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51.
Yi Sun Mahendra S. Rao Richard E. Zigmond Story C. Landis 《Developmental neurobiology》1994,25(4):415-430
Vasoactive intestinal peptide (VIP) expression increases in sympathetic neurons when they are grown in dissociated cell or explant cultures and when they are axotomized in vivo. In dissociated cell culture, the magnitude of the VIP increase was reduced when nonneuronal cells were removed and medium conditioned by ganglionic nonneuronal cells increased VIP in neuron-enriched cultures. Antiserum Against cholinergic differentiation factor (also leukemia inhibitory factor; CDF/LIF), but not against ciliary neurotrophic factor, immunoprecipitated this activity. Medium conditioned by sympathetic ganglion explants also contained a VIP-stimulatory molecule that was immunoprecipitated by CDF/LIF antiserum, and CDF/LIF antiserum partially blocked VIP induction in explants. CDF/LIF mRNA was increased in dissociated cell cultures, in ganglion explants and in vivo after axotomy. Our results suggest that CDF/LIF released from ganglionic nonneuronal cells plays an important role in regulating VIP after axotomy. 1994 John Wiley & Sons, Inc. 相似文献
52.
用浅麻醉的Wistar大鼠40只,以辐射热照尾作为伤害性刺激,经玻璃微电极引导尾核痛兴奋神经元(PEN)和痛抑制神经元(PIN)的放电,同时测量甩尾反射潜伏期(TFL)作为甩尾痛阈的指标。结果表明:(1)自然状态下辐射热照尾引起尾核中PEN放电频率增加和PIN放电频率减少与甩尾反射(TF)相伴行。放电变化发生在TF之前,结束在TF之后,PEN和PIN放电变化与TFL呈高度正相关。(2)辐射热照尾同时引起一侧尾核PEN放电频率增加和另一侧PIN放电频率减少,二者协同活动,并发生在TF之前,结束在TF之后。(3)侧脑室注射55μg/10μl吗啡呈镇痛作用时,尾核PEN放电频率减少和PIN放电频率增加,放电变化仍发生在TF之前,结束在TF之后。结果提示,尾核中PEN、PIN放电和TF是中枢不同水平同时对痛觉调制所产生的结果。 相似文献
53.
Zhuang XC Sun YZ Cui J Zhu JM Jiang C Xiang QL Li CS 《Journal of gravitational physiology : a journal of the International Society for Gravitational Physiology》1994,1(1):P61-P63
In the environment of microgravity, the disused atrophy of skeletal muscle, especially leg's muscle, would occur. The three purposes of this study were: 1. To observe the dynamic changes of disused atrophy of skeletal muscle under simulated weightlessness; 2. To approach the mechanism of disused atrophy of muscle; 3. To approach the countermeasures for reducing the degree of atrophy of muscle. 相似文献
54.
55.
环境因子对荒漠沙蜥种群密度影响的研究 总被引:6,自引:1,他引:5
本文研究人类改造荒漠的活动,植被,潜在的可利用的食物资源,竞争种的密度,土壤理化性质等坏境因子对荒漠沙蜥种群密度的影响。结果说明:人类的活动对沙蜥种群密度没有显著影响;决定沙蜥种群密度的主导因子是潜在的可利用的食物资源,植被,土壤含水量,竞争种的密度。这些因子的任何改变都能改变沙蜥的种群密度,均具有调节种群的作用。 相似文献
56.
Helga Seyschab Yujie Sun Richard Friedl Detlev Schindler Holger Hoehn 《Human genetics》1993,92(1):61-68
The predominant cell cycle change induced by X-rays and clastogens in peripheral blood mononuclear cells is the accumulation of cells in the G2 phase of the cell cycle. We show that this accumulation consists of cells that are either delayed or arrested within the G2 phase. Since both X-rays and DNA crosslinking chemicals are known to damage DNA, the G2 phase inhibition caused by these agents is thought to be one of the primary manifestations of (unrepaired) DNA damage. This interpretation is supported by two additional findings. (1) Older individuals have elevated baseline levels of mononuclear blood cells that are delayed and/or arrested in the G2 phase of the cell cycle. This coincides with the increased chromosomal breakage rates reported for older individuals. (2) Irrespective of their age, individuals with inherited genetic instability syndromes (such as Fanconi anemia and Bloom syndrome) exhibit elevated G2 phase cell fractions. We show that the method used to detect such induced or spontaneous cell cycle changes, viz. BrdU-Hoechst flow cytometry, is a rapid and highly sensitive technique for the assessment of genetic cell damage.Dedicated to Professor Ulrich Wolf on the occasion of his 60th birthday 相似文献
57.
