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PubMed1991

Fatty acid composition of human myelin proteolipid protein in peroxisomal disorders.

Myelin proteolipid protein (PLP) is an acylated protein which contains approximately 2 mol of ester-bound fatty acids. In this study, the amount and composition of fatty acids covalently bound to human myelin PLP were determined during development and in peroxisomal disorders. Palmitic, oleic, and stearic acids accounted for most of the PLP acyl chains. However, in contrast to PLP in other species, human PLP contains relatively more very long chain fatty acids (VLCFA). The fatty acid composition remained essentially unchanged between 1 day and 74 years of age. The total amount of fatty acid bound to PLP was not altered in any of the pathological cases examined. However, in the peroxisomal disorder adrenoleukodystrophy, the proportions of saturated and, to a lesser extent, monounsaturated VLCFA bound to PLP were increased at the expense of oleic acid. Smaller, but significant, changes were observed in adrenomyeloneuropathy. The reduction in the levels of oleic acid was also observed in two other peroxisomal disorders, the cerebrohepatorenal (Zellweger) syndrome and neonatal adrenoleukodystrophy, as well as in the lysosomal disorder Krabbe globoid cell leukodystrophy. However, in these disorders, the decrease in oleic acid occurred at the expense of stearic acid, and not VLCFA. The results indicate that, although a characteristic PLP fatty acid pattern is normally maintained, changes in the acyl chain pool can ultimately be reflected in the fatty acid composition of the protein. The altered PLP-acyl chain pattern in peroxisomal disorders may contribute to the pathophysiology of these devastating disorders.

Adrenoleukodystrophy↗

PubMed1982

Neonatal adrenoleukodystrophy: clinical, pathologic, and biochemical delineation of a syndrome affecting both males and females.

We describe the detailed clinical, pathologic, and biochemical features of brother and sister with the neonatal onset form of adrenoleukodystrophy, together with evidence of the biochemical defect. When compared with reports of previous cases, it becomes clear that this is a newly described clinical entity with remarkable uniformity of signs and very different from the usual childhood form. Some pathologic features are shared, including the morphologic abnormality of the adrenal in both neonatal and childhood forms, but deposition of abnormally metabolized lipids is more systemic and widespread in the neonatal form. The biochemistry of the disease is presented in both children and parents. Plasma values of long-chain fatty acid C26:0 are 0.328 +/- 0.18 micrograms/ml in a control population and 0.381 +/- 0.312 micrograms/ml in the father and mother. Values for C26:0 in the plasma of childhood adrenoleukodystrophy are 1.62 +/- 0.87 micrograms/ml and in our two cases, 2.79 micrograms/ml in the male, 1.83 micrograms/ml in the female. The basic biochemical defect appears to be a diminished capacity to oxidize these fatty acids leading to accumulation in cholesterol esters. Fatty acid oxidation to CO2 by cultured skin fibroblasts was 51% of control value for stearic acid, 5% for lignoceric acid in the male, and 39% of control value for stearic acid, 5% for lignoceric acid in the female. The genetics of this disease is different; whereas childhood adrenoleukodystrophy is X-linked, the neonatal onset form affects males and females equally and is most probably autosomally recessive in inheritance.

Adrenal Glands↗

PubMedDate not supplied

Potato phosphorylase catalyzed synthesis of amylose-lipid complexes.

On-line size-exclusion chromatography monitoring of potato phosphorylase catalyzed amylose synthesis--starting from alpha-D-glucose-1-P and maltohexaose--revealed rather monodisperse amylose populations. In the presence of lipids, amylose-lipid complexes spontaneously formed and precipitated. They were recovered by centrifugation, freeze-dried, and characterized by wide-angle X-ray diffraction and differential scanning calorimetry. The presence of lipids during amylose synthesis led to lower amylose degrees of polymerization (DP). Lipid chain length defined amylose DP, which increased in the order myristic acid (C14), glyceryl monostearate (GMS), stearic acid (C18), and docosanoic acid (C22). The thermal stability of the complexes increased in the same manner, with the C22 complexes having the highest dissociation temperature. In addition, we hypothesized that these results provide additional evidence for the fringed micellar organization of (semi-enzymically synthesized) amylose-lipid complexes.

