that this kind of radiation may be a confounding factor in the neurodegenerative disease Alzheimer´s.

Alzheimer’s disease is the leading cause for dementia in the elderly, and its global prevalence is supposed to increase dramatically in the following decade – up to 80 million patients by 2040.

– It is crucial that we investigate the potential factors behind this disease, says postdoc Stefan J. Kempf, University of Southern Denmark. His research focuses on possible connections between radiation and cognitive impairments.

In a new study, he and an international consortia involving colleagues from Italy, Japan, Germany and Denmark show that low doses of ionising radiation induce molecular changes in the brain that resemble the pathologies of Alzheimer’s.

The study has been published in Oncotarget. Co-authors are from Institute of Radiation Biology/Institute of Pathology, Helmholtz Zentrum München, German Research Center for Environmental Health and Institute for Environmental Sciences in Japan.

Large numbers of people of all age groups are increasingly exposed to ionizing radiation from various sources. Many receive chronic occupational exposure from nuclear technologies or airline travel. The use of medical diagnostics and therapeutic radiology has increased rapidly – for example more than 62 million CT scans per year are currently carried out in USA.

Approximately one third of all diagnostic CT examinations are scans of the head region.

– All these kinds of exposures are low dose and as long as we talk about one or a few exposures in a lifetime I do not see cause for concern. What concerns me is that modern people may be exposed several times in their lifetime and that we don’t know enough about the consequences of accumulated doses, says Stefan J. Kempf.

Recent data suggest that even relatively low radiation doses, similar to those received from a few CT scans, could trigger molecular changes associated with cognitive dysfunction.

In their new study, the researchers have elucidated molecular alterations in the hippocampus of mice. The hippocampus is an important brain region responsible for learning and memory formation and it is known to be negatively affected in Alzheimer´s.

The authors induced changes in the hippocampus by two kinds of chronic low-dose-rate ionizing radiation treatments. The mice were exposed to cumulative doses of 0.3 Gy or 6.0 Gy given at low dose rates of 1 mGy over 24 hours or 20 mGy over 24 hours for 300 days.

– Both dose rates are capable of inducing molecular features that are reminiscent of those found in the Alzheimer’s disease neuropathology, says Stefan J. Kempf.

When a patient gets a head scan, the doses varies between 20 and 100 mGy and lasts for around one minute. When a person flies, he or she gets exposure to ionising radiation coming from space but the rates are by far smaller than a CT scan.

– When you compare these figures you will find that we exposed the mice to a more than 1000 times smaller cumulative dose than what a patient gets from a single CT scan in the same time interval. And even then we could see changes in the synapses within the hippocampus that resemble Alzheimer´s pathology.

According to Stefan J. Kempf, the data indicate that chronic low-dose-rate radiation targets the integration of newborn neurons in existing synaptic wires.

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Paper: Chronic low-dose-rate ionising radiation affects the hippocampal phosphoproteome in the ApoE?/? Alzheimer mouse model. Forfattere: Stefan Kempf, Dirk Janik, Zarko Barjaktarovic, Ignacia Braga-Tanaka III, Satoshi Tanaka, Frauke Neff, Anna Saran, Martin Røssel Larsen, Soile Tapio. OncoTarget, 20. september 2016.

https://www.eurekalert.org/pub_releases/2016-10/uosd-ctr102716.php

October 29, 2016 Posted by | radiation | , , | 1 Comment

Mutational signatures of ionizing radiation in second malignancies

This article is important, and should be seen by as many people as possible, as this scientific study will impact greatly the future of our anti-nuclear cause.
By establishing the genetic signatures of any cancer caused by ionizing radiation, any future denial from the nuclear lobby is now impossible. Those scientifically established signatures will also be extremely helpful in court for any future suit from radiation victims.

