Grasemann H, Ioannidis I, de Groot H, Ratjen F
Institute for Physiological Chemistry, University of Essen, Germany.
Eur J Pediatr. 1997 Jul;156(7):575-8. doi: 10.1007/s004310050667.
Nitric oxide (NO) is produced in the upper and lower respiratory tract and can be detected in exhaled air of both healthy individuals and subjects with pulmonary diseases. Recent studies have shown that exhaled NO is mainly derived from the upper airways. There is, however, evidence that in aqueous solutions NO is rapidly converted to distinct oxides of nitrogen. We therefore studied the stable NO metabolites nitrate and nitrite in broncho-alveolar lavage (BAL) fluid and serum as indicators of NO formation in the lower respiratory tract. The study population consisted of 31 healthy children undergoing elective surgery for non-pulmonary illnesses and 13 immunosuppressed children with pneumonia. Nitrate and nitrite were determined photometrically. Nitrate was found in BAL fluid of all children. In children with pneumonia, nitrate concentrations in BAL fluid were significantly higher than in healthy children. A significant correlation was observed between nitrate in BAL fluid and serum of immunosuppressed children with pneumonia. Nitrite was not detected in any of the BAL fluid or serum samples.
Our results suggest that in the lower airways significant amounts of NO are metabolised to nitrate. Studies on NO in pulmonary diseases should therefore include determination of nitrate in lower airway fluids.
一氧化氮（NO）在上、下呼吸道产生，在健康个体和肺部疾病患者的呼出气体中均可检测到。近期研究表明，呼出的NO主要来源于上呼吸道。然而，有证据表明，在水溶液中NO会迅速转化为不同的氮氧化物。因此，我们研究了支气管肺泡灌洗（BAL）液和血清中稳定的NO代谢产物硝酸盐和亚硝酸盐，作为下呼吸道中NO生成的指标。研究对象包括31名因非肺部疾病接受择期手术的健康儿童和13名患有肺炎的免疫抑制儿童。采用光度法测定硝酸盐和亚硝酸盐。在所有儿童的BAL液中均检测到硝酸盐。在患有肺炎的儿童中，BAL液中的硝酸盐浓度显著高于健康儿童。在患有肺炎的免疫抑制儿童的BAL液和血清中的硝酸盐之间观察到显著相关性。在任何BAL液或血清样本中均未检测到亚硝酸盐。
我们的结果表明，在下呼吸道中大量的NO被代谢为硝酸盐。因此，关于肺部疾病中NO的研究应包括测定下呼吸道液体中的硝酸盐。
