Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “STEARIC ACID”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 757 records · Page 42Linked to original sources
PubMed1975

[Inestability of fatty acid desaturation enzymes in liver slices (author's transl)].

A study was made on the microsomal oxidative desaturating activity of fatty acids in rat liver slices incubated in different media. [1-14C] linoleic acid desaturation activity decreased during the incubation in Krebs-Ringer-Bicarbonate. The addition of glucose or pyruvate in the incubation medium did not alter the decrease of the linoleic desaturation activity compared to the controls. Linoleic desaturation to gamma-linolenic acid descreased even when the slices were incubated in different media and at different temperatures. However, the inclusion of aminoacids in the media prevented the decrease of linoleic acid desaturation. Microsomal stearic acid desaturation to oleic acid in liver slices was less modified by incubation than linoleic acid desaturation. Glucose inclusion in the medium enhanced 9-desaturation. The stability of the desaturases in the liver slices is discussed. The results evidence once more that 9-desaturation and 6-desaturation are accomplished by different enzymes controlled by separate mechanisms.

Animals↗
PubMed1992

Myocardial extraction of lactates, non-esterified fatty acids and their fractions in patients with dilated cardiomyopathy at rest and after the cold pressor test.

UNLABELLED: A decrease in the myocardial extraction or excretion of lactates indicates its hypoxia. The authors analyzed changes in the extraction of lactates, non-esterified fatty acids (NEFA) and their fractions: C 14:0, C 16:0, C 16:1, C 18:1, C 18:2 in a group of 15 patients with dilated cardiomyopathy (DC) and in 10 controls at rest and after the cold pressor test (CPT). At rest, 5 patients with DC produced lactates or extracted less than 10%. During CPT, production of lactates was observed in another four patients (mean values: 17.9 +/- 32.6% vs 24.5 +/- 5.2%, ns). NEFA extraction was found in the DC group: 18.4 +/- 20.6% vs. 13.9 +/- 33.3% /p < 0.05/). The acids involved were C 14:0, C 16:0, C 16:1 and C 18:0. In the controls, NEFA extraction did not change significantly: 12.1 +/- 8.6% vs 29.7 +/- 33.2%. CONCLUSIONS: 1. In part of patients with DC, production of lactates was found. The degree of lactate excretion increased due to CPT; 2. In DC, adrenergic stimulus (CPT) impairs the myocardial utilization of NEFA. This applied mainly to myristic acids, palmitic acid, palmitooleic acid and stearic acid; 3. This phenomenon probably is a result of profound functional and morphological damage to the mitochondrial system in DC.

Adult↗
PubMed1992

[Differentiation of fattening and slaughtering performance and carcass quality of broiler genotypes with and without the dwarf factor and fast or slow feathering under heat stress].

In a comparative study the influences were tested of the origins NWR (normal-growth White Rocks) and ZWR (dwarf-growth White Rocks) with a speed for slow (K) and fast (k) feathering as well as the effect of a high environmental temperature (UT, 32 +/- 2.5 degrees C) on the fattening and slaughtering performance of male broilers and their meat quality. Also investigated were effects of these factors on the fatty acid pattern of the two valuable parts--breast and leg. Dwarf broilers kept under high UT had a lower liveweight (LM8) in their 8th week as compared with NWR and animals kept under the usual UT. No influence was found of the feathering on the fattening and slaughtering performance. The effect of heat stress (high UT) and of the dwarfing gene on the breast and leg parts was statistically highly significant (P < 0.001). Dwarfed broilers and animals under normal UT exhibited a smaller slaughtering proportion as compared with normal animals and animals under a higher UT. The abdominal fat content was significantly higher under heat stress. Meat quality showed no dependence on the origin or the climatic conditions. In the fatty acid analysis no dependence could be detected of the FS pattern on the origins (genotypes), whereas an effect was found of the UT on some unsaturated and saturated fatty acids. Palmitic acid and stearic acid formed the largest part of all saturated FS investigated. Among the unsaturated FS the oil, linoleic, and palmitic acids reached the highest share. The effect of higher UT was not uniform in the FS pattern. The sum of saturated FT was increased under heat stress, thus suggesting a more favourable fat quality of the meat.

