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151.
本实验合并应用枸杞有效成份和大蒜有效成份,作用于U_14腹水型宫颈癌小鼠,腹腔注射第四天,发现一般状况改善,取腹水观察,癌细胞破损,DNA、RNA荧光染色强度减弱,有大量白细胞和巨噬细胞围绕;流式细胞分析G_1期细胞堆积,超微结构显示胞质中线粒体肿胀,嵴破坏甚至中空,粗面内质网扩大、脱颗粒,肯定了其作用的效果。此因枸杞有效成分活化巨噬细胞与肿瘤细胞紧密结合而起到溶瘤作用,与大蒜有效成分直接杀伤而作用维持短暂结合起来,可大大提高抗癌作用。 相似文献
152.
慢性缺氧对大鼠膈肌组织化学和超微结构影响的研究 总被引:6,自引:0,他引:6
研究慢性缺氧和参麦注射液治疗对大鼠膈肌组织化学和超微结构的影响,结果显示:缺氧使膈肌SDH活性降低,Ⅰ类纤维极显著减少,运动终板ChE活性极显著降低,线粒体肿胀变性,神经肌肉运动终板突触前部囊泡减少,突触间隙模糊,终板模电子密度降低;参麦治疗可恢复缺氧膈肌的SDH活性及Ⅰ类纤维数目,显著提高终板ChE活性,线粒体结构恢复正常,运动终板突触前部囊泡丰富,突触间隙清晰,终板膜电子密度正常。表明慢性缺氧降低膈肌有氧氧化能力,影响其能量代谢及神经冲动的传递,从而减弱其收缩力,而参安治疗可改善缺氧造成的上述损害,为其临床应用提供了实验医学依据。 相似文献
153.
记述了采自河南省内乡宝天曼自然保护区的地蛛属蜘蛛1新种:宝天曼地蛛Alypnsbaolianmanensis sp.nov.,该新种近似于绥宁地蛛Alypus suiningensis Zhang,1985。 相似文献
154.
莱氏衣原体膜上Mg~(2+)-ATPase用DOC溶解后,经Sepharose-6B和DEAE-CelluloseDE-52离子交换柱,得到了部分纯化的Mg~(2+)ATPase,并将此ATPase与不同极性头部的磷脂和膜糖脂重组,研究了不同的极性头部的磷脂和膜糖脂对ATPase活性的影响。此酶的活性不依赖酸性磷脂,PG、DPG、大豆磷脂等明显抑制酶活性,中性磷脂DMPC、PE、PC则能增加酶活性,其中尤以非双层脂PE的作用最为明显。从莱氏衣原体膜上提取的糖脂(MGDG,DGDG)单独和ATPase重组时,酶活性增加并不明显,当MGDG和DGDG以等比例混合时,能大大地增加酶活性。这表明Mg~(2+)-ATPase的活性很大程度上与磷脂的表面电荷及磷脂的组成相关。 相似文献
155.
从对照和用DEHP处理的大鼠肝脏提取核蛋白,以含酰基CoA氧化酶(AOX)基因表达调控部位的DNA片段和该基因的不同蛋白结合位点的DNA片段作为核蛋白结合反应的探针,通过凝胶电泳迁移率改变实验和Southwestern印迹分析检查了DEHP对AOX基因反式作用因子的影响。结果表明,降血脂药物DEHP可显著增加AOX基因反式作用因子的含量和(或)与基因的结合活性,在转录水平上促进基因的表达。 相似文献
156.
Casein Kinase II Activity in the Postischemic Rat Brain Increases in Brain Regions Resistant to Ischemia and Decreases in Vulnerable Areas 总被引:1,自引:1,他引:0
Abstract: Casein kinase II (CKII) is a protein kinase acting in the intracellular cascade of reactions activated by growth factor receptors, and that has a profound influence on cell proliferation and survival. In this investigation, we studied the changes in the activity and levels of CKII in the rat brain exposed to 10. 15 and 20 min of transient forebrain ischemia followed by variable periods of reperfusion. The cytosolic CKII activity decreased during reperfusion by ∼ 30 and ∼ 50% in the selectively vulnerable areas, striatum and the CA1 region of the hippocampus, respectively. In the resistant CA3 region of hippocampus and neocortex, the activity increased by ∼ 20 and ∼ 60%, respectively. The postischemic changes in CKII activity were dependent on the duration of the ischemic insult. The levels of CKII did not change after ischemia, suggesting that the enzyme is modulated by covalent modification or is interacting with an endogenous inhibitor/activator. Treatment of the cytosolic fraction from cortex of rats exposed to ischemia and 1 h of reperfusion with agarose-bound phosphatase decreased the activity of CKII to control levels, suggesting that CKII activation after ischemia involves a phosphorylation of the enzyme. The correlation between postischemic CKII activity and neuronal survival implies that preservation or activation of CKII activity may be important for neuronal survival after cerebral ischemia. 相似文献
157.
