The molecular and cellular consequences of the chernobyl accident

In this paper the results of research at 5–10 and 24 years after the Chernobyl accident are summarized. These results include the investigation of genomic instability, formation of the adaptive response, genome damage, and oxidative status. The studies were performed on cells in culture, mice, children and adults who lived in the contaminated areas, and liquidators of the consequences of the Chernobyl accident. Inhibition of cell proliferative activity, late cell death, and the increase in micronucleus and giant cell frequency were observed after the exposure of cells in culture in the accident zone followed by their culturing in laboratory conditions. In the progeny of the exposed cells, the effect of enhanced radiosensitivity was detected. Thus, it can be assumed that exposure of parental cells in culture in the area of the accident induced genomic instability that resulted in the development of various abnormalities in progeny cells. At the organism level, the Chernobyl zone exposure of mice caused an increase in radiosensitivity; as well, a decrease in the endotheliocyte density in the cerebral cortex and other brain tissues was observed. In the blood lymphocytes of children stimulated by PHA, a more than two times increase in micronucleus cell frequency was detected. A reduced number of individuals with significant adaptive response was found in both the juvenile and adult groups. In all investigated populations, an increased number of individuals with enhanced radiosensitivity were observed in response to low-dose radiation exposure. At 24 years after the accident liquidators were subjected to examinations, which revealed an increased frequency of cells with micronuclei and chromosome-type aberrations in blood lymphocytes, an elevated level of DNA double strand breaks, and a reduced level of reactive oxygen species compared to those of the control group. This means that the genomic instability that was accumulated by the residents of the contaminated regions and liquidators as a result of the accident leads to damage of the genetic apparatus, an increase in radiosensitivity, and hypoxia as late consequences that all are risk factors and increase the probability of the development of tumor and non-tumor diseases. The development of the above-mentioned pathological processes may occur in the distant future.

     

15 years after the accident at the Chernobyl Nuclear Power Plant

Health effects as a result of the accident at the Chernobyl nuclear power plant occurred in 1986 are considered in the paper. Wrong prognosis of the health effects with respect to mortality and morbidity among the population exposed to low radiation doses is shown. Proven increase in thyroid cancer cases among people who were children aged from 0 to 18 at the time of the accident is shown. Linear relationship between thyroid cancer cases and dose to thyroid ranged from 0.2 to 4.0 Gy is considered. An additional absolute risk of thyroid cancer in children varies in the range 1.9-2.6 cases per 10(4) person-year Gy. During the fifteen years following the accident no cases of acute and chronic radiation sickness have been revealed because the population living in contaminated areas received low radiation doses. Also, exposures to low radiation doses did not result in excess of malignant tumors among population. In some cases the outcomes of acute radiation sickness were as follows: radiation damages to the skin, cancer cataracts, development of oncopathology.     

Monosodium glutamate for accidental,retrospective, and medical dosimetry using electron spin resonance

The risk of a radiation episode has increased in the last years due to several reasons. In case of a nuclear incident, as with the use of an improvised nuclear device, determination of the radiation doses received by the victims is of utmost importance to define the appropriate medical treatment or to monitor the late effects of radiation. Dose assessment in case of accidents can be performed using commonplace materials found in the accident area. In this paper, the dosimetric properties of monosodium glutamate are investigated by electron spin resonance spectroscopy (ESR), for retrospective and accidental dosimetry. The spectroscopic parameters were optimized to achieve higher signal intensity and better signal-to-noise ratio. As a result, the lowest detectable dose was 0.1 Gy, and monosodium glutamate showed a linear dose–response curve for doses ranging from 0.1 Gy to 10 kGy. The dosimetric signal was monitored from minutes right after irradiation, until 1 year. No changes in the signal intensity were observed over this period, meaning that doses could be assessed immediately after radiation exposure and can still be reconstructed long after the accident. This property also implies that late effects due to victim’s radiation exposure could be better monitored and understood. ESR signal intensity for samples irradiated with a photon energy below 100 keV was decreased by only 27% and no dose-rate dependence was noticed. Therefore, the ability to measure doses as low as 0.1 Gy, the high stability of the dosimetric signal, as well as independence on dose rate, tissue equivalence, low-cost, and wide commercial availability make monosodium glutamate a very good dosimetric material not only for retrospective and accidental but also for medical dosimetry.     

