Identification of a Strong Promoter of Bacteriophage MB78 that Lacks Consensus Sequence Around Minus 35 Region and Interacts with Phage Specific Factor

A strong promoter of bacteriophage MB78 does not have minus 35 consensus sequence although it has a TGn motif immediately upstream of minus 10 sequence as well as the AT rich UP element. It is efficiently recognised by the sigma 70 RNA polymerase, however, a phage-specific factor competes with sigma 70 RNA polymerase for binding to this region, the binding of the factor being stronger than that of the polymerase. Contrary to the reports in the literature the polymerase appears not to bind to the UP element whereas the phage-specific factor does. The latter seems to be involved in the regulation of the promoter activity. This revised version was published online in July 2006 with corrections to the Cover Date.     

Properties of voltage-gated currents of microglia developed using macrophage colony-stimulating factor

Microglia were isolated from a murine neonatal brain cell culture in which their development had been stimulated by supplementation with the macrophage/microglial growth factor macrophage colony-stimulating factor (M-CSF). Using the whole-cell configuration of the patch-clamp technique, voltage-gated membrane currents were recorded from these microglial cells. Hyperpolarization induced inward rectifying K⁺ currents, as described for microglia from untreated cultures. These currents activated negative to the K⁺ equilibrium potential and, with a strong hyperpolarization, displayed time-dependent inactivation. The inactivation was abolished when extracellular NaCl was replaced by N-methyl-d-glucamine (NMG), thereby indicating a partial block of this K⁺ conductance by Na⁺. Inward rectifying currents were also blocked by extracellularly applied Cs⁺ or Ba²⁺. They were slightly diminished following treatment with extracellular tetraethylammonium chloride (TEA) but were not affected by 4-aminopyridine (4-AP). Upon long lasting depolarizing voltage pulses to potentials positive to 0 mV, the cells exhibited a slowly activating H⁺ current which could be reduced by application of inorganic polyvalent cations (Ba²⁺, Cd²⁺, Co²⁺, La³⁺, Ni²⁺, Zn²⁺) as well as by 4-AP or TEA. Based on their kinetics and pharmacological characteristics, both currents detected on M-CSF-grown microglia are suggested to correspond to the inward rectifier and the H⁺ current of macrophages.     

Human cerebral potentials evoked by CO2 laser stimuli causing pain

Summary Brief radiant heat pulses, generated by a CO₂ laser, were used to activate slowly conducting afferents in the hairy skin in man. In order to isolate C-fibre responses a preferential A-fibre block was applied by pressure to the radial nerve at the wrist. Stimulus estimation and evoked cerebral potentials (EP), as well as reaction times, motor and sudomotor activity were recorded in response to each stimulus. With intact nerve, the single supra-threshold stimulus induced a double pain sensation: A first sharp and stinging component (mean reaction time 480 ms) was followed by a second burning component lasting for seconds (mean reaction time 1350 ms). Under A-fibre block only one sensation remained with characteristics and latencies of second pain. The heat pulse evoked potential consisted of a late vertex negativity at 240 ms (N240) followed by a prominent late positive peak at 370 ms (P370). Later activity was not reliably present. Under A-fibre block this late EP was replaced by an ultralate EP beyond 1000 ms, which in the conventional average looked like a slow halfwave of 800 ms duration. This potential was distinct from eye movements, skin potentials or muscle artefacts. With cross-correlation methods waveforms similar to the N240/P370 were detected in the latency range from 900 to 1500 ms during A-fibre block, indicating a much greater latency jitter of the ultralate EP. Latency corrected averaging with a modified Woody filter yielded a grand mean ultralate EP (N1050/P1250), the shape of which was surprisingly similar to the late EP (N240/P370). The similarity of these components indicates that both EPs may be secondary responses to afferent input into neural centers, onto which myelinated and unmyelinated fibres converge. Such convergence may also explain through the known mechanisms of short term habituation and selective attention, why ultralate EPs are not reliably present without peripheral nerve block.     

