L-精氨酸对低氧性肺动脉高压大鼠肺动脉平滑肌细胞凋亡的影响

目的 探讨L-精氨酸(L-Arg)对低氧性肺动脉高压大鼠不同节段肺动脉平滑肌细胞凋亡的影响。方法 将Wistar大鼠(n=19)随机分为对照组(n=7)、低氧组(n=6)及低氧 L-Arg组(n=6)。经右心导管法测定各组大鼠肺动脉压力和右室(RV)/左室 室间隔(LV S)比值,以分光光度法间接测定血浆一氧化氮(NO)含量,通过TUNEL法检测各组大鼠不同节段的肺动脉平滑肌细胞凋亡数目,并计算肺动脉平滑肌细胞凋亡数目与肺动脉平滑肌细胞数目比值。结果 低氧组大鼠肺动脉平均压(PAMP)显著高于对照组[(2.71±0.29)kPa vs(2.05±0.14)kPa,P<0.01],低氧 L-Arg组大鼠的PAMP显著低于低氧组[(2.23±0.18)kPa vs(2.71±0.29)kPa,P<0.05];低氧组大鼠RV/(LV S)比值显著高于对照组[(0.42±0.03)kPa vs(0.30±0.05)kPa,P<0.01],低氧 L-Arg组大鼠RV/(LV S)比值显著低于低氧组[(0.36±0.02)kPa vs(0.42±0.03)kPa,P<0.01];低氧组大鼠血浆NO含量明显低于对照组[(3.54±0.47)μmol/L vs(4.79±0.17)μmol/L,P<0.05],低氧 L-Arg组大鼠血浆NO含量显著高于低氧组[(5.21±0.26)μmol/L vs(3.54±0.47)μmol/L,P<0.01];低氧组大鼠与终末细支气管伴行的肺动脉和与呼吸细支气管伴行的肺动脉平滑肌细胞凋亡数目与平滑肌细胞数目比值明显低于对照组[(0.051±0.016     

Corticotropin-releasing hormone acts on guinea pig ileal smooth muscle via protein kinase A

In contraction studies corticotropin-releasing hormone (CRH) was found to relax ileal but not gastric and jejunal smooth muscles of the guinea-pig, precontracted with BaCl₂. Under whole-cell patch-clamp conditions, CRH concentration-dependently activated Ca²⁺-sensitive K⁺ currents (I _K) with ED₅₀=20 pM at 100 nM and ED₅₀=0.13 pM at 500 nM intracellular Ca²⁺ respectively. This increase was accompanied by significant hyperpolarization of the cell membranes. CRH 9–41 peptide fragment did not affect I _K amplitude, membrane potential or contraction. The CRH-induced increase of I _K densities was accelerated in the presence of high intracellular Ca²⁺ concentrations (500 nM) and was abolished by pretreatment of cells with either ryanodine or thapsigargin, which cause depletion of intracellular Ca²⁺ stores, as well as in cells treated under conditions prohibiting intracellular Ca²⁺ store refilling. The effect of CRH on I _K was not affected by bath application of various selective inhibitors of membrane-bound phospholipases, protein kinase C, cGMP-dependent protein kinase or Ca²⁺/calmodulin-dependent protein kinase II, but was effectively antagonized by blockers of protein kinase A (PKA) or adenylyl cyclase. Neither forskolin nor the catalytic subunit of PKA could mimic the effect of CRH on I _K. Thus, it was suggested that CRH exerts its relaxing activity on ileal smooth muscle cells via PKA-dependent phosphorylation of some intracellular target coupled to sarcoplasmic reticulum Ca²⁺ storage machinery. Received: 18 January 1999 / Received after revision: 8 March 1999 / Accepted: 9 March 1999     

The effects of oxytocin on the pattern of electrical propagation in the isolated pregnant uterus of the rat

