非常规分割放射治疗的放射生物学基础与临床应用

如何进一步提高肿瘤的放疗疗效是放射临床医师及放射生物学家长期以来密切关注的问题。在放射生物学对放疗的时间、剂量、分割次数深入研究基础上,20世纪70年代开始提出了多种非常规分割的放疗方法,如超分割放疗（HRT）、加速超分割放疗（HART）,包括连续加速超分割放疗（CHART、CHART—WEL）、同时小野加量加速超分割放疗（CBHART）、分段加速超分割放疗（SCHART）、后程加速超分割放疗（LCHART）、逐步增量加速超分割放疗（EHART）等和连续加速常规分割放疗（CAIR）,并在临床应用中取得了明显的治疗效果。     

Development of a Flexible Metamaterial Film with High EM Wave Absorptivity by Numerical and Experimental Methods

The present study is intended to develop and test a cost-effective and efficient printing method for fabricating flexible metamaterial film with high electromagnetic wave absorptivity. The film can be easily applied to the surfaces with curved aspects. Firstly, numerical parametric study of the absorption characteristics of the film is performed for the range of frequency varying from 2.0 to 9.0 GHz based on commercial software package. Secondly, the flexible metamaterial films are fabricated, and experiments are conducted. The flexible metamaterial film consists of a flexible dielectric film made of polyimide (PI) and an array of split-ring resonators. The split-ring resonators of different geometric dimensions are fabricated on the PI film surface by using a silver nanoparticles ink jet printer. The performance of the flexible structure is then measured and dependence of operation frequency with higher absorptivity on the dimensions of the split-ring resonators is investigated. A comparison between the numerical and experimental data shows that the numerical predictions of the operation frequency with higher absorptivity closely agree with the experimental data.     

Association of Vitamin D in Different Trimester with Hemoglobin during Pregnancy

The association between vitamin D and hemoglobin has been suggested. Vitamin D can affect erythropoiesis by the induction of erythroid progenitor cell proliferation and enhance iron absorption by regulating the iron-hepcidin-ferroportin axis in monocytes. However, this relationship in pregnant women is scarce. The purpose of this study was to investigate the association between plasma vitamin D levels with hemoglobin concentration in pregnant women considering each trimester and iron supplementation. The data were obtained from Zhoushan Pregnant Women Cohort, collected from 2011 to 2018. Plasma 25(OH)D was measured in each trimester using liquid chromatography–tandem mass spectrometry. Generalized estimating equations and multiple linear regressions were performed. Finally, 2962 pregnant women and 4419 observations in the first trimester were included in this study. Plasma 25(OH)D in first trimester (T1) (β = 0.06, p = 0.0177), second trimester (T2) (β = 0.15, p < 0.0001), and third trimester (T3) (β = 0.12, p = 0.0006) were positively associated with Hb. Association between plasma 25(OH)D levels in T1 and Hb concentration was positively associated with gestational age (β = 0.005, p = 0.0421). Pregnant women with VD deficiency in T1 (OR = 1.42, 95% CI: 1.07–1.88) or T2 (OR = 1.94, 95% CI: 1.30–2.89) presented an increased risk of anemia, compared with women without VD deficiency. Moreover, the significant relationship between VD and Hb was only observed among women with iron supplementation during pregnancy. Plasma 25(OH)D levels in each trimester were positively associated with Hb concentration. Iron supplementation might be an important factor affecting the relationship between VD and Hb.     

Research Progress on Emerging Viral Pathogens of Small Ruminants in China during the Last Decade

China is the country with the largest number of domestic small ruminants in the world. Recently, the intensive and large-scale sheep/goat raising industry has developed rapidly, especially in nonpastoral regions. Frequent trading, allocation, and transportation result in the introduction and prevalence of new pathogens. Several new viral pathogens (peste des petits ruminants virus, caprine parainfluenza virus type 3, border disease virus, enzootic nasal tumor virus, caprine herpesvirus 1, enterovirus) have been circulating and identified in China, which has attracted extensive attention from both farmers and researchers. During the last decade, studies examining the etiology, epidemiology, pathogenesis, diagnostic methods, and vaccines for these emerging viruses have been conducted. In this review, we focus on the latest findings and research progress related to these newly identified viral pathogens in China, discuss the current situation and problems, and propose research directions and prevention strategies for different diseases in the future. Our aim is to provide comprehensive and valuable information for the prevention and control of these emerging viruses and highlight the importance of surveillance of emerging or re-emerging viruses.     

