我国成人肝微粒体的制备和几种细胞色素P450单加氧酶的活性

7例人肝标本均取自我国成年男性,其中5例来自非疾病死亡者,1例为肝血管瘤手术切除的正常肝组织,1例取自交通事故死亡者。该7例人肝微粒体细胞色素P450和细胞色素b5含量分别为0.36±0.08和0.23±0.05nmol·mg^-1蛋白,氨基比林和乙基吗啡N-脱甲基酶活性分别为1.07±0.23和1.82±0.31nmol·mg^-1·min^-1,7-乙氧基香豆素O—脱乙基酶、硝苯吡啶氧化酶和(-)-吡喹酮羟化酶活性分别为0.30±0.10,0.43±0.18和0.69±0.43nmol.mg^-1·min^-1。     

Selective modulation of spike duration by serotonin and the neuropeptides, FMRFamide, SCPB, buccalin and myomodulin in different classes of mechanoafferent neurons in the cerebral ganglion of Aplysia

An examination of the cellular properties and synaptic outputs of mechanoafferent neurons found on the ventrocaudal surface of the cerebral ganglion of Aplysia indicated that the cerebral mechanoafferent (CM) neurons are a heterogeneous population of cells. Based on changes in action potential duration in response to bath applications of 5-HT in the presence of TEA, CM neurons could be divided into 2 broad classes: mechanoafferents whose spikes broaden in response to 5-HT (CM-SB neurons) and mechanoafferents whose spikes narrow in response to 5-HT (CM-SN neurons). Morphological and electrophysiological studies of the CM-SN neurons indicated that they were comprised of previously identified interganglionic cerebral-buccal mechanoafferent (ICBM) neurons and a novel set of sensory neurons that send an axon into the LLAB cerebral nerve and have perioral zone receptive fields that are similar to those of ICBM neurons. Changes in spike width due to 5-HT were correlated with changes in synaptic output as indicated by the magnitudes of EPSPs evoked in postsynaptic neurons. Electrical stimulation of cerebral nerves and connectives also produced spike narrowing or broadening, and the sign of the effect was a function of the parameters of stimulation. Both heterosynaptic facilitation and heterosynaptic depression of EPSPs evoked in follower cells could be demonstrated. A variety of putative neuromodulators other than 5-HT were also found to affect the duration of action potentials in both classes of CM neurons. FMRFamide had effects opposite to that of 5-HT. SCPB and a recently characterized Aplysia neuropeptide, buccalin, broadened the spikes of both CM classes. Another neuropeptide, myomodulin, decreased the duration of CM-SB neuron spikes but had no effect on CM-SN spikes. Since the CM neurons appear to mediate a variety of competing behaviors, including feeding, locomotion, and defensive withdrawal, the various neuromodulator actions may contribute to the mechanisms whereby behaviors are selected and modified.     

大鼠肝微粒体细胞色素P4503A参与吡喹酮A环羟化代谢

三乙酰竹桃霉素(TAO)可使地塞米松(DEX)诱导的大鼠肝微粒体内未结合细胞色素P450(P450)含量降低,红霉素(ERY)和乙基吗啡(EMP)N-脱甲基酶活性降低和吡喹酮(PZQ)A环一羟化物生成速率降低。TAO和ERY对PZQA环一羟化物的生成表现为竟争性抑制,且PZQA环一羟化物生成速率与ERY,EMPN-脱甲基酶活性高度相关。结果表明,P4503A(CYP3A)参与了PZQA环的羟化。     

圆瓣姜花的二萜化合物及其细胞毒活性研究1

从圆瓣姜花(HedychiumforrestiiDiels.)根的乙醇提取物中分离并鉴定了4个有细胞毒活性的二萜成分,其中圆瓣姜花素A为新化合物。     

Identification and characterization of neurons initiating patterned neural activity in the buccal ganglia of Aplysia

Two patterns of neural activity were identified in excised buccal ganglia of Aplysia californica. Both are expressed in many cells, and each can be expressed independently. Using cells B4 and B5 as monitors of the activity patterns, we searched the buccal ganglia for cells initiating the patterns. Two electrically coupled cells, B31 and B32, can initiate what we termed pattern 2. The cells are active before pattern 2 is expressed. Stimuli initiating pattern 2 excite B31/B32. Depolarizing B31/B32 induces the pattern, while hyperpolarizing them can prevent its expression. The cells have unusual features. Their somata do not sustain conventional action potentials, and depolarization causes a regenerative response. B33 differs from B31/B32 in that its soma sustains conventional action potentials but otherwise has similar features. B34 also seems to be inexcitable but has weaker synaptic input than B31/B32 and appears unable to induce pattern 2. B35 and B36 have prominent regenerative capabilities. B35 is also able to initiate pattern 2. B37 is presynaptic to B31/B32 and can initiate pattern 2 via its effects on them. The newly identified cells provide a starting point for investigating factors that initiate and control different patterns of neural activity in the buccal ganglia. Since the buccal ganglia are involved in generating feeding behavior, further studies on the newly identified cells may provide insights into the neural control of feeding behavior, and provide a neural substrate for studying modulation of the feeding patterns by associative learning.     

