RESUMO
Exposure to high-dose radiation causes life-threatening intestinal damage. Histopathology is the most accurate method of judging the extent of intestinal damage following death. However, it is difficult to predict the extent of intestinal damage. The present study investigated extracellular microRNAs (miRNAs or miRs) in serum and feces using a radiation-induced intestinal injury mouse model. A peak of 25-200 nucleotide small RNAs was detected in mouse serum and feces by bioanalyzer, indicating the presence of miRNAs. Microarray analysis detected four miRNAs expressed in the small intestine and increased by >2-fold in serum and 19 in feces following 10 Gy radiation exposure. Increased miR-375-3p in both serum and feces suggests leakage due to radiation-induced intestinal injury and may be a candidate for high-dose radiation biomarkers.
RESUMO
This article discusses tritium concentrations in monthly precipitation in part of the Difficult-to-Return Zone in Namie Town during 2012-2021. The tritium concentrations, which were measured with a low background liquid scintillation counter after carrying out an enrichment procedure, fluctuated seasonally from 0.10 ± 0.02 to 0.85 ± 0.02 Bq L-1. This range of concentrations is concluded to not be unusual based on comparisons with the concentrations at other sites and estimates of the past range of the concentrations. Moreover, no significant variations in observed tritium concentrations were observed due to decommissioning work at the Fukushima Dai-ichi Nuclear Power Plant. These results contribute to understanding the background level of tritium concentration in precipitation before the oceanic discharge of treated water from the Fukushima plant. In addition, this article evaluates the amount of tritium supplied to the ocean by terrestrial rainwater pouring into the Pacific Ocean via Ukedo River, which flows through Namie Town; this information will contribute to the discussion on the impact of the oceanic discharge of treated water.
Assuntos
Acidente Nuclear de Fukushima , Monitoramento de Radiação , Poluentes Radioativos da Água , Trítio , Poluentes Radioativos da Água/análise , Japão , Radioisótopos de Césio/análise , ÁguaRESUMO
137Cs in river systems can be taken up by aquatic animals. In this paper, total 137Cs concentration in the Ukedo River system and 137Cs presence in dissolved, acid-soluble and -insoluble fractions in river water samples were determined. Total 137Cs concentration had the maximum value of 2.08 Bq kg-1 below the Ogaki Dam in May 2012. In the base flow condition, > 87% of 137Cs existed in the dissolved state, and the acid-soluble state and the insoluble state were <13% and the undetectable level, respectively. After the heavy rain event, the particulate fraction (acid-soluble state + insoluble state) was elevated to 65%, which corresponds to twice as much as that in the base flow condition. Particulate 137Cs, especially the acid-soluble Cs, can play a role when taken into the food chain in aquatic ecosystems.
Assuntos
Radioisótopos de Césio , Poluentes Radioativos da Água , Animais , Isótopos de Césio , Radioisótopos de Césio/análise , Ecossistema , Água , Poluentes Radioativos da Água/análiseRESUMO
In Japan, the deuterium plasma experiment using the Large Helical Device was started at the National Institute for Fusion Science (NIFS) in March 2017 to investigate high-temperature plasma physics and hydrogen isotope effects in research leading towards the realisation of fusion energy. The deuterium plasma experiment produces small amount of tritium by fusion reactions. To understand any impacts by the experiment to the surrounding environment, monthly precipitation samples have been collected at the NIFS site since November 2013 to assess the relationship between isotope composition and chemical species in precipitation including tritium. By comparing data before and after the deuterium plasma experiment start, it was found that tritium released from the main stack of the fusion test facility had no impact on the environment surrounding NIFS.
Assuntos
Hidrogênio , Deutério/análise , Japão , Trítio/análiseRESUMO
Low-background liquid scintillation counter is one of the popular measuring instruments used to investigate tritium radioactivity in environmental media. These instruments require the liquid sample and organic solvent to be mixed for tritium measurement. In the European Union, the registration, evaluation, authorization and restriction of chemicals regulation was established to control the use of chemical substances of very high concern. It is important to find continuously available alternative reagents. In this paper, a performance evaluation was conducted using four scintillation cocktails according to Japanese conventional procedure; although one of them, Gold Star LT2, contains nonylphenol ethoxylate, it will continue to be available for research and development. From the evaluation results it was confirmed that Gold Star LT2 would be a satisfactory alternative scintillator, which is similar performance of Ultima Gold LLT.
Assuntos
Partículas beta , Contagem de Cintilação , TrítioRESUMO
The small intestine is one of the most highly regenerative and radiosensitive tissues in mammals, including humans. Exposure to high doses of ionizing radiation causes serious intestinal damage. Recently, several investigations have been conducted using radioprotective agents to determine ways for reducing intestinal damage caused by radiation exposure. However, a thorough understanding of functional changes occurring in the small intestine of mice exposed to highdose radiation is necessary for developing novel and more potent radioprotective agents. In this study, we examined changes in microRNA (miRNA/miR) expressions in the small intestine of mice at 72 h after Xray exposure (10 Gy). We identified seven upregulated miRNAs and six downregulated miRNAs in the small intestine of mice following radiation exposure using miRNA microarray analysis. Particularly, miR34a5p was highly expressed, which was confirmed by reverse transcription-quantitative PCR. Forkhead box P1 (Foxp1) was predicted to be a target of the mRNA of miR34a5p using OmicsNet. Decreased Foxp1 expression in the small intestine following radiation exposure was confirmed, suggesting that Foxp1 expression recovery may induce the suppression of radiationinduced enteritis. Therefore, miR34a5p is a potential target molecule for developing novel radioprotective agents.
Assuntos
Intestino Delgado/efeitos da radiação , MicroRNAs/metabolismo , Radiação Ionizante , Animais , Peso Corporal/efeitos da radiação , Regulação para Baixo/efeitos da radiação , Fatores de Transcrição Forkhead/genética , Fatores de Transcrição Forkhead/metabolismo , Intestino Delgado/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , RNA Mensageiro/metabolismo , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismo , Regulação para Cima/efeitos da radiaçãoRESUMO
miR-375-3p is a highly expressed microRNA in pancreatic ß cells. We have previously reported that when mice were exposed to 7 Gy X-ray irradiation, miR-375-3p was increased in the serum and there was cytotoxicity in pancreatic ß cells. However, it was unknown whether miR-375-3p is then released from injured pancreatic ß cells to the extracellular space. The present study investigated the effect of ionizing radiation and streptozotocin (STZ) treatment on the expression of extracellular miR-375-3p into culture supernatants using the rat pancreatic ß cell line RIN-5F. Cell growth was reduced, and cell death was increased at 24 h following exposure to 7 Gy irradiation as well as 24 h following treatment with 30 mM STZ compared with the control. Expression levels of miR-375-3p were significantly increased 24 h after 30 mM STZ treatment, yet this was only observed at 48 h following exposure to 7 Gy compared with the control. This suggests that the mechanism of cell death in RIN-5F is different between 7 Gy irradiation and 30 mM STZ treatment. The results of the present study suggest that injured pancreatic ß cells enhance the release of miR-375-3p from cells into extracellular space.