多发性硬化与病毒感染研究进展

多发性硬化发病机制复杂,病毒感染在其发病中可能起着举足轻重的作用,目前多项研究支持他们之间的关联性;分子模拟、免疫调节网络的失调、表位扩展、旁路激活、超抗原激活和直接细胞损伤等是病毒感染导致多发性硬化发病的主要机理。本文就相关研究进行综述。     

瑞舒伐他汀治疗颈动脉粥样硬化斑块的临床研究

目的:研究瑞舒伐他汀对颈动脉粥样硬化斑块的治疗效果。方法:将在本院接受治疗的250例颈动脉粥样硬化斑块患者随机分成治疗组125例和对照组125例,治疗组服用瑞舒伐他汀10mg/晚,对照组行其他非瑞舒伐他汀药物治疗,进行为期6个月的观察对比。结果:治疗组治疗后总胆固醇(TC)、甘油三酯(TG)、低密度脂蛋白(LDL)水平显著下降,高密度脂蛋白(HDL)水平显著升高(P<0.05),颈动脉内膜-中层厚度(IMT)、斑块面积变小,与治疗前比较,差异有统计学意义(P<0.05);对照组治疗前后无显著性差异(P>0.05)。结论:瑞舒伐他汀对降低血脂、减缓不稳定型心绞痛早期动脉粥样硬化、稳定斑块和预防脑血管疾病起到非常重要的作用。     

冠脉结扎法制做大鼠心肌缺血模型

目的探讨大鼠心肌缺血动物模型的构建。方法缝扎大鼠冠脉左前降支,于左室前外侧壁形成缺血区域,约占左室壁面积的20%～50%。结果完成85例动物模型制作,存活74只,其中60只据术中所见、心电图、及病理检查证实有明确的心肌缺血,心功能下降。结论该方法制作简单可行,动物存活率满意;但模型欠稳定,需标本量较大以充分筛选。     

生境片段化对千岛湖地表甲虫物种多样性的影响

在千岛湖片段化景观中选取20个陆桥岛屿和8个大陆样点,从2012年7月到2014年4月,按季度(春、夏、秋季)6次采用巴氏陷阱法收集地表甲虫,分析其物种多度、组成、多样性和季节动态,以及不同岛屿上的地表甲虫的物种多样性与岛屿面积和隔离度等岛屿空间特征的关系.结果表明: 共收集记录到地表甲虫26科101种3370头.大陆和大岛地表甲虫的物种丰富度有显著差异,且小岛地表甲虫密度显著高于大陆;大陆地表甲虫的物种组成变化较大,而岛屿上分布的地表甲虫的物种组成则变化较小.地表甲虫的物种丰富度与岛屿面积呈显著正相关,密度与隔离度呈显著正相关.夏季岛屿上地表甲虫物种丰富度高于春秋两季,岛屿与大陆样地的Shannon指数、Simpson指数和Pielou均匀度指数均在夏季最高、秋季最低.     

人工覆盖地表对北京典型绿化树光合特性的影响

地表硬化影响城市绿化树生长及生态服务功能的发挥,研究人工覆盖地表下城市绿化树关键生理过程具有重要意义.采用田间模拟试验方法,布设对照(自然地表)、透水硬化和不透水硬化3种覆盖地表,栽植北京2种典型绿化树白蜡和元宝枫,栽植后第4年野外测定其叶片光合及相关生理生态参数,分析人工覆盖地表对北京典型绿化树光合特性的影响.结果表明:白蜡和元宝枫光合作用对不同人工覆盖地表的响应存在差异,对于白蜡而言,透水硬化和不透水硬化地表均使其净光合速率显著降低,对于元宝枫而言,仅不透水硬化地表导致其净光合速率显著降低,透水硬化地表并未对其造成显著影响.透水硬化和不透水硬化地表的空气相对湿度和土壤体积含水率低于对照,植物可利用水分减少,叶片气孔导度下降是白蜡和元宝枫净光合速率降低的主要原因.透水硬化和不透水硬化地表使白蜡PSⅡ有效光化学量子产量(F_v′/F_m′)下降,不透水硬化地表使元宝枫PSⅡ实际光化学量子效率(Φ_PSⅡ)和表观电子传递速率(ETR)升高.     

