Effects of unpredictable chronic stress on behavior and brain-derived neurotrophic factor expression in CA3 subfield and dentate gyrus of the hippocampus in different aged rats

Background Brain-derived neurotrophic factor (BDNF) is a stress-responsive intercellular messenger modifying hypothalamic-pituitary-adrenal (HPA) axis activity. The interaction between stress and age in BDNF expression is currently not fully understood. This study was conducted to observe unpredictable stress effect on behavior and BDNF expression in CA3 subfield (CA3) and dentate gyrus of hippocampus in different aged rats. Methods Forty-eight Wistar rats of two different ages (2 months and 15 months) were randomly assigned to six groups: two control groups and four stress groups. The rats in the stress group received three weeks of unpredictable mild stress. The depression state and the stress level of the animals were determined by sucrose preference test and observation of exploratory behavior in an open field (OF) test. The expressions of BDNF in CA3 and dentate gyrus of the hippocampus were measured using immunohistochemistry. Results Age and stress had different effects on the behavior of different aged animals (age: F=6.173, P <0.05, stress: F=6.056, P <0.05). Stress was the main factor affecting sucrose preference (F=123.608, P <0.05). Decreased sucrose preference and suppressed behavior emerged directly following stress, lasting to at least the eighth day after stress in young animals (P <0.05). The older stress rats showed a lower sucrose preference than young stress rats (P <0.05). Older control rats behaved differently from the younger control animals in the OF test, spending more time in the central square (P <0.05), exhibiting fewer vertical movements (P <0.05) and less grooming (P <0.05). Following exposure to stress, older-aged rats showed no obvious changes in vertical movement and grooming. This indicates that aged rats were in an unexcited state before the stress period, and responded less to stressful stimuli than younger rats. There was significantly lower BDNF expression in the CA3 and dentate gyrus regions of the hippocampus following stress in both age groups (P <0.05), a reduction that was still present at the eighth day after stress (P <0.05). Stress and age were the main factors affecting the expression of BDNF (F=9.408, P <0.05; F=106.303, P <0.05). The aged stress group showed lower BDNF expression compared to the young stressed group at every testing time point. Conclusion Stress has age-dependent effects on behavioral responses and hippocampal BDNF expression in rats.     

N,N-′4,4′-二苯甲烷双马来酰亚胺的均相合成

以4,4′-二胺基二苯基甲烷和顺丁烯二酸酐为原料,采用均相体系、共沸蒸馏的方法,一步合成了N,N-′4,4′-二苯甲烷双马来酰亚胺(BM I),收率为86%。并用高效液相色谱测定出产物的相对含量为98.3%,用红外光谱表征了产物的分子结构,用毛细管法测定了产物熔点为158~160°C。     

改良法分离大鼠IOUs构建小肠的初步研究

目的采用改良方法分离大鼠小肠上皮类器官单位(IOUs),鉴定IOUs裸鼠体内发育能力.方法取出生5～8 d大鼠的小肠组织,采用改良分离法获得IOUs,与细胞外基质胶混合后植入裸鼠皮下,定期取材,组织学鉴定.结果采用改良方法分离时间明显缩短,体内植入所有实验组均有多个囊泡样组织形成,植入2周后部分囊腔凹陷可见隐窝样结构,2周后部分囊泡内壁可见分化较成熟的上皮细胞突出,类似绒毛结构;上皮下可见少量平滑肌样细胞围绕囊状管腔周围.结论初步证实改良方法分离出IOUs用于组织工程肠管构建的可行性,并为出生后组织修复重构的研究奠定了基础.     

