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At least 109 records · Page 6Linked to original sources
PubMed1979

Serum radioactivity of 14C-triolein and 3H-oleic acid ingested in a test meal:a rapid test of pancreatic exocrine insufficiency.

A double-tracer technique to estimate lipid digestion was investigated. 3H-labelled oleic acid and 14C-labelled triolein were ingested in a test meal. The serum radioactivity of 3H after ingestion of labelled oleic acid depends on absorption and metabolism of free fatty acids, while serum radioactivity of 14C from triolein, in addition to the former, depends on triglycerol digestion. This study shows that the ratio between 3H and 14C 2h after the test meal gives a good qualitative and quantitative estimation of lipid digestion: the 3H/14C ratio in patients with maldigestion is significantly higher than for normals (P less than 0.01), the predictive value of the 3H/14C ratio in the diagnosis of maldigestion is high, that of a positive result being 1.0 and that of a negative 0.93, and quantitatively the 3H/14C ratio shows a highly significant correlation with faecal fat (P less than 0.001). The test is very easy to perform, lasts for only 2 h, and is without discomfort to the patient or nursing and laboratory staff. It gives information like or superior to that of faecal fat measurement.

Adult↗
PubMed1985

The serum 14C-triolein/3H-oleic acid assimilation test for differential diagnosis of maldigestion and malabsorption.

In 125 consecutive patients the measurement of serum radioactivities after simultaneous ingestion of 14C-triolein and 3H-oleic acid was investigated as a test of lipid assimilation. The sum of the 2-h and 4-h concentrations of 14C in serum (se(2 + 4)14C) was most useful as an index of lipid assimilation, and the 2-h serum 3H/14C ratio (se-3H/14C) reflected lipid digestion. Normal values were se(2 + 4)14C greater than or equal to 1.0% of the dose ingested per litre serum and se-3H/14C less than 1.3. Se(2 + 4)14C correlated significantly with faecal fat (r = -0.56, P less than 0.001) and indicated malassimilation in 26 of the 50 patients with a faecal fat excretion greater than 7 g/day. False-negative values appeared mainly in the patients with moderate steatorrhoea and gastrointestinal anastomoses. Only one false-positive se(2 + 4)14C value was found. Se-3H/14C was abnormal in 24 of the 34 patients with maldigestion with 2 false-positive results. When the results of se(2 + 4)14C and se-3H/14C were combined, the predictive value of the test result 'normal lipid assimilation' was 0.75, that of the test result 'maldigestion' was 0.93, and that of 'malabsorption' was 0.71. It is concluded that the serum 14C-triolein/3H-oleic acid assimilation test is convenient and inexpensive and may be useful when quantitative faecal collections are not available.

Adult↗
PubMedDate not supplied

Reversible MR changes in the cat brain after cerebral fat embolism induced by triolein emulsion.

BACKGROUND AND PURPOSE: Clinical cerebral-fat embolism shows both reversible and irreversible changes. We used MR imaging to investigate the reversibility of embolized lesions induced with a fat-emulsion technique and to evaluate the histologic findings. METHODS: A fat emulsion was made with 0.05 mL of triolein and 20 mL of normal saline and vigorous to-and-fro movement through a three-way stopcock. In 50 cats, the internal carotid artery was infused with the fat emulsion. Cats were divided into six groups on the basis of time delay after embolization: 1 hour; 1 and 4 days; and 1, 2, and 3 weeks. MR imaging and histologic examination were performed at these times. RESULTS: Embolized lesions were hyperintense on T2-weighted images, isointense or mildly hyperintense on diffusion-weighted images, isointense on apparent diffusion coefficient maps, and enhancing on gadolinium-enhanced T1-weighted images at 1 hour. These MR imaging findings were less evident at day 1 and reverted to normal after day 4 (isointense on all images). Electron microscopy showed minimal findings in the cortical lesion in groups 1 and 2 (group 1 at 1 hour and group 2 at 1 hour and 1 day). Light microscopic findings revealed evidence of necrosis-small focal gliosis and demyelination in the periventricular white matter-in only one cat. The number of intravascular fat globules was not significantly different between groups, as visualized by oil red O staining. CONCLUSION: Cerebral-fat embolism induced by a triolein emulsion revealed reversible MR findings and minimal histologic findings.