 In the isolated pregnant myometrium of the rat, the pattern of propagation was investigated by recording simultaneously from 240 different extracellular sites while the contraction of the tissue was recorded isometrically. Analysis of all recorded electrograms allowed the two-dimensional spread of activity in the myometrium to be reconstructed. From these activation maps, the conduction velocities were measured in the longitudinal, oblique and transversal directions. At low concentrations (10^–9 and 5×10^–9 M), oxytocin significantly increased the frequency and duration of electrical bursts and the average spike intervals, without affecting the homogeneity of action potential propagation, concomitant with a significant increase in the amplitude of contractions. At high concentrations (10^–8 and 5×10^–8 M), oxytocin induced conduction blocks and the size of inexcitable areas was increased, concomitantly with an increase in muscle contractures. In contrast, the conduction velocities in the longitudinal, oblique and circular directions were not influenced by oxytocin at any concentrations. Received: 9 June 1998 / Received after revision: 14 September 1998 / Accepted: 23 September 1998     

Ocular pursuit of predicted motion trajectories

The initiation and maintenance of slow eye movements (SEMs) usually depend on the perception of a moving stimulus. However, the endogenous representation of predictable target motion can be sufficient to initiate and maintain brief episodes of SEM even when the stimulus is not present. In this note, we show that expectancies generated by predictable stimulus motion trajectories can also produce smooth deceleration, reversal of direction, and subsequent acceleration in these movements, and explore the limits of the predictive component of the SEM control system quantitatively.     

用于内皮细胞与平滑肌细胞联合培养的流动腔系统

内皮细胞与平滑肌细胞的联合培养是体外研究这两种细胞生物学特性的重要手段。静态条件下联合培养的内皮细胞的形态及功能特性与在体条件下均有差异,这可能是没有血流切应力对内皮细胞直接作用的结果。为了了解切应力对与平滑肌细胞联合培养的内皮细胞的生物学作用,本文建立了用于多孔ＰＥＴ膜联合培养模型的力学系统,通过本系统可以产生０～４０ｄｙｎ／ｃｍ２的稳定层流切应力,并应用本系统观察了切应力对联合培养的内皮细胞的形态学影响,结果表明,在４０ｄｙｎ／ｃｍ２切应力作用下,与平滑肌细胞联合培养的内皮细胞沿流体方向发生了重排。这一系统的建立为研究切应力作用下与平滑肌细胞联合培养的内皮细胞的形态和功能提供了手段。     

混合性子宫内膜间质和平滑肌肿瘤2例临床病理分析

目的探讨混合性子宫内膜间质和平滑肌肿瘤（MESSMT）的临床病理特征及诊断和鉴别诊断。方法对2例MESSMT患者进行苏木精-伊红和免疫组化SP法染色光镜观察,结合临床资料进行分析并复习相关文献。结果肉眼观：2例均为子宫全切标本,肿物呈结节状,位于肌壁间,与肌壁分界尚清,1例伴有显著的黏液变及囊性变;光镜：肿瘤由梭形和圆形两种细胞构成,弥漫密集或不规则束状排列,两种成分均超过30%。肿瘤间质有明显的玻璃样变,形成网格状和类似花环或＂星爆样＂结构。肿瘤与子宫肌壁大部分分界清楚,局部舌状浸润。免疫组化：内膜间质成分细胞表达vimentin、CD10阳性,平滑肌成分表达vimentin、SMA、Desmin、h-caldesmon阳性。结论 MESSMT是一种非常罕见的子宫间叶性肿瘤类型,应与富于细胞性平滑肌瘤等肿瘤鉴别,免疫组化具有重要辅助作用。     

通脉宁胶囊对LPC诱导血管平滑肌细胞增殖及细胞周期的影响

目的观察通脉宁胶囊不同剂量药物血清对溶血磷脂酰胆碱(LPC)诱导的血管平滑肌细胞增殖活性及细胞周期的影响.方法组织贴块法进行血管平滑肌细胞(VSMC)培养,应用血清药理学的方法,LPC10-8 mol/L作为刺激因子,将通脉宁胶囊分为大、中、小3个剂量组.MTT法测定细胞增殖活性,流式细胞仪检测细胞周期.结果通脉宁大、中、小剂量组可明显降低细胞的OD值呈剂量依赖性地抑制LPC诱导的VSMC增殖. 明显降低细胞的S期数目百分比,增加G0/G1期数目百分比,使VSMC阻滞在G0/G1期,抑制细胞进入S期.结论从细胞分子水平说明通脉宁胶囊主要是通过影响细胞内DNA合成,减少有丝分裂,增加G0/G1期数目百分比,减少S期数目百分比而发挥抑制VSMC增殖作用.     

