Phospholipid surface tension: the diagnostic utility of amniotic fluid and its lipid extract, an analysis of the value of precipitation with cold acetone.
In prevention of the respiratory distress syndrome (RDS), measurements of surface tension values (a biophysical property) of amniotic-fluid samples are correlated with their lecithin/sphingomyelin (L/S) ratios (a biochemical property). According to some authors, precipitation of phospholipid with cold acetone is essential for determining the L/S ratio, because it separates surfactant and nonsurfactant phospholipidic fractions. Here we report the first study of the ability of three amniotic-fluid components to decrease surface tension: The complete lipid extract (without precipitation), and the fractions precipitated and (or) remaining soluble after addition of cold acetone. Addition of increasing aliquots of lipid extracts to these three samples showed that: (a) measurement of surface tension rapidly and reliably indicates fetal lung maturity, and (b) both precipitated and soluble phospholipid fractions decrease surface tension similarly, making it unlikely that the precipitation step in fact separates surfactant and nonsurfactant material.
Ruiz Budría
J
J
Department of Organic Chemistry, University of Zaragoza, Spain.
Abbad Bara
J M
JM
Fabre Gonzalez
E
E
Higueras Sanz
M T
MT
Serrano Ostáriz
J L
JL
D000096:Acetone; D000653:Amniotic Fluid / Q000032:analysis*; D011232:Chemical Precipitation; D003080:Cold Temperature; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D010713:Phosphatidylcholines / Q000032:analysis; D010743:Phospholipids / Q000032:analysis*; D011247:Pregnancy; D011296:Prenatal Diagnosis; D011663:Pulmonary Surfactants / Q000032:analysis; D012127:Respiratory Distress Syndrome, Newborn / Q000175:diagnosis* / Q000517:prevention & control; D013109:Sphingomyelins / Q000032:analysis; D013500:Surface Tension; D014020:Tissue Extracts / Q000032:analysis
D010713:Phosphatidylcholines; D010743:Phospholipids; D011663:Pulmonary Surfactants; D013109:Sphingomyelins; D014020:Tissue Extracts; D000096:Acetone