慢性乙型肝炎肝组织Ⅰ、Ⅲ型胶原及MMP1、TIMP1的表达

目的观察慢性乙型肝炎患者肝组织Ⅰ、Ⅲ型胶原蛋白的沉积以及基质金属蛋白酶1(MMP1)和金属蛋白酶组织抑制因子1(TIMP1)的表达,从胶原降解的角度探讨慢性乙型肝炎肝纤维化的发病机制。方法不同纤维化程度慢性乙型肝炎肝组织标本50例,用免疫组化方法检测肝组织Ⅰ、Ⅲ型胶原蛋白及MMP1、TIMP1的表达。结果随着肝组织纤维化程度的加剧,慢性乙型肝炎患者肝组织Ⅰ、Ⅲ型胶原蛋白及TIMP1表达显著增加,肝组织Ⅰ、Ⅲ型胶原表达与TIMP1呈明显正相关。结论慢性乙型肝炎患者肝纤维化的发生与TIMP1增加、间质胶原蛋白的分解降低有关。     

化妆品中新银盐法测定砷的问题研究

目的：通过对聚乙烯醇-硝酸银-乙醇分光光度法测定化妆品中砷的存在问题的实验研究分析，完善国家卫生规范检验方法。方法：消化处理后样品中的五价砷在碘化钾和氯化亚锡的作用下还原为三价砷经聚乙烯醇-硝酸银-乙醇溶液吸收形成黄色胶态银，比色测定。对不同室温下的标准系列的显色数据进行了方差分析。结果：不同室温下混合吸收液对同一含量的砷氢的吸收显色存在的差异有统计学意义（P〈0．01）。结论：作为国家的卫生规范检验方法，聚乙烯醇＋硝酸银＋乙醇混合吸收分光光度法存在缺陷，为此建议增加相应的实验必要条件。     

SPECT探头系统的校正与调试

本文阐明了对SPECT探头校正与调试的重要性,特别是对探头校正与调试的具体方法与步骤作了详细介绍。     

回旋加速器辐射防护

本文介绍了几点回旋加速器在机房设计、安装、使用时应该加强的辐射防护知识.     

ACS：180碱泵加液量异常对测量结果的影响及质量控制

化学发光仪中,碱泵系统提供的碱性辅助试剂是被测物反应结束后产生化学发光的必要条件,碱泵加量精度下降,会影响测量结果的准确性。质量控制的方法分为,碱泵加液量精度测试和碱泵系统清洗以及碱泵的修复。     

肺动脉栓塞多排螺旋CTA血管成像

目的探讨肺动脉栓塞多排螺旋CTA血管成像扫描延迟时间的最佳值，最佳肺动脉血管成像。方法收集了45例肺动脉栓塞多排螺旋CTA血管成像，造影剂用量按1．5ml／kg，注射速率3ml／sec。扫描延迟时间用Bolus Tracking第一组20例；test Bolus为二组15例；常规计算时间为一组10例。准直器宽度2．5mm，层厚3mm。数据重建用最大密度投影（MIP）和容积显示（VR3D）等常规方法。一、二、三组图像分别由两位高年资医师阅片。结果第一组20例中19例和第二组15例图像肺动脉均清晰显示。第三组10例中4例图像模糊，第三组与第一、二组图像质量有显著差异。结论肺动脉栓塞CTA血管造影中扫描延迟时间用Test Bolus和Bolus Tracking较优，常规计算时间延迟图像质量较差。     

龙岩市2000～2004年性病疫情特征分析

[目的]了解性病的流行趋势和特点，为制定防治措施提供科学依据。[方法]对龙岩市2000-2004年性病疫情资料进行分析。[结果]2000～2004年累计报告性病9044例，年均发病率为63．10／10万，2001年高达85.65／10万。病例中，淋病占47．42％，尖锐湿疣和非淋菌性尿道炎分别占16．70％和15．36％；男性5926例，女性3118例；20-29岁、30-39岁分别占30．38％、40．33％；季节分布以秋季为多，其次是夏季和冬季，分别占全年度的33.09％、27.30％和23．35％；地区分布以新罗区最多，占发病总数的35．12％，其次是上杭县，占21．48％。非婚性接触传播占75.72％，静脉吸毒传播占0．01％，经血液传播者占0．02％。[结论]龙岩市性病发病维持在较高水平，防治工作任重道远。