Adipose Tissue↗
PubMed1992

Structural elucidation of a novel phosphonoglycosphingolipid in eggs of the sea hare Aplysia juliana.

A novel phosphonoglycosphingolipid (AJPnGL) was isolated from eggs of the sea hare Aplysia juliana. The structure was determined to be Gal alpha 1-->2Gal beta 1-->4(2-aminoethylphosphonyl-->6)Glc beta 1-->1Cer by FAB/MS, 1H-NMR, hydrogen fluoride degradation, methylation analysis, partial acid hydrolysis and GC analysis of the component sugars, fatty acids and long-chain bases. The ceramide moiety of this lipid consisted of branched nonadeca-4-sphingenine and octadeca-4-sphingenine as main long-chain bases and palmitic acid and stearic acid as major fatty acids. Since the sugar chain (Gal alpha 1-->2Gal beta 1-->4Glc beta 1-->) and the ceramide moiety of AJPnGL were identical with those of the main neutral glycosphingolipid of eggs of A. juliana, the biosynthesis of AJPnGL may occur by the addition of 2-aminoethylphosphonate to the main neutral glycosphingolipid, Gal alpha 1-->2Gal beta 1-->4Glc beta 1-->1Cer.

Animals↗
PubMed1992

Amiodarone-induced endothelial injury is associated with phospholipase C-mediated hydrolysis of membrane phospholipids.

Phospholipids accumulate within the lysosomes of various cells from individuals taking amiodarone. Studies on cultured cells suggest that inhibition of lysosomal phospholipase A1 and phospholipase A2 by amiodarone may be responsible for this derangement in phospholipid metabolism. Inhibition of lysosomal phospholipases by amiodarone has been suggested as a mechanism of its toxicity, but this relationship has not been clearly established. To examine this question, membrane phospholipids of cultured bovine pulmonary artery endothelial cells (BPAEC) were labeled with 14C-stearic acid, 3H-arachidonic acid, 14C-choline, or 14C-ethanolamine. Radiolabeled BPAEC were then exposed to various concentrations of amiodarone, and endothelial phospholipase activity was measured by isolating and quantifying various phospholipase products. These findings were compared to a standard indicator of endothelial cytotoxicity using 51Cr release. Six-hour exposures to 5 to 20 micrograms/ml amiodarone produced no BPAEC toxicity and were accompanied by some evidence of decreased phospholipid hydrolysis. At concentrations above 20 micrograms/ml, amiodarone caused significant BPAEC toxicity as indicated by 51Cr release, and this was closely associated with the liberation of substantial amounts of 3H-arachidonic acid and 14C-stearic acid from phosphatidylcholine and phosphatidylethanolamine. In BPAEC labeled with 14C-choline and 14C-ethanolamine, cytotoxic doses of amiodarone caused accumulations of 14C-phosphocholine and phosphorylethanolamine, expected products of phospholipase C, but without increases in phospholipase A products. We conclude that exposure of BPAEC to toxic concentrations of amiodarone is associated with extensive hydrolysis of phosphatidylcholine and lysophosphatidylethanolamine via a phospholipase C-specific mechanism, and suggest that this may be a mechanism in the pathogenesis of amiodarone toxicity.

Amiodarone↗
PubMed2000

A study on fatty acid composition of fish oil from two marine fish, Eusphyra blochii and Carcharhinus bleekeri.

Two species of marine fish found in coastal waters of Karachi (Pakistan) were studied, Eusphyra blochii (Hammer-headed Shark) and Carcharhinus bleekeri (Shark) for their fatty acid composition. The isolation, identification and characterization of these fatty acids were carried out by gas liquid chromatography (GLC) and a combination of TLC-GLC technique. A large variation was observed between hammer-headed shark liver oil and shark liver oil. Twenty five individual fatty acids from the oil of marine fish were analyzed among those the palmitic acid was a major saturated fatty acid while stearic acid was the other major constituent. Among unsaturated fatty acids monoenoic e.g. oleic and palmitoleic acids were the major constituents and traces of dienoic and trienoic fatty acids were also found. In addition medicinally important polyunsaturated fatty, acid eicosapentaenoic and docosahexaenoic acids were also identified.

