Is exposure to ionising radiation associated with childhood cardiac arrhythmia in the Russian territories contaminated by the Chernobyl fallout? A cross-sectional population-based study.

OBJECTIVE: To investigate childhood cardiac arrhythmia and chronic exposure to caesium-137 (137Cs) resulting from the Chernobyl accident. DESIGN: Prospective cross-sectional study using exposed/unexposed design conducted in the Bryansk region from May 2009 to May 2013 on children selected on the basis of 137Cs soil deposition: control territories ([137Cs]<37 kBq per square metre, where children were considered as unexposed) and contaminated territories ([137Cs]>555 kBq per square metre, where children were considered as exposed). SETTING: Russian territories affected by the Chernobyl fallout (Bryansk region). PARTICIPANTS: This cross-sectional study included 18 152 children aged 2-18 years and living in the Bryansk region (Russia). MAIN OUTCOME MEASURES: All children received three medical examinations (ECG, echocardiography and 137Cs whole-body activity measurement) and some of them were given with a 24-hour Holter monitoring and blood tests. RESULTS: Cardiac arrhythmia was diagnosed in 1172 children living in contaminated territories and 1354 children living in control territories. The crude prevalence estimated to 13.3% in contaminated territories was significantly lower than in control territories with 15.2% over the period 2009-2013 (P<0.001). Considering 137Cs whole-body burden as exposure, cardiac arrhythmia was found in 449 contaminated children and 2077 uncontaminated children, corresponding to an estimated crude prevalence of 14.5% and 14.2%, respectively, which does not differ significantly (P=0.74). Also, we investigated the association between territory, exposure to 137Cs and cardiac arrhythmia: the adjusted OR was not significant (0.90 with 95% CI 0.81 to 1.00; P=0.06) for the territory. For 137Cs whole-body burden, the ORs close to 1 did not reach statistical significance (P for trend=0.97). CONCLUSION: This study does not observe an association between cardiac arrhythmia and 137Cs deposition levels in the Bryansk region exposed to Chernobyl fallout. The suspected increase of cardiac arrhythmia in children exposed to Chernobyl fallout is not confirmed.

Low-concentration uranium enters the HepG2 cell nucleus rapidly and induces cell stress response.

This study aimed to compare the cell stress effects of low and high uranium concentrations and relate them to its localization, precipitate formation, and exposure time. The time-course analysis shows that uranium appears in cell nuclei as a soluble form within 5 min of exposure, and quickly induces expression of antioxidant and DNA repair genes. On the other hand, precipitate formations began at the very beginning of exposure at the 300-µM concentration, but took longer to appear at lower concentrations. Adaptive response might occur at low concentrations but are overwhelmed at high concentrations, especially when uranium precipitates are abundant.

Ex vivo decrease in uranium diffusion through intact and excoriated pig ear skin by a calixarene nanoemulsion.

Cutaneous contamination by radionuclides is a major concern in the nuclear industry. In case of skin exposure to uranium, no efficient emergency treatment is available to remove the actinide from the skin. For this purpose, we developed a nanoemulsion containing calixarene molecules displaying good chelating properties towards uranium. In this paper, we describe the ability of this formulation to trap uranium and limit its transfer from the cutaneous contaminated site into the blood. Uranium percutaneous diffusion kinetics was assessed with Franz cells over 24 h through intact and excoriated pig ear skin biopsies, after or without application of the nanoemulsion. Uranium distribution in the skin layers was analysed by SIMS microscopy. The results showed that prompt application of the calixarene nanoemulsion allows a 94% and 98% reduction of the amount of uranium diffused respectively through intact and excoriated skin. The formulation is still efficient in case of delayed application up to 30 minutes since the 24 h-uranium transfer through excoriated skin is reduced by 71%. Besides, no accumulation of uranium or uranium-calixarene chelate was observed in the different skin layers. In conclusion, this study demonstrated the efficiency of the calixarene nanoemulsion, which can be regarded as a promising treatment for uranium cutaneous contamination.