ABSTRACT
1. There is a significant correlation between lecithin/sphingomyelin (L/S) ratios based on densitometry (L/S)D and L/S ratios based on phosphorus determinations ((L/S)P). 2. The fetal lung is mature when the (L/S)D, determined according to Verhoeven, A.G.J. and Merkus, H.M.W.M. (1974) Clin. Chim. Acta 53, 229--232, is 1.2. This value is equivalent to an (L/S)P of 1.8. 3. The acetone precipitation procedure, introduced by Gluck, L., Kulovich, M.V., Borer, R.C. and Keidel, W.N. (1974) Am. J. Obstet. Gynecol. 120, 142--155, is a necessary step for isolating surface-active lecithin. 4. Standardization of the (L/S)D test is feasible and should permit different laboratories to use the same transition point.
Subject(s)
Amniotic Fluid/analysis , Phosphatidylcholines/analysis , Sphingomyelins/analysis , Animals , Brain Chemistry , Cattle , Egg Yolk , Fatty Acids/analysis , Female , Humans , Infant, Newborn , Lung/embryology , Pregnancy , Prenatal Diagnosis , Respiratory Distress Syndrome, Newborn/diagnosis , Surface TensionABSTRACT
A method is presented for the determination of the activity of sphingomyelinase. It is based on the determination of sphingomyelin before and after enzymatic conversion with the aid of a quantitative paper chromatographic analysis of phospholipids. This method is used for the determination of sphingomyelinase activity in various tissues such as those of the human brain and liver and fibroblast cultures. Normal values are presented.
