Analysis Of Lipid Extracts Research Articles

Cellular and Biochemical Characterization of the Anti-Inflammatory Effects of DuP 654 in the Arachidonic Acid Murine Skin Inflammation Model (Part 1 of 2)

The possible utility of DuP 654, a potent 5-lipoxygenase inhibitor, for treating human inflammatory skin disease was investigated in murine skin treated with 1.0 mg arachidonic acid (AA). When DuP 654 was applied to murine skin treated with AA, it inhibited the resulting inflammation and influx of cells. High performance liquid chromatography and radioimmunoassay analysis of lipid extracts from AA-treated ears indicated that the influx of polymorphonuclear leukocytes (PMN) was temporally preceded by an appearance of significant amounts of 5-HETE (6.7 +/- 1.4 ng/ear) and Leukotriene B4 LTB4 0.92 +/- 0.2 ng/ear) when compared with extracts of untreated ears (5-HETE, 02 +/- 0.3 ng/ear; LTB4, less than 0.1 ng/ear). The levels of the 5-lipoxygenase products were reduced by treatment with 10 micrograms/ear DUP 654. Lipid extracts from AA-treated ears contain chemotactic activity for human PMN and this chemotactic activity in the AA-treated ears could be reduced but not eliminated by immunosorption with anti-LTB4 antibodies coupled to protein A-agarose. The appearance of the chemotactic activity was inhibited by DuP 654. Taken together, these data suggest that DuP 654 may have utility in human inflammatory skin disease.

Vitamin D supply to the rat fetus and neonate.

The prevention of neonatal rickets by oral supplementation with vitamin D2 (ergocalciferol) has tended to obscure our ignorance of the natural mechanism by which young mammals receive an adequate supply of vitamin D. To investigate the possibility of specific intrauterine transfer and storage of vitamin D in fetal tissues, vitamin D-deficient female rats were given depot injections of 3H- or 14C-labeled vitamin D3 (cholecalciferol) before mating and the 3H-labeled animals were killed at stages during the last third of gestation. Analysis of lipid extracts from whole fetuses revealed a linear increase in the concentration of 25-hydroxyvitamin D3, 24,25-dihydroxyvitamin D3, and D3 itself between days 14 and 19 of gestation. During this period the elimination half-time of 3H-labeled molecules in maternal plasma fell from 27.1 to 4.4 d, suggesting that a specific mechanism was transferring vitamin D molecules into the fetuses. The vitamin was stored predominantly as 25-hydroxyvitamin D3 and 24,25-dihydroxyvitamin D3, with the highest concentrations in fetal muscle. Immediately after birth, pups from 3H- and 14C-labeled mothers were exchanged and later killed after 1-3 wk of suckling. Analysis of total lipid extracts for 3H and 14C content determined the relative contributions of vitamin D supplied before birth via the placenta and after birth in the maternal milk. The vitamin D content of the rat milk was relatively high, between 1.0 and 3.5 micrograms/liter. Nevertheless, the supply of vitamin D in utero, rather than from milk, was the main determinant of vitamin D status in early neonatal life. This is the first indication in a mammal of a specific transfer mechanism that allows the fetus to accumulate vitamin D from the mother during the last third of gestation.

Lipogranulomas in non-fatty human livers. A mineral oil induced environmental disease.

Forty-four cases of lipogranulomas (LG) in non-fatty livers (NFL), consisting of 38 biopsies and six autopsy livers, were studied. LG in NFL have a distinct morphologic characteristic and virtually all are attached to or closely associated with the walls of hepatic venules. The reason for this peculiar location remains unexplained. Our data from lipid histochemistry and analysis of lipid extracts from the livers and foodstuffs by thinlayer chromatography and gas-liquid chromatography indicate that LG in NFL most likely represent a reaction to absorbed saturated hydrocarbons, like mineral oil, used widely in the food industry. The incidence of LG is increasing, as evidenced by a 1.7% incidence in 1952-53 compared with 4.6% in 1978-80. LG seldom present a diagnostic problem provided serial sections are examined. An awareness of the characteristic morphology will prevent an extensive granuloma work-up. They appear to be an incidental finding in liver biopsies, and of no clinical significance at present; however, their long-term implication, if any, must await future observations.

