Many in vitro studies focus on effects of wall shear stress (WSS) and wall shear stress gradient (WSSG) on endothelial cells, which are linked to the initiation and progression of atherosclerosis in the arterial syste...Many in vitro studies focus on effects of wall shear stress (WSS) and wall shear stress gradient (WSSG) on endothelial cells, which are linked to the initiation and progression of atherosclerosis in the arterial system. Limitation in available flow chambers with a constant WSSG in the testing region makes it difficult to quantify cellular responses to WSSG. The current study proposes and characterizes a type of converging parallel plate flow chamber (PPFC) featuring a constant gradient of WSS. A simple formula was derived for the curvature of side walls, which relates WSSG to flow rate (Q), height of the PPFC (h), length of the convergent section (L), its widths at the entrance (w0) and exit (w1). CFD simulation of flow in the chamber is carried out. Constant WSSG is observed in most regions of the top and bottom plates except those in close proximity of side walls. A change in Q or h induces equally proportional changes in WSS and WSSG whereas an alteration in the ratio between w0 and w1 results in a more significant change in WSSG than that in WSS. The current design makes possible an easy quantification of WSSG on endothelial cells in the flow chamber.展开更多
Objective To investigate in vitro cytotoxicity and oxidative stress response induced by multiwalled carbon nanotubes （MWCNTs）. Methods Cultured macrophages （murine RAW264.7 cells） and alveolar epithelium cells typ...Objective To investigate in vitro cytotoxicity and oxidative stress response induced by multiwalled carbon nanotubes （MWCNTs）. Methods Cultured macrophages （murine RAW264.7 cells） and alveolar epithelium cells type II （human A549 lung cells） were exposed to the blank control, DNA salt control, and the MWCNTs suspensions at 2.5, 10, 25, and 100 ug/mL for 24 h. Each treatment was evaluated by cell viability, cytotoxicity and oxidative stress. Results Overall, both cell lines had similar patterns in response to the cytotoxicity and oxidative stress of MWCNTs. DNA salt treatment showed no change compared to the blank control. In both cell lines, significant changes at the doses of 25 and 100 ug/mL treatments were found in cell viabilities, cytotoxicity, and oxidative stress indexes. The reactive oxygen species （ROS） generation was also found to be significantly higher at the dose of 10 ug/mL treatment, whereas no change was seen in most of the indexes. The ROS generation in both cell lines went up in minutes, reached the climax within an hour and faded down after several hours. Conclusion Exposure to MWCNTs resulted in a dose-dependent cytotoxicity in cultured RAW264.7 cells and A549 cells, that was closely correlated to the increased oxidative stress.展开更多
Resurrection fern has a unique ability to maintain cell wall integrity when the plant cell is desiccated. It uses proteins such as late embryogenesis proteins and heat shock proteins to maintain their cellular functio...Resurrection fern has a unique ability to maintain cell wall integrity when the plant cell is desiccated. It uses proteins such as late embryogenesis proteins and heat shock proteins to maintain their cellular functions. The purpose of this experiment is to determine the effects of environmental stressors on the physiological response of the resurrection fern (Pleopeltis polypodioides). The physiological response of resurrection fern plants was subjected to various temperatures (-50°C, 0°C, 25°C, and 50°C) for 7 days. Results indicated that there was a significant difference between hydrated and desiccated ferns based on the temperature. Additionally, electrolyte leakage measurements confirmed cell damage following exposure to temperature extremes of -50°C and 50°C.展开更多
Hydroxylated multi-walled carbon nanotubes(h-MWCNTs) and carboxylated MWCNTs(c-MWCNTs)have potential applications in biomedicine, but their toxicity to human endothelial cells under stressed conditions associated with...Hydroxylated multi-walled carbon nanotubes(h-MWCNTs) and carboxylated MWCNTs(c-MWCNTs)have potential applications in biomedicine, but their toxicity to human endothelial cells under stressed conditions associated with chronic diseases was less studied in vitro. This study stressed human umbilical vein endothelial cells(HUVECs) with ER stress inducer thapsigargin(TG), and investigated the toxicity of h-MWCNTs and c-MWCNTs to normal and stressed HUVECs. h-MWCNTs and c-MWCNTs modestly reduced cellular viability, significantly promoted soluble ICAM-1(sICAM-1),soluble VCAM-1(sVCAM-1) as well as intracellular ROS, and decreased the expression of transcription factor KLF2 and KLF4. Pre-treatment with TG significantly reduced cellular viability, promoted IL-6 and THP-1 monocyte adhesion, and increased the expression of a panel of ER stress genes. ANOVA indicated no interaction between MWCNTs and TG pre-treatment on most of the endpoints. It was concluded that the toxicity of h-MWCNTs and c-MWCNTs to HUVECs might not be exacerbated by ER stress展开更多
文摘Many in vitro studies focus on effects of wall shear stress (WSS) and wall shear stress gradient (WSSG) on endothelial cells, which are linked to the initiation and progression of atherosclerosis in the arterial system. Limitation in available flow chambers with a constant WSSG in the testing region makes it difficult to quantify cellular responses to WSSG. The current study proposes and characterizes a type of converging parallel plate flow chamber (PPFC) featuring a constant gradient of WSS. A simple formula was derived for the curvature of side walls, which relates WSSG to flow rate (Q), height of the PPFC (h), length of the convergent section (L), its widths at the entrance (w0) and exit (w1). CFD simulation of flow in the chamber is carried out. Constant WSSG is observed in most regions of the top and bottom plates except those in close proximity of side walls. A change in Q or h induces equally proportional changes in WSS and WSSG whereas an alteration in the ratio between w0 and w1 results in a more significant change in WSSG than that in WSS. The current design makes possible an easy quantification of WSSG on endothelial cells in the flow chamber.