L.-Y. Chau T. A. Lin W.-T. Chang C.-H. Chen M.-J. Shue Y.-S. Hsu C.-Y. Hu W.-H. Tsai G. Y. Sun 《Journal of neurochemistry》1993,60(2):454-460
Abstract: Addition of endothelins (ETs) to neuroblastomaglioma hybrid cells (NG108-15) induced increases in cytosolic free Ca2+ ([Ca2+]i) levels of labeled inositol monophosphates and inositol 1,4,5-trisphosphate [Ins(1,4,5)P3]. The increases in [Ca2+]i elicited by the three ETs (ET-1, ET-2, and ET-3) were transient and did not show a sustained phase. Chelating extracellular Ca2+ in the medium by adding excess EGTA decreased the ET-mediated Ca2+ response by 40-50%. This result indicates that a substantial portion of the increase in [Ca2+]i was due to influx from an extracellular source. However, the increase in [Ca2+]i was not affected by verapamil or nifedipine (10?5M). A rank order potency of ET-1 ET-2 ET-3 is shown for the stimulated increase in [Ca2+]i, as well as labeled inositol phosphates, in these cells. ATP (10?4M) and bradykinin (10?7M) also induced the increases in [Ca2+]i and Ins(1,4,5)P3 in NG108-15 cells, albeit to a different extent. When compared at 10?7M, bradykinin elicited a five- to sixfold higher increase in the level of Ins(1,4,5)P3, but less than a twofold higher increase in [Ca2+]i than those induced by ET-1. Additive increases in both Ins(1,4,5)P3 and [Ca2+]i were observed when ET-1, ATP, and bradykinin were added to the cells in different combinations, suggesting that each receptor agonist is responsible for the hydrolysis of a pool of polyphosphoinositide within the membrane. ET-1 exhibited homologous desensitization of the Ca2+ response, but partial heterologous desensitization to the Ca2+ response elicited by ATP. On the contrary, ET-1 did not desensitize the response elicited by bradykinin, although bradykinin exhibited complete heterologous desensitization to the response elicited by ET-1. Taken together, these results illustrate that, in NG108-15 cells, a considerable amount of receptor cross talk occurs between ET and other receptors that transmit signals through the polyphosphoinositide pathway. 相似文献
158.
Depression of Neuronal Protein Synthesis Initiation by Protein Tyrosine Kinase Inhibitors 总被引:2,自引:1,他引:1
Abstract— Growth factors stimulate cellular protein synthesis, but the intracellular signaling mechanisms that regulate initiation of mRNA translation in neurons have not been clarified. A rate-limiting step in the initiation of protein synthesis is the formation of the ternary complex among GTP, eukaryotic initiation factor 2 (elF-2), and the initiator tRNA. Here we report that genistein, a specific tyrosine kinase inhibitor, decreases tyrosine kinase activity and the content of phosphotyrosine proteins in cultured primary cortical neurons. Genistein inhibits protein synthesis by >80% in a dose-dependent manner (10–80 μg/ml) and concurrently decreases ternary complex formation by 60%. At the doses investigated, genistein depresses tyrosine kinase activity and concomitantly stimulates PKC activity. We propose that a protein tyrosine kinase participates in the initiation of protein synthesis in neurons, by affecting the activity of elF-2 directly or through a protein kinase cascade. 相似文献
159.
Abstract: Muscarinic receptor-mediated cyclic GMP formation and release of nitric oxide (NO) (or a precursor thereof) were compared in mouse neuroblastoma N1E-115 cells. [3 H]Cyclic GMP was assayed in cells prelabeled with [3 H]guanine. Release of NO upon the addition of muscarinic agonists to unlabeled neuroblastoma cells (NO donor cells) was quantitated indirectly by its ability to increase the [3 H]cyclic GMP level in labeled cells whose muscarinic receptors were inactivated by irreversible alkylation (NO detector cells). Carbachol increased NO release in a concentration-dependent manner, with half-maximal stimulation at 173 μ M (compared to 96 μ M for direct activation of cyclic GMP formation). The maximal effect of carbachol in stimulating release of NO when measured indirectly was lower than that in elevating [3 H]cyclic GMP directly in donor cells. Hemoglobin was more effective in blocking the actions of released NO than in attenuating direct stimulation of [3 H]cyclic GMP synthesis. There was a good correlation between the ability of a series of muscarinic agonists to release NO or to activate [3 H]cyclic GMP formation directly, and the potency of pirenzepine in inhibiting the two responses. Furthermore, there was a similar magnitude of desensitization of both responses by prolonged receptor activation or stimulation of protein kinase C. NO release was also regulated in relation to the cellular growth phase. A model is proposed in which a fraction of NO generated upon receptor activation does not diffuse extracellularly and stimulates cyclic GMP synthesis within the same cell where it is formed (locally acting NO). The remainder of NO that is extruded extracellularly might travel to neighboring cells (neurotransmitter NO) or might be taken back into the cells of origin (homing NO). 相似文献
160.
川西峨眉晚白垩世夹关期河流沉积中的痕迹化石群落* 总被引:9,自引:1,他引:8
晚白垩世夹关组中的痕迹化石群落至少由12个痕迹属17个痕迹种组成,其中包括5个新痕迹种,即Cystichrtium cuwatitivum,Steinichnus laryus,Paradidymaulichnus emeiertsis,Monmorphichnus lineates和Rusophycus univalvis.这一化石群落主要是无脊椎动物的进食迹、觅食迹、爬迹、停息迹和居住迹,其中多数呈下浮痕和全浮痕保存,并形成于经常干旱的河流环境(大多出现在泛滥平原沉积中).该群落可识别出两个痕迹化石组合,即1) Scoyenia-Steinichnus-Rusophycus组合,它主要产自泛滥平原和漫滩环境;2)Skolithos-Arenicolites组合,它代表一种水道砂坝或曲流砂坝环境. 相似文献