COGNITIVE ASPECTS OF DEPRESSION IN VICTIMS OF RADIATION ACCIDENTS, THE COVID-19 PANDEMIC, AND WARS

The relevance of the work is due to the significant increase in depression with cognitive disorders (CD) worldwide, and in Ukraine in particular, in victims of emergencies situations (ES), and the importance, but insufficient development of clinical and psychopathological aspects of medical and psychological-psychiatric care for this contingent of people. Despite the modern achievements of psychiatry in the study of depression in ES, an important problem is CD, which worsen the quality of life of patients, increase the risk of relapse, progressive course, and suicidal behavior. In order to improve the level of psychological and psychiatric care for depressed patients with CD in post-stress disorders by radiation accidents, the COVID-19 pandemic, and wars, the study of domestic and foreign literature on these disorders, which have both common features and certain differences, was conducted.Conclusions. The study confirms the significant prevalence of depression with CD in victims of radiation accidents, the COVID-19 pandemic, and wars, the insufficient development of clinical and psychopathological aspects and theneed for further study of this problem, as well as the creation of state measures of psychological and psychiatric care for these patients.

Responding to radiation accidents: what more do we need to know?

A short review of the various types of radiation incidents and accidents that have occurred is used to provide a context for discussing the findings on medical management of the victims of such incidents and accidents reported in a recent Special Issue of the Journal of Radiological Protection. The review demonstrates that accidents and incidents giving rise to high radiation doses may involve over-exposure of a single individual, a few individuals, or very large numbers. In general, these exposures will be relatively short-term, ranging from a few seconds to a few days, but chronic situations resulting in high exposures can occur. Some of these exposures may be highly localised, whereas others may result in almost uniform whole-body irradiation. This diversity of situations means that it is not feasible to have a single protocol for the diagnosis and treatment of over-exposed individuals. If the over-exposures are limited to one or a few individuals, these can be addressed on a case-by-case basis. However, where large numbers have been exposed or may have been exposed, there is a need to implement a rapid and effective system of triage. Furthermore, this system is likely to have to be implemented by individuals who have little or no direct experience of radiation-induced injuries. For those individuals who may have been significantly exposed, the key consideration is not to determine the radiation dose that they have received, but to establish their present clinical status and how it is likely to develop with time. There is at most a very limited role for bone-marrow transplantation in the treatment of acute radiation syndrome, whereas there are good arguments for administering various treatments to boost bone marrow function together with other supportive interventions, e.g. in control of infections and handling both fluid loss and bleeding. However, there is concern that the focus to date has been only on the licencing of drugs related to the management of haematopoietic effects. Although a great deal is known about the diagnosis and treatment of injuries arising from high dose exposures, this knowledge is biased towards situations in which there is relatively uniform, external whole-body exposure. More attention needs to be given to assessing the implications of various inhomogeneous exposure regimes and to developing medical countermeasures optimised for addressing the complex, multi-organ effects likely to arise from such inhomogeneous exposures.

Mesenchymal stromal cells in the regeneration of radiation-induced organ sequelae: will they make the difference?

Mesenchymal stromal cells (MSCs) are a stem cell product with good safety that demonstrate significant clinical efficacy in the treatment of different pathologies, including radiation diseases (e.g. radiological burns, pelvic radiation disease). While the first results for some first human applications for the treatment of radiation disease suggest benefit, larger trials with clinically important endpoints are needed before definitive conclusions can be drawn. However, the supply and cost of MSCs remain the two main limitations for this innovative therapeutic product. Exosomes (EXOs), a stem cell product associated with MSC therapy, have shown promising efficacy and safety in humans. MSC-EXO therapeutics represent a promising next-generation approach for treating radiation diseases involving a primary (major) inflammatory component. Provided that conditions for MSC-EXO production and bio-banking are agreed in the near future, the transition to industrial production of MSC-EXOs will be possible, and this is required to initiate well-controlled clinical trials for approval by the European Medicines Agency (EMA) and US Food and Drug Administration (FDA).

COMORBID INTERNAL DISEASES IN MILITARY SERVANTS WHO HAVE SENSED THE EXPOSURE OF EXTREME FACTORS OF MILITARY SERVICE

OBJECTIVE

to analyze comorbid pathology by methods of its quantitative assessment in servicemen exposed toextreme factors of military service (a set of factors of radiation accidents, the influence of modern armed conflictsand modern combat trauma without blood loss).