基金supported partly by a grant from Shanghai Science and Technology Committee International Collaboration Program (Project No. 055207078)
文摘Objective To investigate in vitro cytotoxicity and oxidative stress response induced by multiwalled carbon nanotubes （MWCNTs）. Methods Cultured macrophages （murine RAW264.7 cells） and alveolar epithelium cells type II （human A549 lung cells） were exposed to the blank control, DNA salt control, and the MWCNTs suspensions at 2.5, 10, 25, and 100 ug/mL for 24 h. Each treatment was evaluated by cell viability, cytotoxicity and oxidative stress. Results Overall, both cell lines had similar patterns in response to the cytotoxicity and oxidative stress of MWCNTs. DNA salt treatment showed no change compared to the blank control. In both cell lines, significant changes at the doses of 25 and 100 ug/mL treatments were found in cell viabilities, cytotoxicity, and oxidative stress indexes. The reactive oxygen species （ROS） generation was also found to be significantly higher at the dose of 10 ug/mL treatment, whereas no change was seen in most of the indexes. The ROS generation in both cell lines went up in minutes, reached the climax within an hour and faded down after several hours. Conclusion Exposure to MWCNTs resulted in a dose-dependent cytotoxicity in cultured RAW264.7 cells and A549 cells, that was closely correlated to the increased oxidative stress.
文摘Resurrection fern has a unique ability to maintain cell wall integrity when the plant cell is desiccated. It uses proteins such as late embryogenesis proteins and heat shock proteins to maintain their cellular functions. The purpose of this experiment is to determine the effects of environmental stressors on the physiological response of the resurrection fern (Pleopeltis polypodioides). The physiological response of resurrection fern plants was subjected to various temperatures (-50°C, 0°C, 25°C, and 50°C) for 7 days. Results indicated that there was a significant difference between hydrated and desiccated ferns based on the temperature. Additionally, electrolyte leakage measurements confirmed cell damage following exposure to temperature extremes of -50°C and 50°C.
基金financially supported by College Outstanding Young and Middle-aged Innovative Research Team Project of HubeiProvince (No. T201717)the Health and Family Planning Commission Scientific Research Project of Hubei Province (No. WJ2017Z027)
文摘Hydroxylated multi-walled carbon nanotubes(h-MWCNTs) and carboxylated MWCNTs(c-MWCNTs)have potential applications in biomedicine, but their toxicity to human endothelial cells under stressed conditions associated with chronic diseases was less studied in vitro. This study stressed human umbilical vein endothelial cells(HUVECs) with ER stress inducer thapsigargin(TG), and investigated the toxicity of h-MWCNTs and c-MWCNTs to normal and stressed HUVECs. h-MWCNTs and c-MWCNTs modestly reduced cellular viability, significantly promoted soluble ICAM-1(sICAM-1),soluble VCAM-1(sVCAM-1) as well as intracellular ROS, and decreased the expression of transcription factor KLF2 and KLF4. Pre-treatment with TG significantly reduced cellular viability, promoted IL-6 and THP-1 monocyte adhesion, and increased the expression of a panel of ER stress genes. ANOVA indicated no interaction between MWCNTs and TG pre-treatment on most of the endpoints. It was concluded that the toxicity of h-MWCNTs and c-MWCNTs to HUVECs might not be exacerbated by ER stress