牙周病患者血清细胞因子测定的临床意义

目的：探讨了牙周病患者血清IL-8、IL-10、IL-18和M—CSF检测的临床意义。方法：应用放射免疫分析和酶联免疫法对55例牙周病患者进行了治疗前后血清IL-8、IL-10、IL-18和M-CSF水平检测，并与35名正常健康人作比较。结果：牙周病患者在治疗前血清IL-8、IL-10、IL-18和M-CSF水平均非常显著地高于正常人组（P〈0．01），经治疗后-个月，与正常人组比较仍有显著性差异（P〈0．05）。结论：细胞因子IL-8、几-10、几-18和M-CSF在牙周病的发生、发展过程中相互作用，观察其浓度的变化对探讨其发病机理、预防和指导用药均有重要价值。     

碱性成纤维细胞生长因子与卵巢癌的关系

目的　探讨碱性成纤维细胞生长因子 (basic fibroblast growth factor,b FGF)对卵巢癌细胞增殖、浸润和肿瘤血管生成的影响 ,及 b FGF单克隆抗体 (b FGF monoclonal antibody,b FGF- MAb)的治疗作用。　方法　将人卵巢癌细胞株 SKOV3接种于 2 4孔板 ,加入不同浓度的 b FGF,每日行结晶紫染色后测定光密度 (D4 90 )值 ,绘制细胞生长曲线 ;将 SKOV3细胞团接种于铺设有细胞外基质凝胶的 4孔板 ,每日测定癌细胞在凝胶中的浸润距离 ;建立 SKOV3细胞裸鼠皮下移植瘤模型 ,每周两次分别将 b FGF、b FGF-MAb和生理盐水注射于移植瘤周围 ,8周后测量肿瘤体积 ;对移植瘤组织切片行 因子的免疫组化染色、测定肿瘤内微血管密度 (microvessel density,MVD)。　结果　 b FGF能促进 SKOV3细胞增殖并呈浓度依赖 ,实验第 5天 ,5 ng/ml、10 ng/ml组细胞 D4 90 值是对照组的 1.0 9倍和 1.2 1倍 ;b FGF能促进 SKOV3细胞浸润并呈浓度依赖 (P<0 .0 5 ) ,第 7天 ,5 ng/ml、10 ng/ml组细胞浸润距离分别是对照组的 1.5 3倍和2 .4 5倍 ;b FGF组移植瘤体积和 MVD分别是对照组的 1.80倍和 1.4 6倍 (P<0 .0 5 ) ,b FGF- MAb组移植瘤体积和 MVD分别是对照组的 6 3.7%和 6 2 .8% (P<0 .0 5 )。　结论　b FGF能明显促进卵巢癌细胞的增殖、     

(His)6 -eIF3s4融合蛋白在人乳腺癌细胞Bcap37中的表达

目的：构建真核细胞翻译起始因子3第4亚单位（eIF3s4）真核表达载体用于进一步功能研究。方法：设计引物,以K562细胞的总RNA为模板,采用RT-PCR方法扩增eIF3s4的全长编码区cDNA,克隆于pGEM-TEasy载体,经DNA测序并与GenBank数据库序列进行比对后,将该cDNA序列亚克隆于真核表达载体pcDNA4/HisMaxB载体,构建成（His）6-eIF3s4融合蛋白的表达载体,用LipofectamineTM2000瞬时转染人乳腺癌细胞株Bcap37,利用Westernblot方法检测（His）6-eIF3s4融合蛋白的表达。结果：DNA序列测定表明,利用RT-PCR方法克隆的eIF3s4全长编码区cDNA序列与GenBank数据库序列一致,Westernblot结果证实（His）6-eIF3s4融合蛋白在Bcap37细胞中获得预期表达。结论：成功地构建了eIF3s4的真核表达载体并在人乳腺癌细胞Bcap37中表达,为建立稳定的eIF3s4高表达细胞系,进而研究eIF3s4与肿瘤细胞多药耐药相关性打下了基础。     

