Acute radiation syndrome in a non-destructive testing worker: a case report

BACKGROUND: In Korea, there were repeated radiation exposure accidents among non-destructive testing workers. Most of the cases involved local injury, such as radiation burns or hematopoietic cancer. Herein, we report a case of acute radiation syndrome caused by short periods of high exposure to ionizing radiation. CASE PRESENTATION: In January 2017, Korea Information System on Occupational Exposure (KISOE) found that a 31-year-old man who had worked in a non-destructive testing company had been overexposed to radiation. The patient complained of symptoms of anorexia, general weakness, prostration, and mild dizziness for several days. He was anemic. The venous injection areas had bruises and bleeding tendency. Blood and bone marrow testing showed pancytopenia and the patient was diagnosed with acute radiation syndrome (white blood cells: 1400/cubic mm, hemoglobin: 7.1 g/dL, platelets: 14000/cubic mm). He was immediately prohibited from working and blood transfusion was commenced. The patient’s radiation exposure dose was over 1.4 Gy (95% confidence limits: 1.1–1.6) in lymphocyte depletion kinetics. It was revealed that the patient had been performing non-destructive tests without radiation shielding when working in high places of the large pipe surface. CONCLUSIONS: Exposure prevention is clearly possible in radiation-exposed workers. Strict legal amendments to safety procedures are essential to prevent repeated radiation exposure accidents.

MMP Inhibitor Ilomastat Improves Survival of Mice Exposed to γ-Irradiation / 生物医学与环境科学（英文）

There is still a need for better protection against or mitigation of the effects of ionizing radiation following conventional radiotherapy or accidental exposure. The objective of our current study was to investigate the possible roles of matrix metalloproteinase inhibitor, ilomastat, in the protection of mice from total body radiation (TBI), and the underlying protective mechanisms. Ilomastat treatment increased the survival of mice after TBI. Ilomastat pretreatment promoted recovery of hematological and immunological cells in mice after 6 Gy γ-ray TBI. Our findings suggest the potential of ilomastat to protect against or mitigate the effects of radiation.

Green tea ameliorates recognition memory defects in acute radiation syndrome caused by gamma irradiation / 동물의과학연구지

An evidence suggests that even low-dose irradiation can lead to progressive cognitive decline as well as memory deficits in both humans and experimental animals in part due to hippocampal dysfunction. To determine whether or not green tea (GT) and epigallocatechin gallate (EGCG) could attenuate memory impairment as well as suppress hippocampal neurogenesis, passive avoidance and object recognition memory test as well as TUNEL assay and immunohistochemical detection with markers of neurogenesis (Ki-67 and doublecortin (DCX)) were performed using adult mice treated with relatively low-dose gamma irradiation (2.0 Gy). GT was administered intraperitonially at a dosage of 50 mg/kg of body weight at 36 and 12 hr preirradiation and at 30 minutes post-irradiation, or orally at a dosage of 250 mg/kg of body weight/day for 7 days before autopsy. EGCG (25 mg/kg of body weight) was administered intraperitonially at 36 and 12 hr pre-irradiation and at 30 minutes post-irradiation. In the passive avoidance and object recognition memory test, mice trained for 1 day after acute irradiation (2 Gy) showed significant memory deficits compared with sham controls. The number of TUNEL-positive apoptotic nuclei in the dentate gyrus increased by 12 h after irradiation. In addition, the numbers of Ki-67- and DCX-positive cells significantly decreased. GT treatment prior to irradiation attenuated memory defects, blocked apoptotic death, as well as reduced the number of DCX-positive cells. Therefore, GT may attenuate memory defects in adult mice exposed to a relatively low dose of radiation possibly by inhibiting the detrimental effects of irradiation on hippocampal neurogenesis.

Stem cell therapy: A novel & futuristic treatment modality for disaster injuries.

Stem cell therapy hold the potential to meet the demand for transplant cells/tissues needed for treating damages resulting from both natural and man-made disasters. Pluripotency makes embryonic stem cells and induced pluripotent stem cells ideal for use, but their teratogenic character is a major hindrance. Therapeutic benefits of bone marrow transplantation are well known but characterizing the potentialities of haematopoietic and mesenchymal cells is essential. Haematopoietic stem cells (HSCs) have been used for treating both haematopoietic and non-haematopoietic disorders. Ease of isolation, in vitro expansion, and hypoimmunogenecity have brought mesenchymal stem cells (MSCs) into limelight. Though differentiation of MSCs into tissue-specific cells has been reported, differentiation-independent mechanisms seem to play a more significant role in tissue repair which need to be addressed further. The safety and feasibility of MSCs have been demonstrated in clinical trials, and their use in combination with HSC for radiation injury treatment seems to have extended benefit. Therefore, using stem cells for treatment of disaster injuries along with the conventional medical practice would likely accelerate the repair process and improve the quality of life of the victim.

