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Thyroid cancer incidence increases worldwide annually, primarily due to factors such as ionizing radiation (IR), iodine intake, and genetics. Papillary carcinoma of the thyroid (PTC) accounts for about 80% of thyroid cancer cases. RET/PTC1 (coiled‐coil domain containing 6 [CCDC6]‐rearranged during transfection) rearrangement is a distinctive feature in over 70% of thyroid cancers who exposed to low doses of IR in Chernobyl and Hiroshima‒Nagasaki atomic bombings. This study aims to elucidate mechanism between RET/PTC1 rearrangement and IR in PTC. N‐thy‐ori‐3‐1 cells were subjected to varying doses of IR (2/1/0.5/0.2/0.1/0.05 Gy) of IR at different days, and result showed low‐dose IR‐induced RET/PTC1 rearrangement in a dose‐dependent manner. RET/PTC1 has been observed to promote PTC both in vivo and in vitro. To delineate the role of different DNA repair pathways, SCR7, RI‐1, and Olaparib were employed to inhibit non‐homologous end joining (NHEJ), homologous recombination (HR), and microhomology‐mediated end joining (MMEJ), respectively. Notably, inhibiting NHEJ enhanced HR repair efficiency and reduced IR‐induced RET/PTC1 rearrangement. Conversely, inhibiting HR increased NHEJ repair efficiency and subsequent RET/PTC1 rearrangement. The MMEJ did not show a markable role in this progress. Additionally, inhibiting DNA‐dependent protein kinase catalytic subunit (DNA‐PKcs) decreased the efficiency of NHEJ and thus reduced IR‐induced RET/PTC1 rearrangement. To conclude, the data suggest that NHEJ, rather than HR or MMEJ, is the critical cause of IR‐induced RET/PTC1 rearrangement. Targeting DNA‐PKcs to inhibit the NHEJ has emerged as a promising therapeutic strategy for addressing IR‐induced RET/PTC1 rearrangement in PTC. [ABSTRACT FROM AUTHOR]

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The expansion of the nuclear industry has led to various radioactive effluents, originating from routine operations or catastrophic incidents such as those at Three Mile Island (USA), Chernobyl (Ukraine), and Fukushima (Japan). Research conducted after these events emphasizes Cesium-137 (137Cs) and iodine 131 (131I) as major contributors to harmful airborne dispersion and fallout. These isotopes infiltrate the human body via inhalation, ingestion, or wounds, posing significant health risks. Understanding contamination mechanisms and devising effective countermeasures are crucial in mitigating nuclear incident consequences. We propose that concurrent administration of Pru-Decorp™/Pru-Decorp-MG and potassium iodide (KI) could synergistically reduce the levels of 137Cs and block uptake of 131I, respectively, in nuclear incident scenarios. Pru-Decorp™ capsules contain insoluble ferric hexacyanoferrate(II) and are equivalent to USFDA-approved Radiogardase®-Cs, offering radiation exposure mitigation for Cs and Tl contamination. Pru-Decorp-MG capsules consist of insoluble PB and magnesium hydroxide, serving as a prophylactic measure to reduce the risk of internal Cs and Tl contamination for rescue responders. Pru-Decorp™/Pru-Decorp-MG binds Cs/Tl ions in the gastrointestinal tract, hindering absorption and promoting excretion, while KI saturates the thyroid gland with stable iodine, decreasing the uptake of radioactive iodine isotopes. Our hypothesis is supported by studies demonstrating the effectiveness of combination therapies, such as calcium alginate, iron(III) ferrocyanide, and KI , in decreasing the retention of radioisotopes in vital organs. To test this hypothesis, we propose a comprehensive research plan, including in vitro studies simulating gastrointestinal conditions, animal studies to evaluate the efficacy of both drugs simultaneously, and safety clinical trials comparing Pru-Decorp™/Pru-Decorp-MG alone, KI alone, and their combination. Expected outcomes include insights into the synergistic effects of Pru-Decorp™/Pru-Decorp-MG and KI, guiding the development of optimized treatment protocols for simultaneous administration during radioactive contamination incidents. This research aims to address significant critical gaps in nuclear incident preparedness by providing evidence-based recommendations for concurrent antidote use in scenarios involving multiple isotope contamination. Ultimately, this will enhance public health and safety during nuclear emergencies. [Display omitted] • Explore interactions between Pru-Decorp™, Pru-Decorp-MG, and potassium iodide (KI). • Concurrent administration may have synergistic effects. • Lack of existing studies on Prussian blue and potassium iodide interaction. • Safety and efficacy studies of combination therapy of KI and Prussian Blue. • Challenges include ethical concerns in clinical trials for combined therapy. [ABSTRACT FROM AUTHOR]

