乙酰胆碱对人胃粘膜上皮细胞和胃腺癌细胞内Ca2+、Mg2+浓度的影响

目的:探讨乙酰胆碱对人胃粘膜上皮细胞和胃腺癌细胞内Ca2 、Mg2 浓度的影响。方法:利用大型生化分析仪,检测了乙酰胆碱作用后培养的人胃粘膜上皮细胞和胃腺癌细胞内Ca2 、Mg2 的浓度。结果:与正常胃粘膜上皮细胞比较,胃腺癌细胞内Ca2 、Mg2 浓度偏低(P>0 01)。在乙酰胆碱作用下,胃粘膜上皮细胞内Ca2 浓度升高(P<0 01),Mg2 浓度降低(P<0 01);胃腺癌细胞仅有Ca2 浓度升高(P<0 05),Mg2 浓度无变化。阿托品能阻断乙酰胆碱的作用(P<0 05)。结论:乙酰胆碱对胃粘膜上皮细胞和胃腺癌细胞的作用是通过毒蕈碱受体实现的。     

田径运动肌肉损伤及康复对策研究

在田径教学、训练与比赛中,由于没有完全遵循人体运动的生理规律和调控生物节律,不能使机体的工作运行保持在良好的竞技状态,导致各种各样的运动创伤,严重地影响教学、训练与运动成绩的提高.文章从运动医学理论对田径运动中肌肉损伤的原因进行分析,寻找科学的田径运动损伤康复手段。     

Influence of Microstructure and Sintering Routes on Transport Properties of Apatite Materials for Fuel Cells

1 Results Oxy-apatite materials are thought as zirconia-substitutes in Solid Oxide Fuel Cells due to their fast ionic conduction. However, the well known difficulties related to their densification prevent them from being used as such. This study presents strategies to obtain oxy-apatite dense materials and the influence of elaboration route on transport properties. Particular emphasis is put on the microstructure effect on ion conduction. By the combined use of freeze-drying and conventional or spark p...     

塑料半薄切片法观察豆科植物根表面传递细胞

豆科植物合欢、紫云英、苜蓿等在接种根瘤菌后，部分根毛密集生长稍有膨大的根段，经FAA固定，GMA包埋，半薄切片（3um),PAS反应染色，在光学显微镜油镜下观察根的横切面发现，其表皮细胞或外皮层细胞的外切向壁上有明显的壁内突结构，属典型的根表面传递细胞，采用半薄切片，不仅操作简单，费用较少，且较易确定传递细胞发生的部位。     

钢液定氧测头响应时间和热平衡态

本文分别研究了ＺｒＯ２（ＭｇＯ）固体电解质管头壁厚，参比电极量对定氧测头响应时间的影响，得出了以ＺｒＯ２管头壁厚为０．６０－０．８０ｍｍ，Ｃｒ／Ｃｒ２Ｏ３参比电极加入量为４０－６０ｍｇ所组成的定氧测头响应速度最快，同时采用了“双偶法”对定氧测头在工作过程中的热平衡态进行了研究。结果表明：氧浓差电池中的传热是响应过程的控速步骤，氧电势曲线上峰值的产生是起源于电池中的热平衡态。     

骨髓干细胞的可塑性及其在栓塞性疾病中的应用

栓塞性血管阻塞在急性心肌梗死、脑梗塞、血栓闭塞性脉管炎、糖尿病足等发病过程中起着重要作用。目前临床上针对这些疾病的治疗手段主要有：药物溶栓、血管旁路移植和介入手术等,多年来其治疗方法无实质性进展。上个世纪九十年代人们发现了干细胞新的生物学特性—可塑性,对干细胞可塑性的研究以及相关技术的发展为心脏病、老年痴呆、帕金森等的治疗带来了希望,也为栓塞性疾病的治疗开辟了新途径,有望成为治疗手段之一。     

温度对荒漠沙蜥在体心脏单相动作电位的影响

采用吸附式电极记录了荒漠沙蜥在不同体温条件下 ,在体心脏的单相动作电位 (MAP:Monophasic Action Potential) .实验温度为 :5℃ ,10℃ ,15℃ ,2 0℃ ,2 5℃ ,30℃和 35℃ 7个温度等级 .结果表明 :(1)在最适温度 (2 0～ 2 5℃ )时 ,荒漠沙蜥心脏单相动作电位的基本波形与高等动物及人类基本相似 ;但也有其特殊性 :动作电位 0期除极期最大幅值为 11.4 2± 2 .5 8m V;复极 2期电位幅值基本保持恒定 ,呈平台期 (PP2 :Plateau Phase2 ) ;在复极 3期末 ,电位基本恢复到 0电位(膜电位为 0 m V) .(2 )随着体温的升高 (5～ 35℃ ) ,荒漠沙蜥心脏单相动作电位时程呈温度依赖性减小 ;0期最大除极速度 (Vmax)呈温度依赖性增加 (5℃为 77.0 8± 4 7.11m V/ms;35℃为 614.63±10 5 . 0 2 m V/ms) ;低于最适温度时 (2 0～ 2 5℃ ) ,在 2相平台期末 ,又出现一次除极电位 (后隆起波 ) .其最大电位为 0 .5 8± 0 .18m V.(3)随着体温的升高 ,荒漠沙蜥心脏单相动作电位复极 1期电位呈温度依赖性降低 (5℃为 2 .2 4± 1.31m V/ms;35℃为 0 .82± 0 .4 9m V/ms) .(4 )心电图 (ECG)的同步记录表明 :心电图中的 QRS波与心脏单相动作电位 0期除极完全相对应 ;T波与动作电位的复极 3期相对应 .     

Changes in glycosaminoglycan sulfation and protein kinase C subcellular distribution during differentiation of the human colon tumor cell line Caco-2

Summary During the spontaneous differentiation (day 5 to day 15 of the culture) of Caco-2 cells, the sulfation of cell layer glycosaminoglycans increased, whereas protein kinase C activity was concomitantly redistributed from the membrane to the cytosol. The protein kinase C activators, 4-phorbol 12-myristate, 13-acetate and 1,2-dioctanoyl-glycerol inhibited glycosaminoglycan sulfation. By contrast, 4-phorbol 12, 13 didecanoate was ineffective.These results suggest that membrane-bound PKC may exert a modulatory effect on glycosaminoglycan sulfation, and this effect is gradually attenuated as Caco-2 cell differentiation progresses.     

Failure of opioids to affect excitation and contraction in isolated ventricular heart muscle

Summary The opioid agonists morphine (selective for -receptors) and ethylketocyclazocine (selective for kappa-receptors), at concentrations evoking strong effects in neuronal structures, did not significantly affect the configuration of the intracellularly recorded action potential and the force of contraction in ventricular heart muscle isolated from guinea pigs, rabbits and man. These results suggest that any changes of heart functions in vivo in response to opioid-like drugs are probably not mediated postsynaptically at the myocardial cell membrane but rather presynaptically, influencing the release of noradrenaline and/or acetylcholine from the nerve terminals.     

Lack of effect of dihydroergotamine on endothelial and smooth muscle cell proliferation and endothelial cell prostanoid production

Summary The most important effect of dihydroergotamine is venoconstriction, but certain metabolic effects and changes in vessel prostanoid activity have also been suggested. In this study endothelial cell production of 6-keto PGF₁ and TxB₂ was quantitated in vitro. No evidence of altered prostanoid production was noted after incubation with dihydroergotamine (exposure ranging from 5×10^–3 to 5×10^–7 g/l). Similarly, no effect of dihydroergotamine on the growth rates of endothelial cells or smooth muscle cells in vitro was documented.