干细胞迁移机理的近场扫描光学显微术研究

将内皮细胞生长因子(VEGF)置于甲基纤维素碟中形成VEGF的浓度梯度分布,并将人脐带间充质干细胞(Mesenchymal stem cells,MSCs)于此浓度梯度中培养,观察VEGF能否诱导MSCs定向迁移。应用近场扫描光学显微术(Near-field scanning optical microscopy,NSOM)同时获取了VEGF诱导前后的MSCs的形貌和光学信息。结果表明,近场光学图观测到形貌图上所没有的黑色斑点,分析认为这些黑斑为细胞的黏着斑。近场光学图显示经过VEGF诱导后细胞的黏着斑数量明显增加。同时,对诱导前后干细胞的骨架蛋白进行免疫荧光标记并用共聚焦显微镜进行观察,结果表明细胞骨架由诱导前的无序状态转变为诱导后的有序状态,说明诱导后的干细胞处于迁移状态。光学超微结构图则显示了诱导后干细胞表面的光学细节比诱导前细胞大量增加,出现了大量直径约200 nm的光斑,这是由于细胞表面大量分泌黏附分子等蛋白分子引起的,这些结果为VEGF能够诱导MSCs进行定向迁移提供了实验依据和可视化证明。也表明NSOM不但能提供高分辨的光学分辨率,还可提供生物细胞精细结构的更深层次的光学信息。     

载脂蛋白E与阿尔兹海默病的相关研究进展*

载脂蛋白E（Apolipoprotein E,ApoE ）的等位基因ε4是阿尔兹海默病（Alzheimer’s disease,AD）主要的危险遗传因子，它主要与晚发型以及散发型阿尔兹海默病相关。阿尔兹海默病的两个主要病理学特征均被发现与ApoE 有着极为密切的关系。本文介绍了ApoE在阿尔兹海默病中所起的主要作用的研究进展以及目前国内外关于基于ApoE的阿尔兹海默病相关药物研究。     

Significance of plaque morphology in modifying flow characteristics in a diseased coronary artery: Numerical simulation using plaque measurements from intravascular ultrasound imaging

The paper deals with numerical investigation of the effect of plaque morphology on the flow characteristics in a diseased coronary artery using realistic plaque morphology. The morphological information of the lumen and the plaque is obtained from intravascular ultrasound imaging measurements of 42 patients performed at Cleveland Clinic Foundation, Ohio. For this data, study of Bhaganagar et al. (2010) [1] has revealed the stenosis for 42 patients can be categorized into four types – type I (peak-valley), type II (ascending), type III (descending), and type IV (diffuse). The aim of the present study is to isolate the effect of shape of the stenosis on the flow characteristics for a given degree of the stenosis. In this study, we conduct fluid dynamic simulations for the four stenosis types (type I–IV) and analyze the differences in the flow characteristics between these types. Finely refined tetrahedral mesh for the 3-D solid model of the artery with plaques has been generated. The 3-D steady flow simulations were performed using the turbulence (k–ε) model in a finite volume based computational fluid dynamics solver. The axial velocity, the radial velocity, turbulence kinetic energy and wall shear stress profiles of the plaque have been analyzed. From the axial and radial velocity profiles results the differences in the velocity patterns are significantly visible at proximal as well as distal to the throat, region of maximum stenosis. Turbulent kinetic energy and wall shear stress profiles have revealed significant differences in the vicinity of the plaque. Additional unsteady flow simulations have been performed to validate the hypothesis of the significance of plaque morphology in flow alterations in diseased coronary artery. The results revealed the importance of accounting for plaque morphology in addition to plaque height to accurately characterize the turbulent flow in a diseased coronary artery.     

