Effects of Chronic Low-Dose Internal Radiation on Immune-Stimulatory Responses in Mice

The Linear-No-Threshold (LNT) model predicts a dose-dependent linear increase in cancer risk. This has been supported by biological and epidemiological studies at high-dose exposures. However, at low-doses (LDR ≤ 0.1 Gy), the effects are more elusive and demonstrate a deviation from linearity. In this study, the effects of LDR on the development and progression of mammary cancer in FVB/N-Tg(MMTVneu)202Mul/J mice were investigated. Animals were chronically exposed to total doses of 10, 100, and 2000 mGy via tritiated drinking water, and were assessed at 3.5, 6, and 8 months of age. Results indicated an increased proportion of NK cells in various organs of LDR exposed mice. LDR significantly influenced NK and T cell function and activation, despite diminishing cell proliferation. Notably, the expression of NKG2D receptor on NK cells was dramatically reduced at 3.5 months but was upregulated at later time-points, while the expression of NKG2D ligand followed the opposite trend, with an increase at 3.5 months and a decrease thereafter. No noticeable impact was observed on mammary cancer development, as measured by tumor load. Our results demonstrated that LDR significantly influenced the proportion, proliferation, activation, and function of immune cells. Importantly, to the best of our knowledge, this is the first report demonstrating that LDR modulates the cross-talk between the NKG2D receptor and its ligands.

Bringing together scientific disciplines for collaborative undertakings: a vision for advancing the adverse outcome pathway framework

BACKGROUND

Decades of research to understand the impacts of various types of environmental occupational and medical stressors on human health have produced a vast amount of data across many scientific disciplines. Organizing these data in a meaningful way to support risk assessment has been a significant challenge. To address this and other challenges in modernizing chemical health risk assessment, the Organisation for Economic Cooperation and Development (OECD) formalized the adverse outcome pathway (AOP) framework, an approach to consolidate knowledge into measurable key events (KEs) at various levels of biological organisation causally linked to disease based on the weight of scientific evidence (http://oe.cd/aops). Currently, AOPs have been considered predominantly in chemical safety but are relevant to radiation. In this context, the Nuclear Energy Agency's (NEA's) High-Level Group on Low Dose Research (HLG-LDR) is working to improve research co-ordination, including radiological research with chemical research, identify synergies between the fields and to avoid duplication of efforts and resource investments. To this end, a virtual workshop was held on 7 and 8 October 2020 with experts from the OECD AOP Programme together with the radiation and chemical research/regulation communities. The workshop was a coordinated effort of Health Canada, the Electric Power Research Institute (EPRI), and the Nuclear Energy Agency (NEA). The AOP approach was discussed including key issues to fully embrace its value and catalyze implementation in areas of radiation risk assessment.

CONCLUSIONS

A joint chemical and radiological expert group was proposed as a means to encourage cooperation between risk assessors and an initial vision was discussed on a path forward. A global survey was suggested as a way to identify priority health outcomes of regulatory interest for AOP development. Multidisciplinary teams are needed to address the challenge of producing the appropriate data for risk assessments. Data management and machine learning tools were highlighted as a way to progress from weight of evidence to computational causal inference.

Mothers' grief following the death of a child

AIM OF THE STUDY

Research has shown that caring for a dying child is among the hardest and more demanding tasks in nursing, because the staff are forced to manage their heavy work with inadequate skills and experience. This article deals with the findings of a recent study, the purpose of which was to analyse the mother's grief and coping with grief following the death of a child under the age of 7 years.

DESIGN

Data were collected from mothers using a survey (n=91) and an interview (n=50). As the topic was very sensitive ethically and emotionally, survey data were collected first and the mothers were asked to give their consent to taking part in an interview. The study employed both quantitative and qualitative methods. The data were analysed using statistical methods and content analysis. However, only the qualitative part of the study is presented in this article.

FINDINGS

The findings show that nursing staff had skills to support grieving mothers, but that there were many feelings and experiences of grief that remained unidentified by staff. The staff's ability to meet the mothers' individual needs while the child was in hospital and after the child's death was inadequate. The information received from staff was perceived to be insufficient or offensive to mothers.

CONCLUSIONS

The development of basic and further education and of various support measures would enable the staff to better cope with their work. Focusing on interactive skills and meeting the patient's individual needs using reflective practice would improve the quality of care. Communication and collaboration between different occupational groups should be promoted, because mothers were dissatisfied with dissemination of information, and ambiguous responsibilities between different occupational groups hampered the acquisition of information.