Nunn J F, Sharer N, Royston D, Watts R W, Purkiss P, Worth H G
Br J Anaesth. 1982 Jun;54(6):593-7. doi: 10.1093/bja/54.6.593.
Normal serum concentrations of methionine, leucine, isoleucine and valine have been found in 10 anaesthetists using nitrous oxide under their regular working conditions without scavenging of patients' exhaled gas. Mean inhaled concentrations of nitrous oxide ranged from 150 to 400 p.p.m. The results indicate either that there was no significant inhibition of methionine synthase (attributable to oxidation of vitamin B12 by nitrous oxide) or that methionine concentrations were maintained by dietary intake or by the alternative betaine pathway of methylation of homocysteine. In either case, anaesthetists working under these conditions should not be at risk from reduced methionine concentrations. We also report normal serum activities of aspartate transaminase and gamma glutamyl transpeptidase.
在10名麻醉师于常规工作条件下使用氧化亚氮且未对患者呼出气体进行清除的情况下，已发现其血清中甲硫氨酸、亮氨酸、异亮氨酸和缬氨酸浓度正常。氧化亚氮的平均吸入浓度范围为百万分之150至400。结果表明，要么不存在甲硫氨酸合酶的显著抑制作用（归因于氧化亚氮对维生素B12的氧化），要么甲硫氨酸浓度是通过饮食摄入或同型半胱氨酸甲基化的替代甜菜碱途径维持的。无论哪种情况，在这些条件下工作的麻醉师都不应面临甲硫氨酸浓度降低的风险。我们还报告了天冬氨酸转氨酶和γ-谷氨酰转肽酶的血清活性正常。