Analysis of differential plaque depositions in the brains of Tg2576 and Tg-APPswe/PS1dE9 transgenic mouse models of Alzheimer disease

Adequate assessment of plaque deposition levels in the brain of mouse models of Alzheimer disease (AD) is required in many core issues of studies on AD, including studies on the mechanisms underlying plaque pathogenesis, identification of cellular factors modifying plaque pathology, and developments of anti-AD drugs. The present study was undertaken to quantitatively evaluate plaque deposition patterns in the brains of the two popular AD models, Tg2576 and Tg-APPswe/ PS1dE9 mice. Coronally-cut brain sections of Tg2576 and Tg-APPswe/PS1dE9 mice were prepared and plaque depositions were visualized by staining with anti- amyloid β peptides antibody. Microscopic images of plaque depositions in the prefrontal cortex, parietal cortex, piriform cortex and hippocampus were obtained and the number of plaques in each region was determined by a computer-aided image analysis method. A series of optical images representing a gradual increase of plaque deposition levels were selected in the four different brain regions and were assigned in each with a numerical grade of 1-6, where +1 was lowest and +6, highest, so that plaques per unit in mm(2) increased "sigmoidally" over the grading scales. Analyzing plaque depositions using the photographic plaque reference panels and a computer-aid image analysis method, it was demonstrated that the brains of Tg2576 mice started to accumulate predominantly small plaques, while the brains of Tg-APPswe/PS1dE9 mice deposited relatively large plaques.     

Recent Development of Active Ingredients in Mouthwashes and Toothpastes for Periodontal Diseases

Periodontal diseases like gingivitis and periodontitis are primarily caused by dental plaque. Several antiplaque and anti-microbial agents have been successfully incorporated into toothpastes and mouthwashes to control plaque biofilms and to prevent and treat gingivitis and periodontitis. The aim of this article was to review recent developments in the antiplaque, anti-gingivitis, and anti-periodontitis properties of some common compounds in toothpastes and mouthwashes by evaluating basic and clinical studies, especially the ones published in the past five years. The common active ingredients in toothpastes and mouthwashes included in this review are chlorhexidine, cetylpyridinium chloride, sodium fluoride, stannous fluoride, stannous chloride, zinc oxide, zinc chloride, and two herbs—licorice and curcumin. We believe this comprehensive review will provide useful up-to-date information for dental care professionals and the general public regarding the major oral care products on the market that are in daily use.     

多孔陶瓷板中城市燃气预混燃烧的试验研究与数值计算

符号表尸可燃混合气体的密度。可燃混合气体的流速。轴向距离。Stefan－Boltzmann常数Tg混合气体的温度R通用气体常数ho多孔陶瓷材料的导热系数DO单元体的内径J单元体的壁厚Tin燃气入口端面的环境温度几单元体的壁温P混合气体压力Te。烟气出口端面的环境温度HO对流换热系数l单元体轴向全长。’积分变量A板面面积。板面孔的数量1引言多孔陶瓷板中的燃气预混燃烧具有热效率高，污染物排放量低的特点，符合九十年代人们对燃烧的要求，因此对多孔陶瓷板中的可燃气体的预混燃烧的研究逐渐成为了国际上的一个热点。目前国内有些厂家己在生产…     

An ALE approach to mechano‐chemical processes in fluid–structure interactions

Mathematical modeling and simulation of fluid–structure interaction problems are in the focus of research already for a longer period. However, taking into account also chemical reactions, leading to structural changes, including changes of mechanical properties of the solid phase, is rather new but for many applications is highly important area. This paper formulates a model system for reactive flow and transport in a vessel system, the penetration of chemical substances into the solid wall. Inside the wall, reactions take place that lead to changes of volume and of the mechanical properties of the wall. Numerical algorithms are developed and used to simulate the dynamics of such a mechano‐chemical fluid–structure interaction problem. As a proof of concept scenario, plaque formation in blood vessels is chosen. The arbitrary Lagrangian Eulerian approach (ALE) is chosen to solve the systems numerically. Temporal discretization of the fully coupled monolithic model is accomplished by backward Euler scheme and spatial discretization by stabilized finite elements. The numerical approach is verified by numerical tests, and effective methods to maintain mesh qualities under large deformations are described. For realistic system parameters, the simulations show that the plaque formation in blood vessel is a long‐time effect. The time scale of the formation is in the simulation of comparable order as in reality. Copyright © 2016 John Wiley & Sons, Ltd.     