四制香附对大鼠离体子宫平滑肌收缩的影响及作用机制研究

目的：探讨建昌帮四制香附及其石油醚部位对未孕大鼠离体子宫平滑肌收缩作用的影响及其机制。方法：采用雌性未孕大鼠,灌胃己烯雌酚致敏,制备离体子宫标本,通过powerlab生物信号采集系统考察生香附、四制香附及其石油醚部位各提取液及α-香附酮对由缩宫素引起的大鼠离体子宫平滑肌收缩的抑制作用,并通过加入受体拮抗剂初步探讨其作用机制。结果：各样品对未孕大鼠离体子宫平滑肌收缩的抑制作用强弱依次为：四制香附石油醚部位﹥四制香附﹥α-香附酮﹥生香附,且α-香附酮、四制香附及其石油醚部位呈现剂量依赖性地抑制子宫平滑肌的收缩作用。结论：四制香附及其石油醚部位抑制子宫平滑肌收缩的作用优于α-香附酮和生香附。     

冠状血管平滑肌细胞发生机制的研究进展

冠状血管为心脏提供营养及氧供,对心脏的正常工作至关重要。冠状血管的管壁主要由平滑肌细胞及内皮细胞构成,平滑肌细胞的结构和功能对冠状血管及心脏的正常工作有重要影响。控制细胞分化、迁移及平滑肌前体细胞数量的分子通路决定了冠状血管的结构及容量。这些信号通路的异常会导致血管畸形,故了解这些机制有益于利用前体细胞进行体内细胞重排从而诱导血管再生。     

烫伤血清对大鼠结肠平滑肌细胞骨架的影响

目的 了解烫伤血清对体外培养的大鼠结肠平滑肌细胞骨架的影响,初步探讨伤后胃肠动力障碍的可能机制. 方法 分离培养健康成年Wistar大鼠结肠平滑肌细胞.另取2只健康成年Wistar大鼠,其中1只不致伤,另一只致深Ⅱ度烫伤,采集2只大鼠血液分离血清,用培养液配成体积分数20%的烫伤血清和体积分数20%的正常血清.采用随机数字表法将大鼠平滑肌细胞分为烫伤血清组和正常血清组,分别用2种血清培养.于处理1、3、6、12 h时(每组每时相点样本数均为10),用流式细胞仪检测细胞肌动蛋白表达水平,并采用蛋白质印迹法检测β微管蛋白的相对含量.对数据行t检验. 结果 (1)烫伤血清组细胞处理1、3、6、12 h时,肌动蛋白荧光强度分别为59±4、26±6、39±6、42±6,正常血清组分别为95±10、91±10、102±9、97±9,组间比较,差异均有统计学意义(t值分别为10.528、18.069、18.748、16.647,P＜0.05或P＜0.01);烫伤血清组组内比较,处理3 h时降至最低点,6、12 h持续回升.(2)烫伤血清组处理1、3、6、12 h时,β微管蛋白的相对含量分别为14.44±0.26、8.61±0.19、11.76±0.31、12.13±0.29;正常血清组分别为22.37±1.15、21.87±1.79、23.24±1.55、21.99±2.02,组间比较差异有统计学意义(t值分别为21.176、23.365、23.000、15.273,P值均小于0.01);烫伤血清组组内比较,处理3 h时达最低,6、12 h有所回升但势头缓慢.结论 烫伤血清作用初始阶段,可使体外培养的大鼠肠道平滑肌细胞骨架含量减少,随后细胞骨架含量呈回升趋势,这可能与平滑肌细胞对烫伤血清刺激的耐受、适应和自我修复有关.