Independent motile microplast formation correlates with glioma cell invasiveness

Diffuse brain invasion co ntributes to the poor prognosis for patients with gliomas. Analyzing glioma cell migration in vitro, we have demonstrated the spontaneous shedding of anucleate cell fragments that separate from glioma cell bodies and maintain viability from hours to days. Unlike previously described cell fragments that are released from cells as diffusible vectors, glioma cell fragments are independently motile. We used computerized time-lapse microscopy to characterize the formation of these independent motile microplasts (IMMPs) in human cell cultures derived from the most highly invasive glial tumor, glioblastoma. IMMPs were larger than previously described cell fragments, ranging in size from approximately 2% to nearly half of the area of their parent cells. Complex cell-like behaviors—including establishment of polarity, extension of lamellipodia and filopodia, and change in direction of movement—remained intact in IMMPs. The average direction and velocity of the IMMPs were indistinguishable from those of their parent cells. IMMPs formed at a significantly higher rate in glioma cell lines rendered more invasive by overexpression of invasion-related genes than in vector-transfected controls. The correlation with cell invasiveness indicates that IMMP formation may be related to the cell-invasive phenotype. Further investigation will determine whether IMMPs represent a novel addition to the growing list of viable cell fragments with biological relevance. Electronic Supplementary Material Supplementary material is available to authorised users in the online version of this article at .     

单微颗粒在血管内运动状态的力学分析

目的分析单个微颗粒在血管内的受力情况及影响其运动状态的因素。方法以靶向给药中血管流体中的微颗粒为研究对象,将血管模型简化成平行平板流动腔内的泊肃叶流动,依次分析单个微颗粒在流场中所受各个力的具体计算方法,通过力与力矩平衡条件列出微颗粒运动状态的方程,利用数值计算方法得到微颗粒所受力与颗粒粒径、流体流量之间的关系以及临界运动状态时粒径与流量的关系。结果流量增加和微颗粒粒径越大,微颗粒越容易滚动、滑移和上升;在流量和粒径关系图上,上升运动的临界线要高于滑移运动的临界线,而滚动运动临界线处于最下方。结论对于人体血液流量,微颗粒不会做上升运动。随着流量减少,一定粒径的颗粒可以从滑移运动过渡到纯滚动运动,在有弹性变形的情形下会出现完全静止。恰当选择颗粒的粒径及颗粒的表面黏附度对药物颗粒通过血液输送到达标靶位置至关重要。