Fine J M, Gordon T, Thompson J E, Sheppard D
Am Rev Respir Dis. 1987 Apr;135(4):826-30. doi: 10.1164/arrd.1987.135.4.826.
We evaluated the importance of pH, titratable acidity, and specific chemical composition in acid aerosol-induced bronchoconstriction in 8 asthmatic subjects. We administered aerosols of HCl and H2SO4 at pH 2.0 in an unbuffered state and buffered with glycine. The buffered acids were given in order of increasing titratable acidity (defined as the number of ml of 1 N NaOH required to neutralize 100 ml of acid solution to pH 7.0). Each set of buffered or unbuffered acid aerosols was given on a separate day and each aerosol was inhaled through a mouthpiece during 3 min of tidal breathing. Bronchoconstriction was assessed by measurement of specific airway resistance (SRaw) before and after inhalation of each aerosol. SRaw increased by more than 50% above baseline in 1 of 8 subjects after inhalation of unbuffered HCl and in no subjects after inhalation of unbuffered H2SO4, even at pH 2.0. In contrast, SRaw increased by greater than 50% in all 8 subjects after inhalation of HCl and glycine at pH 2.0 and 7 of 8 subjects after inhalation of H2SO4 and glycine at pH 2.0. The mean titratable acidity required to increase SRaw by 50% above baseline was calculated for each challenge by linear interpolation; these values for H2SO4 and glycine (5.1 ml of 1 N NaOH) and HCl and glycine (2.2 ml of 1 N NaOH) were slightly, but significantly, different (p = 0.01) and were considerably higher than the titratable acidity of the unbuffered acids at pH 2 (1.0 ml of 1 N NaOH).(ABSTRACT TRUNCATED AT 250 WORDS)
我们评估了pH值、可滴定酸度和特定化学成分在8名哮喘患者中酸雾诱发支气管收缩中的重要性。我们以未缓冲状态和用甘氨酸缓冲的方式给予pH值为2.0的HCl和H2SO4气雾剂。缓冲酸按照可滴定酸度增加的顺序给予（可滴定酸度定义为将100 ml酸溶液中和至pH 7.0所需的1 N NaOH的毫升数）。每组缓冲或未缓冲的酸雾剂在不同日期给予，每次气雾剂在潮式呼吸3分钟内通过口含器吸入。通过测量每次气雾剂吸入前后的比气道阻力（SRaw）来评估支气管收缩。吸入未缓冲的HCl后，8名受试者中有1名的SRaw比基线增加超过50%，而吸入未缓冲的H2SO4后，即使在pH 2.0时，也没有受试者的SRaw增加超过50%。相比之下，吸入pH值为2.0的HCl和甘氨酸后，所有8名受试者的SRaw均增加超过50%，吸入pH值为2.0的H2SO4和甘氨酸后，8名受试者中有7名的SRaw增加超过50%。通过线性插值计算每次激发使SRaw比基线增加50%所需的平均可滴定酸度；H2SO4和甘氨酸（5.1 ml 1 N NaOH）以及HCl和甘氨酸（2.2 ml 1 N NaOH）的这些值略有不同，但具有显著差异（p = 0.01），并且明显高于pH 2时未缓冲酸的可滴定酸度（1.0 ml 1 N NaOH）。（摘要截断于250字）
