Title: Is the L/S ratio really a lecithin/sphingomyelin ratio?
Abstract: Foetal lung maturity is-commonly assessed by determining the ratio of lecithin/sphingomyelin (L/S) in centrifuged amniotic fluid. In the routine determination of the L/S ratio by TLC, other bands were frequently noted between and overlapping the lecithin and sphingomyelin spots. Two-dimensional chromatography revealed that 2 additional phospholipids were present in the lecithin-sphingomyelin region. Treatment of dried extracts with cold acetone prior to TLC, as suggested in the original L/S ratio procedure, did not remove the interfering phospholipids. These phospholipids have been tentatively identified as phosphatidylserine and phosphatidylinositol, both normal components of amniotic fluid. A solvent system was developed to allow one-dimensional separation of these phospholipids from lecithin anc sphingomyelin. Comparison of data obtained for individual cases using the new solvent and the conventiona solvent indicates that the extra phospholipids contribute significantly to the routine ‘L/S’ ratio. It remains to b< determined whether the true L/S ratio is a more reliable index of foetal lung maturity than the empirical ‘L/S’ ratk now in use. Foetal lung maturity is-commonly assessed by determining the ratio of lecithin/sphingomyelin (L/S) in centrifuged amniotic fluid. In the routine determination of the L/S ratio by TLC, other bands were frequently noted between and overlapping the lecithin and sphingomyelin spots. Two-dimensional chromatography revealed that 2 additional phospholipids were present in the lecithin-sphingomyelin region. Treatment of dried extracts with cold acetone prior to TLC, as suggested in the original L/S ratio procedure, did not remove the interfering phospholipids. These phospholipids have been tentatively identified as phosphatidylserine and phosphatidylinositol, both normal components of amniotic fluid. A solvent system was developed to allow one-dimensional separation of these phospholipids from lecithin anc sphingomyelin. Comparison of data obtained for individual cases using the new solvent and the conventiona solvent indicates that the extra phospholipids contribute significantly to the routine ‘L/S’ ratio. It remains to b< determined whether the true L/S ratio is a more reliable index of foetal lung maturity than the empirical ‘L/S’ ratk now in use.
Publication Year: 1979
Publication Date: 1979-01-01
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 1
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