Journal Article↗
PubMed1991

Structure of triphosphonoglycosphingolipid containing N-acetylgalactosamine 6-O-2-aminoethylphosphonate in the nervous system of Aplysia kurodai.

A phosphonoglycosphingolipid, named F-21, was found in the nervous system of Aplysia kurodai by two-dimensional thin-layer chromatography (Abe, S., Araki, S., and Satake, M. (1986) Biomed. Res. (Tokyo) 7, 47-51). F-21 was isolated from the nervous tissue of Aplysia in this study, and its chemical structure was characterized as follows, where 2-AEP is 2-aminoethylphosphonate. (Formula; see text) The major aliphatic components of the ceramide portion were palmitic acid (75%), stearic acid (22%), octadeca-4-sphingenine (43%), and anteisononadeca-4-sphingenine (54%). Some information on the steric interactions in the sugar moiety was obtained by NMR spectroscopy. The ring protons of the internal galactose, H1, H3, and H4 and the H3 of the side chain galactose were shifted, as compared to the corresponding protons of dephosphonylated F-21. This may indicate the interactions between the 2-AEP residue of N-acetylgalactosamine and the internal galactose and between the N-acetyl group of N-acetylgalactosamine and the side chain galactose, implying a sterically restricted and unique structure that may relate to some biological functions of F-21.

Acetylgalactosamine↗
PubMed1990

Lean beef: impetus for lipid modifications.

Health-conscious consumers want lean beef. The beef industry has responded by physically removing much of the adipose tissue from retail products and by initiating attempts to produce--genetically and environmentally--cattle with more muscle, less external fat, and less seam fat, without sacrificing the quality dependent on the amount of marbling present. Offering lean beef that is closely or completely trimmed of external fat has improved retail beef sales. Impetus for modification of the lipid composition of bovine muscle and adipose tissue, including marbling, has resulted from the following: (a) diet/health concerns of consumers and demands for leaner beef, (b) research clarifying effects of dietary fatty acids and cholesterol on serum cholesterol levels, (c) dietary guidelines and recommendations from health organizations, and (d) dietary recommendations by physicians and dietitians to reduce beef consumption. Analysis of cholesterol content of marbling dissected from the rib (longissimus dorsi) muscle revealed that marbling contributes little to total cholesterol content. Cholesterol content of marbling was 117 mg/100 gm intramuscular adipose tissue (equivalent to about a 2 mg cholesterol contribution to a 100-gm serving of uncooked meat). The difference in fatty acid composition of lean meat and of adipose tissue is primarily in the percentage of polyunsaturated fatty acids, which is higher in lean meat. The most prevalent fatty acids in adipose tissue including marbling were: palmitic acid (24.1%), stearic acid (13.5%), and oleic acid (37.7%).

Adipose Tissue↗
PubMed1989

[Chemical composition and biological quality of defatted hazelnut flour].

The results of the chemical composition and biological quality of deffated hazel nut flour are shown. The samples analyzed contained significant amounts of proteins (19%) comparable to legume flour, higher than cereals and lower than deffated oleaginous flours. The oil extracted from the seed was analyzed and the average results obtained were the following: Refraction index, 1.47; saponification No. 184.8; iodine No. 85.0. The average composition of the fatty acids obtained by gas liquid chromatography was: Palmitic acid 2.3% Palmitoleic acid 37.0% Stearic acid 0.5% Oleic acid 39.5% Linoleic acid 6.9% Linolenic acid 1.1% Eicosanoic acid 2.3% Eicosaenoic acid 4.6% Docosenoic acid 3.4% Tetraeicosanoic acid 0.3% These results indicate a good-quality oil due to the low content of linolenic acid. The nutritive value of the deffated meal measured in the rats gave a net protein ratio (NPR) of 3.58, lower than the corresponding casein value (4.10). The true protein digestibility measured in the rat gave a value of 7.3%, compared to 95% for casein. The amounts of iron and phosphorous are comparatively lower than those reported for rape-seed meal and sunflower meal.

