970 resultados para Basic research


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The objective of this study was to investigate juvenile rhesus monkeys responding to various gonadotropin regimen Stimulations. Thirty-two prepubertal rhesus monkeys were randomly allocated into five groups for ovarian stimulation as follows: Groups I, II

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D-Serine, the endogenous coagonist of N-methyl-D-aspartate receptors (NMDARs), is considered to be an important gliotransmitter, and is essential for the induction of long-term potentiation. However, less is known about the role of D-serine in another for

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Fourteen new lignans, tiegusanins A-N (1-14), together with 13 known compounds were isolated from the aerial parts of Schisandra propinqua var. sinensis. The structures and absolute configurations of 1-13 were established using a combination of spectrosco

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The 70% EtOH extract of Polygonum cuspidatum showed inhibitory action against HIV-1-induced syncytium formation at non-cytotoxic concentrations in vitro with a 50% effective concentration (EC50) of 13.94 +/- 3.41 mu g/mL. Through bioactivity-guided fractionation, 20 phenolic compounds, including eight stilbenoids, were isolated from the roots of Polygonum cuspidatum, and their anti-HIV-1 activities were evaluated. Results showed that compounds 1, 13, 14, and 16 demonstrated fairly strong antiviral activity against HIV-1-induced cytopathic effects in C8166 lymphocytes at non-cytotoxic concentrations, with EC50 values of 4.37 +/- 1.96 mu g/mL, 19.97 +/- 5.09, 14.4 +/- 1.34 mu g/mL, and 11.29 +/- 6.26 mu g/mL and therapeutic index (TI) values of 8.12, > 10.02, > 13.89, and > 17.71, respectively. Other compounds showed either weak or no effects. Compound 6 also showed weak inhibition (153.42 +/- 19.25 mu g/mL); however, it possesses very good water solubility and showed almost no cytotoxicity (> 2000 mu g/mL), therefore achieving a fairly good TI (13.04). The activities of the two compounds (3 and 18) from Polygonum multiflorum were also assayed. The relationship between molecular structures and their bioactivities was also discussed.

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Three new dibenzocyclooctadiene lignans, wilsonilignans A-C (1-3), together with nine known ones, were isolated from the fruits of Schisandra wilsoniana. The structures of 1-3 were elucidated by spectroscopic methods including extensive 1D and 2D NMR techniques. Compounds 1-3 were also evaluated for their anti-HIV-1 activities and showed bioactivity with EC50 values of 3.26, 6.18, and 2.87g/ml, respectively.

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为研究氟代柠檬酸(Fluorocitrate)对体外培养的神经胶质瘤细胞生长的影响,采用MTT法研究不同的氟代柠檬酸浓度(0.0025mmol/L,0.005mmol/L,0.01 mmol/L,0.025mmol/L和0.1 mmol/L)和作用时间(36h,48h和60h)对神经胶质瘤细胞G422增殖的影响.结果发现:(1)氟代柠檬酸可抑制G422细胞的增殖,并且其抑制作用随氟代柠檬睃浓度的增加而增强;(2)高浓度(0.01 mmol/L,0.025 mmol/L和0.1 mmol/L)氟代柠檬酸对G422细胞的增殖抑制作用随作用时问的延长而增强:(3)低浓度(0.0025mmol/L和0.005mmol/L)氟代柠檬酸对G422细胞的增殖抑制作用不随作用时间的延长而改变.实验表明,氟代柠檬酸能够抑制神经胶质瘤细胞的增殖,其抑制能力随氟代柠檬酸浓度的增加和作用时间的延长而加强.

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眶额叶皮质与中脑边缘多巴胺奖赏系统有着复杂的相互纤维联系.先前的研究探讨了药物成瘾过程中眶额叶皮质的脑电活动.在本实验中,将探讨食物奖赏和渴求过程中该皮质的脑电活动.实验采用了两个环境:对照环境和食物刺激相关的环境.首先,训练大鼠在食物刺激相关的环境中吃巧克力花生豆,而后在该环境中设置两种不同的刺激方式:能看到和闻到但不能吃到(渴求实验),或者仍旧可以吃到巧克力花生豆(奖赏实验):同时进行左侧眶额叶皮质的脑电记录.结果发现,在食物刺激相关的环境中大鼠Delta频段(2-4Hz)的脑电活动与食物刺激显著相关,此外,与在对照环境中相比,其相对功率在食物渴求时下降而在食物奖赏时升高.本实验表明,食物相关的奖励可以改变大鼠眶额叶皮质的脑电活动,而且,Delta频段的脑电活动能够作为监测该奖励的一个指标.

