尼莫地平对老龄大鼠大脑皮层和海马细胞内游离钙浓度的影响

采用Fura－2／AM荧光探剂法测定不同龄大鼠大脑皮层和海马两个脑区细胞内游离钙浓度（[Ca2 ]i）以及尼莫地平对老龄大鼠（24月龄）上述两个脑区[Ca2 ]i的影响，另外用同位素标记法测定尼莫地平对老龄大鼠上述两脑区细胞线粒体摄钙的影响。结果发现，随增龄两个脑区细胞[Ca2 ]i呈渐进性增长，应用尼莫地平后．老龄大鼠两脑区细胞[Ca2＋]i的升高明显被抑制（P＜0．01），同时细胞线粒体摄钙能力亦明显升高（P＜0.01）但无明显剂量依赖性。提示尼莫地平可通过阻断钙通道、促进细胞内钙库对Ca2＋封存等不同途径降低神经细胞[Ca2＋]i，延缓神经细胞的损伤和老化。     

血吸虫感染鼠血清SEAIC水平与肝脏病变关系的动态观察

采用分离纯化的兔抗ＳＥＡ－ＩｇＧ以生物素－亲和素放大系统，用ＣａｐｔｕｒｅＥＬＩＳＡ方法检测感染血吸虫鼠血清中抗ＳＥＡ循环免疫复合物（ＳＥＡＩＣ）水平在感染后各周的动态变化；并在观察肝脏病变的同时，采用图像分析技术，动态测定各周肝内虫卵肉芽肿的直径和面积。结果表明，血清ＳＥＡＩＣ在感染后４ｗｋ即可检出，６－７ｗｋ时达高峰，以后有所下降，但至实验观察结束时（１２ｗｋ）仍维持在较高水平。感染后４ｗｋ，肝组织内发现虫卵，但到５ｗｋ时尚未形成虫卵肉芽肿病变，至６ｗｋ时，肝内形成巨大的虫卵结节，其直径和面积于７ｗｋ时达高峰，此后逐渐下降，其动态变化与血清ＳＥＡＩＣ水平的动态变化相吻合，表明血清ＳＥＡＩＣ水平的高低可以作为反映肝脏病变程度的指标，并提示ＳＥＡＩＣ在日本血吸虫病的免疫发病机理中可能起重要作用。     

超声引导下心包穿刺置管引流术治疗心包积液的疗效分析

 目的 探讨超声引导下心包穿刺置管引流急慢性心包积液的疗效。方法 回顾分析2009-01至2019-08医院161例行超声引导下心包穿刺置管引流术患者的临床资料,并对其病因、症状、缓解情况进行分析。结果 161例心包积液患者前三位的病因分别为肿瘤、心力衰竭、创伤或手术,经超声引导下心包穿刺置管术治疗后症状缓解率均在70%以上。结论 超声引导下心包穿刺置管引流术治疗心包积液疗效确切,可作为临床治疗心包积液特别是急性心包压塞的首选治疗方式。     

重混凝土屏蔽质子放疗机房的感生放射性估算

目的 估算肿瘤质子治疗时重混凝土屏蔽墙中铁元素因中子活化产生的感生放射性⁵⁶Mn及其水平。方法 采用Geant4程序构建某质子治疗机房的重混凝土屏蔽墙模型,模拟245 MeV的质子束照射水模体产生的次级中子,统计屏蔽墙内放射性核素⁵⁶Mn的分布。将屏蔽墙按每10 cm厚度分层,计算前3层屏蔽墙中放射性核素⁵⁶Mn产生的周围剂量当量率。结果 在最大的束流照射条件（1.872×10¹⁰个）下,前3层屏蔽墙内的放射性核素⁵⁶Mn个数分别为3.10×10⁸、1.60×10⁸和9.33×10⁸个;对治疗室内1 m远处产生的周围剂量当量率分别为2.13×10^-3、8.82×10^-4 和9.10×10^-4 μSv/h,总的周围剂量当量率为3.92×10^-3 μSv/h。结论 在质子治疗时,距离射束中心轴越近,屏蔽墙的感生放射性越强;屏蔽墙前端中子活化铁元素产生的感生放射性最强,感生放射性随着屏蔽墙厚度增大呈指数形式减小,应主要考虑质子治疗机房屏蔽墙前端产生的感生放射性。     