Animals↗
PubMed1989

Mechanism of psychotropic effect of toluene.

An acute 30 min exposure to toluene vapours (0.32 mmol/l of the air) provoked in the rat brain a decrease of total nonesterified fatty acids (arachidonic acid -21.7%, oleic acid -18.3%, stearic acid -7.9% in the brain cortex and arachidonic acid -6.8% in the hypothalamus). The results are in harmony with the hypothesis of the NEFA decreasing effect of the inhibitory substances in the brain.

Animals↗
PubMed1988

Evidence for carboxyl-terminal processing and glycolipid-anchoring of human carcinoembryonic antigen.

We have investigated the post-translational modification of carcinoembryonic antigen (CEA) for membrane-anchoring in QGP-1 cells derived from a human pancreatic carcinoma. Pulse-chase experiments with [3H]leucine demonstrated that CEA was initially synthesized as a precursor form with Mr 150,000 having N-linked high-mannose-type oligosaccharides, which was then converted to a mature form with Mr 200,000 containing the complex type sugar chains. The mature protein thus labeled was found to be released from the cell surface by treatment with phosphatidylinositol-specific phospholipase C, suggesting that CEA is a phosphatidylinositol-linked membrane protein. This was confirmed by metabolic incorporation into CEA of 3H-labeled compounds such as ethanolamine, myo-inositol, palmitic acid, and stearic acid. The 3H-labeled fatty acids incorporated were specifically removed from the protein by nitrous acid deamination as well as by phosphatidylinositol-specific phospholipase C treatment. Since the available cDNA sequence predicts that CEA contains a single methionine residue only in its carboxyl-terminal hydrophobic domain, processing of the carboxyl terminus was examined by pulse-chase experiments with [35S]methionine. It was found that CEA with Mr 150,000 was initially labeled with [35S]methionine but its radioactivity was immediately lost with chase. Taken together, these results suggest that CEA is anchored to the membrane by simultaneously occurring proteolysis of the carboxyl terminus and replacement by the glycophospholipid immediately after the synthesis.

Carcinoembryonic Antigen↗
PubMed1988

[Polyphosphoinositide metabolism in temporary cerebral ischemia--the reversibility after recirculation].

Brain cell membranes are known to abound in polyphosphoinositides (PPI) which contain large amounts of arachidonic acid and stearic acid. When a state of cerebral ischemia comes about, there occurs severe energy depletion and decomposition of PPI into diglyceride (DG) and inositol triphosphate (IP3) through activation of phospholipase C. Previous studies clarified rapid postischemic degradation of PPI, a time during which the metabolically active fraction of PPI is lost, but there have been no reports on PPI metabolism after the establishment of recirculation following ischemia. The authors examined relationship between the duration of the ischemia and the reversibility of PPI metabolism in rats with cerebral ischemia lasting 5 or 30 min that was followed by recirculation, and, further studied acyl group composition of PPI and DG in rats with 30 min of ischemia. Global cerebral ischemia was produced in male Wistar rats (220-250 g) by occlusion of basilar and bilateral common carotid arteries. The brains were frozen in situ at 1, 5, or 30 min of ischemia, or at 30 or 60 min of recirculation following either 5 or 30 min of ischemia. Phosphatidylinositol (PI), phosphatidylinositol, 4-phosphate (PIP), phosphatidylinositol, 4, 5-bisphosphate (PIP2), and DG were measured by TLC, and GLC. And also their acyl group compositions were determined. PI showed no significant changes. In contrast, both PIP and PIP2 sharply decreased immediately after onset of cerebral ischemia. then continued to fall gradually from 5 min onwards. And PIP and PIP 2 increased after onset of recirculation in both 5 and 30 min ischemia groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Effect of oleic acid on mitochondrial oxidative phosphorylation in rat brain slices.

