The concentration of lamellar bodies expressed as the optical density at 700 nm in amniotic fluid samples was calculated after centrifugation of the samples to obtain the lamellar bodies in a relatively pure form. The lamellar body concentrations obtained were compared with lecithin/sphingomyclin (L/S) ratios from the same samples. The advantages of the method compared with the L/S ratio are discussed as is the dependence on total volume that the method shares with all other procedures which depend on the measurement of a single concentration.
KikkawaYYonedaKSmithFPackardBSuzukiK. The type II epilhelial cells of the lung. II Chemical composition and phospholipid synthesis. Lab Invest1975; 32: 295–302.
4.
StrangLB. Growth and development of the lung: Foetal and postnatal. Ann Rev Physiol1977; 39: 253–76.
5.
Duck-ChongCG. Lamellar body phospholipid content of amniotic fluid: A possible index of fetal lung maturity. Ann Clin Biochem1976; 16: 191–6.
6.
Duck-ChongCGBrownLMHensleyWJ. Sedimentation of lung-derived phospholipid during low speed centrifugation of amniotic fluid. Clin Chem1981; 27/8: 1424–6.
7.
IvieMNovyMJReynoldsJWO'GradyPSwansonR. Modified lamellar body phospholipid assay compared with L/S ratio and phosphatidyl glycerol assay for assessment of foetal pulmonary status. Clin Chem1987; 33: 24–31.
8.
Bar KaiGReichmanBModanMMeirEGoldmanBMashiachS. Determination of foetal lung maturity by fluorescence polarization of the amniotic fluid lamellar bodies. Obstet Gynecol1986; 68/2: 168–72.
9.
DubinSB. Determination of lamellar body size I number density and concentration by differential light scattering from amniotic fluid: Physical significance of A 650. Clin Chem1988; 34/5: 938–43.
10.
DubinSB. Characterization of amniotic fluid lamellar bodies by resistive pulse counting: Relationship to measurement of foetal lung maturity. Clin Chem1989; 35: 612–16.
11.
TouchstoneJCChenJCBeaverKM. Improved separation of phospholipids in thin layer chromatography. Lipids1980; 15: 61–2.
12.
CherayilGDWilkinsonEJBakowfHI. Amniotic fluid Lecithin/Sphingomyelin ratio changes related to centrifugal force. Obstet Gyencol1977; 50: 682–7.
13.
OultonMMartinTRFaulknerTStinsonDJohnsonJP. Developmental study of a lamellar body fraction isolated from human amniotic fluid. Pediat Res1980; 14: 722–8.
14.
FujitaH. Mathematical Theory of Sedimentation Analysis. London and New York: Academic Press, 1962.
15.
GostingLJ. Solution of boundary spreading equation for electroforesis and velocity of ultra centrifuge. J Am Chem Soc1952; 74: 1548–52.
16.
OultonM. The role of centrifugation in the measurement of surfactant in amniotic fluid. Am J Obstet Gynecol1979; 135: 337–43.