Abstract

Ionizing radiation is a potent carcinogen, inducing cancer through DNA damage. The signatures of mutations arising in human tissues following in vivo exposure to ionizing radiation have not been documented. Here, we searched for signatures of ionizing radiation in 12 radiation-associated second malignancies of different tumour types. Two signatures of somatic mutation characterize ionizing radiation exposure irrespective of tumour type. Compared with 319 radiation-naive tumours, radiation-associated tumours carry a median extra 201 deletions genome-wide, sized 1–100 base pairs often with microhomology at the junction. Unlike deletions of radiation-naive tumours, these show no variation in density across the genome or correlation with sequence context, replication timing or chromatin structure. Furthermore, we observe a significant increase in balanced inversions in radiation-associated tumours. Both small deletions and inversions generate driver mutations. Thus, ionizing radiation generates distinctive mutational signatures that explain its carcinogenic potential.

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Introduction

Exposure to ionizing radiation increases the risk of subsequent cancer. This risk exhibits a strong dose–response relationship, and there appear to be no safe limits for radiation exposure1. This association was first noted by March who observed an increased incidence of leukaemia amongst radiologists2. A leading cause of radiation-induced cancers appears to be exposure to medical radiation, either in the form of radiotherapy for an unrelated malignancy3 or diagnostic radiography4, 5. These iatrogenic tumours arise as de novo neoplasms in a field of therapeutic radiation after a latency period that can span decades6, and are not recurrences of the original cancer7.

Many, but not all, environmental carcinogens induce cancer by increasing the rate of mutation in somatic cells. The physicochemical properties of a given carcinogen govern its interaction with DNA, leading to recurrent ‘signatures’ or patterns of mutations in the genome. These can be reconstructed either from experimental model systems8, 9 or from statistical analyses of cancer genomes in exposed patients10, 11, 12. Ionizing radiation directly damages DNA, and can generate lesions on single bases, single-stranded nicks in the DNA backbone, clustered lesions at several nearby sites and double-stranded DNA breaks13. In experimental systems exposed to radiation, including the murine germline and Arabidopsis thaliana cells, ionizing radiation can cause all classes of mutations, with possible enrichment of indels14, 15, 16, 17, 18, 19, 20, 21, 22. Targeted gene screens in radiation-induced sarcoma have indicated an increased burden of deletions and substitutions with frequent inactivation of TP53 and RB1 (refs 23, 24, 25). In addition, a transcriptome profile that represents a state of chronic oxidative stress has been proposed to be specific to radiation-associated sarcoma26.

We studied the genomes of 12 radiation-associated second malignancies of four different tumour types: osteosarcoma; spindle cell sarcoma; angiosarcoma; breast cancer. These were secondary tumours that arose within a field of therapeutic ionizing radiation and were not thought to be recurrences of the original malignancy treated with radiation. We chose this experimental design for several reasons: the tumours are classic radiotherapy-induced cancers with high attributable risks for the radiation exposure; the radiation exposure occurs over a short time period relative to the evolution of the cancer; and the mutational signatures of sporadic breast cancers and sarcomas have been well documented10, 27, 28, 29. It should be noted that in the absence of biomarkers, a diagnosis of a tumour being radiation-induced cannot be definitively made (see Supplementary Note 1 for clinical details and further discussion).

We subjected these 12 tumours, along with normal tissues from the same patients, to whole-genome sequencing and obtained catalogues of somatic mutations. We compared our findings to 319 radiation-naive breast cancers and sarcomas processed by the same sequencing and bioinformatics pipeline: 251 breast tumours; 33 breast tumours with pathogenic BRCA1 or BRCA2 germline mutations; 35 osteosarcomas (see Methods for cohort details). In addition, we validated our findings in a published series of radiation-naïve and radiation-exposed prostate tumours from ten patients30.

The main aim of our analyses was to search for tumour-type independent, overarching signatures of ionizing radiation. Overall we identified two such signatures in radiation-associative second malignancies, an excess of balanced inversions and of small deletions.