Amylose↗

PubMed1985

16,16-Dimethyl PGE2 and fatty acids protect hepatocytes against CCl4-induced damage.

16,16-Dimethyl PGE2 (dmPGE2) has previously been shown to protect the in vivo rat liver against CCl4-induced damage. These studies were undertaken to determine if this protection could be demonstrated in vitro where factors of absorption, secretion, and blood flow are not present. Primary hepatocyte cultures were established by perfusing rat liver with collagenase. Hepatocytes were plated at a density of 2 X 10(4) cells/cm, allowed 90 min to attach, then stabilized in L15 medium for 18 h. Hepatocytes were then challenged with CCl4 with concomitant exposure to 10(-9) to 10(-5) M dmPGE2, stearic acid, oleic acid, or ethanol vehicle (0.00001 to 0.1%). After 1 h, challenge was aspirated and cells were stained with 0.04% trypan blue to determine viability. Hepatocytes in the vehicle groups took up more trypan when exposed to CCl4 than those treated with dmPGE2, stearic acid, or oleic acid at concentrations of 10(-9) to 10(-7) M. At 0.1% ethanol vehicle protected as well as all other treatments. Protection against CCl4 by dmPGE2, stearic, and oleic acids as well as high concentrations of ethanol may occur by altering the metabolism of CCl4.

16,16-Dimethylprostaglandin E2↗

PubMed1990

Increasing cytostatic effects of ricin A chain and Staphylococcus aureus enterotoxin A through in vitro hydrophobization with fatty acid residues.

In order to impart an ability for receptor-independent transmembrane transfer to water-soluble proteins, it has been suggested that they be hydrophobized by lipid groups (fatty acids, etc.). To this end, systems of reversed micelles of surfactants in organic solvents were used as reaction media for protein modification. It was shown that after introduction of a hydrophobic anchor (stearic acid residue) the toxic effect of ricin A-chain (in the absence of B-chain) on intact cells became very close to that of the native toxin. As a result of stearic acid acylation, the activity of Staphylococcal enterotoxin A increased by nearly 1.5-2 orders. The observed phenomena can be explained by receptor-independent intracellular translocation of the hydrophobized toxins.

Acylation↗

PubMed1976

Influence of the degree of hydrolysis of beef tallow on its absorption in the young pig.

Beef tallow was hydrolyzed to produce a series of fats with 3, 10, 20, 46, and 100% free fatty acids, which were incorporated at the level of 10% into semipurified diets. These diets along with a low-fat control diet were each fed to five piglets from 10 to 22 days of age. Tridodecyl glycerol ether was used as an indicator of fat absorption. Feces samples were collected between 19 and 22 days of age and the pigs were killed to allow samples of digesta to be collected. Analysis of feces and digesta allowed the progress of fat absorption to be monitored through the digestive tract. The corrected absorbability of the total lipid was between 88 and 93% for the partially hydrolyzed tallows, but was only 75% for the completely hydrolyzed tallow. The oleic acid was well absorbed (95-99%) in all the diets; palmitic and stearic acids were also well absorbed in the intact and partially hydrolyzed tallow (82-84% and 63-77%, respectively, the for palmitic and stearic acids), but their absorption was impaired in the completely hydrolyzed tallow (62% and 38ll intestine is the major site of fat uptake. Comparison of the amounts of fatty acids in the ileal digesta and in thl feces showed that there was no change in the total amount of fat in the digesta as it passed through the large intestine.

Animals↗

PubMed2006

Quantification of phosphatidylserine, phosphatidic acid and free fatty acids in an ultrasound contrast agent by normal-phase high-performance liquid chromatography with evaporative light scattering detection.

