Quan Zhe, Purser Christine, Baker Rodney C, Dwyer Terry, Bhagat Rajesh, Sheng Yinghong, Leszczynski Jerzy R
Department of Pharmacology and Toxicology, The University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 39216, USA.
J Chromatogr Sci. 2010 Feb;48(2):140-4. doi: 10.1093/chromsci/48.2.140.
Elevation in one or more compounds in exhaled breath condensate (EBC) has been reported to be related to one or another lung disease. The increased concentration might be caused by increased chemicals in the airway surface liquid. However, it might also be due to an increased delivery of liquid samples into the airstream. Being evenly distributed throughout the body, urea is a likely candidate for a marker of such dilution. A liquid chromatography-tandem mass spectrometry method was developed for determination of EBC urea. Urea in EBC samples was converted to 2-hydroxypyrimidine (2-HPM) through a one step reaction, along with (15)N(2)-urea added as an internal standard. The product ion m/z 97/42 was selected for quantification with m/z 99/43 from (15)N(2)-2-HPM as a standard. Concentrations of urea in EBC from five lung cancer patients were found to be 35.1, 2.2, 103.5, 19.3, and 3.6 microM, respectively. The highest values were in patients dying of respiratory distress, whose lungs were filled with fluid. Lower values were seen in patients whose conditions were improving. Lately, one of the low EBC urea values was observed in a patient whose airway status did not contribute to his poor clinical condition.
据报道，呼出气体冷凝物（EBC）中一种或多种化合物水平的升高与某种肺部疾病有关。浓度升高可能是由于气道表面液体中化学物质增加所致。然而，这也可能是由于液体样本向气流中的输送增加。尿素均匀分布于全身，可能是这种稀释的标志物。开发了一种液相色谱 - 串联质谱法来测定EBC中的尿素。EBC样本中的尿素通过一步反应转化为2 - 羟基嘧啶（2 - HPM），同时加入（15）N（2） - 尿素作为内标。选择产物离子m/z 97/42进行定量，以（15）N（2） - 2 - HPM的m/z 99/43作为标准。发现五名肺癌患者的EBC中尿素浓度分别为35.1、2.2、103.5、19.3和3.6微摩尔。最高值出现在死于呼吸窘迫且肺部充满液体的患者中。病情正在改善的患者中尿素值较低。最近，在一名气道状况与临床状况不佳无关的患者中观察到了较低的EBC尿素值之一。