PPAR-γ配体抑制胆管癌的体内有效作用途径实验研究

目的探讨PPAR-γ(peroxisome proliferactor-activated receptor gamma,PPAR-γ)配体罗格列酮(rosiglitazone,RGZ)抑制胆管癌的体内有效作用途径。方法采用不同RGZ给药方法和途径对胆管癌细胞系QBC939荷瘤裸鼠进行干预,7d后处死,测量瘤体体积和重量,计算各组肿瘤生长抑制率。结果RGZ对胆管癌细胞有明显的增殖抑制作用,连续多次灌胃组[12mg/(kg.d)](临床途径组)抑制作用明显,而单次灌胃组、单次与多次腹腔灌注组抑制作用均不明显。统计学处理,连续多次灌胃组与其他给药途径比较,P<0.05,有统计学意义;而其他方法与对照组比较,P>0.05,无统计学意义。结论连续多次给药法是PPAR-γ配体RGZ对胆管癌有效抑制作用方法之一。     

苏州地区2011-2019年儿童细菌性脑膜炎病原分布及耐药性分析

目的:探讨苏州地区细菌性脑膜炎患儿病原构成及耐药性。方法:回顾性分析2011-2019年在苏州大学附属儿童医院住院的细菌性脑膜炎患儿脑脊液培养结果,总结不同年龄段患儿的病原分布特点及耐药情况。结果:535例患儿中,162例脑脊液细菌培养阳性,阳性率为30.3%;菌种主要为肺炎链球菌42株(25.9%)、无乳链球菌39株(24.1%)、大肠埃希菌36株(22.2%)等。>1～3岁组阳性率为53.6%,均高于其他各年龄组(P均<0.05)。革兰阴性杆菌组的患儿年龄与革兰阳性球菌组、革兰阳性杆菌组比较差异均有统计学意义(P<0.05),年龄越小越容易感染革兰阴性杆菌。新生儿组以无乳链球菌和大肠埃希菌为主,29 d～1岁组病原种类较多,多见肺炎链球菌、无乳链球菌和大肠埃希菌,而>1岁患儿以肺炎链球菌为主。脑脊液培养前使用过抗菌药物的患儿细菌检出阳性率低于未使用过抗菌药物的患儿(P<0.05)。药敏试验显示,肺炎链球菌及无乳链球菌对万古霉素、利奈唑胺敏感率达100%;肺炎链球菌对青霉素的耐药率较高,为85.7%;大肠埃希菌对氨苄西林、头孢噻肟、头孢曲松的耐药率分别为...     

糖皮质激素及其胞浆受体拮抗剂对凋亡嗜酸粒细胞转归的影响

目的探讨糖皮质激素及糖皮质激素胞浆受体拮抗剂RU38486对A549细胞吞噬凋亡的嗜酸粒细胞的影响。方法．CD15 的嗜酸粒细胞体外培养48 h老化凋亡后加入到预先用地塞米松或RU38486干预的A549细胞中进行吞噬,光镜下对已固定染色的细胞进行吞噬率统计。放射免疫法检测A549细胞上清中白介素6和白介素8水平。结果A549细胞在地塞米松诱导后1 h吞噬能力开始升高,4 h达最高峰;加入RU38486后抑制了地塞米松所增强的吞噬能力。结论地塞米松促进A549细胞吞噬凋亡的嗜酸粒细胞是通过A549细胞糖皮质激素胞浆受体发挥作用的。     

局部晚期不可手术食管癌同步放化疗联合尼妥珠单抗的初步临床分析

目的:探讨局部晚期食管癌同步放化疗联合尼妥珠单抗治疗的不良反应及疗效。方法:回顾性分析北京大学肿瘤医院2015—2020年间使用同步放化疗联合尼妥珠单抗治疗的30例患者资料,采用 Kaplan- Meier法生存分析。 结果:中位随访时间22.5个月,总客观有效率为93%。1、2、3年...     