慢性肾衰竭大鼠股骨cbfa1表达与骨密度关系的研究

目的探讨股骨核心结合因子-a1(cbfa1)对慢性肾衰竭大鼠股骨密度变化的影响。方法将12只大鼠随机分为空白对照组、慢性肾衰竭模型组。造模成功后测量各组大鼠股骨的整体骨密度(Whole-bone mineral density,W-BMD)、松质骨骨密度(Trabecular-bone mineral density,T-BMD)、皮质骨骨密度(Cortical-bone mineral density,C-BMD),留取血清测定钙、磷等生化参数,采用免疫组织化学和HE染色的方法分别检测大鼠股骨中Cbfa1蛋白的表达及松质骨和皮质骨的形态学改变。结果与空白对照组比较,慢性肾衰竭模型组W-BMD、C-BMD降低,T-BMD升高(P0.001);股骨松质骨Cbfa1表达增多,皮质骨Cbfa1表达减少(P0.001);相关分析显示W-BMD与皮质骨Cbfa1蛋白表达呈正相关(r=0.979,P0.001),与松质骨Cbfa1蛋白表达呈负相关(r=-0.974,P0.001),与血清钙浓度呈正相关(r=0.730,P0.001),与血清磷浓度呈负相关(r=-0.652,P0.001)。结论 Cbfa1是肾性骨病导致的骨密度改变的预测因素,可能是Cbfa1对骨形态的影响而导致骨密度的改变。     

Genome-wide high resolution parental-specific DNA and histone methylation maps uncover patterns of imprinting regulation in maize

Genetic imprinting is a specific epigenetic phenomenon in which a subset of genes is expressed depending on their parent-of-origin. Two types of chromatin modifications, DNA methylation and histone modification, are generally believed to be involved in the regulation of imprinting. However, the genome-wide correlation between allele-specific chromatin modifications and imprinted gene expression in maize remains elusive. Here we report genome-wide high resolution allele-specific maps of DNA methylation and histone H3 lysine 27 trimethylation (H3K27me3) in maize endosperm. For DNA methylation, thousands of parent-of-origin dependent differentially methylated regions (pDMRs) were identified. All pDMRs were uniformly paternally hypermethylated and maternally hypomethylated. We also identified 1131 allele-specific H3K27me3 peaks that are preferentially present in the maternal alleles. Maternally expressed imprinted genes (MEGs) and paternally expressed imprinted genes (PEGs) had different patterns of allele-specific DNA methylation and H3K27me3. Allele-specific expression of MEGs was not directly related to allele-specific H3K27me3, and only a subset of MEGs was associated with maternal-specific DNA demethylation, which was primarily located in the upstream and 5′ portion of gene body regions. In contrast, allele-specific expression of a majority of PEGs was related to maternal-specific H3K27me3, with a subgroup of PEGs also associated with maternal-specific DNA demethylation. Both pDMRs and maternal H3K27me3 peaks associated with PEGs are enriched in gene body regions. Our results indicate highly complex patterns of regulation on genetic imprinting in maize endosperm.Genetic imprinting is an epigenetic phenomenon, where genes are expressed in a parent-of-origin dependent manner in many plant species and mammals. Although first discovered in plants (Kermicle and Alleman 1990), research on genetic imprinting is much more advanced in mammals in terms of the number of imprinted genes identified and the understanding of their regulatory mechanisms (Koerner and Barlow 2010; Barlow 2011; Bartolomei and Ferguson-Smith 2011). Only a small number of imprinted genes were observed in plants for a long time since the phenomenon is highly specific to the triploid endosperm (Raissig et al. 2011). However, recent studies have indicated that genetic imprinting in plants is much more prevalent than previously thought, with hundreds of genes shown to be imprinted in several plant species (Gehring et al. 2011; Hsieh et al. 2011; Luo et al. 2011; Waters et al. 2011; Zhang et al. 2011). In contrast to mammals, where the regulation of genetic imprinting has been extensively studied (Koerner and Barlow 2010; Barlow 2011; Abramowitz and Bartolomei 2012), the understanding of regulation of parental imprinting in plants is highly limited.DNA methylation is one of the primary modifications reported to be associated with genetic imprinting. In Arabidopsis, DNA methylation around several maternally expressed imprinted protein-coding genes (MEG) including FWA, FIS2, and MPC was shown to be important for their maternally preferred expression, as all these genes exhibited biallelic expression in endosperm fertilized with met1 pollen (Kinoshita et al. 2004; Jullien et al. 2006; Tiwari et al. 2008). Two studies using RNA-seq in Arabidopsis also showed that a number of MEGs exhibited biallelic expression in paternal met1 endosperm, and the maternal alleles of dozens of paternally expressed imprinted genes (PEGs) were reactivated in maternal dme endosperm (Hsieh et al. 2011; Wolff et al. 2011). In maize, five confirmed endosperm MEGs (Fie1, Fie2, Mez1, Meg1, and Mee1) contain differentially methylated regions (DMRs) (Gutierrez-Marcos et al. 2004; Gutierrez-Marcos et al. 2006; Haun et al. 2007), and activation of the Fie1 maternal allele in the endosperm requires DNA demethylation of the maternal allele (Hermon et al. 2007).Another modification associated with genetic imprinting involves histone methylation. Polycomb repressive complex 2 (PRC2) is known to mediate the trimethylation of histone H3 lysine 27 (H3K27me3) (Schuettengruber and Cavalli 2009). Results on PHE1, the only well-studied PEG in plants, indicated that silencing of its maternal allele depends on a functional PRC2 complex in addition to DNA demethylation (Kohler et al. 2003, 2005; Makarevich et al. 2008). Recently, a number of MEGs and PEGs were shown to be biallelically expressed in maternal fie or fis2 endosperm (Hsieh et al. 2011; Wolff et al. 2011).Although the studies above suggest that DNA methylation and the PRC2 complex could be responsible for monoallelic expression of imprinted genes, there is not yet any general rule for the function of DNA and histone methylation on the regulation of genetic imprinting in plants. A high resolution genome-wide map of allele-specific DNA methylation and allele-specific histone modification will be crucial to gain better understanding of the regulation of genetic imprinting. Recently, several genome-wide studies have provided evidence that allele-specific patterns of DNA methylation or parent-of-origin dependent differentially methylated regions (pDMRs) are associated with some imprinted genes in mice and plants (Zhang et al. 2011; Ibarra et al. 2012; Xie et al. 2012; Rodrigues et al. 2013). Several studies in mammals also suggest a mutually exclusive relationship between allele-specific DNA methylation and histone modification or among different histone modifications (Xin et al. 2001; Fournier et al. 2002; Carr et al. 2007; Lindroth et al. 2008; Singh et al. 2010; Hon et al. 2012).Here we report a genome-wide analysis of allele-specific DMRs, H3K27me3, and imprinted gene expression in maize endosperm. Thousands of pDMRs and allele-specific H3K27me3 peaks were identified. Correlation of pDMRs, allele-specific H3K27me3 profile, and the expression of imprinted genes showed that MEGs and PEGs have different patterns of DNA methylation and H3K27me3. This study reveals complex patterns of genetic imprinting regulation in maize endosperm.     