本文用ABC—GDN免疫组织化学方法,研究了γ-氨基丁酸(Gamma—Aminobutyric Acid,GABA)在大鼠胰腺的定位和分布,并用相邻切片法,观察它与胰岛素的共存关系。结果发现GABA免疫反应阳性细胞主要分布于胰腺内分泌部(胰岛)。在外分泌部亦有少许分布。大部分胰岛细胞呈GABA免疫反应阳性,集中位于胰岛的中央部。相邻连续切片免疫染色证实GABA与胰岛素共存于胰岛B细胞中。外分泌部胰腺GABA免疫反应阳性细胞,呈零散分布于腺泡和导管上皮间。本文为进一步探讨GABA在胰腺的生理作用提供了形态学依据。 相似文献
58.
The effects of IL-1α and IL-1β on cultured human fetal membranes were studied. These cytokines are known to regulate prostaglandin synthesis by the separated components of the fetal membranes (amnion, chorion and decidua), but their effects on intact tissue are unknown. IL-1α increased PGE2 levels on the fetal side of the membrane, indicating increased production of prostaglandin from the amnion, but had little effect on levels of PGE2 on the maternal side of the membrane. Low levels of IL-1β (0.1 - 1.0 ng/ml) increased PGE2 levels on the fetal side of the meembrane, and also increased the production of PGE2 metabolites and PGF2α, suggesting that this cytokine stimulated the decidua as well as the amnion. High concentrations of both cytokines appeared able to stimulate prostaglandin production by the side of the membrane opposing that to which they were added, but it is not clear whether this was mediated by factors released by the stimulated membrane, or by direct transfer of small quantities of cytokines through the membrane. Taken together, these results indicate that IL-1β was a potent stimulator of the synthesis of prostaglandins by decidua and by amnion, whereas IL-1α only stimulated the amnion. 相似文献
59.
The metabolism of leukotriene B4 (5(S),12(R)-dihydroxy-6-cis-8,10-trans-14-cis-eicosatetraenoic acid) by isolated guinea pig eosinophils was investigated. Incubation of guinea pig eosinophils with [3H]-leukotriene B4 resulted in the rapid conversion of leukotriene B4 to several more polar metabolites. Two of these metabolites were identified by ultraviolet spectroscopy and gas chromatography-mass spectrometry as the omega oxidation products 5(S),12(R),20-trihydroxy-6,8,10,14-eicosatetraenoic acid (20-hydroxy-leukotriene B4) and 5(S),12(R),19-trihydroxy-6,8,10,14-eicosatetraenoic acid (19-hydroxy-leukotriene B4). Two novel metabolites, 5(S),12(R),18,19-tetrahydroxy-6,8,10,14 eicosatetraenoic acid (18,19-dihydroxy-leukotriene B4) and 5(S),12(R)-dihydroxy-1,18-dicarboxylic-6,8,10,14,16-octadecapentaenoic acid (Δ16,17–18-carboxy-19,20-dinor-leukotriene B4) were tentatively identified. The identification of these compounds indicates that guinea pig eosinophils are capable of metabolizing leukotriene B4 by both omega and beta oxidation. This catabolic activity may play a role in modulating inflammatory reactions by removing the chemoattractant leukotriene B4 from inflammatory sites. 相似文献
60.
本文报道在湛江市附近海域海鸟体内获得的两种吸虫,经鉴定为新种,命名为巨口类茎吸虫,新种Microphalloides macrostonrs sp.nov.,珊瑚多黄吸虫,新种Multivitellus coralius sp.nov. 相似文献