EXPERIMENTAL CONDITIONS FOR USE OF NITROXIDES IN CELL STUDIES

细胞氧和氮氧代谢的EPR研究通常 涉及多种实验条件，包括不同的 样品制备、细胞浓度和光谱仪 设置. 所得光谱的后处理也不同 大大 在这里，我们表明，实验条件可以影响 结果往往出乎意料。 我们提供的数据的影响， 细胞密度、细胞浴培养基类型和氮氧化物浓度 在样品中，功率水平和调制强度设置 光谱仪，对氧和氮氧化物的消耗结果。 我们 我还比较了从简单的线高测量中获得的信息 利用从最小二乘光谱模拟获得的信息 技术. 我们最一致的结果是在低（105 细胞/ml或更低）细胞密度，培养基单独不降低 氮氧化物，低（0.1mW）功率，调制水平适合良好 (100：1或更好）的信噪比，并通过快速 结合Levenberg-Marquard优化的卷积算法 (for测定氧和氮氧浓度）。

EPR studies of cellular oxygen and nitroxide metabolism often involve a variety of experimental conditions including different sample preparations, cellular concentrations, and spectrometer settings. Post-processing of the resulting spectra also varies greatly. Here, we show that experimental conditions can affect results often in unexpected ways. We present data on the effects of cell density, type of cell bathing media, and nitroxide concentration in the sample, and power levels and modulation intensity setting of the spectrometer, on oxygen and nitroxide consumption results. We also compare information obtained from simple line height measurements with information obtained from least-squares spectral simulation techniques. Our most consistent results are obtained at low (105 cells/ml or less) cell density, media which alone does not reduce nitroxides, low (0.1mW) power, modulation levels appropriate for good (100:1 or better) signal-to-noise, and lineshape analysis by a fast convolution algorithm combined with Levenberg-Marquard optimization (for determining oxygen and nitroxide concentrations).