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Neoadjuvant radiotherapy (RT) is commonly used as standard treatment for rectal cancer. However, response rates are variable and survival outcomes remain poor, highlighting the need to develop new therapeutic strategies. Research is focused on identifying novel methods for sensitising rectal tumours to RT to enhance responses and improve patient outcomes. This can be achieved through harnessing tumour promoting effects of radiation or preventing development of radio-resistance in cancer cells. Many of the approaches being investigated involve targeting the recently published new dimensions of cancer hallmarks. This review article will discuss key radiation and targeted therapy combination strategies being investigated in the rectal cancer setting, with a focus on exploitation of mechanisms which target the hallmarks of cancer.
The Fe3+ substituted for Al3+ at the 2 octahedral positions is one of the most common impurities in the kaolinite structure detected by electron paramagnetic resonance (EPR). Evidence has been provided for a relationship between the shape of EPR spectra for structural Fe and the structural disorder in kaolinite. It is proposed that the structural Fe be used as a sensitive probe for the degree of disorder of natural kaolinites. With this aim in view, an EPR disorder index (E) is defined from the width of selected EPR lines. Using reference kaolinites, it is shown that this index can account as well for long-range disorder detected by means of X-ray diffraction (XRD) as for local perturbations such as radiation-induced defects (RID). It is shown that the disorder observed through EPR has some points in common with the XRD-measured one. The influence on E of the presence of RID is shown by the study of artificially and naturally irradiated kaolinites.
The success of the insect sterile technique (IST) in managing insect pests raised the hypothesis that a similar approach could be employed to control weed populations. Here, we investigated the feasibility of employing irradiated sterile pollen as a means to disrupt seed production in dioecious weeds, specifically focusing on Palmer amaranth (Amaranthus palmeri S. Watson). Our goal was to determine the optimal irradiation dose that strikes a balance between inducing sterility and preserving competitiveness, as excessive doses could result in pollen mortality, while low doses may retain fertility. Plants were grown in a greenhouse during the summer of 2020 and spring of 2021. Once they reached the flowering stage, male and female individuals were isolated. Mature pollen samples were collected and exposed to varying dosages (0, 100, 200, 300, 400, and 500 Gy) of gamma rays. These irradiated and non-irradiated pollen samples were used in pollen viability assessments and hand-pollination experiments. In the hand-pollination study conducted in 2020, we employed six pollination treatments using different irradiation doses. The results showed that 300 Gy was the most effective dose, resulting in a maximum reduction of 30% in seed set compared with open pollination when irradiated pollen had prior access to the stigma through artificial pollination before open pollination. In 2021, to simulate real field conditions, three additional treatments were introduced into the study, further confirming the effectiveness of the optimal 300 Gy dose. Our findings indicate that the sterile pollen technique (SPT) using irradiated pollen can be a valuable approach for reducing weed seed production. SPT also holds potential for broad-spectrum weed control by mixing sterile pollen from multiple weed species in a single application. Additionally, it could aid in managing herbicide-resistant weeds that have survived in-season control efforts. This research contributes to the development of novel and sustainable weed management strategies.
Mouse testicular tissue is composed of seminiferous tubules and interstitial tissue. Mammalian spermatogenesis is divided into three stages: spermatocytogenesis (mitotic divisions) in which spermatogonial stem cells (SSCs) turn into spermatocytes, followed by two consecutive meiotic divisions in which spermatocytes form spermatids. Spermatids differentiate into spermatozoa during spermiogenesis. Various factors affect the process of spermatogenesis and the organization of cells in the testis. Any disorder in different stages of spermatogenesis will have negative effects on male fertility. The aim of the current study was to compare the in vitro and in vivo spermatogenesis processes before and after transplantation to azoospermic mice using ultrastructural techniques. In this study, mice were irradiated with single doses of 14 Gy 60Co radiation. SSCs isolated from neonatal mice were cultured in vitro for 1 week and were injected into the seminiferous tubule recipient’s mice. Testicular cells of neonatal mice were cultured in the four groups on extracellular matrix-based 3D printing scaffolds. The transplanted testes (8 weeks after transplantation) and cultured testicular cells in vitro (after 3 weeks) were then processed for transmission electron microscopy studies. Our study’s findings revealed that the morphology and ultrastructure of testicular cells after transplantation and in vitro culture are similar to those of in vivo spermatogenesis, indicating that spermatogenic cell nature is unaltered in vitro.
