In this communication, we report a novel preparation of the helical carbon nanofibril-fabricated thin film from the iodine-doped filmy helical polyacetylene through a carbonization process. Carbonization of the helical polyacetylene films by way of iodine doping is found to afford carbon and graphitic films completely preserving morphologies and even helical nanofibril structures.
The glycocalyx layer on the surface of an endothelial cell is an interface barrier for uptake of macromolecules, such as low-density lipoprotein and albumin, in the cell. The shear-dependent uptake of macromolecules thus might govern the function of the glycocalyx layer. We therefore studied the effect of glycocalyx on the shear-dependent uptake of macromolecules into endothelial cells. Bovine aorta endothelial cells were exposed to shear stress stimulus ranging from 0.5 to 3.0 Pa for 48 h. The albumin uptake into the cells was then measured using confocal laser scanning microscopy, and the microstructure of glycocalyx was observed using electron microscopy. Compared with the uptake into endothelial cells under static conditions (no shear stress stimulus), the albumin uptake at a shear stress of 1.0 Pa increased by 16% and at 3.0 Pa decreased by 27%. Compared with static conditions, the thickness of the glycocalyx layer increased by 70% and the glycocalyx charge increased by 80% at a shear stress of 3.0 Pa. The albumin uptake at a shear stress of 3.0 Pa for cells with a neutralized (no charge) glycocalyx layer was almost twice that of cells with charged layer. These findings indicate that glycocalyx influences the albumin uptake at higher shear stress and that glycocalyx properties (thickness and charge level) are involved with the shear-dependent albumin uptake process. blood flow; shear stress; glycocalyx charge; glycocalyx thickness; in vitro model ATHEROSCLEROTIC LESIONS appear in regions of low shear stress in relatively large arteries, such as the carotid bifurcation and the coronary artery (3). Atherosclerosis is initiated by the uptake of low-density lipoprotein (LDL) (24), which is highly associated with hemodynamic stress. Some studies demonstrate that the transport of macromolecules such as albumin across the cell membrane is strongly affected by the shear stress on endothelial cells (17,27). Kudo et al. (11,12) measured the effect of shear stress on albumin uptake into endothelial cells in vitro and reported an increased uptake at lower shear stress and a decreased uptake at higher shear stress. However, the mechanism of this biphasic response of uptake remains unclear.The endothelial cell surface is characterized by various extracellular domains of membrane-bound molecules, the glycocalyx (20), which can sense the shear force of flowing blood (9, 15). Luft (14) visualized the endothelial glycocalyx layer in vitro using ruthenium red staining in an electron microscopic study and found that the glycocalyx layer is about 20 nm thick. Subsequent in vitro electron microscopic observations of the molecules revealed that the glycocalyx thickness is Ͻ100 nm (26). In vivo studies (19, 21) have revealed thicker glycocalyx layers ranging from 0.5 m to over 1.0 m. This difference in thickness is due to the preparation and staining techniques, which cause the collapse of the glycocalyx structures (14,20,32,33).The glycocalyx surface forms a complex three-dimensional array of soluble plasma components, including ...
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