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Phosphatidylserine: selective enhancer of histamine release   总被引:15,自引:0,他引:15  
Phosphatidylserine, in contrast with other phospholipids, markedly enhanced histamine release from rat peritoneal mast cells induced by dextran or protein antigens. This enhancing effect was selective for dextran and protein antigens and did not extend to the action of compound 48/80 or chymotrypsin. These findings suggest a role for phosphatidylserine in the response of mast cells to antigens.  相似文献   

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Extracellular histamine stimulates accumulation of adenosine 3',5'-monophosphate in human leukocytes and prevents antigenic release of histamine from cells of allergic donors. Both effects occur at histamine concentrations that can be achieved by antigenic release of the amine in vitro.  相似文献   

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The first attempt to exploit deep-sea manganese nodules ended in failure as a result of the collapse of world metal prices, the onerous provisions imposed by the U. N. Conference on the Law of the Sea (UNCLOS), and the overoptimistic assumptions about the viability of nodule mining. Attention then focused on cobalt-rich manganese crusts from seamounts. Since the mid-1980s, a number of new players have committed themselves to long-term programs to establish the viability of mining deep-sea manganese nodules. These programs require heavy subsidy by host governments. Gold-rich submarine hydrothermal deposits located at convergent plate margins are now emerging as a more promising prospect for mining than deep-sea manganese deposits.  相似文献   

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The anterior cingulate cortex (ACC) and the related medial wall play a critical role in recruiting cognitive control. Although ACC exhibits selective error and conflict responses, it has been unclear how these develop and become context-specific. With use of a modified stop-signal task, we show from integrated computational neural modeling and neuroimaging studies that ACC learns to predict error likelihood in a given context, even for trials in which there is no error or response conflict. These results support a more general error-likelihood theory of ACC function based on reinforcement learning, of which conflict and error detection are special cases.  相似文献   

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Bilateral ablation of dorsolateral frontal cortex in the newborn animal failed to produce the frontal lobe syndrome typical of the adolescent and adult stages. The crucial tests (delayed response, string tests, and discrimination learning) were performed 3 to 4 months postoperatively. At this time, no significant differences between normal animals and animals with prefrontal lesions were found.  相似文献   

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学报编辑的职业道德直接影响学报出刊质量。编辑的职业道德包括爱岗敬业、对读者负责、爱护支持作者、提高自身素质和具有团队合作精神等。作为学报编辑,要恪守职业道德,积极主动工作、开放式工作、提高效率等。  相似文献   

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Nuclear localization of histamine in neonatal rat brain   总被引:6,自引:0,他引:6  
The concentration of histamine in the brains of neonatal rats is considerably higher than that in adults. Subcellular fractionation studies revealed that about 90 percent of the histamine content of neonatal rat brain is confined to the crude nuclear fraction obtained by differential fractionation. Purified nuclei prepared from these fractions retained 90 percent of their histamine content. The nuclear localization of histamine in the brains of neonatal rats suggests a function for histamine in modulating the growth processes of the neonatal brain.  相似文献   

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Administration of methamphetamine or amphetamine to rats and mice produces a rapid increase in the level of immunoassayable plasma insulin not attributable to hyperglycemia. While in the mouse this release of insulin is followed consistently by a profound hypoglycemia, in the rat this response is variable. Studies in vitro demonstrate that insulin is released by a direct effect of methamphetamine on the pancreas.  相似文献   

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在室内恒温(18℃)条件下,较为系统地研究了几种CO2颗粒肥的释放动态,结果表明,①广丰产有机CO2缓释颗粒肥的CO2释放量明显优于某地产的CO2气肥;广丰产有机CO2缓释颗粒肥存放1年后对CO2释放量并无影响。②广丰有机CO2缓释颗粒肥的基质,虽然也能释放CO2,但释放总量明显降低。③土壤干燥及低温会降低CO2的释放量。  相似文献   

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A group of pigeons that had previously received noncontingent food delivery acquired the key-peck response (in autoshape training) more slowly than did a naive control group; key-peck acquisition was most rapid for a group given operant treadle-press training in the initial phase.  相似文献   

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采用瞬间液晶模板法一步制备负载啶虫脒/F127(分子式为(EO)106(PO)70(EO)106)的介孔硅(Mesoporous silica).利用红外光谱法(Fourier transform infrared spectroscopy,FTIR)、差式扫描量热法(Differential scanning calorimeter,DSC)、扫描电镜(Scanning electron microscope,SEM)、电子显微镜(Transmission electron microscope,TEM)和氮气吸附脱附法(Brunauer-Emmett-Teller,BET)对介孔硅的结构进行了表征,并探究了载药介孔硅的释药行为.结果表明,啶虫脒成功负载于介孔硅且以非晶相存在于介孔硅中.介孔硅在水平方向上呈高度结晶的片状结构,且属于IM-3M结构.去除模板剂后的介孔硅均呈现出典型的Ⅳ型特征和笼状孔道结构;孔径分布于3~4 nm之间,具有均一的介孔孔道.载药介孔硅的药物释放曲线动力学拟合模型与Korsmeyer-Peppas模型较为符合.  相似文献   

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Lectin is released from soybean seeds during water uptake. Hemagglutination activity data show that the lectin is a preferential release product within the first 8 hours of hydration. A qualitative filter-paper assay for detection of lectin released by single seeds is used to show that the release phenomenon is independent of seed viability and insensitive to azide.  相似文献   

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