Animals↗
PubMed1978

Properties of cholesteryl oleate and triolein in mixed monolayers at the air-water interface.

The properties of cholesteryl oleate and triolein in mixed monolayers at the air-water interface have been measured between 24 and 37 degrees C. Analysis of force-area curves obtained as a function of the mol fraction of cholesteryl oleate indicates that at relatively low surface pressures these compounds are miscible in two dimensions up to a limit of about 0.5 mol fraction. At higher pressures either cholesteryl oleate or both lipids are expelled from the monolayer to form a bulk phase which is in rapid equilibrium with the surface phase. In the monolayer phase, orientation of the ester function of cholesteryl oleate is toward the aqueous phase, interaction with triolein is minimal, and packing is uniform over the solubility range. This together with the susceptibility of the cholesteryl oleate to enzymatic hydrolysis, suggests the applicability of monolayer systems to the study of cholesterol esterase activity. Comparison of our results with the bulk properties of these lipids suggests that the expelled cholesteryl oleate exists as a smectic mesophase and thus the system may provide a model for studying the transfer of molecules between the interior and surface of lipid deposits of the type found in atherosclerotic lesions.

Cholesterol Esters↗
PubMed1984

Use of the triolein breath test for the demonstration of fat malabsorption in coeliac disease.

Different screening tests for fat malabsorption were evaluated in patients with coeliac disease. The triolein breath test correlated well with results of faecal fat determination. Urinary excretion of oxalate with or without dietary oxalate loading was not correlated with faecal fat measurements. It is concluded that the triolein breath test is a useful procedure for the detection of fat malabsorption in patients with coeliac disease.

Adult↗
PubMed1982

Two-stage triolein breath test differentiates pancreatic insufficiency from other causes of malabsorption.

In 24 patients with malabsorption, [14C]triolein breath tests were conducted before and together with the administration of pancreatic enzymes (Pancrease, Johnson and Johnson, Skillman, N.J.). Eleven patients with pancreatic insufficiency had a significant rise in peak percent dose per hour 14CO2 excretion after Pancrease, whereas 13 patients with other causes of malabsorption had no increase in 14CO2 excretion (2.61 +/- 0.96 vs. 0.15 +/- 0.45, p less than 0.001). The two-stage [14C]triolein breath test appears to be an accurate and simple noninvasive test of fat malabsorption that differentiates steatorrhea secondary to pancreatic insufficiency from other causes of steatorrhea.

Breath Tests↗
PubMed1982

[Non-invasive diagnosis of isolated chylopericardium using precordial pericardial imaging after oral administration of 131I-triolein: report of a case].

Chylopericardium is a rare disease and affects both sexes equally from neonate to adult. Usually, there are abnormal connections between the pericardial cavity and thoracic lymphatic systems. These connections are detected by (1) recovery of orally administered Sudan III from pericardial fluid, (2) evidence of radioactivity in the pericardial fluid by paracentesis after oral administration of 131I-labeled triolein, and (3) lymphangiography. However, these method are technically difficult and invasive, thus sometimes dangerous for children. We employed precordial pericardial imaging after oral administration of 131I-labeled triolein on a 9-year-old Japanese girl with isolated chylopericardium before and after surgery. Abnormal connections and the back-ward flow to the pulmonary lymphatics were demonstrated by this method. This is an easy, non-invasive, reliable and safe method for detecting the abnormal connections of pericardial and lymphatic systems in children with chylopericardium.

Child↗
PubMed1963

USE OF LABELLED TRIOLEIN, VITAMIN A, AND D-XYLOSE IN THE DIAGNOSIS OF MALABSORPTION.

This paper discusses the type of results given by a group of test procedures used in the study of small intestinal dysfunction. While the chemical estimation of faecal fat remains the most valuable criterion for the laboratory detection of malabsorption, the occurrence of abnormal faecal or blood radioactivity also denotes the presence of malabsorption, although some patients with staetorrhoea appear to ;absorb' labelled triolein normally. Analysis of data from the other tests shows that steatorrhoea is not necessarily present in patients who give abnormal results and that the presence of malabsorption does not preclude a normal capacity for handling the test substances. These reservations impair the value of the vitamin A and xylose ;tolerance' tests and serum carotene levels as screening procedures for the determination of malabsorption states. On the other hand, these tests show patterns of results which are useful in differentiating idiopathic from secondary steatorrhoea, since patients with secondary malabsorption often handle one or more of these test substances normally.

