Electric field-driven fiber formation (electrospinning) is developing into a practical means for preparing novel porous filament with unusual structures and affordable mechanical properties. Polycaprolactone (PCL) was dissolved in solvent mixtures of methylene chloride/N,N-dimethyl formamide with ratios of 100/0, 75/25, and 50/50 (v/v) for electrospinning. The filament was formed by coagulation of the spinning solution following the well-known principle of phase separation in polymer solutions valid in other wet shaping processes. A strand of electrospun porous filament consisted of fibers ranging from 0.5 to 12 m in diameter. To evaluate the feasibility of three-dimensional fabric as scaffold matrices, the plain weave, which is the simplest of the weaves and the most common, was prepared with porous PCL filament. The growth characteristics of MCF-7 mammary carcinoma cells in the woven fabrics showed the important role of matrix microstructure in proliferation. This study has shown that woven fabrics, consisting of porous filaments via electrospinning, may be suitable candidates as tissue engineering scaffolds.

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Antimycin A (AMA), an inhibitor of electron transport in mitochondria, has been used as a reactive oxygen species (ROS) generator in biological systems. Here, we investigated the in vitro effect of AMA on apoptosis in HeLa cells. AMA inhibited the growth of HeLa cells with an IC(50) of about 50 microM. AMA efficiently induced apoptosis, as evidenced by flow cytometric detection of sub-G1 DNA content, annexin V binding assay, and DAPI staining. This apoptotic process was accompanied by the loss of mitochondrial membrane potential (DeltaPsi(m)), Bcl-2 down-regulation, Bax up-regulation, and PARP degradation. All caspase inhibitors used in this experiment, especially pan-caspase inhibitor (Z-VAD), could rescue some HeLa cells from AMA-induced cell death. When we examined the changes of the ROS, H(2)O(2) or O(2) (.-), in AMA-treated cells, H(2)O(2) and O(2) (.-) were markedly increased. In addition, we detected the depletion of GSH content in AMA-treated cells. Pan-caspase inhibitor showing the efficient anti-apoptotic effect significantly reduced GSH depletion by AMA. Superoxide dismutase (SOD) and catalase did not reduce intracellular ROS, but these could strongly rescue the cells from apoptosis. However, these anti-apoptotic effects were not accompanied by the recovery of GSH depletion. Interestingly, catalase significantly decreased the CMF negative (GSH depletion) and propidium iodide (PI) positive cells, indicating that catalase strongly maintained the integrity of the cell membrane in CMF negative cells. Taken together, these results demonstrate that AMA potently generates ROS, induces the depletion of GSH content in HeLa cells, and strongly inhibits the growth of HeLa cells throughout apoptosis.

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We evaluated the antioxidant properties of mulberry leaves extract (MLE) and flavonoids isolated from MLE. MLE was prepared by extraction with methanol. Flavonoids were analyzed by high-performance liquid chromatography. Oxidative hemolysis of normal human red blood cells (RBCs) was induced by the aqueous peroxyl radical [2,2'-Azobis (2-amidinopropane) dihydrochloride, AAPH]. MLE contained three flavonoids in the order quercetin (QC) > kaempferol (KF) > astragalin (AG). Oxidative hemolysis of RBCs induced by AAPH was suppressed by MLE, AG, KF, and QC in a time- and dose-dependent manner. MLE and these three flavonoids prevented the depletion of cystosolic antioxidant glutathione (GSH) in RBCs. AG had the greatest protective effect against AAPH-induced oxidative hemolysis and GSH depletion in RBCs.