Radiation-epidemiological studies of thyroid cancer incidence among children and adolescents in the Bryansk oblast of Russia after the Chernobyl accident (1991–2001 follow-up period)

In this study, thyroid cancer incidence (follow-up period: 1991–2001) has been analyzed, including persons who were exposed as children at an age between 0 and 17 years and who are living in the Bryansk oblast, the worst contaminated area of Russia after the Chernobyl accident. According to the census of 1989, the population of this oblast comprises 375 thousand people. Thyroid doses from incorporated radioiodine isotopes—both for the thyroid cancer cases and the study population—were determined based on the official methodology approved by the Russian Scientific Commission on Radiation Protection. Between 1991 and 2001, a total of 199 thyroid cancer cases were diagnosed at cancer centers (the so-called oncological dispensaries) of the investigated regions. The performed analysis relies on medical and dosimetric information available from the Russian National Medical and Dosimetric Registry which was established after the Chernobyl accident. Diagnoses were confirmed histologically for 95% of the cases. The analysis described revealed statistically significant radiation risk only for those exposed as children at an age of 0–9 years. In this group, the standardized incidence ratio (the national incidence rate was used as a reference) in the considered time period is estimated to be 6.7 (5.1, 8.6 95%CI) and 14.6 (10.3, 20.2 95%CI) for girls and boys, respectively. The risk dependence on age at exposure has also been studied. It has been shown that the smaller the age the higher the risk. For girls whose age at exposure was 0–4 years, the excess relative risk per 1 Gy for the period 1991–2001 was 45.3 (5.2, 9,953 95%CI; with internal control) and 28.8 (4.3, 2,238 95%CI; with external control), respectively. For boys whose age at exposure was 0–9 years the corresponding excess relative risk per 1 Gy was 68.6 (10.0, 4,520 95%CI) and 177.4 (−276, 10⁶ 95%CI), respectively. Dependence of radiation risk on time was studied, with the focus on two follow-up periods 1991–1996 and 1997–2001, respectively. In 1997–2001 the radiation risk is shown to decrease among girls, and increase among boys.     

Bipolarization of Risk Perception about the Health Effects of Radiation in Residents after the Accident at Fukushima Nuclear Power Plant

The late health effects of low-dose rate radiation exposure are still a serious public concern in the Fukushima area even four years after the accident at Fukushima Daiichi Nuclear Power Plant (FNPP). To clarify the factors associated with residents’ risk perception of radiation exposure and consequent health effects, we conducted a survey among residents of Kawauchi village in May and June 2014, which is located within 30 km of FNPP. 85 of 285 residents (29.8%) answered that acute radiation syndrome might develop in residents after the accident, 154 (54.0%) residents responded that they had anxieties about the health effects of radiation on children, and 140 (49.1%) residents indicated that they had anxieties about the health effects of radiation on offspring. Furthermore, 107 (37.5%) residents answered that they had concerns about health effects that would appear in the general population simply by living in an environment with a 0.23 μSv per hour ambient dose for one year, 149 (52.2%) residents reported that they were reluctant to eat locally produced foods, and 164 (57.5%) residents believed that adverse health effects would occur in the general population by eating 100 Bq per kg of mushrooms every day for one year. The present study shows that a marked bipolarization of the risk perception about the health effects of radiation among residents could have a major impact on social well-being after the accident at FNPP.     

Long-term follow-up cytogenetic survey and biological dosimetry in persons evacuated from 30-km Chernobyl NPP zone

The paper presents the results of the follow-up cytogenetic survey and biological dosimetry carried out in inhabitants of Pripiat' town and nearby villages, who were departured from the Chernobyl NPP 30-km exclusive zone during first days after the Chernobyl catastrophe. The unstable chromosome aberration level in inhabitants were significantly increased above control in terms up to 1 year after evacuation and declined gardually during next 14 years. In early period the cytogenetic damage frequency in evacuees showed no dependence on gender. The chromosome type aberration level appeared to be lower in young persons comparing with adults. The dicentrics plus centric rings yield had a positive correlation with duration of staying at Chernobyl zone. The average doses of protracted exposure were calculated from the dicentrics and centric rings yields; the dose estimations appeared to be 1.4 times higher in persons evacuated 3-11 days after the accident than that of in persons with shorter departure time. Uing the Bayesian analysis the probabilistic distribution of biological doses was constructed for the studied evacuees group. This distribution was characterized by a mean dose of 360 mGy, the modal doses of 200-450 mGy and 80% of probability density within the dose range 0-1000 mGy, that seems to be sufficient for considering the increased risk of late somatic radiation effects for this cohort.     

