Disaturated phosphatidylcholine

Ma LY, LaCagnin LB, Bowman L, et al. 1989. Carbon tetrachloride inhibits synthesis of pulmonary surfactant disaturated phosphatidylcholines and ATP production in alveolar type II cells. Acta Biochem Biophys 1003 136-144. 

Thus it is possible to estimate the time for surfactant adsorption required for the formation of black spots. Table 11.2 presents the clinical and threshold concentrations for total phospholipids (PL) and for disaturated phosphatidylcholine (DSPC) in each preparation. The most abundant PL of the lung surfactant system is DSPC, principally the DPPC species, which is believed the essential determinant of surfactant function in vivo [2], While DPPC is the only PL in EX, both IN and SU contain other PLs and small quantities of hydrophobic surfactant-associated proteins that may add to the desired functional properties of the material in situ. 

PL, phospholipids DSPC, disaturated phosphatidylcholine, namely, dipalmitoylphosphatidylcholine (DPPC) in IN and EX, and DPPC plus other disaturated PCs in SU ... 

Muneshige A, Okazaki T, Quirk JG, MacDonald PC, Nozaki M, Johnston JM. A rapid and specific enzymatic method for the quantification of phosphatidylcholine, disaturated phosphatidylcholine, and phosphatidylglycerol in amniotic fluid. Am J Obstet Gynecol 1983 145 474-80. 

Tsai MY, Cain M, Josephson MW. Improved thin-layer chromatography of disaturated phosphatidylcholine in amniotic fluid. Clin Chem 1981 27 ... 

Tsai MY, Shultz EK, Williams PP, Bendel R, Butler J, Farb H, et al. Assay of disaturated phosphatidylcholine in amniotic fluid as a test of fetal lung maturity experience with 2000 analyses. CUn Chem 1987 33 1648-51. 

Infasurf suspension, intratracheal 35 mg phospholipids/mL suspended in 0.9% sodium chloride solution and 0.65 mg proteins with 26 mg phosphatidylcholine, of which 16 mg is disaturated phosphatidylcholine)... 

Type II cells contain characteristic lamellar inclusion bodies. Disaturated phosphatidylcholine appears to be synthesized in the endoplasmic reticulum and then stored in the lamellar bodies where it may also be combined with other surfactant components before being released into the alveoli by exocytosis (Goerke, 1975 Rooney, 1979) (Fig. 12.2). Phosphatidylcholine is synthesized de novo... 

The release of [ C]disaturated phosphatidylcholine by rat type II pneumocytes cultured in the presence of 10 fiM L-isoprenahne was 300 20 % as compared with the controls (Dobbs and Mason 1979). 

Scsirim, J. Ghanbari, H. Taylor, V. Menon, G. Determination of phosphatidylcholine and disaturated phosphatidylcholine content in lung surfactant by high performance liquid chromatography, J.Lipid Res., 1989, 30, 607-611. 

Prolonged inhalation of dusts by humans (156), rodents (157,158), and other species (159,160) is associated with an increase in the number of type II cells and increased secretion of surfactant. The stimulation of surfactant appears to be directly related to the toxicity of the dust. It may be so florid, as in acute silicosis, that flooding of the alveolar spaces with surfactant lipids and associated proteins may occur, a condition known as alveolar lipoproteinosis (156). In experimental lipoproteinosis in the rat, the major lipid component is disaturated phosphatidylcholine (157), but all lipid fractions are increased. In the sheep model of experimental silicosis, phosphatidylglycerol, phosphatidylethanolamine, and phosphatidylinositol, showed the greatest increases following silica exposure (159). The excess production of surfactant in response to silica dust may be an adaptive response, perhaps to reduce particle cytotoxicity or to compensate for oxidant-induced lipid peroxidation (147,161). 

Because disaturated molecular species of phosphatidylcholine, such as those predominating in lung, could not easily be detected and quantified spectrophotometrically at 205 nm, the use of refractive index detection for the purpose was explored and was found to give satisfactory results [413], BDMS ether derivatives can be analysed in the same way. Methodology of this kind could be used to obtain fractions for further resolution and identification by GC-MS, although there is little to suggest that the two techniques are being used in concert at the moment. 

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