Gender differences in DNA damage/repair after laser-generated ultrafast electron beam irradiation
The laser-generated electron acceleration is a developing technology, which can make a revolution in radiation therapy of tumors. The possibility of creating directed ultra-short pulses of enormous capacity (up to kGy/s) allows the precise dose-control induction of local effects on solid tumors with minimal exposure of normal tissues. The obvious advantage of laser-generated electron accelerators is also the significantly smaller size and cost than that of conventional radiotherapy machines.1 There are only a few publications on the biological effects of ultra-short pulsed electron beam radiation.2–5 However, before translating the usage of lasergenerated accelerators into clinical practice, the radiobiological effectiveness of such ultra-short electron bunches should be approved.
Ultrahigh dose-rate FLASH irradiation increases the differential response between normal and tumor tissue in mice
Pulsed, ultrahigh dose-rate irradiation is safer than standard radiotherapy for the treatment of lung cancer and selectively spares normal tissue. Safer Radiation for the Lung Radiation is used to treat a variety of tumor types, including lung cancer. Unfortunately, radiation-induced damage to the surrounding healthy lung is a major problem, which can cause long-term complications and limits the amount of radiation that can be safely delivered to the tumor. Favaudon et al. now present a technology called FLASH, which allows the delivery of pulsed, ultrahigh dose-rate irradiation, which causes less damage to the healthy lung than conventional radiotherapy in mouse models. The authors confirmed that FLASH is effective against tumor cells but causes little damage to normal tissue. These results suggest that FLASH radiation may be a viable option for treating lung tumors, although this will need to be confirmed in human patients. In vitro studies suggested that sub-millisecond pulses of radiation elicit less genomic instability than continuous, protracted irradiation at the same total dose. To determine the potential of ultrahigh dose-rate irradiation in radiotherapy, we investigated lung fibrogenesis in C57BL/6J mice exposed either to short pulses (≤500 ms) of radiation delivered at ultrahigh dose rate (≥40 Gy/s, FLASH) or to conventional dose-rate irradiation (≤0.03 Gy/s, CONV) in single doses. The growth of human HBCx-12A and HEp-2 tumor xenografts in nude mice and syngeneic TC-1 Luc+ orthotopic lung tumors in C57BL/6J mice was monitored under similar radiation conditions. CONV (15 Gy) triggered lung fibrosis associated with activation of the TGF-β (transforming growth factor–β) cascade, whereas no complications developed after doses of FLASH below 20 Gy for more than 36 weeks after irradiation. FLASH irradiation also spared normal smooth muscle and epithelial cells from acute radiation-induced apoptosis, which could be reinduced by administration of systemic TNF-α (tumor necrosis factor–α) before irradiation. In contrast, FLASH was as efficient as CONV in the repression of tumor growth. Together, these results suggest that FLASH radiotherapy might allow complete eradication of lung tumors and reduce the occurrence and severity of early and late complications affecting normal tissue.
The Millennial of Castile (1943): the historical culture of Spanish Fascism
Abstract The creation of new symbols and historical myths were common practices of nationalist politics, especially in Fascist regimes. In 1943 the Franco regime organized the most impressive historical commemoration celebrated in post-war Spain: the Milenario of Castile. With its heterogeneous mixture of history and spectacle, the Milenario of Castile was by far the greatest historical commemoration promoted by the State during the 1940s. Taking the commemoration of the Milenario as a case study, this article examines the historical culture of Spanish Fascism, as well as the attempts of the Falangist intellectual elite to impose a concrete national narrative in post-war Spain. At the same time, the article analyses the historical discourses and aesthetics displayed throughout the commemoration, underlining its Fascist character, and consequently the transnational dimension of the Fascist politics of the past. Finally, the article reflects on the scope and limits of the process of Fascistisation in Franco's dictatorship, especially in its commemorative culture.