CTA成像在下肢血管闭塞病变中的应用及与血管腔内疗效的关系

本文探讨计算机体层扫描血管造影(CTA)检查在下肢血管闭塞病变中的应用价值及与血管腔内疗效的关系。选取经数字减影血管造影(DSA)确诊的93例下肢血管闭塞病变患者,采用CTA检查,分析CTA诊断病变部位结果、血管狭窄程度及与DSA诊断结果的一致性,并探讨CTA征象与患者血管腔内疗效的关系。结果显示,CTA诊断下肢血管闭塞病变部位、狭窄程度与DSA诊断结果均具有较高一致性(P<0.05);病变血管长度>1.41 cm、血管狭窄程度4级、病变血管远端CT值>62.65 Hu、钙化性斑块是下肢血管闭塞病变血管腔内治疗失败的危险因素(P<0.05)。CTA检查是诊断下肢血管闭塞病变的可靠方法,通过检查患者病变血管长度、血管狭窄程度、远端CT值及管腔内粥样斑块性质,有助于降低治疗盲目性,提高血管腔内治疗成功率。     

Synchrotron study of metal localization in Typha latifolia L. root sections

Understanding mechanisms that control plant root metal assimilation in soil is critical to the sustainable management of metal‐contaminated land. With the assistance of the synchrotron X‐ray fluorescence technique, this study investigated possible mechanisms that control the localization of Fe, Cu, Mn, Pb and Zn in the root tissues of Typha latifolia L. collected from a contaminated wetland. Metal localizations especially in the case of Fe and Pb in the dermal tissue and the vascular bundles were different. Cluster analysis was performed to divide the dermal tissue into iron‐plaque‐enriched dermal tissue and regular dermal tissue based on the spatial distribution of Pb and Fe. Factor analysis showed that Cu and Zn were closely correlated to each other in the dermal tissues. The association of Cu, Zn and Mn with Fe was strong in both regular dermal tissue and iron‐plaque‐enriched dermal tissue, while significant (p < 0.05) correlation of Fe with Pb was only observed in tissues enriched with iron plaque. In the vascular bundles, Zn, Mn and Cu showed strong association, suggesting that the localization of these three elements was controlled by a similar mechanism. Iron plaque in the peripheral dermal tissues acted as a barrier for Pb and a buffer for Zn, Cu and Mn. The Casparian strip regulated the transportation of metals from dermal tissues to the vascular bundles. The results suggested that the mechanisms controlling metal localization in root tissues varied with both tissue types and metals.     

Propolis and Diet Rich in Polyphenols as Cariostatic Agents Reducing Accumulation of Dental Plaque

Conducted studies indicate the relationship between oral health and systemic diseases. Moreover, the latest research indicated that cariogenic bacteria may severely influence the course of SARS-CoV-2 infection and increase risk of COVID-19 complications. This article aims to review various applications of propolis and pay attention to a healthy diet rich in polyphenols, which may allow the reduction of dental plaque accumulation. A literature review has been conducted from June until November 2021. It showed that propolis could be a useful agent in decreasing the accumulation of dental plaque. Moreover, a diet rich in polyphenols prevents cariogenic bacteria and reduces the accumulation of dental plaque. A reduction of a dental plaque may influence the risk of a severe course of COVID-19. Therefore, propolis and a diet rich in polyphenols may play an important role in prophylaxis of systemic diseases. Recently, it has been proven that oral infection may affect cardiovascular system, musculoskeletal system, respiratory system, nervous system, as well as may be a risk factor for diabetes mellitus. These aspects should stimulate clinicians to further research about polyphenols.