Background: While there is a robust literature on environmental exposure to iodine-131 (131I) in childhood and adolescence and the risk of thyroid cancer and benign nodules, little is known about its effects on thyroid volume.Methods: To assess the effect of 131I dose to the thyroid on the volume of the thyroid gland, we examined the data from the baseline screening of the Belarusian-American Cohort Study of residents of Belarus who were exposed to the Chernobyl fallout at ages ≤18 years. Thyroid dose estimates were based on individual thyroid activity measurements made shortly after the accident and dosimetric data from questionnaires obtained 10-15 years later at baseline screening. During baseline screening, thyroid gland volume was assessed from thyroid ultrasound measurements. The association between radiation dose and thyroid volume was modeled using linear regression where radiation dose was expressed with power terms to address non-linearity. The model was adjusted for attained age, sex, and place of residence, and their modifying effects were examined.Results: The analysis was based on 10,703 subjects. We found a statistically significant positive association between radiation dose and thyroid volume (P < 0.001). Heterogeneity of association was observed by attained age (P < 0.001) with statistically significant association remaining only in the subgroup of ≥18 years at screening (P < 0.001). For this group, increase in dose from 0.0005 to 0.15 Gy was associated with a 1.27 ml (95% CI: 0.46, 2.07) increase in thyroid volume. The estimated effect did not change with increasing doses above 0.15 Gy.Conclusions: This is the first study to examine the association between 131I dose to the thyroid gland and thyroid volume in a population of individuals exposed during childhood and systematically screened 10-15 years later. It provides evidence for a moderate statistically significant increase in thyroid volume among those who were ≥ 18 years at screening. Given that this effect was observed at very low doses and was restricted to a narrow dose range, further studies are necessary to better understand the effect. [ABSTRACT FROM AUTHOR]

Objective: This single-center, observational case-control feasibility study sought to test key elements of a protocol for an eventual long-term international observational case-control study of a larger patient cohort, to evaluate the risk of breast cancer as a second primary malignancy in females with differentiated thyroid cancer (DTC) given radioiodine therapy (RAI) during childhood or adolescence. Patients: Females developing DTC after the Chernobyl accident in Belarus and ≤19 years old at the time of thyroid surgery were enrolled: patients given RAI (n = 111) and controls of similar age not given RAI (n = 90). Results: One case of breast cancer was newly diagnosed among the RAI patients, but none in controls. Patients given RAI significantly less frequently needed 2nd surgeries than did controls (23%, 26/111 vs. 39%, 35/90, P < 0.05); the main indication for such procedures usually is suspicion of local recurrence. RAI patients appeared to have had more frequent reproductive difficulties than did controls: 78% (87/111) of the former vs. 93% (84/90) of the latter had a history of pregnancy (P < 0.01), and the mean number of pregnancies was 1.5 ± 1.2 in RAI patients vs. 1.9±1.1 in controls (P < 0.05). Most notably, infertility was observed in 23% (26/111) of RAI patients vs. 4% (4/90) of controls (P < 0.01). In conclusion, a international observational case-control study on breast cancer after DTC in patients given RAI vs. not given RAI appears to be feasible. Additional research and everyday clinical attention should be devoted to reproductive function after RAI in young females. [ABSTRACT FROM AUTHOR]

Nonconjugated conductive polymers have unique characteristics for providing protection against nuclear radiation including radioactive iodine (carcinogenic) which remains in vapor phase at and above room temperature and is difficult to contain. When iodine comes in contact with such a polymer, a charge-transfer occurs between the double bond and iodine, and as a consequence, the iodine atoms become bound to the polymer chain. Large films/sheets of these polymers covering nuclear reactors and waste storage facilities will act as effective shields against radioactive iodine since iodine atoms will be captured by these polymers and will not be able to escape to the environment. In addition, apparels made of these polymers will reduce exposure to radioactive iodine for doctors, nurses, attendees, and visitors during and after radioiodine therapy of thyroid patients. Thus, these polymeric shields should protect lives and the environment and reduce or avoid the exposure to humans in case of iodine releases from nuclear reactors: in normal day-to-day operations, due to accidents, and in disasters up to the magnitude of Fukushima Daiichi and Chernobyl. [ABSTRACT FROM AUTHOR]