The codling moth Cydia pomonella is a major pest of global significance impacting pome fruits and walnuts. It threatens the apple industry in the Loess Plateau and Bohai Bay in China. Sterile insect technique (SIT) could overcome the limitations set by environmentally compatible area-wide integrated pest management (AW-IPM) approaches such as mating disruption and attract-kill that are difficult to suppress in a high-density pest population, as well as the development of insecticide resistance. In this study, we investigated the effects of X-ray irradiation (183, 366, 549 Gy) on the fecundity and fertility of a laboratory strain of C. pomonella, using a newly developed irradiator, to evaluate the possibility of X-rays as a replacement for Cobalt60 (60Co-γ) and the expanded future role of this approach in codling moth control. Results show that the 8th-day is the optimal age for irradiation of male pupae. The fecundity decreased significantly as the dosage of radiation increased. The mating ratio and mating number were not influenced. However, treated females were sub-sterile at a radiation dose of 183 Gy (20.93%), and were almost 100% sterile at a radiation dose of 366 Gy or higher. Although exposure to a radiation dose of 366 Gy resulted in a significant reduction in the mating competitiveness of male moths, our radiation biology results suggest that this new generation of X-ray irradiator has potential applications in SIT programs for future codling moth control.
This chapter considers how did Ghanaian physicists made nuclear science their own under the watchful eye of the International Atomic Energy Agency within what I term a “nuclear protectorate?” During the long battle to secure a nuclear reactor for the Ghana, GAEC sustained one of its additional roles as outlined in the initial 1963 Act 204 that had established it: monitoring radiation at the nation’s x-ray facilities. This work gave GAEC a mandate to apply physics to human bodies. Hospitals and ports turned on radiation sources and GAEC scientists monitored them to measure the levels of exposure to radiographers. Nuclear physicists also introduced new ways to irradiate insects to sterilize pesky disease-carrying flies and kill insect eggs on crops to prolong shelf live. While it took a long time to expand their research programs with an actual reactor, GAEC scientists managed to flourish in their continued quest to make physics relevant to Ghanaian life. The IAEA came to depend on Ghanaian experts as some of the most highly trained nuclear scientists in Africa. They were constantly in demand to represent the continent in IAEA committees, training programs, and observational teams.
Article Chosen: Smith-Bindman R, Aubin C, Bailitz J., et al. Ultrasonography versus Computed Tomography for Suspected Nephrolithiasis. New Engl J Med 2014;371;1100-10.
With its particular ability to image solute clusters in three dimensions and impurity segregation to selected interfaces and grain boundaries, atom probe tomography has provided unique insight into the effects of irradiation on materials microstructures. This article reviews the contribution of atom probe tomography to our understanding of behaviors and responses of structural materials under irradiation. Possible atom probe tomography based approaches and common data analysis methods to analyze the microstructural features often observed in irradiated materials are described. In particular, the analysis of solute clustering, solute segregation, and void imaging are discussed in the context of radiation-induced hardening of austenitic steels and reactor pressure vessel steels, and the development of oxide dispersion strengthened steels, radiation-induced solute segregation to grain boundaries for stress corrosion cracking or corrosion issues, and to understand the swelling response of irradiated materials. While highlighting the unique information that atom probe tomography can offer, common limitations, current challenges, and outstanding technical questions regarding data analysis and interpretation are also presented.
In order to confirm the results of previous experiments concerning the chemical behaviour of organic molecules in the space environment, organic molecules (amino acids and a dipeptide) in pure form and embedded in meteorite powder were exposed in the AMINO experiment in the EXPOSE-R facility onboard the International Space Station. After exposure to space conditions for 24 months (2843 h of irradiation), the samples were returned to the Earth and analysed in the laboratory for reactions caused by solar ultraviolet (UV) and other electromagnetic radiation. Laboratory UV exposure was carried out in parallel in the Cologne DLR Center (Deutsches Zentrum für Luft und Raumfahrt). The molecules were extracted from the sample holder and then (1) derivatized by silylation and analysed by gas chromatography coupled to a mass spectrometer (GC–MS) in order to quantify the rate of degradation of the compounds and (2) analysed by high-resolution mass spectrometry (HRMS) in order to understand the chemical reactions that occurred. The GC–MS results confirm that resistance to irradiation is a function of the chemical nature of the exposed molecules and of the wavelengths of the UV light. They also confirm the protective effect of a coating of meteorite powder. The most altered compounds were the dipeptides and aspartic acid while the most robust were compounds with a hydrocarbon chain. The MS analyses document the products of reactions, such as decarboxylation and decarbonylation of aspartic acid, taking place after UV exposure. Given the universality of chemistry in space, our results have a broader implication for the fate of organic molecules that seeded the planets as soon as they became habitable as well as for the effects of UV radiation on exposed molecules at the surface of Mars, for example.
