Activity-dependent Decay of Early LTP Revealed by Dual EPSP Recording in Hippocampal Slices from Young Rats

The early maintenance of long-term potentiation (LTP) was studied in the CA1 region of hippocampal slices from 12- to 18-day-old rats in a low-magnesium solution (0.1 mM). The α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) and N-methyl-D-aspartate (NMDA) receptor-mediated components of the field excitatory postsynaptic potential were estimated in parallel using early and late measurements of the composite potential. At the normal test stimulus frequency of 0.1 Hz, LTP was seen initially as a predominant increase in the AMPA component, but converted, via a substantial decay of this component and a gradual growth of the NMDA component, into nearly equal changes of the two components. Interrupting the test stimulation for 10 min, changing the test stimulus frequency to 1/60 Hz after LTP induction, or using a test stimulus frequency of 1/60 Hz during the entire experiment significantly reduced the decay of the potentiation of the AMPA component while enhancing the potentiation of the NMDA one. The ratio between the magnitudes of the two excitatory postsynaptic potential (EPSP) components showed a decaying time course that was independent of the manipulations used. Application of the NMDA antagonist D(-)-2-amino-5-phosphonopentanoic acid (50μM) after LTP induction stabilized the LTP of the AMPA component until washout was started. On the other hand, the phosphatase inhibitor okadaic acid (1 μM) resulted in decay of the potentiation of both EPSP components back to around baseline and altered the time course of the ratio between the components. Our results show that the early maintenance of LTP is controlled in an activity-dependent and NMDA-dependent manner. This process accelerates the decay of LTP of both AMPA and NMDA components in parallel, suggesting that it is similar to homosynaptic long-term depression, although it operates at the normal test stimulus frequency. The data support a scenario in which LTP ensues as a selective AMPA receptor modification and subsequently converts to another modification, possibly a presynaptic one.     

3种氟喹诺酮类药物抗生素后效应的研究

应用AVANTAGF分析仪的光密度法测定了环丙沙星（CPLX）、氧氟沙星（OFLX）和氟罗沙星（FLRX）的抗生素后效应（PAE）．结果表明氟喹诺酮类抗菌药物对革兰氏阳性球菌和革兰氏阴性杆菌均产生明显的PAE．并随抗菌药物浓度的增大、对受试菌的PAE逐渐延长．呈现了明显的浓度依赖性；3种抗菌药物对铜绿假单胞菌的PAE都较长．MIC均较小．显示了良好的杀菌效果：氯罗沙星对除金葡球菌之外的受试菌的PAE均比其它2药较长．PAE的存在提示在临床设计给药方案时．可适当延长给药间期．减少给药次数与剂量．仍能维持抗菌效果。     

中国汉译西医学著作在日本的流传和影响

调查了十九世纪汉译西洋医学著作在日本的出版和流传情况，有９种汉译西洋医学著作曾在日本出版，其中６种曾多次再版，７种有和训或和译本，这些著作曾在日本医生中广泛流传，促进了西洋医学在日本的传播和普及，对日本医学从传统医学向现代医学的转变起过一定的作用。本文还分析了汉译西洋医学著作能够在日本广泛流传的原因     

系统性红斑狼疮的肺胸膜损害

分析了系统性红斑狼疮并肺、胸膜损害30例,胸膜改变占首位,共19例,(63.3％),其中胸膜积液16例,合并心包积液3例。其次为SLE肺炎5例(16.7％),尿毒症肺水肿3例(10％),弥漫性肺间质纤维化2例(6.7％),肺不张1例(3.35％)。对临床表现、诊断、治疗和预后进行了讨论。     

d-宁烯、丹参及姜黄素衍生物对ras基因产物膜结合和细胞间隙信息传导的影响

目的旨在寻找新型抗肿瘤药物,进一步研究d-宁烯、丹参及姜黄素衍生物的抗肿瘤机理。采用分子生物学方法及划痕标记染料示踪技术,研究了4种人实体瘤起源的细胞系的细胞间隙信息传导(GJIC)、H-ras癌基因表达以及ras癌基因产物(P21^ras蛋白)表达状态,并观察了4种天然产物对它们的影响。结果表明,细胞内染料传输功能的丧失与ras基因突变率呈正相关;单萜化合物d-宁烯和酚类化合物丹参衍生物的抗肿瘤作用可能与抑制P21^ras蛋白膜结合和增强细胞间隙信息传导功能有关。提示Ras癌基因产物P21^ras蛋白膜结合的抑制与细胞间隙信息传导功能的增强有直接关系。     

HL－60和抗分化HL－60细胞的基本生物学和细胞遗传学特征比较

对本实验室克隆的人急性早幼粒白血病细胞株ＨＬ－６０及其抗维甲酸分化亚系ＨＬ－６０／ＲＡ进行细胞增殖、细胞周期、分裂中期细胞染色体分布和Ｇ－显带核型分析。发现两者在倍增时间和细胞形态上基本一致。在细胞周期分布上，两者都具有肿瘤细胞的周期分布特征，但ＨＬ－６０／ＲＡ细胞的Ｓ期细胞群少于ＨＬ－６０细胞。两者染色体数量分布比较集中，染色体众数分别为４５±３（ＨＬ－６０）和４５±１（ＨＬ－６０／ＲＡ），呈近二倍体核型，Ｇ－显带核型分析表明两者都接近正常二倍体核型，都含较多的异常染色体。上述结果说明ＨＬ－６０和ＨＬ－６０／ＲＡ细胞的遗传学来源一致。     