原子力显微镜观测人血小板与Ⅰ型胶原膜相互作用过程中的形态学变化

目的:利用原子力显微镜从可视化的角度观察人血小板与Ⅰ型胶原膜相互作用后受激活化过程中的形态学变化。方法:实验于2006-06/08在暨南大学生物纳米技术实验室完成。①人血小板的提取:新鲜血液由健康无服药志愿者提供。抗凝剂(38g/L枸橼酸钠)与血液以1∶9的比例800r/min离心5min,将上层血浆以3000r/min离心10min,弃上清,加入生理盐水以3000r/min离心洗涤3次留沉淀。37℃下静置30min。所有操作均在室温下进行,pH为7.4。②Ⅰ型胶原膜的制备:把新鲜剥离的带负电的云母浸入NiCl2溶液中,使其表面带正电荷,通过静电作用将Ⅰ型胶原组装其上,室温下干燥。③血小板形态的观测:将新分离的血小板均匀铺展在膜材上与之作用,作用后用25g/L戊二醛固定10min,再用超纯水漂洗,室温下干燥后原子力显微镜观测。结果:①Ⅰ型胶原膜的表面形貌观察结果:胶原膜呈网孔状,胶原纤维清晰可辨;未受激血小板表面形貌观察结果:为了排除血小板在分离等前处理过程中受到激活的可能,对直接用戊二醛固定的血小板进行成像发现:约95%的血小板未被激活,血小板呈分散分布。对单个血小板的扫描成像发现血小板呈扁平圆盘状,表面比较平滑,血小板之间较分散,无聚集及伪足等活化标志。②Ⅰ型胶原膜上血小板形貌观测结果:与I型胶原作用后立刻用原子力显微镜观测,发现血小板聚集现象并不显著,仅在小范围内出现了交联聚集的现象。通过扫描样品上不同位置的血小板聚集体,发现血小板表面有许多呈平行排列的纤维束,它们把血小板整齐的连接起来,且血小板间层层相叠;这些嵌入在纤维蛋白原网内的血小板,大多保持了圆盘状的结构,但表面都分布着颗粒状或纤维条状物质;与Ⅰ型胶原作用1h后用原子力显微镜观测,发现单个血小板大多处于活化过程中的树突型,伸出了伪足,并有着彼此间相互聚集的趋势,通过对血小板超微结构的观察发现其中心分布着大小不一的团簇状物质。在每个血小板周围,都有许多分泌物,这些分泌物有着不断向血小板外部扩散的趋势,而且扩散的方向多指向另一血小板。结论:①通过原子力显微镜对Ⅰ型胶原诱导活化的血小板形态结构的变化研究发现,其内部α颗粒释放时带出的纤维蛋白原同样也可导致血小板的聚集。②通过对血小板受激活化的体外模拟,可为血小板的凝血过程与及机制的研究以及(抗)凝血生物材料的开发提供参考。     

基于Linux操作系统嵌入式心电记录仪的设计

介绍了一种基于ARM9和Linux操作系统的心电记录仪。该记录仪以32位低功耗ARM9微处理器S3C2410X为核心,在其上移植了Linux操作系统,利用轻量级的图形用户界面支持系统MiniGUI进行软件界面开发,实现了心电信号的实时采集显示、心率计算、心律失常分析并利用GPRS进行心律失常报警等功能。为了检验系统的性能,使用心电信号模拟发生器(MPS450多参数模拟器)产生各种类型的心电信号,用该记录仪进行采集分析,记录仪分析获得的心率值与模拟发生器产生的心率值基本相同,当模拟发生器产生异常心电时,记录仪通过GPRS发出报警信息,同时在主界面上显示心律失常类型。实验结果表明,该记录仪能实时采集显示心电波形,当发生心动过速、心动过缓、心律不齐、漏搏、停搏时,能通过GPRS进行实时报警,实现了心电信号的无线远程实时监护。     