In this study, laboratory and field cage experiments were conducted to assess the performance of sterile mass-reared Mexican fruit fly Anastrepha ludens (Loew) irradiated at various doses. In small laboratory cages, the radiation dose was found to have no effect on adult emergence, flying adults or survival at 25 days. In field cages, non-irradiated males and males irradiated at 20 and 40 Gy were found to exhibit greater mating propensity than males irradiated at 60 and 80 Gy. In large field cages in competition with wild males, cohorts of flies (male and female) irradiated at the low dose of 40 Gy and wild non-irradiated flies mated randomly, while flies irradiated at the high standard dose of 80 Gy mated assortatively. Irrespective of the radiation dose, laboratory flies courted and attempted copulation significantly earlier in the day than wild flies. In large field cages, cohorts of flies irradiated at low doses, e.g. 40 Gy, tended to induce greater sterility into a cohort of wild flies than those irradiated at 80 Gy, but the difference was not significant. Our results suggest that lowering the radiation dose currently applied to mass-reared flies in the Mexican fruit fly eradication campaign would substantially improve male mating performance. This could result in greater sterility induction without posing a risk in areas where target pest populations naturally prevail and are under suppression during the early stages of eradication programmes.
The papers presented in this special issue are focused on developing and validating procedures for artificial rearing of selected fruit fly species of economic importance for use in area-wide integrated pest programmes with a sterile insect technique (SIT) component. They are the result of a 5-year coordinated research project (CRP) on ‘Development and Improvement of Rearing Techniques for Anastrepha and Bactrocera Fruit Flies’ that was coordinated by the Joint FAO/IAEA Programme of Nuclear Techniques in Food and Agriculture. Twenty-two CRP participants from 18 countries worked on both basic and advanced rearing procedures of different fruit fly species to overcome technical bottlenecks and to develop appropriate and relevant procedures for use in mass-rearing facilities. A variety of studies were undertaken for three groups of tephritid species: (1) those for which mass-rearing for SIT application was available, but further refinement would be useful; (2) those for which mass-rearing for SIT application was under development in the laboratory, but that had not reached mass-rearing status; and (3) those for which research to develop colonization and rearing methods was needed. Many of the protocols developed or improved during the CRP have been transferred to the different fruit fly mass-rearing facilities worldwide.
The aim of our study was to distinguish the stress-related molecular response of thepulmonate mollusc Lymnaea stagnalis from the Chernobyl area in comparisonwith the consequences of other harmful effects, including the short-term effects ofradiation and heating. Specimens inhabiting ponds near the Chernobyl nuclear power plant,the cooling channel of the electric power station and the soil-reclamation channel (groupsR, T and C, correspondingly), and specimens adapted to laboratory conditions (a controlgroup (CL), a disposable group exposed to 2 mGy X-ray radiation over the body (RL), and agroup exposed to 25 °C for 4 days (TL)) were compared. Despite high variability ofresponses, Principle Component Analysis distinctly separated the laboratory and feralgroups into two sets. In the feral groups, low levels of the stress-related andmetal-binding protein metallothionein (MT), protein carbonyls and lactate dehydrogenase inthe digestive gland were indicated. The main separating criteria selected byclassification and regression tree analysis were the protein carbonyls, cholinesterase andMT. Molluscs from group R were clearly distinguished by the lowest levels of MT,Mn-superoxide dismutase and lactate dehydrogenase, and the highest level of glutathione,demonstrating that the oppression of the gene-determined stress-related response and itspartially metabolic compensation can be possible markers for chronic environmental effectsof irradiation.
Nitrides and/or carbonitrides formation of high efficiency was found on titanium target under irradiation of high-intensity pulsed ion beam (HIPIB) with a few shots at a low pressure of 10−2 Pa order, which is extraordinary in comparison with conventional thermo-chemical diffusion process such as gas nitriding and/or carbonitriding of metals necessarily heated at high temperatures during a processing time of hours. The underlying mechanism of the nitrides and carbonitrides formation on titanium targets was explored by a comparative study on three typical HIPIB sources, i.e., TEMP-6, TEMP-4M, and ETIGO-II, varying the irradiation intensity within several J/cm2 per shot of a 60–70 ns pulse duration and the shot number of similar ion species. It is revealed that ambient gases and ion source material are the main sources providing the nitrogen and carbon species for the phase transformation on titanium target at the low pressures, whereas the ion species of HIPIB composition is negligible at a low implantation dose of 1013–1014 ions/cm2. The adsorbed gaseous species, the deposited layer of the ion source material, and in-situ formed compound top layer from reactions between ablation plasma and the ambient species during HIPIB irradiation, can be effectively incorporated into the irradiated target surfaces under a controlled HIPIB-target interaction.
