Do protons and X-rays induce cell-killing in human peripheral blood lymphocytes by different mechanisms?

Purpose: Significant progress has been made in the technological and physical aspects of dose delivery and distribution in proton therapy. However, mode of cell killing induced by protons is less understood in comparison with X-rays. The purpose of this study is to see if there is any difference in the mode of cell-killing, induced by protons and X-rays in an ex vivo human peripheral blood lymphocyte (HPBL) model. Materials and methods: HPBL were irradiated with 60 MeV proton beam or 250-kVp X-rays in the dose range of 0.3–4.0 Gy. Frequency of apoptotic and necrotic cells was determined by the Fluorescein (FITC)-Annexin V labelling procedure, 1 and 4 h after irradiation. Chip-based DNA Ladder Assay was used to confirm radiation-induced apoptosis and necrosis. Chip-based DNA Ladder Assay was used to confirm radiation-induced apoptosis. Results: Ex vivo irradiation of HPBL with proton beams of 60 MeV or 250 kVp X-rays resulted in apoptotic as well as necrotic modes of cell-killing, which were evident at both 1 and 4 h after irradiation in the whole dose and time range. Generally, our results indicated that protons cause relatively higher yields of cell death that appears to be necrosis compared to X-rays. The analysis also demonstrates that radiation type and dose play a critical role in mode of cell-killing. Conclusion: Obtained results suggest that X-rays and protons induce cell-killing by different modes. Such differences in cell-killing modes may have implications on the potential of a given therapeutic modality to cause immune modulation via programmed cell death (X-rays) or necrotic cell death (proton therapy). These studies point towards exploring for gene expression biomarkers related necrosis or apoptosis to predict immune response after proton therapy

Current advances in radiotherapy for soft tissue sarcomas

Radiotherapy (RT) is a part of the routine treatment of locally advanced or high-grade soft-tissue sarcomas (STS). However, RT has changed significantly over the last 20 years. Modern RT techniques have extended its potential application in STS treatment. That includes advances in contouring, fractionation regimens, RT techniques and combined treatment. This article summarizes the available data, current strategies and future research directions in RT for STS

Diallyl trisulfide-induced prostate cancer cell death is associated with Akt/PKB dephosphorylation mediated by P-p66shc

PURPOSE: P66Shc, an isoform of adaptor proteins, is known to mediate various signals including those leading to apoptosis or cell proliferation. Previously, we have shown that diallyl trisulfide (DATS)-induced prostate cancer cell death was mediated by increased ROS formation. In this study, we investigated the role of p66Shc protein and its serine 36 phosphorylation in DATS induced decrease in prostate cancer cell viability (PC-3). METHODS: PC-3 prostate cancer cells were used in this study. Stable cell lines expressing p66ShcS36A or an empty vector have been obtained. Cell viability, concentration of ROS, changes in P-p66Shc and P-Akt and DNA damage were determined. RESULTS: We observed that DATS treatment increased p66Shc phosphorylation at serine 36. Importantly, the phosphorylation was abolished by JNK inhibitor SP600125. Cells expressing plasmid-encoded variant of p66ShcS36A showed much higher resistance to DATS-induced cells death. In addition to that, we observed that DATS-induced ROS formation was completely abolished in cells expressing the p66ShcS36A variant. Interestingly, SP600125 proved to prevent DATS-induced Akt inactivation. In order to confirm that the observed effect is related to phosphorylation of p66Shc, we performed experiments on a stable cell line expressing p66ShcS36A. In such cells, DATS-induced Akt dephosphorylation was significantly reduced. On the other hand, hydrogen peroxide induced Akt activation in PC-3 cells, which was abrogated in cells expressing p66ShcS36A. CONCLUSIONS: Our results uncover a novel signaling pathway with p66Shc being indispensable for DATS-induced inactivation of Akt due to hypophosphorylation

Dynamics of Solid Proteins by Means of Nuclear Magnetic Resonance Relaxometry

Funding This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 668119 (project “IDentIFY”).Peer reviewedPublisher PD