Analysis of thyroid cancer data from the Ukraine after ’Chernobyl’ using a two-mutation carcinogenesis model

The thyroid cancer data of children in the northern regions of the Ukraine after the reactor accident at Chernobyl were combined with thyroid dose measurements in the same regions and analysed using a two- mutation carcinogenesis model. The best fit was obtained for radiation acting as an initiating agent, i.e. on the first mutation of the model. The observed relatively high increase of thyroid cancer incidence after 1990 in children exposed to radiation released after the reactor accident could be ascribed to the high thyroid doses and the relatively low background thyroid cancer incidence in children. The maximum annual incidence is predicted to occur fairly soon after the reactor accident, i.e. about 10 years. For adults, the predicted relative increase of annual thyroid cancers is much lower than for children younger than 20 years. The modelling results are used to derive risk estimates for radiation-induced thyroid cancer. These risk estimates are dependent on age at exposure, follow-up time and the background thyroid cancer incidence. The calculated excess absolute risk for a population of all ages is about one-third of that currently used by ICRP, but for children the calculated absolute risks are about a factor of 3 higher than derived in other epidemiological studies. The model results indicate that the excess absolute radiation risk per unit dose for children is about the same as or a little lower than that for adults. Received: 11 May 1999 / Accepted: 30 December 1999     

Leukemia incidence in the Russian cohort of Chernobyl emergency workers

Of all potentially radiogenic cancers, leukemia, a type of cancer of the blood, has the highest risk attributable to ionizing radiation. Despite this, the quantitative estimation of radiation risk of a leukemia demands studying very large exposed cohorts, because of the very low level of this disease in unexposed populations and because of the tendency for its radiation risk to decrease with time. At present, the Japanese cohort of atomic bomb survivors is still the primary source of data that allows analysis of radiation-induced leukemia and the underlying dose–response relationship. The second large cohort that would allow to study radiation-induced leukemia is comprised of individuals who were exposed due to the accident of the Chernobyl nuclear power plant in 1986. The objective of the present study was to estimate radiation risks of leukemia incidence among the Russian cohort of Chernobyl emergency workers, for different time periods after the accident. Twenty-five years after the Chernobyl accident and based on the results of the present study, one can conclude that the radiation risk of leukemia incidence derived from the Russian cohort of Chernobyl emergency workers is similar to that derived from the cohort of atomic bomb survivors: The time-averaged excess relative risk per Gray (ERR Gy⁻¹) equals 4.98 for the Russian cohort and 3.9 for the life span study (LSS) cohort; excess absolute risk decreases with time after exposure at an annual rate of 9% for the Russian cohort, and of 6.5% for the LSS cohort. Thus, the excess in risk of leukemia incidence in a population due to a single exposure is restricted in time after exposure by the period of about 15 years.     

Consequences of an amphibian malformity for development and fitness in complex environments

1. Environmental stressors have both lethal and sublethal effects, such as altered developmental rates and the induction of malformations. Ecological interactions, including predation and competition, often amplify such effects, for instance by inducing behavioural changes that increase susceptibility to the stress. 2. Using experimental mesocosms, we asked whether the density of conspecific competitors and predation risk from larval water beetles (Dytiscus spp.) affect the development of malformations in tadpoles of the wood frog (Rana sylvatica). We also examined whether such malformities increase the susceptibility of tadpoles to predation. 3. The risk of predation decreased the frequency of malformities in both low‐ and high‐density treatments, although this effect was greater at low density. Behavioural observations suggested that reductions in activity by amphibian larvae induced by predators mediated these responses by decreasing cumulative exposure to ultraviolet‐B radiation, the putative stressor causing the observed malformity. These results suggest that predators can reduce negative impacts of stressors by inducing behavioural changes in prey organisms. 4. Malformed individuals were twice as vulnerable to predators as non‐malformed individuals, suggesting that sublethal effects can ultimately cause increased mortality.     

Molecular cytogenetic characterization of chromosome 9-derived material in a human thyroid cancer cell line