Sonazoid is a new contrast agent for ultrasound imaging. The product is an aqueous suspension of perfluorobutane microbubbles coated with phospholipids obtained from hydrogenated egg phosphatidylserine (H-EPS). A normal-phase high-performance liquid chromatographic (HPLC) method with evaporative light scattering detection was developed for quantification of free fatty acids, phosphatidylserine and phosphatidic acid in H-EPS and Sonazoid. Separation of the lipids was carried out on an HPLC diol column and a gradient of chloroform and methanol with 0.2% formic acid titrated to pH 7.5 with ammonia. The calibration standards contained stearic acid, distearoyl-phosphatidic acid (DSPA) and distearoyl-phosphatidylserine (DSPS) in the concentration range of 0.016-1.0mg/ml (0.4-25microg injected). The method was validated with a limit of quantification of the three lipids set to 0.4microg (approximately 20-60microM). The best fit of the three calibration curves were obtained when the logarithmic transformed theoretical lipid concentration was plotted against the logarithmic transformed area under the peak and fitted to a second order polynomial equation. Stearic acid, DSPA and DSPS were analysed with an intermediate precision ranging from 4.4% to 5.3% R.S.D. and they were extracted from an aqueous suspension with a recovery ranging from 103.3% to 113.3%. The sum of total phospholipid concentration determined in H-EPS ranged from 96.4% to 103.2% of the theoretical values. The lipids in the ultrasound product were quantitated with a repeatability ranging from 6.2% to 11.7% R.S.D.

Chromatography, High Pressure Liquid↗

PubMed1993

Controlled release of theophylline from inert matrices: effect of channeling material on release rate.

Sustained release theophylline tablets containing stearic acid wax and lactose fast flo as chanelling agent were prepared and evaluated. The fusion technique was used for dispersing the drug in the different levels of stearic acid. The release rate of theophylline from the prepared tablets increased with the increase of the level of the channeling material in the formula. The drug release from tablets containing high level of wax (30 and 60%) and low level of channeling material (59% and 29%) followed the diffusion controlled model for inert porous matrix. The drug release increased significantly with the increase of lactose fast flow level in the formula. After 2 hours of testing dissolution, the tablets start to erode and the mechanism of drug release deviate from the diffusion controlled model. The mechanism of drug release was dependent on the level of the channeling material in the matrix.

Chemistry, Pharmaceutical↗

PubMed1982

Fatty acid composition of adipose tissue, blood, lipids, and glucose tolerance in patients with different degrees of angiographically documented coronary arteriosclerosis.

Forty-eight patients with symptoms of angina pectoris were studied for adipose tissue fatty acid composition and cardiovascular risk factors while hospitalized for selective coronary angiography. Patients with manifest diabetes mellitus and deviations form the "normal" customary diet were excluded. Pairwise comparison between the groups with absent, slight, moderate, and severe coronary arteriosclerosis showed reasonable comparability for age, relative body weight, and skinfold measurements. The proportion of smokers, but not of hypertensives, showed a significant positive relationship with the degree of arteriosclerosis. Serum cholesterol was similar in all four groups, while triglycerides were clearly, but not significantly (P greater than 0.05) higher in patients with coronary arteriosclerosis. The oral glucose tolerance test (OGTT) index was significantly higher in moderate and severe disease. Significantly higher proportions for palmitic acid lower proportions for linoleic acid were also found in these two groups. Multiple linear regression analysis showed a positive association with coronary arteriosclerosis for: OGTT index greater than palmitic acid greater than arachidonic acid greater than triglycerides. The close negative association between the proportion of stearic acid in adipose tissue and coronary heart disease observed in two previous studies could not be confirmed. On the basis of the present study, stearic acid correlates with age rather than with arteriosclerotic disease.

Adipose Tissue↗

PubMed1977

Lipid metabolism of the yellow clam, Mesodesma mactroides: 3-saturated fatty acids and acetate metabolism.