Energy deposition by high-intensity pulsed ion beam into a metal target has been studied with time-of-flight (TOF) of ions which can be related to the original ion kinetic energy E0 and the ion mass with . It is found that the TOF effect has a profound influence on the kinetic energy distribution of implanted ions and subsequent energy deposition process into the target. The HIPIB of mixed H+ and C+ was extracted from a magnetically insulated ion diode at a peak accelerating voltage of 350 kV, leading to an ion current density of 300 A/cm2 at the target. The widespread ion energy spectrum remarkably varied in shape as arriving at the target surface, from the original Gaussian-like of 80-ns duration to a pulse form of a sharp front and a long tail extending to about 140-ns duration. Energy loss of the mixed ions into a Ti target was simulated utilizing a Monte Carlo method. The energy deposition generally showed a shallowing trend and could be divided into two phases proceeded with sequent arrivals of H+ and C+. Note that, the peak value of deposited energy profile appeared at the beginning of mixed ion irradiation phase, other than the phase of firstly arrived H+ with peak kinetic energy and peak ion current. This study indicated that TOF effect of ions greatly affects the HIPIB-matter interaction with a kinetic energy spectrum of impinging ions at the target, noticeably differing from that of original output of the ion source; consequently, the specific energy deposition phenomena of the widespread ion energy can be studied with the TOF correlation of ion energy and ion current, otherwise not obtainable in common cases assuming fixed ion energy distribution in accordance with the original source output.
Infective larvae (third-stage larvae) of both Angiostrongylus cantonensis and A. costaricensis from their snail intermediate host were subjected to either X-ray or gamma-ray irradiation. The viability of the irradiated larvae was assayed by oral inoculation of the larvae into rodents (A. cantoflensis in mice and rats, A. costaricensis in mice only). From the results of worm recovery, the minimal dose of irradiation that inhibited the infectivity of the third-stage larvae of A. cantonensis and A. costaricensis was 2 and 4 kGy, respectively.
The leucocyte responses in peripheral blood and pulmonary airways are described following vaccination of mice with radiation-attenuated parasites, and subsequent challenge with normal parasites. Percutaneous vaccination stimulated a large and sustained expansion of the circulating lymphocyte pool, more marked than after intradermal vaccination with lung schistosomula which induced comparable levels of resistance. Macrophages and lymphocytes infiltrated the pulmonary airways in response to vaccination by both routes, the lymphocytes being particularly abundant after intradermal vaccination. Exposure of mice to an equivalent number of normal cercariae induced an earlier lymphocytosis of short duration; far fewer macrophages and lymphocytes infiltrated the lungs than after vaccination. An intense but transient pulmonary eosinophilia peaked at 3 weeks after primary exposure to either normal or attenuated parasites. Percutaneous challenge of vaccinated mice elicited higher levels of circulating lymphocytes than challenge of unsensitized controls. However, whilst leucocyte numbers of all cell types were still elevated in the airways at challenge as a consequence of vaccination, no further cellular recruitment was observed coincident with parasite elimination. Our data are compatible with the hypothesis that the mechanism of immunity in once-vaccinated mice involves a T lymphocyte-macrophage interaction triggered by antigen release from lung schistosomula.
Histopathological data on the cellular reactions (foci) around Schistosoma mansoni schistosomula in the lungs of both irradiated (750 rad) and unirradiated, passively immunized and normal rats were consistent with the idea that a significant proportion of immune-mediated attrition in passively immunized rats occurs in the lungs. In unirradiated rats, immune serum elicited an enhanced (i.e. larger) and accelerated (i.e. more rapidly developing) inflammatory cellular infiltration around lung-stage parasites when administered 5 days post-infection, when the parasites were already in the lungs. This demonstrated the antigenicity of lung-stage schistosomula and their potential as targets for immune attack. In irradiated rats, innate immunity was decreased as judged by an increase in the number of worms recovered by portal perfusion, and was accompanied by an overall decreased percentage of trapped parasites compared with unirradiated controls, suggesting that trapping in the lungs is involved in innate, as well as acquired immunity. In contrast to the results in unirradiated rats, passive transfer of immune serum into irradiated recipients did not result in larger lung foci than in the NRS-recipients. However, there was evidence of an accelerated response resulting in an essentially similar ratio of trapped parasites (VRS- compared with NRS-recipients) in irradiated rats, as compared with unirradiated rats, reflecting the similar levels of resistance manifested in both groups of rats. This also lent credence to the notion that it was the speed of immune recognition of the migrating schistosomula and the establishment of trapping foci that were of greater importance rather than the size of the enveloping granulomata. Investigations into the cellular composition of the foci surrounding trapped parasites in unirradiated rats revealed a predominance of mononuclear cells, with equal proportions of lymphocytes and macrophages. Eosinophils represented less than 3% of the cellular composition of the foci and were typically distant from the parasites themselves, arguing against their role in specific immunity in this model. Irradiation of recipient rats resulted in a corresponding increase in the percentage of macrophages in lung foci.