Duration of mulching caused variable pools of labile organic carbon in a Phyllostachys edulis plantation

Aims Soil total organic carbon and labile organic carbon are important indicators in evaluating soil quality. Mulching is widely applied to promote the emergence of bamboo shoot in winter time through stand management. Yet the consequences of mulching on soil quality in Phyllostachys edulis have not been well studied. We aim at the quantitative effect of mulching duration on soil quality in P. edulis stands.
Methods Several P. edulis stands located in Huangyan District of Taizhou, Zhejiang Province of China, had been applied with mulching for 1-2 years and were used in this study to assess the mulching effects. We also selected stands without mulching treatment as the reference sites (or control, CK) for comparisons.||||Important findings Total soil organic carbon (TOC), light fraction organic matter (LFOM), and easily-oxidized carbon (EOC) contents at stands with 1-year and 2-year mulching treatments were significantly increased compared with those at the CK sites. The 1-year mulching increased TOC, LFOM and EOC by 11.2%-74.2%, 31.7%-196.9% and 5.0%-79.6%, respectively, than those of CK sites, while by 22.2%-90.8%, 36.7%-238.5%, and 21.9%-97.5% with 2-year treatment. However, the contents of water-soluble organic carbon (WSOC) changed insignificantly. Among the indicators, we found that WSOC:TOC in CK was higher than that with the mulching treatments, while EOC:TOC with 1-year treatment was higher than that with 2-year treatment, and EOC:TOC with 2-year treatment was higher than that of CK. Additionally, WSOC, EOC, and LFOM at all three treatments showed high correlations with TOC, with a higher correlation coefficient of WSOC with TOC of 0- 30 cm soil layers in CK than those with mulching treatments. The correlation coefficient of EOC and LFOM with TOC was the highest at the 2-year mulching sites. More importantly, TOC, WSOC, EOC, and LFOM were significantly (p < 0.05), or extremely significantly (p < 0.01), correlated with soil nutrient content, including total N, hydrolysis N, available P, available K, exchangeable Ca, and exchangeable Mg in all treatments. In sum, it appeared that mulching in short term can increase the contents of TOC, soil labile organic carbons and soil nutrients in bamboo soils, yielding an improved soil quality and thus can be promoted as a plausible practice for the sustainable management of P. edulis stands.     

核因子кB与动脉粥样硬化新进展

动脉粥样硬化(atherosclerosis,As)是一种炎症性病变,它以血管壁上巨噬细胞源性的泡沫细胞和大量趋化因子、细胞因子和生长因子堆积为主要特征.这些因手调节着固有细胞的迁移、分化和转归,最终影响动脉粥样硬化斑块形成,其中一个关键的调节因子就是转隶因子核因子-кB(NF-кB).过去它都被一直认为是一个促进动脉粥样硬化的因子,主要是由于它调节许多与动脉粥样硬化有关促炎基因的表达.最近有文献报道说NF-кB有可能在促炎、抗炎、细胞的生存和增值方面巧妙地监护着动脉粥样硬化过程的平衡.因此,本文就NF-кB与动脉粥样硬化病变有关的启动、泡沫细胞的形成、炎症、免疫、平滑肌细胞增值、纤维帽形成、细胞凋亡关系的新进展作一综述.     

河水漫溢对塔里木河下游荒漠河岸林地表植被与土壤种子库的影响

采用种子萌发法,研究了河水漫溢对塔里木河下游荒漠河岸林地表植被与土壤种子库的影响.结果表明：塔里木河下游漫溢区地表植被分属8科13属14种,非漫溢区为10科21属26种植物;与非漫溢区相比,漫溢区地表植被中出现了一些浅根系和喜湿的草本植物;漫溢区单位面积物种数、植被盖度、植株密度、物种多样性指数和丰富度指数均比非漫溢区有明显增加.漫溢区土壤种子库中有物种19种,比非漫溢区增加了5种;漫溢区土壤种子库总密度比非漫溢区增加了3.94倍;与非漫溢区相比,漫溢区1年生草本植物种子的比例增加了23.07%,而灌木植物种子比例减少了20.99%;多年生草本的变化则不明显;河水漫溢提高了土壤种子库的生物多样性.漫溢区和非漫溢区土壤种子库与地表植被的共有物种分别为18和9种,土壤种子库与地表植被的相似性系数分别为0.842和 0.667.     

星星草(Puccinellia tenuiflora)人工草地氮素积累对松嫩盐碱草地植被演替的影响

通过对星星草(Puccinellia tenuiflora)生长不同年数盐碱土壤氮素营养状况的比较,研究氮素积累作用的机理,并探讨其在植被演替中的可能作用.结果表明:在一维生态位空间(土壤氮含量)星星草和羊草(Leymus chinense)之间具有较小的生态位分离值和较大的生态位重叠值,表明羊草对土壤高含氮量具有较强的竞争能力.这些也许是羊草以及其他植物在星星草生长一定年数后能够侵入碱斑土壤的机制.星星草作为盐碱土壤改良和植被恢复的先锋植物,它的生长增强了盐碱草地土壤氮素的矿质化作用和生物固氮强度,并减弱了氮素随地表径流的损失.最终促进了盐碱草地的氮素沉积,达到了适合于其它物种(如羊草)生长的水平,从而使碱斑植被得以恢复.