The incidence of papillary thyroid carcinoma (PTC) increases significantly after exposure of the head and neck region to ionizing radiation, yet we know neither the steps involved in malignant transformation of thyroid epithelium nor the specific carcinogenic mode of action of radiation. Such increased tumor frequency became most evident in children after the 1986 nuclear accident in Chernobyl, Ukraine. In the eight years following the accident, the average incidence of childhood PTCs (chPTC) increased 70-fold in Belarus, 200-fold in Gomel, 10-fold in the Ukraine and 50-fold in Tschnigov, Kiev, Rovno, Shitomyr and Tscherkassy compared to the rate of about 1 tumor incidence per 106 children per year prior to 1986 (Likhtarev et al., 1995; Sobolev et al., 1997; Jacob et al., 1998). To study the etiology of radiation-induced thyroid cancer, we formed an international consortium to investigate chromosomal changes and altered gene expression in cases of post-Chernobyl chPTC. Our approach is based on karyotyping of primary cultures established from chPTC specimens, establishment of cell lines and studies of genotype-phenotype relationships through high resolution chromosome analysis, DNA/cDNA micro-array studies, and mouse xenografts that test for tumorigenicity. Here, we report the application of fluorescence in situ hybridization (FISH)-based techniques for the molecular cytogenetic characterization of a highly tumorigenic chPTC cell line, S48TK, and its subclones. Using chromosome 9 rearrangements as an example, we describe a new approach termed 'BAC-FISH' to rapidly delineate chromosomal breakpoints, an important step towards a better understanding of the formation of translocations and their functional consequences.     

Radiobiology and the lessons of Chernobyl

The Chernobyl accident has marked the beginning of a new stage of radiobiology development and revealed scantiness of old concepts. One should (1) search for effective protectors against the long-term influence of low-level radiation and means of removal of radionuclides using criteria that differ principally from those used previously in selecting among nontoxic antioxidants, immunomodulators, and adaptogens; (2) study systematically the synergism of low doses of harmful agents and review the hygienic standardization system with due regard for the risk from their combinations; (3) consider comprehensively, on the basis of the experimental and clinical experience, the problem of "hot" particles and remote consequences of their influence on the respiratory and digestive systems; (4) study independently the problem of chronic stress as a combination of radiation effects and psycho-emotional consequences of the accident and living in the exposed areas; (5) consider it inadmissible to include in the B category the population of the districts influenced by the accident and to use the concept: "35 rads during the lifetime" in standardizing the radiation load; (6) organize a comprehensive analysis of the Chernobyl accident consequences for public health within the contaminated areas as well as for animals and plants using a single approved methodology and programme, the principle of "other equal conditions" being provided.     

Perinatal mortality in Bavaria, Germany, after the Chernobyl reactor accident

As has been shown by the authors of a paper recently published in this journal, a deviation from a long-term trend in perinatal mortality within the former Federal Republic of Germany occurred in 1987, i.e. 1 year following the Chernobyl disaster. It is the aim of this study to make a comparison between the areas of the state Bavaria, Germany, with different fallout levels as well as between the observed and expected numbers of perinatal deaths relating to these areas. The expected numbers of perinatal deaths, defined as external standard, were derived from the remainder of the former FRG. Testing an a priori formulated hypothesis revealed no differences in the temporal development of perinatal mortality between the areas with different fallout levels and subsequent exposures. Including May 1986 into the analysis revealed a significant increase during the first 3 months after the accident, which is due to an excess in May alone. Since no elevated radiation risks for the last days in utero are known, the additional Chernobyl radiation exposure is not plausible as a causative agent. Further analyses on stillbirths showed an increase in Southern Bavaria during the first 2 years following the accident. Later on, the rates were comparable to the expected values again. Received: 23 January 1997 / Accepted in revised form: 4 April 1997     

Long-term effects of radiation exposure among adult survivors of childhood cancer: results from the childhood cancer survivor study

In the last four decades, advances in therapies for primary cancers have improved overall survival for childhood cancer. Currently, almost 80% of children will survive beyond 5 years from diagnosis of their primary malignancy. These improved outcomes have resulted in a growing population of childhood cancer survivors. Radiation therapy, while an essential component of primary treatment for many childhood malignancies, has been associated with risk of long-term adverse outcomes. The Childhood Cancer Survivor Study (CCSS), a retrospective cohort of over 14,000 survivors of childhood cancer diagnosed between 1970 and 1986, has been an important resource to quantify associations between radiation therapy and risk of long-term adverse health and quality of life outcomes. Radiation therapy has been associated with increased risk for late mortality, development of second neoplasms, obesity, and pulmonary, cardiac and thyroid dysfunction as well as an increased overall risk for chronic health conditions. Importantly, the CCSS has provided more precise estimates for a number of dose-response relationships, including those for radiation therapy and development of subsequent malignant neoplasms of the central nervous system, thyroid and breast. Ongoing study of childhood cancer survivors is needed to establish long-term risks and to evaluate the impact of newer techniques such as conformal radiation therapy or proton-beam therapy.     