We tested the effect of oleic acid on oxidative phosphorylation and free fatty acid composition in rat brain slices simultaneously to investigate the relationship between the change in respiratory control ratio and the uptake of oleic acid in the brain mitochondria. The uncoupling of mitochondria was observed when the ratio of oleic acid to stearic acid in the free fatty acid fraction was nearly doubled, but was not recovered even by the addition of fatty acid-free bovine serum albumin. The data suggest that the intactness of oxidative phosphorylation of brain mitochondria is maintained by the precise control of the free fatty acid composition in the mitochondrial membranes.

Animals↗
PubMed1986

Involvement of lysophospholipase D in the production of lysophosphatidic acid in rat plasma.

A vasoactive lipid present in rat plasma that had been incubated at 37 degrees C for 48 h was identified as lysophosphatidic acid with the following fatty acid composition: palmitic acid (25.2%), stearic acid (8.4%), oleic acid (7.0%), linoleic acid (44.4%) and arachidonic acid (11.9%). The involvement of lysophospholipase D in the production of lysophosphatidic acid was suggested on the basis of extensive analyses of phospholipids in the plasma. Results indicated that lysophospholipase D hydrolyzed polyunsaturated lysophosphatidylcholines preferentially to the saturated species. Exogenously added platelet activating factor was found to be first converted to its lyso derivative by an acetylhydrolase in rat plasma and then degraded by lysophospholipase D to 1-alkyllysophosphatidic acid to a similar extent with exogenously added lyso derivative of platelet activating factor; their percent conversions to lysophosphatidic acid were higher than those of saturated 1-acyllysophosphatidylcholines, but lower than those of polyunsaturated 1-acyllysophosphatidylcholines.

Animals↗
PubMed1985

Mechanism of liver mitochondrial dysfunction associated with bile duct obstruction.

To elucidate the mechanism of liver mitochondrial dysfunction induced by obstructive jaundice, the following experiments were performed. In vivo study: Using Wistar male rats, bile ducts were ligated, and serum levels of total bilirubin (T-Bil), GOT, GPT, mitochondrial GOT (mGOT) and total bile acids (TBA) were measured at 3 and 7 days after the ligation. Then, the liver was isolated to determine mitochondrial functions and to measure the content of fatty acids in mitochondrial phospholipids by high performance liquid chromatography. The levels of T-Bil, GOT, GPT, mGOT and TBA were elevated by the bile duct ligation. Mitochondrial functions were deteriorated, and contents of arachidonic acid, palmitic acid and stearic acid in mitochondrial phospholipids decreased. Pretreatment with coenzyme Q10 (E-0216, CoQ10), an antidetergent agent, prevented not only the development of mitochondrial dysfunction and the decrease in mitochondrial phospholipids but also the elevation of GOT, GPT, and mGOT although CoQ10 did not prevent the elevation of T-Bil and TBA levels. In vitro study: Using intact rat liver mitochondria, the effect of taurocholic acid (TCA), one of the physiological bile salts, on the mitochondrial function and on mitochondrial phospholipids was examined. Incubation of mitochondria with TCA induced a dose-dependent deterioration of mitochondrial function and the increase in the content of solubilized phospholipids. The protective effect of CoQ10 was also observed in the in vitro study. These results indicate that degradation of mitochondrial phospholipids by bile acids is responsible for the early phase of liver dysfunction induced by obstructive jaundice.

Alanine Transaminase↗
PubMed1978

A new chromatographic approach to the resolution of individual gangliosides. Ganglioside mapping.