A facile fabrication of sepiolite mineral nanofibers with excellent adsorption performance for Cd2+ ions

In this work, sepiolite mineral nanofibers are facilely prepared by a microwave-hydrogen peroxide method, and the bulk densities of the samples are adopted to evaluate the defibering effect. The samples are systematically characterized through X-ray diffraction, scanning electron microscopy, specific surface area measurement and zeta potential determination, and the adsorptive performance for heavy metal ions in aqueous solution is studied using cadmium ions as the representative. It is found that the specific surface area and cumulative pore volume increase respectively up to 109.21 m² g⁻¹ and 0.234 cm³ g⁻¹ under the microwave power of 400 W, while the zeta potential reaches a maximum when the pH is 5.0. The adsorption efficiency of sepiolite mineral nanofibers for cadmium ions can reach 68.6% as the optimal value. The as-fabricated sepiolite nanofibers can be regarded as a low-cost and environmentally friendly material which is a promising candidate for heavy metal ion removal from industrial wastewater.

In this work, sepiolite mineral nanofibers are facilely prepared by a microwave-hydrogen peroxide method, and the bulk densities of the samples are adopted to evaluate the defibering effect.     

32例国产人工髋关节翻修手术的临床体会

目的：探讨国产人工髋关节翻修原因。方法：回顾总结32例人工髋关节翻修中发现的问题，分析翻修原因。结果：32例中术前诊断松动16例，脱位4例，深部感染2例，白磨通3例，断柄2例，髋周及股部疼痛4例，股骨柄穿通皮质1例。26例取出假体顺利，6部部分骨长入珍珠面而取出假体困难。25例作全髋置换翻修，4例臼怀松动或位置不良致脱位仅翻修髋臼，1例股骨柄穿通皮质更换双动头，2例因深部感染严重而作单纯假体取出、清创术。全组病例经6个月－5年随访，Harris评分术前平均43分，术后平均81分，平均增加38分。结论：目前翻修病例仍以国产人工关节为主。翻修原因主要是：人工关节质量因素和手术技术因素。造成假体过早松动或种种其它并发症，最终失败。提示国产人工关节质量需改进，需相应配套器械，手术操作技术有待提高。