Thyroid cancer risk in Belarus after the Chernobyl accident: Comparison with external exposures

Within the time period 1990–1993, childhood thyroid cancer incidence due to the Chernobyl accident increased dramatically in Belarus, especially with regard to the birth cohort January 1, 1971, to May 31, 1986. This rise subsequently slowed down, i.e. during the period 1994–1996. The respective data were analysed and compared with the results of an analysis on the time dependence of thyroid cancer incidence in a pooled cohort of persons who had been exposed during childhood to external radiation with high dose rates. Concerning the period of 5–10 years following exposure, the excess absolute cancer risk per unit thyroid dose in the latter (external) exposure group was found to exceed the one in the Belarus group by a factor of two. This difference, however, is not statistically significant. The age-adjusted average excess absolute risk per unit thyroid dose for the period of 5–50 years following external childhood exposure was found to be 8 female and 14 male cases per 10⁴ person-year · Gy, which is a factor about 2.5 times higher than for the non-adjusted risk in the pooled cohort, as reported by Ron et al. in 1995. Assessments of future excess thyroid cancer cases due to the Chernobyl accident were done on the basis of the time dependence of thyroid cancer risk following external exposure. The thyroid cancer incidence among the birth cohort considered in Belarus and for a period starting from the cessation of the available observation data (1 January 1997) and extending to 50 years after the Chernobyl accident has been estimated to be about 15,000 cases, with an uncertainty range of 5000–45,000 cases. According to our calculations, 80% of these cases exceed the baseline risk under enhanced thyroid surveillance. Received: 8 June 1999 / Accepted in revised form: 20 November 1999     

Flow-cytometric identification and follow-up of mice exposed to x-irradiation: Evaluation of a model system

An experimental model system is presented that allows the identification and follow-up of mice exposed to ionizing radiation using flow-cytometric measurements of peripheral blood cells. In an experiment, properties of peripheral blood cells were analysed with flow cytometry for a rapid identification of individuals exposed to radiation. Individuals were then followed longitudinally in an attempt to identify those developing neoplasias. Male CBA mice, 25 days old, were subjected to fractionated x-irradiation (4 × 1.31 Gy) to induce haematopoietic malignancies. By repeated blood sampling followed by flow cytometry, frequencies of micronucleated erythrocytes and of proliferating nucleated cells were determined. Neoplasias were diagnosed by histopathology. Five days after the end of radiation exposure, increased frequencies of proliferating cells, polychromatic erythrocytes and micronucleated normochromatic erythrocytes clearly distinguished the exposed group from the control group. Increased cell proliferation in peripheral blood cells could be used to identify animals with manifest tumours, although these animals were at a late stage of tumour development. Animals with thymic lymphoma (not generalized) could not be identified with the flow-cytometric parameters used. We consider that this model system has a potential use when a small number of risk individuals need to be identified and monitored within a large population.     

The outcome of local radiation injuries: 14 years of follow-up after the Chernobyl accident

The Chernobyl nuclear power plant accident on April 26, 1986 was the largest in the history of the peaceful use of nuclear energy. Of the 237 individuals initially suspected to have been significantly exposed to radiation during or in the immediate aftermath of the accident, the diagnosis of acute radiation sickness (ARS) could be confirmed in 134 cases on the basis of clinical symptoms. Of these, 54 patients suffered from cutaneous radiation syndrome (CRS) to varying degrees. Among the 28 patients who died from the immediate consequences of accidental radiation exposure, acute hemopoietic syndrome due to bone marrow failure was the primary cause of death only in a minority. In 16 of these 28 deaths, the primary cause was attributed to CRS. This report describes the characteristic cutaneous sequelae as well as associated clinical symptoms and diseases of 15 survivors of the Chernobyl accident with severe localized exposure who were systematically followed up by our groups between 1991 and 2000. All patients presented with CRS of varying severity, showing xerosis, cutaneous telangiectasias and subungual splinter hemorrhages, hemangiomas and lymphangiomas, epidermal atrophy, disseminated keratoses, extensive dermal and subcutaneous fibrosis with partial ulcerations, and pigmentary changes including radiation lentigo. Surprisingly, no cutaneous malignancies have been detected so far in those areas that received large radiation exposures and that developed keratoses; however, two patients first presented in 1999 with basal cell carcinomas on the nape of the neck and the right lower eyelid, areas that received lower exposures. During the follow-up period, two patients were lost due to death from myelodysplastic syndrome in 1995 and acute myelogenous leukemia in 1998, respectively. Other radiation-induced diseases such as dry eye syndrome (3/15), radiation cataract (5/15), xerostomia (4/15) and increased FSH levels (7/15) indicating impaired fertility were also documented. This study, which analyzes 14 years in the clinical course of a cohort of patients with a unique exposure pattern, corroborates the requirement for long-term, if not life-long, follow-up not only in atomic bomb survivors, but also after predominantly local radiation exposure.     