Unique data is reported on the transfer of 129I iodine from freshwaters to fish as well as the internal distribution within fish from the Fukushima and Chernobyl exclusion zones (ChEZ). Samples of water, sediments and fish were collected in the contaminated ponds Inkyozaka and Suzuuchi, and in the less contaminated Abukuma river in Fukushima, as well as in the contaminated Glubokoye lake and in the less contaminated Starukha lake in ChEZ. In water, 129I was mainly present as low molecular mass (LMM) and negatively charged species, while a minor fraction was associated with colloidal fraction, most probably organic material in water. The sediment-water 129I apparent distribution coefficients, Kd, ranged from 225 to 329 L/kg, equal that of stable iodine, but did not correlate with 129I/127I ratio or 129I/137Cs ratio as the environmental distribution of radioactive iodine was different from that of stable iodine and radioactive cesium. Concentration ratios (CR) of 129I in muscle of freshwater fish ranged from 85 to 544 across waterbodies with limited water exchange, similar in Fukushima and Chernobyl, but varied with respect to fish species. Thus, this is the first results on the transfer of 129I to freshwater fish, showing that the CR for freshwater fish is higher than CR reported for marine fish. Concentrations of 129I in fish muscle were, however, lower than in the intestinal content, indicating the influence of more contaminated dietary ingredients probably of terrestrial origin based due to δ13C signal on as well as of biodilution. The present results highlighted also that the radiation dose in fish was highly inhomogeneously distributed. Based on the present 129I/127I atomic ratio of 10−5 in the most contaminated fish in the ponds in Fukushima and Glubokoye lake in Chernobyl, however, a radiation dose of 10 μSv/y would not pose any harm to the fish population. [Display omitted] • Transfer of 129I to freshwater fish is for first time documented. • Freshwater fish concentration ratios is 85–588 dry weight and higher than reported for marine fish. • Dietary transfer of 129I to freshwater fish seems significant. • 129I apparent distribution coefficients (Kd) ranged from 225 to 329 L/kg in closed waterbodies. • No observed difference in transfer of 129I in Fukushima and Chernobyl freshwater bodies. [ABSTRACT FROM AUTHOR]

BACKGROUND: Hypothyroidism is the most common thyroid abnormality in patients treated with high doses of iodine-131 (131I). Data on risk of hypothyroidism from low to moderate 131I thyroid doses are limited and inconsistent. OBJECTIVE: This study was conducted to quantify the risk of hypothyroidism prevalence in relation to 131I doses received because of the Chornobyl accident. METHODS: This is a cross-sectional (1998--2000) screening study of thyroid diseases in a cohort of 11,853 individuals < 18 years of age at the time of the accident, with individual thyroid radioactivity measurements taken within 2 months of the accident. We measured thyroid-stimulating hormone (TSH), free thyroxine, and antibodies to thyroid peroxidase (ATPO) in serum. RESULTS: Mean age at examination of the analysis cohort was 21.6 years (range, 12.2--32.5 years), with 49% females. Mean 131I thyroid dose was 0.79 Gy (range, 0--40.7 Gy). There were 719 cases with hypothyroidism (TSH > 4 mIU/L), including 14 with overt hypothyroidism. We found a significant, small association between 131I thyroid doses and prevalent hypothyroidism, with the excess odds ratio (EOR) per gray of 0.10 (95% confidence interval, 0.03--0.21). EOR per gray was higher in individuals with ATPO ≤ 60 U/mL compared with individuals with ATPO > 60 U/mL (p < 0.001). CONCLUSIONS: This is the first study to find a significant relationship between prevalence of hypothyroidism and individual 131I thyroid doses due to environmental exposure. The radiation increase in hypothyroidism was small (10% per Gy) and limited largely to subclinical hypothyroidism. Prospective data are needed to evaluate the dynamics of radiation-related hypothyroidism and clarify the role of antithyroid antibodies. [ABSTRACT FROM AUTHOR]

