白三烯C_4对大鼠胃粘膜微循环的影响及其在急性胃粘膜损伤中的作用

探讨了静注白三烯C_4(0.1ng·100g~(-1))对胃粘膜微循环的影响及其在急性胃粘膜损伤中的作用。实验由Wistar系雄性大鼠,实验前禁食24hr,饮水不限。发现:1.胃粘膜表层毛细血管口径迅速变细,部分消失,集合细静脉口径亦变细;10分钟时集合细静脉明显淤血和出血。2.氢气清除法证明,胃粘膜血流量明显减少,注后第15分钟时由注前1.230±0.093(M±SE)降至0.521±0.079ml·min~(-1)·100g~(-1)(P<0.01)。3.反射光谱法证明,胃粘膜局部表层微循环血液量(△Er)和Hb氧饱和度(F),均有不同程度下降。4.静注白三烯C_4(0.1ng·100g~(-1))及盐酸灌胃(0.2N1ml)均未见明显胃粘膜损伤,两者并用则损伤明显加重。结果表明,外源性白三烯C_4可引起严重胃粘膜微循环障碍,是诱发溃疡形成的重要因素之一。     

心室晚电位的时间－频率表示法的进一步改进

在心室晚电位的研究中，我们引入了信号的时间一频率表示法，并根据晚电位的具体特性用Ｗｉｇｎｅｒ分布法（维格纳分布）把信号表示为在时间及频率空间中的能量分布。由于Ｗｉｇｎｅｒ分布的优异性质使我们有可能更准确表示出心室晚电位的存在。但当输入信号是两个信号的线性叠加时，Ｗｉｇｎｅｒ分布的结果会出现一个交叉项，相当于引入干扰。针对此不足，作者介绍改进方案，消除部分交叉项，收到较好的效果，并给出一些仿真及应用实例。     

脑缺血大鼠海马超微结构的形态定量研究

对大鼠双侧颈总动脉夹闭2小时,经透射电镜观察海马,用Weibel氏形态定量法分别测量了海马1区和3区的线粒体和突触的表面积密度(Svi)、表面积—体积比(Si/Vi),并与对照组进行了比较。结果表明:缺血时海马1区受损较严重,表现为线粒体体积缩小,数量减少,Svi下降;突触数量有增多的趋势,但突触的Svi与Si/Vi变化不明显。缺血组海马3区受损较轻,线粒体和突触的结构基本正常,其Svi、Si/Vi与对照组差别不显著,提示了3区对缺血有较强的耐受性。     

淋巴细胞经TCR－CD3活化增殖作用的分析

本文探讨了抗ＣＤ３单抗诱导的淋巴细胞活化增殖及有关影响因素。实验结果表明：①淋巴细胞内钙升高是淋巴细胞活化增殖的重要条件，ＣＤ３ＭｃＡｂ引起的早期胞浆游离钙迅速升高主要由内质网释放钙离子所致，而淋巴细胞增殖不仅需要细胞内钙释放，还需要细胞外钙内流；②ＧＴＰ结合蛋白是淋巴细胞激活过程的一重要环节，经Ｇ蛋白作用物霍乱毒素作用后，淋巴细胞ＤＮＡ合成显著降低；③新霉素和ＰＳＳ可抑制ＰＬＣ和ＰｋＣ的活性，对淋巴细胞ＮＤＡ合成造成剂量依赖性抑制作用。此外，抗ＣＤ３ＭｃＡｂ诱导的淋巴细胞ＤＮＡ合成需要辅佐细胞的存在，高度纯化的Ｔ细胞对ＣＤ３ＭｃＡｂ的刺激不发生增殖反应。     

Two dinucleotide repeat polymorphisms at the D8S1442 and D8S1443 loci

Two polymorphic dinucleotide (CA) repeat clones were isolated from cosmids, cCI8-1121 and cCI8-1199, mapped to chromosome 8p11.2-p12.     

Ex vivo stimulation of cord blood mononuclear cells by dexamethasone and interleukin-7 results in the maturation of interferon-gamma-secreting effector memory T cells

The effects of dexamethasone phosphate and interleukin‐7 upon the proliferation of T‐cells and the production of interferon‐γ in the newborn's cord blood mononuclear cell cultures were studied. The capability of dexamethasone to enhance T‐cell proliferation induced by anti‐CD3 with interleukin‐7 in some newborn cord blood mononuclear cell cultures was identified. Dexamethasone suppressed production of interferon‐γ in 68‐h cell cultures stimulated with anti‐CD3 both in the presence of interleukin‐7 and without it. However, a 68‐h cultivation of newborn blood cells with dexamethasone, anti‐CD3 and interleukin‐7 resulted in the accumulation of T‐lymphocytes capable of producing interferon‐γ after restimulation. As a result of it the amount of interferon‐γ producing CD7⁺ T‐cells and the concentration of interferon‐γ in cultural supernatants were maximal in the cell cultures incubated with anti‐CD3, interleukin‐7 and dexamethasone during the first 68 h and subsequently restimulated with phorbol 12‐myristate 13‐acetate and ionomycin. The stimulation of neonatal or adult blood cells by dexamethasone, anti‐CD3 and interleukine‐7 also causes a decrease in the number of naïve T‐cells and central memory cells and an increase in the number of effector memory CD7⁺CD45RA⁺CD62L^– cells in cultures. It is possible that these effects are caused by the influence of dexamethasone on IL‐7 receptor expression: it is known that IL‐7 receptor alpha‐chain gene is a glucocorticoid‐inducible gene.     

巢蛋白和阶段特异性胚胎抗原-1在大鼠2型星形胶质细胞中的表达

目的 观察1型和2型星形胶质细胞(T1A、T2A)是否表达神经干细胞的标志物、是否具有神经干细胞的特性.方法 取新生大鼠脑皮质,体外培养纯化的O-2A祖细胞、T1A和T2A,应用激光共焦双重免疫荧光标记技术检测巢蛋白和阶段特异性胚胎抗原-1(SSEA-1)的表达;观察O-2A祖细胞、 T1A和T2A在碱性成纤维生长因子(bFGF)和表皮生长因子(EGF)的培养液中生长方式的改变.结果 巢蛋白在O-2A祖细胞和T2A中表达,T1A不表达;SSEA-1仅在T2A中表达.在干细胞培养基中培养10d,T2A形成能增殖和连续传代的细胞球,细胞球巢蛋白标记阳性,贴壁后分化细胞具有神经元、星形胶质细胞和少突胶质细胞样形态;但相同培养条件下的O-2A祖细胞和T1A生长方式无改变.结论 巢蛋白和SSEA-1在两型星形胶质细胞中的表达存在差异,T2A具有神经干细胞的某些生物学特性.