1. Anion-exchange column chromatographies on DEAE-Sephadex, DEAE-Sepharose and QAE-Sephadex were tested for fractionation of ganglioside-molecular species. DEAE-Sepharose gave the best resolution, with good separation of mono-, di-, tri- and even tetrasialogangliosides. Even minor gangliosides could be resolved and detected by silica gel thin-layer chromatography of successive fractions of effluent from a DEAE-Sepharose column. In this two-step chromatographic system, the first step of elution from the column depends on differences in anionic charge and the second step of development on a silica gel plate depends on differences in polarity. With this ganglioside-mapping technique, at least 25 unidentified gangliosides were separated from bovine and human brains in addition to the well-known compounds, G7, GM3, GM2, GM1, GM1 (GlycNeu), GD2, GD3, GD1a, GD1a-GAN, GD1a(AcNeu, GlycNeu), GD1b, GT1a, GT1b and GQ. 2. The procedure was used to compare the gangliosides in human (3, 5 and 35 years old), bovine, cat, rat, rabbit, chicken and dog brains. The ganglioside profiles of human, cat, rat, rabbit and dog brains only differed in minor components. However, the gangliosides in chicken brain were unexpectedly complex, at least 30 minor gangliosides, including 15 monosialogangliosides being recognized. Gangliosides containing N-glycolylneuraminic acid (GDIa and GM1 type) were only found in bovine brain. The concentrations of tri- and tetrasialogangliosides in human brain were found to increase during maturation. 3. The long chain bases of each ganglioside fraction, in which the content of sialic acid was confirmed by measuring the ratio of sialic acid to stearic acid, were also analyzed as their aldehydes. The ratios of C-20 to C-18 sphingosine increased in the series from the mono- to tetrasialoganglioside fraction (0.216-1.777) in all animal brains tested.

Adult↗
PubMed1982

Decreased erythrocyte membrane fluidity and altered lipid composition in human liver disease.

Abnormal plasma lipoproteins in patients with liver disease are associated with characteristic changes in erythrocyte membrane lipid composition. The membranes are enriched in cholesterol and phosphatidylcholine and both the cholesterol/phospholipid and phosphatidylcholine/sphingomyelin molar ratios are increased. Phospholipid fatty acid composition is also abnormal; the proportions of arachidonic acid and stearic acid are decreased and that of palmitic acid raised. In this study we have examined the effects of these membrane lipid abnormalities on membrane fluidity. Erythrocyte membrane fluidity was assessed in 30 patients with a variety of liver diseases and in 25 normal subjects using the hydrophobic, fluorescent probe 1,6-diphenylhexa-1,3,5-triene and the values were related to their lipid composition. Membrane fluidity was significantly decreased in the patient erythrocytes (lipid order parameter, S(v)[37 degrees C] = 0.713 +/- 0.018, mean +/- S.D. compared to 0.686 +/- 0.008 in the normal subjects, P < 0.001) and correlated significantly with the cholesterol/phospholipid ratio (r = 0.88, P < 0.001). The fluidity of lipid extracts from the membranes of patient erythrocytes was also decreased, suggesting that decreased membrane fluidity was mainly a consequence of altered lipid composition rather than protein abnormalities. Incubation of patient erythrocytes for 20 hr with normal, heated plasma removed the excess cholesterol without affecting the phosphatidylcholine/sphingomyelin ratio or phospholipid fatty acid composition; following incubation the fluidity of these membranes was similar to that of normal membranes. We conclude that in liver disease changes in the composition of the phospholipid bilayer matrix in the erythrocyte membrane have little influence on its fluidity; the reduced fluidity is predominantly a result of increases in cholesterol relative to phospholipid.-Owen, J. S., K. R. Bruckdorfer, R. C. Day, and N. McIntyre. Decreased erythrocyte membrane fluidity and altered lipid composition in human liver disease.

Abetalipoproteinemia↗
PubMedDate not supplied

[Lipids of Raillietina tetragona and Raillietina echinobothrida cestodes from the intestines of hens].

Lipids of the cestodes R. tetragona and R. echinobothrida, parasites of chickens, were studied by thin-layer and gas-liquid chromatography methods. The quantity of neutral lipids amounts to 74.4% in R. tetragona and to 73.1% in R. echinobothrida. Triglycerides amount to 35.6% and 38.4% of the neutral lipids in these species, sterols to 21.6% and 17.2%, sterol esters to 25.1% and 32.0%, diglycerides to 2.8% and 1.4% and free fatty acids to 7.8% and 6.5%, respectively. Fatty acids content of worms is similar but not identical of that of chicken intestine lipids. Cestode infection affects the lipid content of chicken intestine resulting in the decrease of triglycerides and oleic acid quantities and in the increase of the amount of free fatty acids and stearic acid.

Animals↗