The aim was to study the pathological features of papillary thyroid carcinoma diagnosed with or before second primary malignancy in patients exposed to post-Chernobyl exposure. The patients selected (n = 6559) were those exposed to radiation at the age of ≤ 18 years old and developed papillary thyroid carcinoma during the years 1990–2020. Of these, 2.1% (n = 140) had second primary malignancies. To compare the histopathological characteristics of papillary thyroid carcinoma in the group under analysis, 91% (n = 128) with sufficient data were included in further analysis. The control group was formed by matching patients with age at exposure to radiation, age at surgery, gender, and place of residence. Median age at exposure was 14 years old for both groups. Besides, no difference in tumour extension and histological features of papillary thyroid carcinoma was noted between patients with synchronous or metachronous primary malignant tumours. Nevertheless, the time lag to the diagnosis of papillary thyroid carcinoma was shortened in the group with metachronous when compared to patients with synchronous second primaries (p < 0.001). Independent differences between patients with second primaries and their matched peers included tumour size {OR (95%CI) = 0.89 (0.45; 1.04)}, multiple tumours {OR (95% CI) = 1.46 (0.86; 2.42)}, lymphatic vessel invasion (OR (95%CI) 0.92 (0.61; 1.53)), blood vessel invasion (OR (95%CI) 0.41 (0.10; 1.23) and presence of numerous psammomas (OR (95%CI) 0.73 (0.39; 1.31)). The possible influence of radiative iodine treatment for development of second primaries was analysed for the group of patients with metachronous malignancies using the same approach (84 patients were compared to 252 matched patients). Independent differences also included tumour size {OR (95% CI) 0.77 (0.45; 1.30)}, lymphatic vessel invasion {OR (95%CI) 0.75(0.43; 1.28)}, blood vessel invasion {OR (95%CI) 0.17 (0.01; 0.87)}. Besides, multiple tumours were revealed more frequently in patients with metachronous primaries (OR (95%CI) 1.92 (1.0; 3.62)). To conclude, patients exposed to Chernobyl irradiation with the development of papillary thyroid carcinoma and second primary malignancy have less biological aggressive pathological characteristics of their thyroid cancers. Accordingly, these patients were less frequently treated with post-surgical radioactive iodine. Thus, 131I-irradiation may have negligible impact on the development of second primaries. • Secondary primary malignancy in papillary thyroid carcinoma could be metachronous or synchronous. • Papillary thyroid carcinoma in patients with secondary primary malignancy has important pathological characteristics. • Adjuvant treatment with 131I of thyroid cancer did not enhance the development of secondary primary malignancy. [ABSTRACT FROM AUTHOR]

Abstract: The studies undertaken by the 131I Working Group, part of the International Atomic Energy Agency''s EMRAS (Environmental Modelling for Radiation Safety) programme, were focused primarily on evaluating the predictive capability of environmental models. Particular emphasis was placed on applying models to evaluate the effectiveness of countermeasures. [Copyright &y& Elsevier]

Large amounts of radioiodines were released into the atmosphere during the accident at the Chernobyl nuclear power plant on 26 April 1986. In order to investigate whether the thyroid cancers observed among children in Belarus could have been caused by radiation exposures from the Chernobyl accident, a team of Belarusian, Russian, and American scientists conducted a case-control study to compare cases and controls according to estimated thyroid dose. The primary purpose of this paper is to present detailed information on the estimated thyroid doses, due to intakes of 131I, that were used in the case-control study. The range of the 131I thyroid doses among the 107 cases and the 214 controls was found to extend from 0.00002 to 4.3 Gy, with medians of approximately 0.2 Gy for the cases and 0.07 Gy for the controls. In addition, the thyroid doses resulting from the intakes of short-lived radioiodines (132I, 133I, and 135I) and radiotelluriums (131mTe and 132Te) were estimated and compared to the doses from 131I. The ratios of the estimated thyroid doses from the short-lived radionuclides and from 131I for the cases and the controls range from 0.003 to 0.1, with median values of approximately 0.02 for both cases and controls. [ABSTRACT FROM AUTHOR]

Purpose The ocular lens is one of the most radiosensitive organs in mammals and a pathological sign after exposure to ionising radiation is the formation of cataracts. We generated a mouse model to mimic the situation after the accident in the Chernobyl power plant. Methods Pregnant and nursing FBV‐mice were treated with iodine131 for diaplacentar and galactogen transfer to the litter. The offspring which incorporated the radioiodine were examined for lens opacities at the age of 6 and 12 months. Iodine131 is a beta radiation emitting nuclide with a short half live of 8 days. Mothers were injected twice with 100 kBq I‐131, on day 14 post conception and day 6 post natal. Cataracts were investigated at 6 and 12 months of age using a slit lamp. Results Depending on the litter size and weight, a single progeny incorporates between 8 to 14 % of entire activity. More than 50% of the injected activity is transmitted from the mother to the entire offspring. Iodine is accumulated in the thyroid and an average thyroid dose of 3.7 Gy was calculated. Because of the short distance between the thyroid and the eye, a lens dose of 0.5 Gy was estimated. In the FBV mice, we observed at the age of 6 months two cataracts among 15 irradiated lenses (13%), but none among 7 unirradiated controls. At the age of 12 months, almost all lenses showed cortical cataracts in both groups. However, there were 17 nuclear cataracts among 66 irradiated lenses (25%), but only 1 among 16 controls (6%). Conclusion These preliminary data indicate that this method is sensitive enough to detect the cataract‐causing potential of low‐dose ionizing radiation in the mouse. However, for detailed analysis larger cohorts and quantification of the data are necessary. [ABSTRACT FROM AUTHOR]