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101.
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Yi-Fei Zhang Jing-Jing Guo Fan Yang Hang-Yu Zhou Na-Na Zhang Xiao-Chuan Xiong Yue Feng Yong-Qiang Deng Cheng-Feng Qin 《Journal of medical virology》2023,95(1):e28290
The geographic range of Zika virus (ZIKV) has expanded from Asia to the Americas, leading to the 2015–2016 pandemic with enhanced neurovirulence. At present, ZIKV is continuously circulating in many Southeast Asian countries. Unfortunately, the persistent evolution of ZIKV in Southeast Asia and its influence on the biological characteristics of the virus remain incompletely understood. In this study, the in vitro and in vivo properties of a new ZIKV isolate obtained from Cambodia in 2019 (CAM/2019) were characterized and compared with those of the Cambodian strain (CAM/2010). Compared with CAM/2010, the CAM/2019 virus showed similar plaque morphology and growth curves in cell cultures and induced comparable viremia and organ viral loads profiles in both BALB/c and A129 (IFNAR1−/−) mice upon intraperitoneal (i.p.) inoculation. Remarkably, the CAM/2019 virus exhibited enhanced neurovirulence in neonatal mice compared with CAM/2010, with a 74-fold reduction in the 50% lethal dose (LD50). Consistently, CAM/2019 produced higher viral loads in the brains of BALB/c neonatal mice than CAM/2010 did. Sequence alignment showed that the CAM/2019 virus has acquired 12 amino acid substitutions, several of which were found to be associated with neurovirulence. In particular, the CAM/2019 virus shared an A1204T substitution in NS2A with the Thai isolate SI-BKK02 that was isolated from a microcephaly case. Taken together, our results indicate that a ZIKV strain isolated with specific mutations has emerged in Cambodia, highlighting the need for extensive molecular and disease surveillance in Cambodia and other Asian countries. 相似文献
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Xin Sun Yunfeng Guo Shengdu Yang Kai Wang Lan Xie Bai Xue 《Macromolecular chemistry and physics.》2023,224(15):2300072
The poly(l -lactic acid) (PLLA)/carbon nanomaterials composite foams with hierarchical surface microstructural and internal conductive pathways are successfully prepared by a simple crystallization-assisted rapid phase separation (CARPS). The dimension and morphology of carbon nanomaterials can induce different crystallization forms to construct the hierarchical surface microstructure, and they are distributed on the phase interface of solvent and non-solvent to form conductive pathways. It is found that the heterogeneous nucleation of nanomaterials promotes a significant increase in crystallinity, and a stacked granular structure formed on the surface promotes the increase of the water contact angle to 148.7°. Foams with interconnecting pore structures contribute to the formation of 85.3% porosity and 12.33 g g−1 oil absorption. Carbon nanomaterials are distributed on the pore walls of the porous foam, which converts the foam from an insulating material to a conducting polymer. Furthermore, the uniform distribution of nanomaterials significantly affects the thermal stability of the PLLA. In belief, the multifunctional biodegradable foam, prepared by a CARPS method, makes it promising for industrial production and has potential applications in electrical conductivity, oil-water separation, and many other fields. 相似文献
106.
Purification of thrombospondin from human platelets 总被引:1,自引:0,他引:1
Summary Thrombospondins are a rapidly growing family of adhesive proteins that have diverse activities to modulate cellular growth, motility, and gene expression. Thrombospondin-1 (TSP) was the first identified member of this family and is the major form of thrombospondin in human platelets. A method is described to prepare TSP from human platelets in biologically active form with minimal degradation or contamination with other platelet proteins. 相似文献
107.
N. Singewald F. Chen L. J. Guo A. Phillippu 《Naunyn-Schmiedeberg's archives of pharmacology》1995,352(6):620-625
The push-pull technique was used to investigate the release of the excitatory amino acid glutamate in the posterior hypothalamic area of the conscious rat. The hypothalamus was superfused through the pushpull cannula with artificial cerebrospinal fluid (CSF), and the superfusate was collected in time periods of 10 min when ionic conditions in the CSF were changed, or in short periods of 3 min when blood pressure changes were evoked. The mean glutamate release rate was 2.8 + 0.7 pmol/min. Depolarization by hypothalamic superfusion with CSF containing 50 mM K+ enhanced the release of glutamate in the presence of Ca2+. The K+-induced release was attenuated by 40% when the hypothalamus was superfused with Ca2+-free CSF. Replacement of Ca2+ by Mg2+ abolished the K+-induced release of glutamate. Hypovolaemia elicited by haemorrhage enhanced the release rate of glutamate. Similarly, a hypotension elicited by i.v. injection of chlorisondamine (3 mg/kg) led to a pronounced and permanent enhancement in glutamate release. The effects of hypovolaemia and chlorisondamine on glutamate release were abolished in aortic denervated rats, indicating that this response is due to a decrease of impulse generation in baroreceptors. A hypovolaemia elicited by blood infusion did not affect the release of glutamate. Similarly, a pronounced pressor response to phenylephrine (15 /kg per minute) infused intravenously for 9 min was ineffective.The results show that the K+-induced release of glutamate in the hypothalamus is dependent on the presence of Ca2+. The increase in glutamate release rate by hypovolaemia or chlorisondamine suggests that the glutamatergic neurons in the posterior hypothalamic area respond to unloading of aortic baroreceptors and possess a counteracting, hypertensive function. 相似文献
108.
目的 探讨上海市≥50岁人群维生素D水平与握力的关系。方法 数据来源于WHO全球老龄化与成人健康研究我国上海市2018-2019年数据,采用logistic回归模型分析维生素D水平与握力的关系,进一步按照性别、年龄及乳制品摄入情况进行分层;采用限制性立方样条曲线绘制维生素D水平与低握力的剂量-反应曲线。结果 共4 391人纳入研究,其中男性2 054人(46.8%);年龄(67.02±8.81)岁;低握力1 421人(32.4%);维生素D不足及缺乏分别为1 533人(34.9%)和401人(9.1%)。在调整相关混杂因素后,logistic回归分析结果显示,维生素D缺乏的人群发生低握力的风险更高(OR=1.41,95%CI:1.09~1.83);在男性中,调整相关混杂因素后,维生素D缺乏与低握力发生风险呈显著正相关(OR=1.67,95%CI:1.12~2.50),而女性中两者之间无关联(OR=1.30,95%CI:0.97~1.74);在60~69岁及≥80岁年龄组中,调整相关混杂因素后,维生素D缺乏与低握力发生风险呈显著正相关(OR=1.57,95%CI:1.05~2.35;OR=2.40,95%CI:1.08~5.31),在乳制品摄入<250 ml/d的人群中,调整相关混杂因素后,二者之间呈显著正相关(OR=1.57,95%CI:1.17~2.09),而在乳制品摄入≥250 ml/d的人群中无明显关联。限制性立方条样图显示,低握力的发生风险可能随维生素D含量的上升而降低,但差异无统计学意义(P>0.05)。结论 维生素D水平与握力存在一定的关系,维生素D缺乏人群出现低握力的风险更高。 相似文献
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以对氨基苯磺酸修饰聚乙二醇端头,制备兼具刚性与极性端头的聚合物,考察其制备LB膜与自组装膜的条件,用原子力/摩擦力显微镜表征自组装膜的表面形貌,对其微摩擦性能进行初步的探讨。 相似文献