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在认知神经科学研究中,Go/NoGo模型是一种非常有效的研究方法。在本试验中,以两只猕猴为研究对象,采用Go/NoGo模型,以不同的视觉线索作为刺激来研究相关认知行为。结果表明猕猴能够很快学会Go/NoGo视觉分辨任务,而且对NoGo任务的完成要优于对Go任务的完成。本实验建立了一种有效的猕猴Go/NoGo视觉分辨实验的方法及计算机控制系统,为进一步记录神经元活动建立了良好的基础。

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In most studies regarding the improving or therapeutical effects induced by enriched environment (EE), EE was performed after the stress treatment or in patients with certain diseases. In the current study, the effects of chronic restraint stress (6 h/day) in mice living in an enriched environment or standard environment (SE) were tested. Mice were randomly divided into 4 groups: non-stressed or stressed mice housed in SE or EE conditions (SE, stress + SE, EE, stress + EE). Prepulse inhibition (PPI) of startle was tested after the 2 weeks or 4 weeks stress and/or EE treatment and 1 or 2 weeks withdrawal from the 4 weeks treatment. After the 4 weeks treatment, spatial recognition memory in Y-maze was also tested. The results showed that EE increased PPI in stressed and non-stressed mice after 2 weeks treatment. No effect of EE on PPI was found after the 4 weeks treatment. 4 weeks chronic restraint stress increased PPI in mice housed in standard but not EE conditions. Stressed mice showed deficits on the 1 h delay version of the Y-maze which could be prevented by living in an enriched environment. Our results indicated that living in an enriched environment reversed the impairing effects of chronic restraint stress on spatial recognition memory. However, EE did not change the effects of stress on PPI. (C) 2010 Elsevier B.V. All rights reserved.

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According to Chen's theory, topological differences are perceived faster than feature differences in early visual perception. We hypothesized that topological perception is caused by the sensitivity in discriminating figures with and without "holes". An E

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Human perception of speed declines with age. Much of the decline is probably mediated by changes in the middle temporal (MT) area, an extrastriate area whose neural activity is linked to the perception of speed. In the present study, we used random-dot pa

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Special thanks to Christopher Blair and Mumtaz Baig for their suggestions. This work was supported by National Basic Research Program of China (973 Program, 2007CB411600), National Natural Science Foundation of China (30621092), and Bureau of Science and Technology of Yunnan Province.

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Geographic variation of Chevrier's field mouse (Apodemus chevrieri) (Milne-Edwards, 1868) (Muridae: Murinae) from southwestern China based on cranial morphometric variables. Zoological Studies 47(4): 393-401. A sample of 134 specimens of Apodemus chevrieri was investigated in the present study. Individuals were divided into male and female groups, and these were respectively subjected to multivariate analysis. Results indicated that 3 geographic populations of A. chevrieri inhabit southwestern China: a Sichuan population in western Sichuan Province; a northwestern Yunnan population ranging from northwestern Yunnan Province eastward to southern Sichuan Province; and a central Yunnan population in central Yunnan Province. In addition, a coefficient of difference analysis was performed among these 3 geographic populations. The results suggested that these 3 geographical populations of A. chevrieri belonged to 2 subspecies. Furthermore, we discuss the relationships of the subspecific differentiation of A. chevneri with changes in latitude in southwestern China.

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We used data on loud duetted and solo songs collected from one habituated polygynous group of black-crested gibbons (Nomascus concolor jingdongensis) on Mt. Wuliang, Yunnan, to test several hypotheses about the functions of these songs. The major function

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A new species of horseshoe bat (Chiroptera: Rhinolophidae) is described from southwestern China. The presence of a wedge-shaped sella and pointed connecting process of the nose leaf aligns the new species to the landeri group in the Afro-Palearctic lineag