Poland). Wojcik focuses on studying cellular effects of radiation, with special focus on factors influencing the radiosensitivity and on combined exposure to radiations of different qualities

Purpose: In case of a mass-casualty radiological event, there would be a need for networking to overcome surge limitations and to quickly obtain homogeneous results (reported aberration frequencies or estimated doses) among biodosimetry laboratories. These results must be consistent within such network. Inter-laboratory comparisons (ILCs) are widely accepted to achieve this homogeneity. At the European level, a great effort has been made to harmonize biological dosimetry laboratories, notably during the MULTIBIODOSE and RENEB projects. In order to continue the harmonization efforts, the RENEB consortium launched this intercomparison which is larger than the RENEB network, as it involves 38 laboratories from 21 countries. In this ILC all steps of the process were monitored, from blood shipment to dose estimation. This exercise also aimed to evaluate the statistical tools used to compare laboratory performance. Materials and methods: Blood samples were irradiated at three different doses, 1.8, 0.4 and 0 Gy (samples A, C and B) with 4-MV X-rays at 0.5 Gy min À1 , and sent to the participant laboratories. Each laboratory was requested to blindly analyze 500 cells per sample and to report the observed frequency of dicentric chromosomes per metaphase and the corresponding estimated dose. Results: This ILC demonstrates that blood samples can be successfully distributed among laboratories worldwide to perform biological dosimetry in case of a mass casualty event. Having achieved a substantial harmonization in multiple areas among the RENEB laboratories issues were identified with the available statistical tools, which are not capable to advantageously exploit the richness of results of a large ILCs. Even though Zand U-tests are accepted methods for biodosimetry ILCs, setting the number of analyzed metaphases to 500 and establishing a tests' common threshold for all studied doses is inappropriate for evaluating laboratory performance. Another problem highlighted by this ILC is the issue of the dose-effect curve diversity. It clearly appears that, despite the initial advantage of including the scoring specificities of each laboratory, the lack of defined criteria for assessing the robustness of each laboratory's curve is a disadvantage for the 'one curve per laboratory' model.

In addition to representing a significant part of the natural background radiation exposure, α-particles are thought to be a powerful tool for targeted radiotherapy treatments. Understanding the molecular mechanisms of recognition, signaling, and repair of α-particle-induced DNA damage is not only important in assessing the risk associated with human exposure, but can also potentially help in identifying ways of improving the efficacy of radiation treatment. α-particles (He2+ ions), as well as other types of ionizing radiation, and can cause a wide variety of DNA lesions, including DNA double-strand breaks (DSBs). In mammalian cells, DNA DSBs can be repaired by two major pathways: non-homologous end-joining (NHEJ) and homologous recombination (HR). Here, we investigated their dynamics in mouse NIH-3T3 cells through the recruitment of key proteins, such as the KU heterodimer for NHEJ and RAD51 for HR upon localized α-particle irradiation. To deliver α-particles, we used the MIRCOM microbeam, which allows targeting of subnuclear structures with submicron accuracy. Using mouse NIH-3T3 cells, we found that the KU heterodimer is recruited much earlier at DNA damage sites marked by H2AX phosphorylation than RAD51. We also observed that the difference in the response of the KU complex and RAD51 is not only in terms of time, but also in function of the chromatin nature. The use of a microbeam such as MIRCOM, represents a powerful tool to study more precisely the cellular response to ionizing irradiation in a spatiotemporal fashion at the molecular level.

Objetivo: Comparar los desenlaces entre la apendicectomía por laparoscopia por puerto único y multipuerto, y establecer si existe diferencia en el riesgo de colección intraabdominal posoperatoria. Método: Se realizó un estudio retrospectivo, observacional, mediante 116 historias clínicas de pacientes llevados a apendicectomía laparoscópica por único puerto y multipuerto en dos centros médicos. Resultados: Desarrollaron colección intraabdominal 12 (10.3%) pacientes. No se encontraron diferencias entre ambas técnicas en cuanto al desarrollo de colección intraabdominal (p = 0.242), no hubo diferencia entre ambas técnicas en cuanto a sangrado intraoperatorio (p = 0.012) y el tiempo quirúrgico fue mayor en el grupo de puerto único (17.4 minutos en promedio). El 62.5% de los pacientes con sangrado > 50 ml desarrollaron colección intraabdominal. Conclusiones: No se evidenció superioridad de ninguna de las dos intervenciones en apendicitis complicada, pero sí se confirma que la apendicectomía laparoscópica por puerto único es un procedimiento seguro, factible, no inferior y con tasas similares de complicaciones en comparación con la técnica convencional de apendicectomía laparoscópica.