生物黏附材料壳聚糖的黏附性能

目的:考察壳聚糖与黏蛋白的相互作用,评价壳聚糖黏附性能的影响因素。方法:于2006-07/12在中国科学院大连化学物理研究所生物医用材料工程实验室完成。将壳聚糖溶液与黏蛋白溶液混合,用紫外分光光度计测定溶液混合前后紫外吸收值的变化,表征壳聚糖的黏附性能。①调节反应溶液的pH值(1.0,3.0,5.0),考察环境pH对壳聚糖黏附性能的影响。②改变反应温度(4,25,37℃),考察环境温度对壳聚糖黏附性能的影响。③选择不同相对分子质量(48000,124000,230000)的壳聚糖,考察壳聚糖相对分子质量对其黏附性能的影响。④选择不同脱乙酰度(56%,67%,97%)的壳聚糖,考察壳聚糖脱乙酰度对其黏附性能的影响。⑤使用不同种类(I-S型及Ⅲ型)黏蛋白,考察黏蛋白中唾液酸含量对壳聚糖黏附性能的影响。结果:①环境介质pH由1.2升至5.0时,壳聚糖黏附性能随之显著升高。②壳聚糖黏附性能随着温度的升高而显著增强。③壳聚糖相对分子质量对于壳聚糖黏附无显著影响。④壳聚糖脱乙酰度增加,其黏附性能显著增强。⑤I-S型黏蛋白与壳聚糖的作用较之Ⅲ型黏蛋白与壳聚糖的相互作用明显增强。结论:壳聚糖的黏附受环境pH、温度、壳聚糖及黏蛋白两种分子电荷密度的显著影响;在酸性环境下增大环境pH值、升高环境温度、增加壳聚糖的脱乙酰度和增加黏蛋白中唾液酸的含量,均有利于壳聚糖的黏附。     

幼年豚鼠视网膜兴奋毒性损伤模型的建立

目的:观察谷氨酸钠不同给药时程对幼年豚鼠视网膜神经节细胞损伤的程度,以建立简便而稳定可靠的视网膜兴奋毒性损伤模型。方法:实验于2005-03/2006-06在泰山医学院动物实验中心和形态学实验室完成。①实验材料:45～50d(幼年)豚鼠35只,体质量280～320g,雌雄不拘;谷氨酸钠(上海伯奥生物科技有限公司生产),纯度99%,pH6.9～7.2,用生理盐水配成300g/L溶液。②实验分组:采用随机数字法将豚鼠分成2组,即正常对照组5只、谷氨酸钠组30只(谷氨酸钠组根据用药时间又分为4个亚组,即1d组5只、3d组6只、7d组9只,14d组10只)。③实验干预:谷氨酸钠组按3g/kg体质量腹腔注射谷氨酸钠,分别连续1,3,7和14d。④实验评估:给药后,再饲养10d后取材,观察视网膜神经节细胞数目和形态学的变化。结果:①各组豚鼠视网膜光镜观察结果:谷氨酸钠1d组视网膜神经节细胞未见明显形态学改变;3d组少数细胞发生皱缩;7d组视网膜神经节细胞损伤较为明显,多数神经节细胞发生核固缩;14d组动物半数死亡(5/10),视网膜神经节细胞损伤严重,明显脱失,残留细胞体积变小。②各组豚鼠视网膜神经节细胞密度:谷氨酸钠14d组、7d组视网膜神经节细胞密度与正常对照组比较差异均显著(P<0.01),谷氨酸钠3d组与正常对照组比较差别有统计学意义(P<0.05),谷氨酸钠1d组与正常对照组比较差异无显著性(P>0.05)。结论:谷氨酸钠对幼年豚鼠视网膜的毒性损伤与用药时程有关,按3g/kg体质量腹腔注射,1次/d,连续7d,能成功建立谷氨酸视网膜兴奋毒性豚鼠动物模型,且无一例死亡,损伤适中。     

Nitric oxide as a regulator of behavior: new ideas from Aplysia feeding

Nitric oxide (NO) regulates Aplysia feeding by novel mechanisms, suggesting new roles for NO in controlling the behavior of higher animals. In Aplysia, (1) NO helps maintain arousal when produced by neurons responding to attempts to swallow food; (2) NO biases the motor system to reject and reposition food that resists swallowing; (3) if mechanically resistant food is not successfully swallowed, NO mediates the formation and expression of memories of food inedibility; (4) NO production at rest inhibits feeding, countering the effects of food stimuli exciting feeding. At a cellular level, NO-dependent channels contribute to the resting potential of neurons controlling food finding and food consumption. Increases in L-arginine after animals eat act as a post-feeding inhibitory signal, presumably by modulating NO production at rest. NO also signals non-feeding behaviors that are associated with feeding inhibition. Thus, depending on context, NO may enhance or inhibit feeding behavior. The different functions of NO may reflect the evolution of NO signaling from a response to tissue damage that was then elaborated and used for additional functions. These results suggest that in higher animals (1) elicited and background transmitter release may have similar effects; (2) NO may be produced by neurons without firing, influencing adjacent neurons; (3) background NO production may contribute to a neuron's resting potential; (4) circulating factors affecting background NO production may regulate spatially separated neurons; (5) L-arginine can be used to regulate neural activity; (6) L-arginine may be an effective post-ingestion metabolic signal to regulate feeding.