二胺氧化酶放射化学法测定及其临床应用

RADIOCHEMICAL ESTIMATION OF DIAMINE OXIDASE AND ITS CLINICAL APPLICATION

用简单、敏感和特异的放射化学法测定血清和胸水二胺氧化酶活性。以β-H^3一腐胺为酶的特异性底物,样本在0.1mol/L、pH7.6磷酸缓冲液中温育,用甲苯提取所产生的~3H-二氢比咯代谢产物,在液体闪烁仪上计数放射性,以放射性计算产物的量,酶活力以被氧化脱氨的腐胺量表示。正常人血清二胺氧化酶活性为74.96±83.27U/ml,肺癌病人血清二胺氧化酶活性明显高于良性肺部疾病病人,恶性胸水中二胺氧化酶活力也明显高于良性胸水;如以250U/ml作为区分良恶性胸水界值,恶性胸水有74%高于此(?),而良性胸水仅有9%高于此限。

A(simple,sensitive and specific)radiochemical estimation of diamine oxidase(DAO)activi- ty in serum and pleural fluid is reported.A sample in 0.1 mol/L phosphate buffer,pH7.6,was incubated with β~3H-putrescine as a specific substrate for 60 min at 37℃.The deaminated products were extracted with toluene and radioactivities determined.The enzyme activity was expressed by the value of the deaminated putrescine.The level of serum DAO in normal subjects was 74.96± 83.27U/ml.The level of sreum DAO in patients with lung cancer was higher than that in pa- tients with benign disease of the lung.The level of malignant pleural effusion was significantly higher than that of benign pleural effusion.When the DAO cut-off in pleural fluid was set as 250 U/ml,the positive rate of malignant effusion was 74%,but that of benign effusion 9%.