Les cellules souches mésenchymateuses (CSM) sont présentes dans divers tissus de l’organisme adulte dont la moelle osseuse. In vitro, les CSM peuvent se différencier en de nombreux types cellulaires du mésoderme, de l’endoderme et de l’ectoderme ; in vivo, elles ont la capacité de migrer vers un organe lésé. Il existe cependant peu d’informations sur le devenir et le potentiel thérapeutique lors de l’injection de ces cellules souches dans un organisme ayant subit une irradiation accidentelle ou thérapeutique. Nos travaux ont permis de mettre en évidence la répartition spatiale et le taux de prise de greffe des CSM injectées par voie intraveineuse (IV) dans un organisme en fonction de la configuration pour une irradiation gamma. Les CSM ont été isolées à partir de moelle osseuse humaine (CSMh) et injectées à des souris immunodéficientes 24 heures après irradiation. Nous avons mis au point trois types de configurations, une configuration d’irradiation corps entier (ICE) à une dose sublétale de 3,5 Gy et deux configurations d’irradiations localisées, pour lesquelles les souris reçoivent une dose locale totale de 8 Gy au niveau de l’abdomen ou de 30 Gy au niveau de la patte droite postérieure. Le taux d’implantation des CSMh dans les différents organes de l’organisme 15 jours après irradiation a été quantifié par amplification du gène humain de la bêta-Globine par PCR. Puis leur localisation in situ a été mise en évidence par marquage immuno-histochimique de la bêta-2-microglobuline humaine sur des sections d’organes murins possédant de l’ADN humain. En absence d’irradiation, les CSMh ont été détectées en très faible quantité. En revanche, le taux de CSMh implantées est plus important au niveau des zones irradiées à forte dose, suggérant que la colonisation des CSMh dans les tissus après irradiation est dépendante de la configuration d’irradiation. L’implantation des CSMh dans les organes n’appartenant pas aux zones surexposées évoque un état inflammatoire généralisé radio-induit. Cette observation met en avant l’existence d’un effet à distance (abscopal) des atteintes tissulaires locales radio-induites. L’ensemble de nos résultats suggère que la thérapie cellulaire par les CSM pourrait être utilisée pour la régénération des tissus normaux lésés suite à une irradiation accidentelle ou chez les patients soumis à une radiothérapie.
Multiple ionization of large clusters when they are irradiated by an
intense ultrashort laser pulse is investigated. Different mechanisms,
responsible for cluster ionization, are investigated. It is found that
the ionization of large clusters, irradiated by a strong intense
ultrashort laser pulse, is realized by means of the surface
thermoemission.
Le concept de niveau de référence diagnostique (NRD) introduit dans la CIPR 73 “ Protection et sûreté radiologique en médecine ” est spécifique aux expositions médicales. Dans ce domaine, en effet, l'un des trois principes de la radioprotection, la limitation réglementaire des doses, ne peut s'appliquer comme pour les expositions professionnelles et publiques. Les niveaux de référence ne sont ni des “ limites de dose ”, ni des “ doses optimales ”, ce sont des outils pour l'optimisation. Ils sont établis pour des examens standardisés et des patients types, et ne devraient pas être dépassés sans justification, pour des procédures courantes. Les NRD sont des indicateurs dosimétriques de la qualité des pratiques destinés à identifier les situations nécessitant une action corrective. Dans le cadre de la transposition de la directive 97/43 Euratom, le directeur général de la santé a confié à l'OPRI, en 1999, une mission spécifique pour la mise en œuvre des niveaux de référence, en concertation avec les sociétés savantes et professionnelles concernées. La méthode recommandée par la Commission européenne, dite du 75e percentile, basée sur le traitement statistique d'enquêtes dosimétriques représentatives, est à l'heure actuelle inopérante en France en raison de l'insuffisance des données. Une démarche spécifique a donc été définie. Dans un premier temps, un travail de standardisation des procédures radiologiques avec adoption des niveaux de référence européens comme point de départ a été effectué. Dans un second temps, une campagne nationale de mesures de doses co-pilotée par l'OPRI (actuellement l'IRSN et la DGSNR), la SFR et la SFPM est en cours de réalisation pour établir des NRD français.