To read more :

http://www.nature.com/ncomms/2016/160907/ncomms12605/full/ncomms12605.html

September 14, 2016 Posted by | radiation, Reference | , , | Leave a comment

DNA damage, cancer caused by ionizing radiation identified

This UPI article was published on Sept. 13, 2016.
I added below the source of that UPI article, the study published on the sciences website “Nature” on Sept. 12, 2016.
This article is important, and should be seen by as many people as possible, as this scientific study will impact greatly the future of our anti-nuclear cause.
By establishing the genetic signatures of any cancer caused by ionizing radiation, any future denial from the nuclear lobby is now impossible. Those scientifically established signatures will also be extremely helpful in court for any future suit from radiation victims.

Researchers found mutational signatures left by radiation-caused changes to DNA, which may lead to better treatment of cancers.

dna-damage-cancer-caused-by-ionizing-radiation-identified

Researchers found mutational signatures which appear to indicate changes to DNA caused by exposure to ionizing radiation, which may allow doctors to better treat cancer caused by non-spontaneous mutations.

LONDON, Sept. 13 (UPI) — Though scientists have suspected ionizing radiation can cause cancer, experiments conducted in England are the first to show the damage it inflicts on DNA and may allow doctors to identify tumors caused by radiation.

In a study published in the journal Nature Communications, scientists showed the effects of gamma rays, X-rays and radioactive particles on DNA, deciphering patterns they think will help differentiate between spontaneous and radiation-caused tumors, allowing for better cancer treatment.

“To find out how radiation could cause cancer, we studied the genomes of cancers caused by radiation in comparison to tumors that arose spontaneously,” Dr. Peter Campbell, a researchers at the Wellcome Trust Sanger Institute, said in a press release. “By comparing the DNA sequences we found two mutational signatures for radiation damage that were independent of cancer type. We then checked the findings with prostate cancers that had or had not been exposed to radiation, and found the same two signatures again. These mutational signatures help us explain how high-energy radiation damages DNA.”

For the study, the researchers looked for mutational signatures in 12 cancer patients with radiation-associated second malignancies, and compared their tumors to 319 from patients not exposed to radiation.

The researchers found two mutational signatures they link to radiation. While one causes small deletions of DNA bases, the other — called a balanced inversion — includes two cuts to DNA, with the middle piece spinning around and rejoining in the opposite direction.

These mutations, especially balanced inversions, which do not happen naturally in the body, increase the potential for cancer to develop, the researchers say.

“This is the first time that scientists have been able to define the damage caused to DNA by ionising radiation,” said Adrienne Flanagan, a professor at the University College London Cancer Institute. “These mutational signatures could be a diagnosis tool for both individual cases, and for groups of cancers, and could help us find out which cancers are caused by radiation. Once we have better understanding of this, we can study whether they should be treated the same or differently to other cancers.”

http://www.upi.com/Health_News/2016/09/13/DNA-damage-cancer-caused-by-ionizing-radiation-identified/5151473765849/

Mutational signatures of ionizing radiation in second malignancies

« Ionizing radiation is a potent carcinogen, inducing cancer through DNA damage. The signatures of mutations arising in human tissues following in vivo exposure to ionizing radiation have not been documented. Here, we searched for signatures of ionizing radiation in 12 radiation-associated second malignancies of different tumour types. Two signatures of somatic mutation characterize ionizing radiation exposure irrespective of tumour type. Compared with 319 radiation-naive tumours, radiation-associated tumours carry a median extra 201 deletions genome-wide, sized 1–100 base pairs often with microhomology at the junction. Unlike deletions of radiation-naive tumours, these show no variation in density across the genome or correlation with sequence context, replication timing or chromatin structure. Furthermore, we observe a significant increase in balanced inversions in radiation-associated tumours. Both small deletions and inversions generate driver mutations. Thus, ionizing radiation generates distinctive mutational signatures that explain its carcinogenic potential. »

http://www.nature.com/ncomms/2016/160907/ncomms12605/full/ncomms12605.html

September 14, 2016 Posted by | radiation | , , | Leave a comment