The fate of labeled palmitate, stearate, and acetate administered to the yellow clam, Mesodesma mactroides, was investigated. 1(-14)C palmitic and 1(-14)C stearic acids were oxidized to CO2 to a limited extent. They were mainly incorporated in diacylglycerols and triacylglycerols and were converted to higher homologs. After administration, palmitic acid was converted to stearic and oleic acids, whereas administered stearic acid was converted to 18:1, 18:2, 20:1, and 20:2 acids. Labeled acetate was readily included by the clam in 12:0, 14:0, 14:1, 15:0, 16:1, 16:1, 16:2, 18:2, 18:1, 18:2, 20:1, 20:2, and 20:3 acids.

Acetates↗

PubMed1994

Effects of antioxidants and fatty acids on low-density-lipoprotein oxidation.

Evidence continues to accumulate that implicates the oxidative modification of low-density lipoprotein (LDL) in the pathogenesis of atherosclerosis. Numerous studies have indicated the existence of oxidized LDL in vivo. Supplementation of animals and humans with antioxidants such as alpha-tocopherol have shown promise in reducing the extent of LDL oxidation. However, another possible means of preventing LDL oxidative modification may be by reducing the amount of oxidizable polyunsaturated fatty acids in the LDL particle. Monounsaturated fatty acids have been shown to decrease the susceptibility of LDL oxidation in human studies. It remains to be seen whether saturated fatty acids can do the same. Stearic acid, found in cocoa butter, would be an ideal saturated fatty acid to test because it has a neutral effect on the plasma lipid profile.

Animals↗

PubMed1976

Serum triglycerides and fatty acid incorporation into human adipose tissue (TIAT). Their relations with adipose tissue characteristics and glucose tolerance.

Fatty acid incorporation into adipose tissue (FIAT), the metabolic process assimilating plasma triglyceride fatty acids liberated by lipoprotein lipase, was recently found to be lower in hyper- than in normotriglyceridaemia. In the present report, the relation of FIAT to glucose tolerance and adipose tissue morphology and fatty acid composition has been studied in a popoulation of men with normo- and hypertriglyceridaemia, using needle biopsy specimens. In addition, the associations between plasma triglyceride concentration and these factors as well as FIAT were examined by statistical methods. FIAT and GLIAT (glucose incorporation into adipose tissue) activities per cell were positively correlated with fat cell diameter but not with fat cell number. FIAT activities per cell and per unit surface area were lower in hyper- than in normo-triglyceridaemic subjects. The k-value of the i.v.glucose tolerance test and glycerol release from adipose tissue did not correlate with FIAT or GLIAT activities. The proportion of stearic acid in adipose tissue was negatively correlated with the serum triglyceride level and with fat cell diameter, but positively correlated with FIAT. Linolenic acid in adipose tissue correlated positively with the k-value. The negative correlation between serum triglycerides and FIAT remained when the other variables which were significantly correlated with FIAT or the serum triglycerides were entered in partial correlat-on analysis. These results suggest that although low FIAT activity is related in part to other characteristics, it occurs in hypertriglyceridaemia independent of glucose tolerance or various characteristics in fat. With serum triglyceride concentration as dependent variable, stepwise regression analysis was performed, entering all other variables as independent ones. The highest multiple --value was 0.76 (p less than 0.001) and it was obtained with three adipose tissue parameters: FIAT (or GLIAT), content of linolenic acid and of stearic acid. The other parameters did not give rise to any further improvement in the prediction of the serum triglyceride concentration which is better than 50% (R2 = 0.57).

Adipose Tissue↗

PubMed1999

Inhibition of neurofibromin and p120 GTPase activating protein (GAP) by dietary fatty acids.

