抽象的
炎症细胞的血小板激活因子(PAF)的产生受溶血-PAF乙酰转移酶调节,并且该酶的活性在稳定的肺炎患者的中性粒细胞中增加。这项研究的目的是确定乙基转移酶活性是否进一步上调,患有急性症状。用于测量来自未刺激的和Ca2+离子载体(A23187)的乙酰基转移酶的酶促亲和力常数(KM)和最大酶活性(VMAX)(VMAX)(VMAX)(A23187)刺激的中性粒细胞的16例患者的急性哮喘和急性哮喘的中性粒细胞重复。排出(n = 9)和从急性发作中恢复后(n = 13)。在急性哮喘期间,使用相同方法(155.1(122.2-179.9)microm; p = 0.0001),在先前的研究中,Km(中位数93.8(64.1-109.7)MICROM)低于在非asthmatic受试者中测得的Km,并且在10次研究中。恢复后,未刺激的中性粒细胞的13名急性患者中有增加。在A23187刺激的嗜中性粒细胞中,急性哮喘(84.3(73.6-100.2)microm)和放电时(83.9(83.1-94.8)microm)相似,但恢复后km的km相似,但增加了km(115.0(115.6-119.5)microm; p; p; p; p; p; p; p; p; p; p; p; p; p; p; p; p; p; p; p; p; p; p;= 0.02)。急性哮喘刺激后,KM的变化也比以前在非腹腔受试者中测量的情况明显少得多(p = 0.003)。尽管急性哮喘期间的Vmax(12.9(四分位间范围10.5-22.5)NMOL X Min(-1)X Mg(-1)蛋白质与放电时没有显着差异(14.4(12.3-20.4)NMOL X Min(-1))X mg(-1))或恢复后(17.3(12.3-18.4)NMOL X Min(-1)X mg(-1)),中位数KM和VMAX在急性哮喘期间倾向于最低,并且在出院时增加和增加恢复后。 An increase in lyso-PAF acetyltransferase activity alone may not account for increased systemic PAF concentrations during acute asthma. However, the reduction in the enzymatic affinity constant and its smaller change following in vitro stimulation suggest that alterations in the affinity of acetyltransferase for acetylcoenzyme A (CoA) and in the regulation of enzyme activity may be occurring during acute asthma.