New advance of research on therapy of severe acute radiation sickness with mesenchymal stem cells / 中国实验血液学杂志

Mesenchymal stem cells (MSC) are a kind of non-hematopoietic adult stem cells with self-renewal and multilineage differentiation potential, which have special biological characteristics, such as secreting various cytokines, promoting hematopoiesis, accelerating stem cells homing and reconstructing hematopoietic microenvironment. MSC are collected and amplified easily, and can be transfected by exogenous gene. Many reports indicated that MSC were applied in therapy for variety of tissues and organs injury, meanwhile the treatment for acute radiation sickness has made significant progress. In this review, the biological characteristics and new research advance on MSC in treatment of severe acute radiation sickness are summarized and discussed.

Radiological Accident and Acute Radiation Syndrome

In mass casualty situation due to radiological accidents, it is important to start aggressive management with rapid triage decisions. External contamination needs immediate decontamination and internal contamination should be treated with special expertise and equipment to prevent the rapid uptake of radionuclides by target organs. Acute radiation syndrome shows a sequence of events that varies with the severity of the exposure. More severe exposures generally lead to more rapid onset of symptoms and severe clinical findings. After the massive exposure, various systems of the body reflect their severe damages that can lead to death within hours or up to several months. The disease progression has classically been divided into four stages: prodromal, latent, manifest illness, and recovery or death. Three characteristic clusters of symptoms including the hematopoietic syndrome, the gastrointestinal syndrome and the cerebrovascular syndrome are all associated with the acute radiation syndrome. The standard medical management of the patients with a potentially survivable radiation exposure includes good medical, surgical and supportive measures. Specific treatment with cytokines and bone marrow transplantation should be considered. The management of internal contamination is much the same as the treatment of poisoning. The standard decontamination should be applied to reduce uptake, and the chelating agents can be administered to enhance the clearance of radioisotopes. Radioactive iodine (131I) as one of the nuclear fission products can increase the incidence of thyroid cancer in children. Potential benefit of potassium iodide prophylaxis is greater especially in neonates, infants and small children.

Amifostine ameliorates recognition memory defect in acute radiation syndrome caused by relatively low-dose of gamma radiation

This study examined whether amifostine (WR-2721) could attenuate memory impairment and suppress hippocampal neurogenesis in adult mice with the relatively low-dose exposure of acute radiation syndrome (ARS). These were assessed using object recognition memory test, the terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling assay, and immunohistochemical markers of neurogenesis [Ki-67 and doublecortin (DCX)]. Amifostine treatment (214 mg/kg, i.p.) prior to irradiation significantly attenuated the recognition memory defect in ARS, and markedly blocked the apoptotic death and decrease of Ki-67- and DCX-positive cells in ARS. Therefore, amifostine may attenuate recognition memory defect in a relatively low-dose exposure of ARS in adult mice, possibly by inhibiting a detrimental effect of irradiation on hippocampal neurogenesis.

Diagnostic and Therapeutic Management of Acute Radiation Syndrome and Internal Contamination

The ARS(Acute Radiation Syndrome) develops, within 60 days after exposure to ionising radiation with typical clinical signs and symptoms as a function of time. The interactions and combined effects of radiation-induced damage to different organ systems are diverse and not yet fully understood. Therefore, when accidental exposure to ionising radiation is documented or suspected, guidance for immediate diagnostic procedures and specialised care are required to handle the complexity of the ARS. The following four organ systems, Neurovascular system (N), Hematopoietic system (H), Cutaneous system (C) and Gastrointestinal system (G) are considered to be of critical significance for the development of ARS and should therefore receive special attention in the medical management of radiation accident cases. The Assessment of the severity of damage, Decision on the kind of hospitalisation, Provision of appropriate therapeutic interventions and Evaluation of the patient's prognosis must be considered in the management of a patient after a radiation accident. When significant levels of radioactive materials are incorporated, pathological consequences may ensue, making emergent treatment particularly important. However, this should not take priority over treatment of life threatening conditions and of acute injuries. Following medical stabilization, careful radiological assessment can be performed to determine the presence of both external and internal contamination. It is important to note that 1) contaminated patients do not represent a direct hazard to health care providers and 2) lifesaving procedures should not be delayed regardless of the level of contamination.