Transwell侵袭小室技术的改良及其在人骨髓间充质干细胞诱导分化中的应用

目的：分离、培养和鉴定人骨髓间充质干细胞（Mesenchymal stem cells，MSCs），应用改良的Transwell侵袭小室技术，探讨血管内皮生长因子（VEGF）及内皮细胞条件诱导液对其体外诱导分化中的作用。方法：采用Percoll（1．073g／ml）分离液分离骨髓单个核细胞，体外培养MSCs，流式细胞术分析鉴定MSCs的纯度，Transwell侵袭小室技术结合LSCM，实时监测MSCs在Matrigel与VEGF／内皮细胞条件诱导液构成的内皮细胞生长微环境中的运动迁移情况。结果：经Percoll分离、体外培养扩增的MSCs，细胞纯度可达95％左右；VEGF组迁移的深度虽高于对照组（P〈0．05），但迁移至聚碳酸脂膜下的细胞与对照组相比，并无统计学意义（P〉0．05）。内皮细胞条件诱导液促进MSCs的迁移，在Matrigel内迁移的深度及迁移至聚碳酸脂膜下的细胞均明显多于对照组（P〈0．05）。结论：共聚焦激光扫描显微术与Transwell侵袭小室技术的结合，能够从时间和空间上对后者进行观察，使该实验得到改良；利用内皮细胞条件诱导液与Matrigel模拟体外内皮细胞生长的微环境，并从空间上观测了MSCs穿越人工基底膜的情况，为MSCs向内皮细胞体外诱导开辟了新的思路。     

早、中、晚孕期胎盘因子体外抗HIV-1的研究

目的 探讨早、中、晚孕期胎盘因子(PF)体外抗人免疫缺陷病毒-1(HIV-1)及在HIV-1垂直传播中的作用.方法 荧光染料Calcien-AM标记的H9/HIV-1ⅢB分别与早、中、晚孕期不同稀释浓度的PF作用后,与MT2细胞培养,荧光显微镜下观察合胞休的形成;用HIV-1ⅢB感染MT2细胞,并分别与早、中、晚孕期不同稀释浓度的PF作用后,用MTT法检测HIV-1感染细胞的存活率,用ELISA方法检测细胞培养上清中p24抗原水平.结果 各孕期PF并不能抑制MT2和H9/HIV-1ⅢB细胞的融合,但可以增加HIV-1感染细胞的存活率及减少HIV-1 p24抗原的表达,且效应以早孕期PF最大,中孕期PF其次晚孕期PF最小,并与剂量呈正相关.结论 PF在体外具有抗HIV-I的作用,并呈现孕期和剂量相关性,可能在阻断HIV-1垂直传播中具有一定作用.     

肝细胞核因子6在小鼠肝内胆管发育过程中的表达

目的 探讨肝细胞核因子6(HNF6)在肝内胆管发育过程中的作用. 方法 用RT-PCR及免疫组织化学等方法 检测HNF6在小鼠胚胎发育的各个阶段以及成年肝中的表达. 结果 RT-PCR结果 显示,HNF6 mRNA的表达在E9d开始出现,与肝芽形成的时间吻合,E13d HNF6 mRNA的表达消失,E15d又重新出现,并一直维持到出生.免疫组织化学显示,CK19免疫反应在E13d开始出现,此时免疫反应阳性细胞在肝索内散在分布.E15d时在近肝门处的门管区丌始出现由单层的、CK19阳性细胞组成的胆管板,之后,阳性细胞反应主要分布于胆管板和小叶间胆管.E9～11d,多数肝索细胞呈HNF6阳性反应,E13d的肝索中未观察剑HNF6的表达.E15～17d,HNF6阳性反应的分布与CK19相似,成年小鼠肝的胆管上皮细胞仍呈HNF6阳性反应. 结论 HNF6可能与肝干细胞的特化关系不大,而与肝发育的启动、肝干细胞向胆管上皮细胞的分化及其分化状态的维持有关.     

神经生长因子对周围神经损伤后再生和修复的实验研究

手术切除５ｍｍ兔的尺神经，在两断端间连接肌桥并套装硅胶管，形成一个封闭腔，向腔内注入神经生长因子。间隔不同时间取尺神经桥接区、桥接区近段、远段、尺神经的脊髓投射节段和相应脊神经节，用光镜和电镜观察神经溃变和再生情况并作图像分析；用酶标示踪和电生理方法检测神经通路的重建状况。结果显示，周围神经离断后，肌束桥接并用硅胶管套装后注入外源性神经生长因子，可明显地促进离断神经的再生和修复。