An approach for evaluating the effects of dietary fiber polysaccharides on the human gut microbiome and plasma proteome

Increases in snack consumption associated with Westernized lifestyles provide an opportunity to introduce nutritious foods into poor diets. We describe two 10-wk-long open label, single group assignment human studies that measured the effects of two snack prototypes containing fiber preparations from two sustainable and scalable sources; the byproducts remaining after isolation of protein from the endosperm of peas and the vesicular pulp remaining after processing oranges for the manufacture of juices. The normal diets of study participants were supplemented with either a pea- or orange fiber-containing snack. We focused our analysis on quantifying the abundances of genes encoding carbohydrate-active enzymes (CAZymes) (glycoside hydrolases and polysaccharide lyases) in the fecal microbiome, mass spectrometric measurements of glycan structures (glycosidic linkages) in feces, plus aptamer-based assessment of levels of 1,300 plasma proteins reflecting a broad range of physiological functions. Computational methods for feature selection identified treatment-discriminatory changes in CAZyme genes that correlated with alterations in levels of fiber-associated glycosidic linkages; these changes in turn correlated with levels of plasma proteins representing diverse biological functions, including transforming growth factor type β/bone morphogenetic protein-mediated fibrosis, vascular endothelial growth factor-related angiogenesis, P38/MAPK-associated immune cell signaling, and obesity-associated hormonal regulators. The approach used represents a way to connect changes in consumer microbiomes produced by specific fiber types with host responses in the context of varying background diets.

Advances in our understanding of the role of the gut microbiome in regulating many aspects of human physiology hold the promise of evolving our view of human nutrition by establishing mechanistic connections between the foods we consume and how they affect health status. One manifestation of this effort is a series of studies, performed on well-phenotyped cohorts, that seek to relate features of gut microbial community composition (organisms, genes), dietary practices, and pre- and postprandial cardiometabolic responses to test meals (1–4). A key question raised by these initiatives relates to the nature of the “bioactive” components of foods. Specifically, what are the nutrients utilized by various gut community members or microbiome-encoded metabolic pathways? What products are produced by biotransformation of these nutrients? How are these products linked to specific host physiologic (or pathophysiologic) processes?Plant-derived dietary fibers represent a “poster child” for these efforts and illustrate the formidable challenges faced. The health benefits of dietary fibers are widely known, as is their inadequate representation in Western diets. However, natural fibers are structurally complex and highly diverse. They contain numerous, typically undefined polysaccharide structures and largely unspecified protein, lipid, and small molecule constituents. Their composition varies as a function of their origin (food staple and cultivar), the different methods employed to recover them from these sources, as well as the different techniques used to incorporate them into processed foods with acceptable organoleptic properties (5). Moreover, analyzing the host effects of metabolism of different fibers is confounded by the fact that there is substantial intra- and interpersonal variation in microbiome configuration (6, 7).Snacking is becoming an ever more dominant feature of daily life worldwide and thus provides an opportunity to introduce nutritious ingredients, such as fibers, into diets. However, obtaining structure-activity relationships for specific fiber types and their corresponding targets in the gut community is foundational for designing snack foods that evoke and/or reinforce microbiome responses that are beneficial to the host.Degradation of dietary polysaccharides is a function primarily performed by bacterial carbohydrate-active enzymes (CAZymes). The gut microbiome harbors tens of thousands of CAZyme genes belonging to at least 136 glycoside hydrolase (GH) and 29 polysaccharide lyase (PL) families [extrapolated and updated from El Kaoutari et al. (8)]. In contrast, the human genome only contains 98 GH and no PL genes (9), of which <20% contribute to the processing of dietary glycans.In the current study, we test the effects of dietary supplementation with two snack food prototypes, one containing pea fiber and the other orange fiber, in two pilot studies of overweight and obese individuals consuming their normal, unrestricted diets. Our strategy was to focus on fiber-associated changes in the abundances of microbial GH and PL genes to determine whether responses to the pea or orange fiber prototypes in the gut microbiome and host are decipherable against a background of varying dietary practices and starting microbiome configurations. Higher order singular value decomposition (10) was utilized as a feature selection tool to identify treatment-discriminating changes in GH and PL gene representation. Mass spectrometric assays of the levels of fecal glycan structures (glycosidic linkages) were subsequently performed and the results were correlated with changes in the abundances of treatment-discriminating GH and PL genes with known or predicted substrate specificities. Our analysis concluded by measuring changes in levels of 1,305 plasma proteins in each study participant as a function of fiber treatment and applying computational tools to identify links between these microbiome and plasma proteome changes in response to fiber consumption. Our results provide an approach, using pilot human studies, for selecting specific fiber preparations, plus informative microbiome and host biomarkers, that can be advanced to proof-of-concept clinical trials which assess their capacity for precise manipulation of microbiome and host features.