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International journal of molecular sciences 22(1), 316 (2021). doi:10.3390/ijms22010316, Published by Molecular Diversity Preservation International, Basel

Issue: Since the start of the global pandemic, a number of publications have suggested using ionising radiation to diagnose a COVID-19 infection. Some proposals call for the use of computed tomography (CT) to screen for presymptomatic SARS-CoV-2-infections. Intent of the consultation: With these proposals in mind, the German Commission on Radiological Protection (SSK) agreed during its 307th meeting on 2 and 3 July 2020 to establish a working group aimed at evaluating the use of ionising radiation in connection with a COVID-19 infection. The working group focussed on radiological protection aspects with a view to using computed tomography to diagnose COVID-19. The group started its work on 5 October 2020. Although not commissioned by the Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU), representatives of the BMU and the Federal Office for Radiation Protection (BfS) were involved in the consultations. Statement: The SSK issues the following statement: 1. The use of CT in asymptomatic persons to diagnose COVID-19 outside of approved studies is not evidentially justified. 2. Pursuant to Section 83 (3) of the German Radiation Protection Act, a CT scan for the diagnosis or follow-up of a COVID-19 pneumonia requires the prior justifying indication from a doctor with the requisite specialist knowledge in radiation protection. To this end, specialist medical associations provide recommendations based on up-to-date findings.

Largely unnoticed, all life on earth is constantly exposed to low levels of ionizing radiation. Radon, an imperceptible natural occurring radioactive noble gas, contributes as the largest single fraction to radiation exposure from natural sources. For that reason, radon represents a major issue for radiation protection. Nevertheless, radon is also applied for the therapy of inflammatory and degenerative diseases in galleries and spas to many thousand patients a year. In either case, chronic environmental exposure or therapy, the effect of radon on the organism exposed is still under investigation at all levels of interaction. This includes the physical stage of diffusion and energy deposition by radioactive decay of radon and its progeny and the biological stage of initiating and propagating a physiologic response or inducing cancer after chronic exposure. The purpose of this manuscript is to comprehensively review the current knowledge of radon and its progeny on physical background, associated cancer risk and potential therapeutic effects.

Le but de cet article est de décrire les possibilités et contraintes avec lesquelles des hommes immigrants gais de 20 à 35 ans vivant au Québec (Canada) composent pour faire face à l’homophobie et à l’hétérosexisme en contexte post-migratoire, et ce, en considérant leurs expériences liées à l’homophobie et à l’expression de leur orientation sexuelle, ainsi qu’aux implications pour leur bien-être. Les témoignages des 25 participants de notre étude qualitative révèlent qu’ils estiment avoir acquis des possibilités pour exprimer leur orientation sexuelle en immigrant au Québec, mais qu’ils demeurent affectés par les effets plus ou moins insidieux de l’homophobie et de l’hétérosexisme. Pour y faire face, ils déploient trois principales stratégies : tenter d’échapper à l’identification comme gai ; veiller à demeurer dans un environnement social exempt d’homophobie ; et s’efforcer d’être accepté en dépit de normes hétérosexistes. Les implications pour leur bien-être sont également discutées. This article aims to describe the opportunities and constraints with which immigrant gay men, aged 20 to 35 years old and living in the Province of Quebec (Canada), face homophobia and heterosexism in post-migratory context. We focus on their experiences related to homophobia and the expression of their sexual orientation, and the implications for their well-being. Results from our qualitative study with 25 participants show that these men consider they have gained new opportunities to express their sexual orientation after migrating to the province of Quebec, but that they are still affected by the more or less insidious effects of homophobia and heterosexism. They use three main strategies to face them: trying to avoid being identified as gay; ensuring they stay in spaces that are free from homophobia; and attempting to be accepted despite heterosexist norms. Implications for their well-being are also discussed.

Impairment or stimulation of the immune system by ionizing radiation (IR) impacts on immune surveillance of tumor cells and non-malignant cells and can either foster therapy response or side effects/toxicities of radiation therapy. For a better understanding of the mechanisms by which IR modulates T-cell activation and alters functional properties of these immune cells, we exposed human immortalized Jurkat cells and peripheral blood lymphocytes (PBL) to X-ray doses between 0.1 and 5 Gy. This resulted in cellular responses, which are typically observed also in naïve T-lymphocytes in response of T-cell receptor immune stimulation or mitogens. These responses include oscillations of cytosolic Ca2+, an upregulation of CD25 surface expression, interleukin-2 and interferon-γ synthesis, elevated expression of Ca2+ sensitive K+ channels and an increase in cell diameter. The latter was sensitive to inhibition by the immunosuppressant cyclosporine A, Ca2+ buffer BAPTA-AM, and the CDK1-inhibitor RO3306, indicating the involvement of Ca2+-dependent immune activation and radiation-induced cell cycle arrest. Furthermore, on a functional level, Jurkat and PBL cell adhesion to endothelial cells was increased upon radiation exposure and was highly dependent on an upregulation of integrin beta-1 expression and clustering. In conclusion, we here report that IR impacts on immune activation and functional properties of T-lymphocytes that may have implications in both toxic effects and treatment response to combined radiation and immune therapy in cancer patients.

This systematic review aims to identify factors that facilitate or hinder the return for HIV test results. Four electronic databases were searched. Two independent reviewers selected eligible publications based on inclusion/exclusion criteria. Quantitative studies published since 1985 were included. Thirty-six studies were included in the final review. Individual level barriers included sociodemographic characteristics, such as being a male, of young age and low education level, risk behaviours such as injecting drugs, having multiple sexual partners, and psychosocial factors. Older age, higher education level, being a woman, having high self-esteem, having coping skills, and holding insurance coverage were identified as facilitators. Interpersonal barriers and facilitators were linked to risk behaviours of sexual partners. Contextual barriers included essentially the HIV testing center and its characteristics. This review identified the most important factors that need to be addressed to ensure that people return for their HIV test results.

International audience; PurposeWe initiated studies on the mechanisms of cell death in head and neck squamous cell carcinoma cell lines (HNSCC) since recent clinical trials have shown that local treatment of HNSCC by carbon hadrontherapy is less efficient than it is in other radioresistant cancers.Methods and MaterialsTwo p53-mutated HNSCC cell lines displaying opposite radiosensitivity were used. Different types of cell death were determined after exposure to carbon ions (33.6 and 184 keV/μm) or X-rays.ResultsExposure to radiation with high linear energy transfer (LET) induced clonogenic cell death for SCC61 (radiosensitive) and SQ20B (radioresistant) cells, the latter systematically showing less sensitivity. Activation of an early p53-independent apoptotic process occurred in SCC61 cells after both types of irradiation, which increased with time, dose and LET. In contrast, SQ20B cells underwent G2/M arrest associated with Chk1 activation and Cdc2 phosphorylation. This inhibition was transient after X-rays, compared with a more prolonged and LET-dependent accumulation after carbon irradiation. After release, a LET-dependent increase of polyploid and multinucleated cells, both typical signs of mitotic catastrophe, was identified. However, a subpopulation of SQ20B cells was able to escape mitotic catastrophe and continue to proliferate.ConclusionsHigh LET irradiation induced distinct types of cell death in HNSCC cell lines and showed an increased effectiveness compared with X-rays. However, the reproliferation of SQ20B may explain the potential locoregional recurrence observed among some HNSCC patients treated by hadrontherapy. An adjuvant treatment forcing the tumor cells to enter apoptosis may therefore be necessary to improve the outcome of radiotherapy.