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BackgroundThe aim of this paper is to provide a comprehensive overview of the scenario on radiotherapy (RT) delivered with palliative intent in Italy.Materials and methodsA structured online questionnaire was submitted to Italian radiation oncologists in order to explore the clinical practice in different areas of palliation, namely: bone, lung, brain, liver, and emergencies suitable to RT.Results209 radiation oncologists took part in the study. Stereotactic body irradiation was found to be the preferred technique in lung and liver metastases, whereas 3D conformal RT was registered as the technique of choice for bone and brain metastases. The majority (98%) of participants stated to treat mainly radiotherapy emergencies with 3D conformal RT at doses ranging from 25 to 50 Gy. Re-irradiation is delivered by the majority of respondents, whereas post-treatment follow-up is done only by 51.4% of them.ConclusionsThis nationwide study highlights some heterogeneity among Italian radiation oncologists regarding treatment and follow-up of metastatic cancer patients.  相似文献   

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刘建全 《生物多样性》2016,24(9):1004-1386
已有的各个物种概念对物种的认识类似盲人摸象, 只包含了物种的某一个方面; 而一个分化后期的成熟物种应涵盖了所有的物种概念。但是, 尚未到达分化后期的物种往往又已开始新一轮的物种分化; 自然中存在的多数“物种”处于分化路上。这种循环往复连续分化产生的物种, 存在种间生殖隔离不彻底、基因流频繁发生、网状进化突出等现象。此外, 对于不同的物种对, 最早开始分化的基因以及不同物种概念所要求的条件的分化顺序不是统一的, 而是随机的。定义一个适合所有“分化路上的物种”概念存在较大困难。但是, 应采用尽可能多的物种概念来界定分化路上的物种、发表新种和进行分类处理; 也应承认种间可能广泛存在不完全的生殖隔离和有限的基因流, 即有不属于两个物种群体的杂交或回交个体的存在。这样划分的物种比只依据一个物种概念认定的物种具有更高的客观性和科学性。  相似文献   

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A “new” red cell antigen has been found so far only in members of Hutterite kindreds with the surname Waldner. The antigen, Wda, is inherited as an autosomal dominant and is not part of the ABO, Chido, Colton, Dombrock, Duffy, Kidd, MN, P, or Rh blood group systems.  相似文献   

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A reasonable degree of synchrony in the sporulation of Clostridium thermosaccharolyticum 3814 was obtained by using three 10% transfers of 8-hr cultures in a medium containing 0.5% L-arabinose, 0.5% peptone, 0.5% yeast extract, and Gc minerals. Sporulation was stimulated by L-arabinose and L-xylose, but was repressed by glucose, mannose, fructose, and D-pentoses. Sporulating cells were long and thin, whereas repressed cells were shorter and thicker. The optimal pH for sporulation was in the range of pH 5.0 to 5.5. As sporulation continued, the accumulated acetate decreased. Label studies indicated that a significant amount of acetate-2-C14 was incorporated into the spore lipid. The calcium, phosphorus, and dipicolinic acid (DPA) concentrations on a dry weight basis were 2.55, 2.60, and 7.25%, respectively. The molar ratio of Ca-DPA was 1.47.  相似文献   

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The cells of organisms as diverse as bacteria and humans can enter stable, nonproliferating quiescent states. Quiescent cells of eukaryotic and prokaryotic microorganisms can survive for long periods without nutrients. This alternative state of cells is still poorly understood, yet much benefit is to be gained by understanding it both scientifically and with reference to human health. Here, we review our knowledge of one “model” quiescent cell population, in cultures of yeast grown to stationary phase in rich media. We outline the importance of understanding quiescence, summarize the properties of quiescent yeast cells, and clarify some definitions of the state. We propose that the processes by which a cell enters into, maintains viability in, and exits from quiescence are best viewed as an environmentally triggered cycle: the cell quiescence cycle. We synthesize what is known about the mechanisms by which yeast cells enter into quiescence, including the possible roles of the protein kinase A, TOR, protein kinase C, and Snf1p pathways. We also discuss selected mechanisms by which quiescent cells maintain viability, including metabolism, protein modification, and redox homeostasis. Finally, we outline what is known about the process by which cells exit from quiescence when nutrients again become available.  相似文献   

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