头孢噻肟在恶性血液病合并感染患者体内杀菌效价及临床疗效比较

目的 对比观察头孢噻肟（ＣＴＸ）与其他两种抗菌药物治疗方案对３０例血液病合并感染患者杀 菌活性（ＳＢＡ）及临床疗效。方法ＳＢＡ采用微量稀释法测定，临床疗效根据临床治疗登记表按三 级标准判定。结果与结论 头孢噻肟的临床反应最佳，杀菌作用时间维持较长，但对绿脓假单胞 菌和阴沟肠杆菌杀菌作用较差；呱拉西林（ＰＩＰ）与阿米卡星（ＡＮ）方案的抗菌谱广，但ＰＩＰ杀菌 作用时间较短，可考虑缩短给药间期，而ＡＮ可按一日一次给全日量的方案，以提高疗效减少不 良反应；头孢哌酮（ＣＰＺ）可主要用于绿脓假单胞菌感染，也可用于其它细菌的混合感染，但给药 间隔时间以一日三次为宜。     

彩色多普勒和磁共振对健康人颅内动脉影像学的比较研究

目的通过彩色多普勒和磁共振血管成像对健康人颅内动脉的检测,初步确定其操作规范及衡量标准。方法正常人200例,按照检查方法分为彩色多普勒血流显像(ColourDopplerFlowImaging,CDFI)组及磁共振血管成像(MagneticReso-nanceAngiography,MRA)组。CDFI组观察大脑中动脉(MiddleCerebralArtery,MCA)、椎动脉(VertebralArtery,VA)各段的血流动力学改变和相应点的血流束内径。MRA组检测相应血管对应部位的血管内径。结果同一条血管不同位置的血流速率有差异(P<0.05);同名血管相应位置的血流速率左侧略高于右侧,女组高于男组,但无统计学意义(P>0.05)。按年龄分组,相邻组间无显著性差异,相隔组间有显著性差异。CDFI所测血流束内径较MRA所测血管内径值偏高,且P<0.05,差异有显著性。结论a)应用CDFI能显示MCA,VA走行,可检测血管的血流动力学的改变。b)要提高临床脑血管疾病诊断的准确性,必须有规范的临床操作和可靠的检测指标。c)对血管内径的测量MRA更佳。     

密闭液性环境干燥环境下供皮区创面愈合的比较研究

目的比较研究密闭液性环境和干燥环境下供皮区创面的愈合过程. 方法 1996年7月～1997年3月以13例成人断层供皮区创面为研究对象,其中男9例,女4例,年龄20～50岁,创面面积(100～400) cm2,取皮深度中厚,约0.44 mm.同一个创面分为实验组(密闭液性环境)和对照组(干燥环境),采用自身对照法.应用大体、组织学及电镜观察等方法进行观察. 结果密闭液性环境下创面愈合较快,创面组织中成纤维细胞较早活跃、且持续时间较长,再血管化和再上皮化均较早和较快发生. 结论密闭液性环境下创面愈合较快,与组织修复细胞较为活跃、再血管化和再上皮化较快发生有关.     

Rosiglitazone down-regulates lipopolysaccharide-induced expression of CD40 and intercellular adhesion molecule 1 in rat peritoneal mesothelial cells through a NF-κB dependent mechanism

Objective To investigate the effect and mechanism by which PPARγ ligand, rosiglitasone, regulates the expression of CD40 and intercellular adhesion molecule 1 (ICAM-1) in the rat peritoneal mesothelial cells (RPMCs) induced by lipopolysaccharide (LPS). Methods RPMCs were harvested from Sprague-Dawley rat peritoneal cavity and maintained under defined in vitro conditions. The cells were randomly divided into groups as follows: medium, LPS (5 mg/L), LPS (5 mg/L)+BAY11-7085(5 μmol/L, NF-κB inhibitor), rosiglitazone (10 μmol/L or 20 μmol/L, peroxisome proliferator-activated receptor γ activator), LPS (5 mg/L)+rosiglitazone (10 μmol/L)+GW9662 (3 μmol/L, peroxisome proliferator-aetivatcd receptor γ antagonist), and LPS (5 mg/L)+vehicle (DMSO 0.2 ml/L). The expressions of CD40 and ICAM-1 RNA in RPMCs were examined by RT-PCR after 3 hour treatment, and the protein expressions of CD40, ICAM-1, p-NF-κB p65 and p-IκBα were examined by Western blot or immunofluorescence after 24 hour treatment. Results Following treatment with LPS, both the expressions of CD40 and ICAM-1 protein in RPMCs were up-regulated significantly (P<0.05), and the phosphoralation of p65 was increased greatly (1.10±0.17 vs 0.55±0.06, P<0.05). BAY11-7085 (5 μmol/L) significantly decreased the protein expression of p-p65 (0.22±0.11 vs 1.10±0.17, P<0.01), CD40 (0.34±0.02 vs 0.50±0.06, P<0.05) and ICAM-1 (0.35±0.16 vs 0.74±0.03, P<0.05). Pretreated with rosiglitazone for 3 h then added with LPS for 1 h, the levels of p-p65, CD40 and ICAM-1 in RPMCs were significantly decreased compared with those of LPS group (0.77±0.08 vs 0.90±0.10, P相似文献