NADH-generating substrates reduce peroxyl radical toxicity in RL-34 cells

There is general agreement that oxidative stress may induce apoptotic and necrotic cell death. Recently it has been shown that NADH can be considered an important antioxidant as it reacts with peroxyl and alkoxyl radicals under in vitro conditions. Therefore, in the present study we hypothesized that an increase in intracellular NADH using specific substrates will protect RL-34 cells against cytotoxicity of 2’-azobis (2-amidinopropane) dihydrochloride (AAPH), which is a peroxyl radical generating compound. Cells treated for 24 hours with 6.0 mM AAPH were severely damaged: mitochondria were vacuolated, and the level of free radicals significantly increased. Both apoptotic and necrotic cells were detected (11.1% and 11.4%, respectively) even after 5 hours of treatment. Pretreatment of the cells with substrates which increase the intracellular level of NADH, such as lactate, beta-hydroxybutyrate, and ethanol, distinctly inhibited AAPH-induced reactive oxygen species (ROS) formation and cell death. On the other hand, acetoacetate (AcA), which decrease the intracellular level of NADH, had opposite effects. Interestingly, NADH-generating substrates augment, while AcA reduced superoxide radical formation induced by AAPH. These results may suggest that although NADH generating substrates may exert some deleterious effects within a cell by inducing reductive stress, they diminish alkoxyl or peroxyl radical cytotoxicity. The protection is associated with a decrease in ROS formation measured by dichlorofluorescein, but with an increase in superoxide radical formation

Out-of-hospital cardiac arrest treated by emergency medical service teams during COVID-19 pandemic: A retrospective cohort study

Background: Out-of-hospital cardiac arrest (OHCA) is a challenge for medical personnel, especiallyin the current COVID-19 pandemic, where medical personnel should perform resuscitation wearing fullpersonal protective equipment. This study aims were to assess the characteristics and outcomes of adultswho suffered an OHCA in the COVID-19 pandemic treated by emergency medical service (EMS) teams.Methods: All EMS-attended OHCA adults over than 18 years in the Polish EMS registry were analyzed.The retrospective EMS database was conducted. EMS interventions performed between March 1,and April 30, 2020 were retrospectively screened.Results: In the study period EMS operated 527 times for OHCA cases. The average age of patientswith OHCA was 67.8 years. Statistically significantly more frequently men were involved (64.3%).298 (56.6%) of all OHCA patients had resuscitation attempted by EMS providers. Among resuscitatedpatients, 73.8% were cardiac etiology. 9.4% of patients had return of spontaneous circulation, 27.2% ofpatients were admitted to hospital with ongoing chest compression. In the case of 63.4% cardiopulmonaryresuscitation was ineffective and death was determined.Conclusions: The present study found that OHCA incidence rate in the Masovian population (centralregion of Poland) in March–April 2020 period was 12.2/100,000 adult inhabitants. Return of spontaneouscirculation in EMS was observed only in 9.4% of resuscitated patients. The presence of shockablerhythms was associated with better prognosis. The prehospital mortality, even though it was high, didnot differ from those reported by other studies

International variation in the management of severe COVID-19 patients

Background: There is little evidence to support the management of severe COVID-19 patients. Methods: To document this variation in practices, we performed an online survey (April 30-May 25, 2020) on behalf of the European Society of Intensive Care Medicine (ESICM). A case vignette was sent to ESICM members. Questions investigated practices for a previously healthy 39-year-old patient presenting with severe hypoxemia from COVID-19 infection. Results: A total of 1132 ICU specialists (response rate 20%) from 85 countries (12 regions) responded to the survey. The survey provides information on the heterogeneity in patient's management, more particularly regarding the timing of ICU admission, the first line oxygenation strategy, optimization of management, and ventilatory settings in case of refractory hypoxemia. Practices related to antibacterial, antiviral, and anti-inflammatory therapies are also investigated. Conclusions: There are important practice variations in the management of severe COVID-19 patients, including differences at regional and individual levels. Large outcome studies based on multinational registries are warranted.publishersversionpublishe