Cambial history of Scots pine trees (Pinus Sylvestris) prior and after the Chernobyl accident as encoded in the xylem

Studies were carried out on wood samples collected in October 1997 from breast height of Scots pine trees (Pinus sylvestris) from site located 5 km south from the Chernobyl nuclear power plant. The radioactive contamination at the site was 3.7x10(5) kBq m(-2). These samples of secondary wood were used as an archive of information about the dynamics of a meristematic tissue cambium affected by ionising radiation from the Chernobyl reactor accident. The results show that frequency of the cambial cells events like anticlinal divisions, intrusive growth and cells elimination, was after the Chernobyl accident, about three times higher in comparison to preceding years. The most interesting finding was that after irradiation the length of tracheids increased. This increase is interpreted as an effect of intracambial competition among cells in the initial layer.     

Analysis of blood lymphocyte subsets in children living around Chernobyl exposed long-term to low doses of cesium-137 and various doses of iodine-131

Epidemiological studies have found that children living around Chernobyl have rates of respiratory tract illness that are higher than those seen in the area before the Chernobyl accident. The present study investigates the possible effects of radiation exposure on the composition of peripheral blood lymphocyte subsets in children living around Chernobyl. Two hundred nineteen healthy children and children suffering from recurrent respiratory diseases aged 6-14 years who received both low doses of radiation to the whole body from (137)Cs and various doses of radiation to the thyroid from (131)I as fallout from the accident were assessed 5 (1991) and 8-10 years (1994-1996) after the accident. A total of 148 healthy children and children suffering from recurrent respiratory diseases living in noncontaminated areas were also evaluated as controls. Children with recurrent respiratory diseases who lived around Chernobyl had a significantly lower percentage of T cells and a higher percentage of NK cells compared to control children with recurrent respiratory diseases during the study period. In contrast to the findings in 1991, a significant decrease in the percentage of helper-inducer cells was observed in children with recurrent respiratory diseases in 1994-1996. In contrast to 1991, there is a positive correlation between the percentage of helper-inducer cells, the helper-inducer/cytotoxic-suppressor cell ratio, and the dose of radiation to the thyroid of healthy children from (131)I in 1994-1996. There was a positive correlation between the dose of radiation to the thyroid from (131)I and the percentage of helper-inducer cells in children with recurrent respiratory diseases 5 years (1991) after the accident. Further, the dose of radiation to the thyroid from (131)I correlated negatively with the percentage of T and B cells and positively with the percentage of NK cells in children with recurrent respiratory diseases 8-10 years (1994-1996) after the accident. These results raise the possibility that long-term exposure to low doses of (137)Cs may have altered the composition of the T-cell subsets and NK cells in children with recurrent respiratory diseases. The differences in the composition of the peripheral blood lymphocyte subsets between healthy children and those with recurrent respiratory diseases may be attributed to long-term low-dose exposure of the whole body to radiation from (137)Cs and exposure of the thyroid to radiation from (131)I subsequent to the Chernobyl accident.     

Animal models and medical countermeasures development for radiation-induced lung damage: report from an NIAID Workshop

Since 9/11, there have been concerns that terrorists may detonate a radiological or nuclear device in an American city. Aside from several decorporation and blocking agents for use against internal radionuclide contamination, there are currently no medications within the Strategic National Stockpile that are approved to treat the immediate or delayed complications resulting from accidental exposure to radiation. Although the majority of research attention has focused on developing countermeasures that target the bone marrow and gastrointestinal tract, since they represent the most acutely radiosensitive organs, individuals who survive early radiation syndromes will likely suffer late effects in the months that follow. Of particular concern are the delayed effects seen in the lung that play a major role in late mortality seen in radiation-exposed patients and accident victims. To address these concerns, the National Institute of Allergy and Infectious Diseases convened a workshop to discuss pulmonary model development, mechanisms of radiation-induced lung injury, targets for medical countermeasures development, and end points to evaluate treatment efficacy. Other topics covered included guidance on the challenges of developing and licensing drugs and treatments specific to a radiation lung damage indication. This report reviews the data presented, as well as key points from the ensuing discussion.