Response of immature baboon fetal lung to intra-amniotic betamethasone.

Intra-amniotic betamethasone (6 mg.) given to six immature fetal baboons, at four and again at three days prior to delivery by cesarean section, between 147 and 158 days' gestation (term = 180 days), significantly increased the amniotic fluid lecithin/sphingomyelin (L/S) ratio. At delivery, treated animal lungs were more mature in that they had a significantly increased deflation stability and significantly decreased minimum surface tension in minced lung when compared to five control animals. Changes in maximum air distensibility lagged behind changes in deflation stability. The major molecular species of pulmonary phosphatidylcholine were analyzed by gas liquid chromatography as the diacylglycerol derivatives. The proportions of 14:0/16:0, 16:0/16:0, and 16:0/18:0, were significantly increased over control proportions while unsaturated species tended to decrease in animals exposed to intra-amniotic betamethasone. The immature fetal baboon pulmonary system responded to intra-amniotic betamethasone with a synchronous increase in the L/S ratio, improved pulmonary stability, and a more mature pulmonary lecithin composition, but did not demonstrate a synchronous increase in tissue distensibility.

The analysis of the molecular species of fetal rabbit lung phosphatidylcholine by consecutive chromatographic techniques.

The major molecular species of pulmonary phosphatidylcholine in the fetal rabbit were analyzed as the diacylglycerol acetate derivatives. After fractionation by Ag+ thin-layer chromatography according to the degree of unsaturation, the intact diacylglycerol acetates were analyzed by gas-liquid chromatography to obtain the carbon number composition. The methyl esters of these acetates were used to obtain the fatty acid profiles. The composition of the molecular species was derived from these sets of data. The proportions of 16 : 0/16 : 0, 14: 0/16 : 0 and 16 : 0/16 : 1 increased with gestation, while 16 : 0/18 : 1 decreased. The concentration of 16 : 0/16 : 0 increased about 50% the last two days of gestation while 16 : 0/16 : 1 increased about 300%. The possibility that 16 : 0/16 : 1 is a precursor of 16 : 0/16 : 0 via biohydrogenation is discussed.

Gas-liquid chromatographic analysis of free long-chain aldehydes.

Quantitative results are reported for gas-liquid chromatography of mixtures of free tetra-, hexa-, and octadecanals and cis-9-octadecenal on polar and nonpolar liquid phases. Stability of the fatty aldehydes during chromatographic analysis and up to 1 year of storage appears to be related to the solvent (carbon disulfide) used. Analysis of the free aldehydes by gas-liquid chromatography eliminates the disadvantages associated with the preparation and analysis of derivatives for this lipid class.

Gas-liquid chromatography of triglyceride mixtures containing both odd and even carbon number fatty acids.

Quantitative GLC of triglycerides has been extended to natural fats containing both odd and even carbon number fatty acids. A 1.83-m glass column containing 3.0% JXR silicone on 100/120 mesh Gas-Chrom Q resolved triglycerides differing by only one carbon number. Peak resolution was significantly improved by hydrogenating each triglyceride sample prior to GLC analysis.The triglycerides of four fish oils (mullet, tuna, menhaden, and pilchard) and one seed fat (Acanthosyris spinescens) containing odd carbon number fatty acids were analyzed by this technique. The method was also useful for determining the triglyceride composition of the cyclopentene fatty acid oil fromHydnocarpus wightiana seeds.

The triglyceride composition of 17 seed fats rich in octanoic, decanoic, or lauric acid.

Seed fats of eight species ofLauraceae (laurel family), six species ofCuphea (Lythraceae family), and three species ofUlmaceae (elm family) were extracted, and the triglycerides were isolated by preparative thin-layer chromatography. GLC of the triglycerides on a silicone column resolved 10 to 18 peaks with a 22 to 58 carbon number range for each fat. These carbon number distributions yielded considerable information about triglyceride compositions of the fats.The most interesting finding was withLaurus nobilis seed fat, which contained 58.4% lauric acid and 29.2-29.8% trilaurin. A maximum of 19.9% trilaurin would be predicted by a 1, 2, 3-random, a 1, 3-random-2-random, or a 1-random-2-random-3-random distribution of the lauric acid(3). This indicates a specificity for the biosynthesis of a simple triglyceride byLaurus nobilis seed enzymes.Cuphea lanceolata seed fat also contained more simple triglyceride (tridecanoin) than would be predicted by the fatty acid distribution theories.

Gas-liquid chromatography of triglycerides from erucic acid oils and fish oils.

By critically selecting optimum operating conditions, quantitative gas-liquid chromatography of triglycerides has been extended to molecules containing substantial amounts of C(20), C(22), and C(24) fatty acids. The triglycerides of four erucic acid oils (water cress, rapessed, nasturtium, andLunaria annua) and two fully hydrogenated fish oils (menhaden and tuna) have been quantitatively analyzed by this technique. The average fatty acid chain length calculated from the triglyceride composition of each oil agreed closely with that determined by GLC of its respective methyl esters. Several conclusions about the triglyceride composition of the fats analyzed are discussed.