Wiehle R D, Richardson M, Besch N, Besch P, Kirshon B, Reiter A, Hutchens T W
Department of Obstetrics & Gynecology, Baylor College of Medicine, Houston, Texas 77030.
Exp Lung Res. 1995 Jan-Feb;21(1):17-39. doi: 10.3109/01902149509031742.
The present clinical evaluation of fetal lung maturity relies largely on the determination of the amniotic surfactant phospholipids phosphotidylglycerol, lecithin, and sphingomyelin, but there are many false negatives as well as false positives among diabetics. The use of other components of lung surfactant, namely, the hydrophobic surfactant proteins (SPs) has long been suggested as an alternative to the classical assay, but tests based on the detection of immunoreactive SP-A have not proved superior or supplanted phospholipid ratios as an index. This report investigates the proteins in a fraction of third-trimester human amniotic fluid (the particulate fraction) enriched in the SP complexes that form the surfactant monolayer. The proteins were analyzed by two-dimensional polyacrylamide gel electrophoresis and visualized by silver staining and immunoblotting. Eight proteins are of particular interest. Three novel proteins (termed AFPP-1, AFPP-4, and AFPP-8) and the alpha-fetoprotein/human serum albumin complex (AFPP-7) can be detected throughout the 28- to 38-week gestational window. The protein that is referred to as AFPP-2 could be identified as SP-A on the basis of immunologic cross-reactivity as well as size and charge characteristics. The time course of appearance of AFPP-2 was also followed in patients with Rh isoimmunization syndrome and was found to be the same as that seen for SP-A. The SP-A was detected as at least five major charged isoforms with multiple subisoforms of different molecular weight and can be distinguished from a related set of proteins (AFPP-5) that appear with a different time course but are possible precursors. Two other proteins (AFPP-3, AFPP-6), which are detectable inconsistently bear some similarity to others reported previously but not extensively characterized. These results define both constant and variable proteins of the particulate fraction of the amniotic fluid and indicate that certain protein isoforms are changing throughout the third trimester. These data enhance the possibility of the utilization of these proteins as markers of lung maturity in conditions such as maternal diabetes.
目前对胎儿肺成熟度的临床评估在很大程度上依赖于羊水表面活性物质磷脂（磷脂酰甘油、卵磷脂和鞘磷脂）的测定，但糖尿病患者中存在许多假阴性和假阳性结果。长期以来，人们一直建议使用肺表面活性物质的其他成分，即疏水表面活性蛋白（SPs）作为经典检测方法的替代方法，但基于免疫反应性SP-A检测的试验并未证明优于磷脂比率或取代其作为指标。本报告研究了妊娠晚期人羊水的一部分（颗粒部分）中的蛋白质，该部分富含形成表面活性物质单层的SP复合物。通过二维聚丙烯酰胺凝胶电泳分析蛋白质，并通过银染和免疫印迹进行可视化。有八种蛋白质特别值得关注。在整个妊娠28至38周期间都可以检测到三种新蛋白质（称为AFPP-1、AFPP-4和AFPP-8）以及甲胎蛋白/人血清白蛋白复合物（AFPP-7）。根据免疫交叉反应性以及大小和电荷特征，被称为AFPP-2的蛋白质可被鉴定为SP-A。还对患有Rh血型免疫综合征的患者追踪了AFPP-2的出现时间进程，发现其与SP-A的相同。SP-A被检测为至少五种主要带电异构体以及不同分子量的多个亚异构体，并且可以与一组相关蛋白质（AFPP-5）区分开来，后者以不同的时间进程出现但可能是前体。另外两种蛋白质（AFPP-3、AFPP-6），其检测结果不一致，与先前报道的其他蛋白质有一些相似之处，但未得到广泛表征。这些结果定义了羊水颗粒部分中的恒定和可变蛋白质，并表明某些蛋白质异构体在整个妊娠晚期都在变化。这些数据增加了在诸如母体糖尿病等情况下利用这些蛋白质作为肺成熟度标志物的可能性。
