| Abstrakt: |
Lipopolysaccharide LPS, which comes from the cell wall of gramnegative bacteria, can stimulate murine macrophage cells to produce nitric oxide NO, cytokines, such as tumor necrosis factoralpha, and interleukins, such as IL6. When examining the biological effects of particles on macrophages, it is important to have no contaminating LPS associated with the particles and none with any cell culture media or supplies since even very low levels of LPS are stimulatory. The presence or absence of LPS was observed in two ways: 1 the amount of NO produced by RAW 264.7 murine macrophage cells, and 2 the Limulus amebocyte lysate LAL test. Treating particles with 70 ethanol at room temperature for 48 h, followed by washing the polymethylmethacrylate PMMA particles with endotoxinfree phosphatebuffered saline three times, decontaminated LPS and LPStreated PMMA particles. When given LPS that had been treated with 70 ethanol for 48 h at room temperature or at 37°C, cells did not produce NO above control levels. Negative LAL tests indicated the presence of extremely low levels or the complete absence of LPS in 70 ethanoltreated LPS. © 1999 John Wiley & Sons, Inc. J Biomed Mater Res, 46, 434–437, 1999. |
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