MATERIALS AND METHODS

Studies of comorbid pathology were performed in 613 servicemen who were treated at theclinical base of the Ukrainian Military Medical Academy (UMMA) in National Military Medical Clinical Center «MainMilitary Clinical Hospital» NMMCC «MMCH» during 1989-2018 years. Soldiers who suffered from acute radiation sick-ness (ARS) in 1961 (n = 34), participants in the liquidation of the consequences of the Chornobyl catastrophe(PLCChC) 15 years after participating in the elimination of its consequences and in a later period (respectivelyPLCChC 1st group (n = 59) and the 2nd group (n = 337)). Soldiers are participants in the anti-terrorist operation(ATO)/Combined Forces (CFO) operation who did not receive modern combat injuries with blood loss (participants inthe ATO/CFO, n = 183). All servicemen did not have any diseases limiting their fitness capabilities for military serv-ice before being exposed to extreme factors of military service. A cumulative CIRS scale was used to comprehensive-ly assess comorbidity.

RESULTS

With increasing time after participation in the elimination of the consequences of radiation accidents, thecourse of arterial hypertension (AH) is aggravated, but the dose-dependence of the severity of AH on the receivedradiation dose has not been established. The easier course of hypertension in ATO/CFO servicemen compared to ARSremote servicemen and group 2 PLCChC servicemen can be explained by their younger age at the time of the surveyand less time after exposure to extreme military service factors. In the military in the remote period after exposureto a complex of factors of radiation accidents, the frequency of diagnosing diseases by individual organs and bodysystem increases comparing to non-irradiated servicemen. The total number of disease severity scores on the cumu-lative scale of CIRS diseases is also higher. However, a dose-dependent effect of the severity of comorbid patholo-gy was also not found. These data indicate a higher prevalence of comorbid pathology in servicemen affected by acomplex of factors of radiation accf5idents, compared with participants in the anti-terrorist operation / environ-mental protection. However, the lower severity of comorbid pathology in ATO/CFO participants can also be explainedby their younger age at the time of the survey and less time after exposure to extreme factors of military service.

CONCLUSIONS

For servicemen, with increasing time after participation in the elimination of the consequences ofradiation accidents, the course of hypertension without its dose dependence becomes more difficult. The total num-ber of disease severity scores on the cumulative scale of CIRS diseases in servicemen in the remote period after participation in the elimination of the consequences of radiation accidents is higher than in non-irradiated service-men. However, a dose-dependent effect of the severity of comorbid pathology was also not found.

Retrospective physical dosimetry in the Czech Republic: an overview of already established methods and recent research

PURPOSE

The threat of serious radiation exposures to members of the public from radiological incidents and nuclear events has led to intensive study of a number of emergency dosimetry techniques for purposes of triage. As such, a national laboratory of retrospective dosimetry was established in our institute. The purpose of this work is to provide a summary of the well-established and already implemented retrospective physical dosimetry techniques based on thermoluminescence (TL), optically stimulated luminescence (OSL) and neutron activation including their specifics. Moreover, we present some new results of the experimental work, in which we compared dosimetry potential of various dental repair materials and human teeth.

MATERIALS AND METHODS

At first, an overview of already established retrospective physical retrospective methods including their main features was compiled. As regards recent research, an experimental comparative study was performed under defined conditions. The materials used were aliquots prepared from both pure and repaired teeth and aliquots of unused dental ceramics of known type. Following irradiation, we compared TL and OSL curves of the materials. We also compared dosimetry characteristics of OSL signal as reproducibility, dose dependence and fading.

RESULTS

After irradiation, the teeth aliquots of dental enamel and dentin exhibited very low OSL and TL signals compared with aliquots containing some dental repair materials or aliquots of pure dental ceramics. With a few exceptions, the OSL signal of dental enamel and dentin aliquots irradiated to 2 Gy was hardly distinguishable from OSL signal corresponding to unirradiated aliquots. In contrast, aliquots of teeth containing some dental repair material and aliquots of pure dental ceramics provided a well reproducible OSL signal exhibiting linear dose response. All the materials tested exhibited a significant fading of the OSL signal. The loss of OSL signal during the first 24 hours after irradiation was from 20 to 99% of its original value obtained immediately after the irradiation.

