Exosomes are spherical membrane nanovesicles secreted from cells, and they play an important role in tumor immune response, metastasis, angiogenesis, and survival. Studies investigating exosomes isolated from cells exposed to photon radiation commonly used in conventional radiotherapy demonstrate the influence of this type of radiation on exosome characteristics and secretion. There is currently no research investigating the effects of densely ionizing particles such as protons and alpha radiation on exosomes. Thus we have evaluated the cellular response of human prostate cancer cells exposed to 0, 2, and 6 Gy of alpha radiation emitted from the Am-241 source. Irradiated PC3 and DU145 cell lines, characterized by differences in radiosensitivity, were studied using apoptosis, LDH, and IL-6 assays. Additionally, the corresponding concentration and size of isolated exosomes were measured using NTA. We found that exposure to ionizing radiation resulted in gross changes in viability and cell damage. There were increased amounts of apoptotic or necrotic cells as a function of radiation dose. We demonstrated that irradiated PC3 cells secrete higher quantities of exosomes compared to DU145 cells. Additionally, we also found no statistical difference in exosome size for control and irradiated cells.
Extracellular vesicles are evaluated by nanoparticle tracking analysis (NTA), providing information on their hydrodynamic diameters, and by atomic force microscopy (AFM) to calculate their geometric diameters. The aim of this study is to explore the influence of Brownian movements in a sample drop and preparation time on imaging-based measurements and to determine the relationship between the geometric and hydrodynamic sizes of the extracellular vesicles measured by the AFM and the NTA, respectively. Exosomes derived from the human prostate cancer cell line PC3 were evaluated by NTA and AFM, and those results were compared with Monte Carlo simulations. The mean size, evaluated by AFM shortly after application on the mica substrate, is less than its real value. It obtains the correct value faster for a thinner sample drop. Fitting the log-normal distribution to the geometric and hydrodynamic diameters leads to the conclusion that the latter could arise from the former by linear scaling by a factor that could be used to characterize the analyzed extracellular vesicles. The size of the vesicles attached to the mica substrate depends on time. The effect of Brownian motion and stretch of the lipid bilayer should be considered in the context of exosome AFM studies.
Introduction: The aim of this work was to study the influence of the applicators used for cervical cancer patients treated with high dose-rate brachytherapy (HDR-BT) in the Maria Sklodowska-Curie National Research Institute of Oncology in Warsaw, Poland on doses in the tumour volumes and organs at risk. Material and methods: The treatment was carried out using Iridium-192 in 4 fractions (7.5 Gy each) given in weekly intervals. Two types of applicators were used for comparison: fletcher and ring. The standard dose distribution parameters, read from the system Oncentra Brachy (version 4.5, Elekta), for bladder, rectum, and sigmoid (D2 cc) and tumour (HRCTV D100, D98, D90) were studied. Patients were divided into two groups (240 treatment plans) depending on the type of applicator used and into four groups according to the tumour volumes (HR-CTV < 25 cm3 or HR-CTV ≥ 25 cm3). The collected data were analysed using the PQStatSoftware (version 1.8.2). Results: The treatment plans prepared with all types of applicators fulfil the dose distribution requirements, however, the dose delivered to the tumour using the ring applicator was found to be the highest. For the bladder and sigmoid the optimal dose distribution was obtained when using the fletcher applicator, while for the rectum the ring applicator gave the smallest dose value. The D2 cc parameter for sigmoid obtained for fletcher treatment has smaller values in the case of patients with small tumour volume and for this type of applicator was observed a statistically significant difference when compared with the ring. Conclusions: The ring applicator gives the optimal parameters of the dose distribution independently on the tumour volume with respect to the fletcher applicator, which is however more often used in clinical practice.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.