Mitotic and meiotic detection of radiation-induced translocations in mouse stem cell spermatogonia using fluorescencein situ hybridization

The efficiency of two methods of detection of translocations induced in mouse stem cell spermatogonia by X-ray doses of 2, 5 and 7 Gy was compared: classical multivalent analysis at diakinesis-metaphase I of meiosis and observation via fluorescencein situ hybridization analysis of mitotic or meiotic stages. Specific DNA libraries for chromosomes 1, 11 and 13 were used. The results obtained indicate that (a) chromosomes 1, 11 and 13 are more involved in multivalent formation than expected on the basis of DNA content and (b) if the mitotic FISH analysis data are corrected for the observed over-representation, the frequencies of induced translocations are similar to those recorded in the classical multivalent studies, suggesting equal scoring efficiencies in both systems.     

The first 50 years of military radiology 1895–1945

Following the discovery of X-rays in 1895 by Wilhelm Röntgen the value to the military surgeon of the new technique was soon realised. The localisation of retained bullets by radiography avoided inappropriate exploration of the wound. The X-rays were first used on casualties from the Abyssinian War of 1896 and the developing radiological technology was progressively applied to military surgery. In addition the needs of warfare stimulated the development of all aspects of radiology.     

Dose- and time-dependent responses for micronucleus induction by X-rays and fast neutrons in gill cells of medaka (Oryzias latipes)

Medaka fish (Oryzias latipes) were exposed to various doses of X-rays or fast neutrons, and the frequency of micronucleated cells (MNCs) was measured in gills sampled at 12- or 24-hr intervals from 12 to 96 hr after exposure. The resulting time course of MNC frequency was biphasic, with a clear peak 24 hr after exposure, irrespective of the kind of radiation applied and the dose used. The half-life of MNCs induced in the gill tissues by the two exposures fluctuated around 28 hr, with no significant dose-dependent trend for either X-ray- or neutron-exposed fish. As assayed 24 hr after exposure, the MNC frequency increased linearly over the control level with increasing doses of both X-rays and fast neutrons. The relative biological effectiveness (RBE) of fast neutrons to X-rays for MNC induction was estimated to be 4.3 +/- 0.6. This value is close to the RBE value of 5.1 +/- 0.3 reported for fast neutron induction of somatic crossing-over mutations in Drosophila melanogaster that arise from recombination repair of DNA double-strand breaks. These results and other data support our conclusion that the medaka gill cell micronucleus assay is a reliable short-term test for detecting potential inducers of DNA double-strand breaks.     

Radiosensitive populations and recovery in X-ray-induced apoptosis in the developing cerebellum

Sprague-Dawley rats received a single dose of 2 Gy X-rays at the age of 1 or 3 days and were killed at different intervals. Dying cells with the morphological characteristics of apoptosis appeared in the external and internal granular layers (EGL and IGL) and white matter (WM) of the cerebellum, mainly 3–6 h after irradiation, and decreased thereafter to reach normal values between 48 h and 5 days later. This process was curbed by the injection of cycloheximide at a dose of 1 g/g body weight. In addition, the number of mitoses in EGL rapidly decreased after irradiation and did not reach normal values until a few days later. Proliferating cell nuclear antigen (PCNA)-immunoreactive cells, which were chiefly found in EGL but also in IGL and WM, dramatically decreased in number from 3 to 48 h after irradiation. PCNA-immunoreactive cells reappeared and reached age-matched values in the following days. Hu (considered as an early neuronal marker) and vimentin immunocytochemistry disclosed that Hu-nonreactive cells in the upper level of EGL, Hu-immunoreactive cells in the inner level of EGL, Bergmann glia and many astrocytes in WM, as well as many non-typified cells in WM, were radiosensitive populations, whereas Purkinje cells were not. The present results indicate that irradiation at P1 or P3 blocks mitosis in EGL and kills sensitive cells mainly in the late G1 and S phases of the cell cycle, probably by apoptosis through a protein synthesis-mediated process. Radiosensitive cells are germinal cells and neuroblasts in EGL, Bergmann glia, astrocytes in WM, and non-typified cells, probably glial cell precursors, in WM. Surviving cells in EGL and PCNA-immunoreactive cells in other cortical layers and white matter reconstitute the cerebellum following a single dose of X-rays.This work was supported in part by CEC project FI3P-CT92-0015 and FIS grant 93-131. M. Olivé is the recipient of a grant from the Pi i Sunyer Foundation. R. Rivera has a grant from the CIRIT     

GM1 ganglioside treatment protects against long-term neurotoxic effects of neonatal X-irradiation on cerebellar cortex cytoarchitecture and motor function

Exposure of neonatal rats to a 5 Gy dose of X-irradiation induces permanent abnormalities in cerebellar cortex cytoarchitecture (disarrangement of Purkinje cells, reduction of thickness of granular cortex) and neurochemistry (late increase in noradrenaline levels), and motor function (ataxic gait). The neuroprotective effects of gangliosides have been demonstrated using a variety of CNS injuries, including mechanical, electrolytic, neurotoxic, ischemic, and surgical lesions. Here, we evaluated whether systemically administered GM1 ganglioside protects against the long-term CNS abnormalities induced by a single exposure to ionizing radiation in the early post-natal period. Thus, neonatal rats were exposed to 5 Gy X-irradiation, and subcutaneously injected with one dose (30 mg/kg weight) of GM1 on h after exposure followed by three daily doses. Both at post-natal days 30 and 90, gait and cerebellar cytoarchitecture in X-irradiated rats were significantly impaired when compared to age-matched controls. By contrast, both at post-natal days 30 and 90, gait in X-irradiated rats that were treated with GM1 was not significantly different from that in non-irradiated animals. Furthermore, at post-natal day 90, cerebellar cytoarchitecture was still well preserved in GM1-treated, X-irradiated animals. GM1 failed to modify the radiation-induced increase in cerebellar noradrenaline levels. Present data indicate that exogenous GM1, repeatedly administered after neonatal X-irradiation, produces a long-term radioprotection, demonstrated at both cytoarchitectural and motor levels.     