Neurofibromin and p120 GTPase activating protein (p120 GAP) down-regulate the activity of cellular Ras proteins. How the activity of these two proteins is controlled is not yet clear. In this study, we analyzed the effects of eight nutritionally relevant fatty acids on GTPase stimulatory activity of full-length neurofibromin and p120 GAP. The fatty acids tested were: saturated stearic acid, monounsaturated oleic acid, three omega-6 and three omega-3 polyunsaturated fatty acids. The analysis was performed by Ras immunoprecipitation GTPase assay. The full-length p120 GAP expressed in insect Sf9 cells and the immunoaffinity purified full-length neurofibromin were used. Neurofibromin was readily inhibited by stearic and oleic acid, but p120 GAP was not inhibited even at high concentrations (> 80 microM). Neurofibromin was also inhibited by low concentrations of all the polyunsaturated fatty acids tested (IC50 of 6 to 16 microM). p120 GAP was 2-3 fold less sensitive to inhibition by these fatty acids. The GTPase stimulatory activity of neurofibromin was also inhibited by arachidonic and oleic acid in the presence of a lipid mixture representing the major lipid components of the cell membrane. Chimeric proteins of neurofibromin and p120 GAP were used to determine that differential sensitivity to fatty acid inhibition maps to the catalytic domain of the proteins. These results indicated that fatty acids can modulate the GTPase function of the c-Ha-Ras protein by inhibiting the GTPase stimulatory activity of two Ras regulators, full-length neurofibromin and p120 GAP, at physiologically relevant concentrations in vitro.

Animals↗

PubMed2006

J-aggregates in matrix stabilized two-dimensional azobenzene derivatives.

A two-component film technique at the air-water interface has been used for fabricating matrix stabilized azobenzene J-aggregates. Langmuir monolayers of (E)-1-(3-chloro-4-(alkyloxy)phenyl)-2-phenyldiazene (CnCD, n=8,10,12) have been prepared with stearic acid (STA) as the two-dimensional matrix. Miscibility studies at a molecular level, explored from the monolayer pressure-area isotherms revealed a phase separation of the CnCD from the stearic acid matrix at a compression pressure of 10 mN/m. A 43-nm strong red shift in the 350 nm pi-pi * absorption feature implied formation of highly ordered J-aggregates of CnCDs in conformity with atomic force microscopy and micro-Raman spectral characteristics. While a one-component CnCD failed to form a 2D monolayer, the STA supported CnCD binary system crossed a mixed monolayer phase followed by compression, leading to the formation of matrix stabilized CnCD J-aggregates.

Air↗

PubMed2004

Fatty acid profiles in relation to triglyceride level in the liver of dairy cows.

To elucidate possible relationships between triglyceride (TG) levels and fatty acid composition in bovine liver, hepatic TG and seven individual fatty acids were measured in 23 Holstein dairy cows, of them 6 are healthy. Liver TG level was greater than 3 % in 12 cows which were ruled fatty liver. Palmitic and oleic acid proportions were significantly higher in fatty liver cows than in the healthy cows, while stearic acid was lower in fatty liver cows. With increased liver TG, stearic acid proportions decreased dramatically. Results indicate that hepatic lipidosis markedly alters the proportions of the various fatty acids in the liver of dairy cows.

Animals↗

PubMed1981

Effects induced by two different estrogens on serum individual phospholipids and serum lecithin fatty acid composition.

Eleven oophorectomized women (mean age 34.5 +/- 5.9) received two treatment cycles, one of the 17-C-alkylated ethinyl estradiol 20 microgram per day, and the second of the non-alkylated estrogen, estradiol valerate 2 mg per day for six weeks in separate periods preceded by six weeks without hormonal replacement therapy. Blood samples were drawn before and after six weeks on each estrogen. The samples were assayed for individual phospholipids i.e. cephalin, lecithin, lysolecithin and sphingomyelin after separation of these lipids by thin layer chromatography. The relative fatty acid composition of serum and high density lipoprotein lecithin and serum cholesterol ester was determined by gas liquid chromatography. Both estrogens reversed the symptoms of estrogen deficiency and had similar effects on serum individual phospholipids i.e. causing an increase in lecithin concomitant with a decrease in lysolecithin. It is suggested that this lecithin-lysolecithin shift could depend on an inhibition of the hepatic lipase and its phospholipase A1-activity. Both estrogens increased serum lecithin arachidonic acid without causing any change in linoleic acid (the major essential fatty acid), which indicates that this increase in arachidonic acid could be an estrogenic effect independent of dietary factors. Ethinyl estradiol caused an increase in palmitic and a decrease in stearic acid in the 1-position of serum lecithin while estradiol valerate did not influence these fatty acids at all. This palmitic-stearic acid shift induced by ethinyl estradiol is interpreted as a non-hormonal "drug-effect" linked to the liver toxicity of 17-C-alkylated steroids in spite of the lack of influence on routine liver function tests.