CONCLUSIONS

The already established physical methods of retrospective dosimetry use a spectrum of verified materials and techniques for dose assessment in the aftermath of serious radiological incidents and nuclear events. In the comparative study, we found that the dosimetry potential of teeth in natural state is much worse compared to teeth repaired with dental ceramics or dental cement fillings. Teeth restored with dental repair materials exhibited relatively favorable dosimetry characteristics. However, they can be usable for a dose reconstruction only on condition that the main practical problems connected with fading and optical bleaching were solved.

The Particle Radiobiology of Multipotent Mesenchymal Stromal Cells: A Key to Mitigating Radiation-Induced Tissue Toxicities in Cancer Treatment and Beyond?

Mesenchymal stromal cells (MSCs) comprise a heterogeneous population of multipotent stromal cells that have gained attention for the treatment of irradiation-induced normal tissue toxicities due to their regenerative abilities. As the vast majority of studies focused on the effects of MSCs for photon irradiation-induced toxicities, little is known about the regenerative abilities of MSCs for particle irradiation-induced tissue damage or the effects of particle irradiation on the stem cell characteristics of MSCs themselves. MSC-based therapies may help treat particle irradiation-related tissue lesions in the context of cancer radiotherapy. As the number of clinical proton therapy centers is increasing, there is a need to decidedly investigate MSC-based treatments for particle irradiation-induced sequelae. Furthermore, therapies with MSCs or MSC-derived exosomes may also become a useful tool for manned space exploration or after radiation accidents and nuclear terrorism. However, such treatments require an in-depth knowledge about the effects of particle radiation on MSCs and the effects of MSCs on particle radiation-injured tissues. Here, the existing body of evidence regarding the particle radiobiology of MSCs as well as regarding MSC-based treatments for some typical particle irradiation-induced toxicities is presented and critically discussed.

The psychological consequences of (perceived) ionizing radiation exposure: a review on its role in radiation-induced cognitive dysfunction

PURPOSE

Exposure to ionizing radiation following environmental contamination (e.g., the Chernobyl and Fukushima nuclear accidents), radiotherapy and diagnostics, occupational roles and space travel has been identified as a possible risk-factor for cognitive dysfunction. The deleterious effects of high doses (≥1.0 Gy) on cognitive functioning are fairly well-understood, while the consequences of low (≤0.1 Gy) and moderate doses (0.1-1.0 Gy) have been receiving more research interest over the past decade. In addition to any impact of actual exposure on cognitive functioning, the persistent psychological stress arising from perceived exposure, particularly following nuclear accidents, may itself impact cognitive functioning. In this review we offer a novel interdisciplinary stance on the cognitive impact of radiation exposure, considering psychological and epidemiological observations of different exposure scenarios such as atomic bombings, nuclear accidents, occupational and medical exposures while accounting for differences in dose, rate of exposure and exposure type. The purpose is to address the question that perceived radiation exposure - even where the actual absorbed dose is 0.0 Gy above background dose - can result in psychological stress, which could in turn lead to cognitive dysfunction. In addition, we highlight the interplay between the mechanisms of perceived exposure (i.e., stress) and actual exposure (i.e., radiation-induced cellular damage), in the generation of radiation-induced cognitive dysfunction. In all, we offer a comprehensive and objective review addressing the potential for cognitive defects in the context of low- and moderate-dose IR exposures.

CONCLUSIONS

Overall the evidence shows prenatal exposure to low and moderate doses to be detrimental to brain development and subsequent cognitive functioning, however the evidence for adolescent and adult low- and moderate-dose exposure remains uncertain. The persistent psychological stress following accidental exposure to low-doses in adulthood may pose a greater threat to our cognitive functioning. Indeed, the psychological implications for instructed cohorts (e.g., astronauts and radiotherapy patients) is less clear and warrants further investigation. Nonetheless, the psychosocial consequences of low- and moderate-dose exposure must be carefully considered when evaluating radiation effects on cognitive functioning, and to avoid unnecessary harm when planning public health response strategies.