Water calorimetric determination of absorbed dose by 280 kVp orthovoltage X-rays

The absorbed dose to water from 280 kVp orthovoltage X-rays was determined by a water calorimeter and compared with that determined by an ionization chamber. X-ray qualities of three different filtrations were investigated: they were characterized by 0.57, 0.695 and 1.76 mm of copper half value layers (HVL). The absorbed dose determined by the calorimeter is found higher by 7-9% than that by an ionization chamber. This difference was greater by 4% than that observed for a 60Co beam with the same two detectors.     

Application of artificial intelligence in diagnosing COVID-19 disease symptoms on chest X-rays: A systematic review

This systematic review focuses on using artificial intelligence (AI) to detect COVID-19 infection with the help of X-ray images.Methodology: In January 2022, the authors searched PubMed, Embase and Scopus using specific medical subject headings terms and filters. All articles were independently reviewed by two reviewers. All conflicts resulting from a misunderstanding were resolved by a third independent researcher. After assessing abstracts and article usefulness, eliminating repetitions and applying inclusion and exclusion criteria, six studies were found to be qualified for this study.Results: The findings from individual studies differed due to the various approaches of the authors. Sensitivity was 72.59%-100%, specificity was 79%-99.9%, precision was 74.74%-98.7%, accuracy was 76.18%-99.81%, and the area under the curve was 95.24%-97.7%.Conclusion: AI computational models used to assess chest X-rays in the process of diagnosing COVID-19 should achieve sufficiently high sensitivity and specificity. Their results and performance should be repeatable to make them dependable for clinicians. Moreover, these additional diagnostic tools should be more affordable and faster than the currently available procedures. The performance and calculations of AI-based systems should take clinical data into account.     

生育年龄月经失调骨密度状况研究

目的了解月经失调对生育年龄女性骨密度的影响。方法选择2005年5月~2006年6月来妇科门诊首次就诊,以月经周期不规律为主诉的20~39岁生育年龄患者共134例。用双能X线骨密度仪分别测量其2~4腰椎及双侧股骨颈的骨密度。结果134例患者中有28例患者2~4腰椎或双侧股骨颈的骨密度低于正常范围,其中达到骨量减少标准(T值-1~-2.5)的有16例,达到骨质疏松标准(T值<-2.5)的有12例。线性相关分析发现28例患者体质量、体质量指数、月经不调年限与腰椎T值、股骨颈T值、2~4腰椎骨密度、左侧股骨颈骨密度、右侧股骨颈骨密度均有密切相关性。χ2检验分析发现,有母系骨质疏松家族史患者骨密度低于正常值的发生率明显高于无母系骨质疏松家族史的患者(P<0.01)。结论月经不调对生育年龄女性骨密度有影响,发病时间越长影响越大,尤其是低体质量、有母系骨质疏松家族史的高危患者。     

Development of a guinea pig cutaneous radiation injury model using low penetrating X-rays

Purpose: A guinea pig skin model was developed to determine the dose-dependent response to soft X-ray radiation into the dermis.

Materials and methods: X-ray exposure (50 kVp) was defined to a 4.0?×?4.0?cm area on the lateral surface of a guinea pig using lead shielding. Guinea pigs were exposed to a single fraction of X-ray irradiation ranging from 25–79?Gy via an XRAD320ix Biological Irradiator with the collimator removed. Gross skin changes were measured using clinical assessments defined by the Kumar scale. Skin contracture was assessed, as well as histological evaluations.

Results: Loss of dermal integrity was shown after a single dose of soft X-ray radiation at or above 32?Gy with the central 2.0?×?2.0?cm of the exposed site being the most affected. Hallmarks of the skin injury included moist desquamation, ulceration and wound contracture, as well as alterations in epithelium, dermis, muscle and adipose. Changes in the skin were time- and radiation dose-dependent. Full-thickness injury occurred without animal mortality or gross changes in the underlying organs.

Conclusions: The guinea pig is an appropriate small animal model for the short-term screening of countermeasures for cutaneous radiation injury (CRI).     

人工智能知识图谱和图像分类用于胸部后前位X线片质量控制

目的 观察人工智能(AI)知识图谱和图像分类对胸部后前位X线片(简称胸片)质量控制(QC)的价值。方法 回顾性分析安徽省影像云平台中595家医疗机构共9 236幅胸片,构建包含21个分类标签的QC知识图谱。先由10名技师据此对胸片进行2轮单人QC和1轮多人QC,分别将结果记为A、B、C;再以AI算法进行分类评估,将结果记为D。最后由1名QC专家对C、D进行审核并确定最终QC结果,以之为参考评估上述4种QC效果。结果 AI算法用于胸片QC的曲线下面积(AUC)均≥0.780,平均AUC为0.939。A、B、C、D胸片QC的平均精确率分别为81.15%、85.47%、91.65%、92.21%。结论 AI知识图谱和图像分类技术可有效用于胸部后前位X线片QC。