Adult↗

PubMed1989

Oxidation of alpha 1-protease inhibitor: role of lipid peroxidation products.

Previously we demonstrated that in vivo exposure of humans to NO2 resulted in significant inactivation of alpha 1-protease inhibitor (alpha 1-PI) in the bronchoalveolar lavage fluid. However, alpha 1-PI retains its elastase inhibitory activity in vitro when exposed to 10 times the concentration of NO2 used in vivo. We suggested exogenous oxidants such as O2 and NO2 exert their effect in vivo in part through lipid peroxidation. We investigated the mechanism of inactivation of alpha 1-PI in the presence or absence of lipids under oxidant atmosphere. alpha 1-PI in solutions containing phosphate buffer (control), 0.1 mM stearic acid (saturated fatty acid, 18:0), or 0.1 mM linoleic acid (polyunsaturated fatty acid, 18:2) was exposed to either N2 or NO2 (50 ppm for 4 h). Elastase inhibitory capacity of alpha 1-PI was significantly diminished in the presence of 0.1 mM linoleic acid and under NO2 atmosphere (75 +/- 8% of control, P less than 0.01), whereas there was no change in elastase inhibitory capacity of alpha 1-PI in the presence or absence (buffer only) of 0.1 mM stearic acid under a similar condition (109 +/- 11 and 94 +/- 6%, respectively). The inactivated alpha 1-PI as the result of peroxidized lipid could be reactivated by dithiothreitol and methionine sulfoxide peptide reductase, suggesting oxidation of methionine residue at the elastase inhibitory site. Furthermore the inhibitory effect of peroxidized lipid on alpha 1-PI could be prevented by glutathione and glutathione peroxidase and to some extent by alpha-tocopherol.

Antioxidants↗

PubMed1997

Changes in cerebral acyl-CoA concentrations following ischemia-reperfusion in awake gerbils.

Transient global cerebral ischemia affects phospholipid metabolism and features a considerable increase in unesterified fatty acids. Reincorporation of free fatty acids into membrane phospholipids during reperfusion following transient ischemia depends on conversion of fatty acids to acyl-CoAs via acyl-CoA synthetases and incorporation of the acyl group into lysophospholipids. To study the effect of ischemia-reperfusion on brain fatty acid and acyl-CoA pools, the common carotid arteries were tied for 5 min in awake gerbils, after which the ligatures were released for 5 min and the animals were killed by microwave irradiation. Twenty percent of these animals (two of 10) were excluded from the ischemia-reperfusion group when it was demonstrated statistically that brain unesterified arachidonic acid concentration was not elevated beyond the range of the control group. Brain unesterified fatty acid concentration was increased 4.4-fold in the ischemic-reperfused animals, with stearic acid and arachidonic acid increasing the most among the saturated and polyunsaturated fatty acids, respectively. The total acyl-CoA concentration remained unaffected, indicating that reacylation of membrane lysophospholipids is maintained during recovery. However, there was a substantial increase in the stearoyl- and arachidonoyl-CoA and a marked decrease in palmitoyl- and docosahexaenoyl-CoA. These results suggest that unesterified fatty acid reacylation into phospholipids is reprioritized according to the redistribution in concentration of acyl-CoA molecular species, with incorporation of stearic acid and especially arachidonic acid being favored.

Acyl Coenzyme A↗