Action of Vibrio cholerae Neuraminidase (Sialidase) upon the Surface of Intact Cells and Their Isolated Sialolipid Components

Abstract The effect of strong electrolyte upon the activity of Vibrio cholerae neuraminidase (VC neuraminidase) toward the surface of intact cells and toward their isolated, purified sialolipid components, was studied in detail. A linear dependence of the logarithm of initial velocity on the square root of ionic strength was observed for purified GM3 over a concentration range of 0 to 0.05 m NaCl in 0.01 m Tris-acetate, pH 6.5. The rate of decrease of the logarithm of the optimum initial velocity, obtained in 0.01 m Tris-acetate alone, with increasing square root of ionic strength was 3 times more rapid with GM1, GD1a, GD1b, and GT1 as substrate mixture than with the smaller sialolipid, GM3, as substrate. These data are consistent with previous results which indicate that ionic interactions upon the enzyme conformationally govern steric availability of the catalytic site. The effect of strong electrolyte upon the activity of neuraminidase toward the surface of intact cells was small in comparison with that observed with purified sialolipid substrates. Analysis of lipid extracts from untreated control and VC neuraminidase-treated samples by thin layer chromatography revealed no detectable difference between the sialolipid content of untreated control samples and samples treated with VC neuraminidase. These findings suggest that the sialolipid components in the intact cell surface are relatively unavailable to the extracellular action of VC-neuraminidase. This is supported by evidence obtained by detailed analysis of the sialyl components in four cell types (Green monkey kidney cells, Morris hepatoma, B-16 melanoma, and human neuroblastoma) before and after VC neuraminidase treatment. The total cellular sialic acid content of these cell types, untreated, varied from 2.3 to 7.1 µg of sialic acid per mg of protein; lipid-bound sialic acid content varied from 0.7 to 1.6 µg of sialic acid per mg of protein. Progress curves for sialic acid release from the surface of intact cells were hyperbolic and had reached a plateau within approximately 30 min. In the plateau region approximately 20% of the total cellular sialic acid had been released consistently, in each case. Analysis of the lipid-bound sialic acid content of the VC neuraminidase-treated intact cells revealed no major changes, all values being greater than 90% of the untreated, control values. The sialolipid composition of each cell type was examined by thin layer chromatography and found nevertheless to consist predominately of VC neuraminidase-labile components. Therefore, the sialolipids of the intact cell surface appear to be more deeply localized so as to be sterically inaccessible to VC neuraminidase, and release of sialic acid from intact cells by VC neuraminidase appears to be from surface sialoglycoproteins.

Hydrocarbons from human meninges and meningiomas

A lipid fraction more non-polar than sterol ester was isolated in the analysis of lipid extracts from a comparative study of normal brain meninges (dura mater) and neoplastic tissue (meningiomas) from human brain. This fraction was analyzed by thin-layer chromatography and gas-liquid chromatography and found to consist of hydrocarbons. The principal component was an homologous series of n-alkanes (C 15-C 34). Also indicated were squalene and in minor proportions two additional homologous series of alkanes. The hydrocarbon fractions of meninges and meningiomas contained the same components, but in different proportions.

Preparation and analysis of lipid extracts from milk and other tissues

Simple and quick analytical methods for the determination of the phosphorus, nitrogen, long chain base-nitrogen, and carbohydrate contents of samples containing even very low quantities of polar lipids have been devised, in order completely to follow fractionation schemes of lipids from milk or other fat-rich tissues. With these analytical methods strong evidence was obtained indicating that a large proportion of the polar lipids present in milk consists of proteolipids, and mucolipids or other glycolipids. Aqueous washing of chloroform-methanol lipid extracts had destroying effects on these complex molecules, which are also partially broken down by lyophilization, as well as by acidic treatment, including silicic acid chromatography when the finest particles of the adsorbent are not completely removed. Possible explanations for these effects are given and bibliographic data presented supporting the statements. The commonly accepted procedures for manipulating lipid extracts are revised.