Body Fluids↗
PubMed1988

Triolein breath test of fat absorption in patients with chronic liver disease.

We have compared the [14C]triolein breath test for fat malabsorption with fecal fat excretion corrected for marker pellet recovery in 23 subjects with chronic liver disease. The breath test identified 15 of the 17 subjects with abnormal fecal fat excretion (sensitivity 88%). However, four of the six subjects with normal fecal fat excretion gave abnormal breath test results (specificity 33%). While three of the four subjects with falsely abnormal breath tests had alcoholic liver disease, the explanation for the low specificity is unclear and may not be confined to patients with alcohol-related disease. We are therefore unable to recommend the breath test as a screen for steatorrhea in patients with chronic liver disease.

Breath Tests↗
PubMed1981

Differential diagnosis of maldigestion and malabsorption of fat. I. Comparison of the radioactivity of triglyceride and non-esterified fatty acid in fecal fat using purified 131I-triolein.

To differentiate maldigestion from malabsorption of fat, we compared the radioactivity of triglyceride with non-esterified fatty acid in fecal fat after ingestion of radiochemically purified 131I-triolein. A large amount of radioactivity was present in the triglyceride fraction from patients with pancreatic insufficiency, while such was found only in non-esterified fatty acid fraction in patients with short bowel syndrome, as determined by thin-layer chromatogram scanning. Thus, the "Digestion-Absorption Index" was calculated as a ratio of the radioactivity of triglyceride to that of non-esterified fatty acid. Mean Digestion-Absorption Index was 0.946 in the maldigestive group, and 0.045 in the malabsorptive group, and there was a statistical significance. However, an overlap in a few cases was confirmed in the area of 0.10 +/- 0.02, when this index was plotted on a table of semilogarithms. We assumed that this overlap was chiefly the result of maldigestion plus malasorption of fat.

Adult↗
PubMed1986

Effects of dietary triolein and sunflower oil on insulin release and lipid metabolism in Zucker rats.

Obese and lean male Zucker rats were fed ad libitum on diets containing either 50 (L) or 200 (H) g/kg diet of either triolein (T) or sunflowerseed oil (S). The specific activity of the hepatic microsomal delta 9 desaturase enzyme was depressed in both lean and obese rats fed the HS diet compared with the other three diets. The fatty acid composition of liver and subcutaneous white adipose tissue lipids were consistent with a lower delta 9 desaturation activity in rats fed the H diets, particularly for the HS diet. In both genotypes, microsomal delta 9 desaturase activity and the ratio of 16:1/(16:0 + 16:1) fatty acids in liver lipids were inversely related to the proportion of 18:2 in liver lipid. Plasma insulin concentrations and rates of glucose-stimulated insulin release in vivo were higher in obese rats compared with lean rats, and plasma insulin levels were higher in rats fed S compared with T. There was no relationship between delta 9 desaturase activity and either plasma insulin concentration or rates of insulin release in vitro. These findings suggest that hepatic delta 9 desaturase activity of Zucker rats is responsive to changes in the proportion of 18:2 in liver lipids but is not affected by changes in insulin secretion.

Animals↗
PubMed2002

Regioselectivity of new bacterial lipases determined by hydrolysis of triolein.

The newly identified lipases of 67 bacterial strains, primarily Bacillus and Pseudomonas, from the ARS Culture Collection have been characterized on the basis of their positional specificity for triglycerides (triolein). Lipase was produced by growing the cultures in tryptone-glucose-yeast extract medium for 24 h at 30 degrees C before addition of triglyceride. The lipase was allowed to act on the triglyceride for 3 days before analysis by thin-layer chromatography. Of the bacterial lipases tested, 55 displayed random specificity, 9 were 1,3-specific, and 3 showed no apparent lipase activity under these conditions.

Bacillus↗
PubMed2001

Modeling of alpha-tocopherol loss and oxidation products formed during thermoxidation in triolein and tripalmitin mixtures.

The degradation of alpha-tocopherol and the formation of alpha-tocopherol and triacylglycerol oxidation products at high temperatures (150-250 degrees C) over a heating period (0-4 h) for a model system ranging between triolein and tripalmitin were modeled by use of an experimental design. The oxidation products of alpha-tocopherol formed under these conditions were alpha-tocopherolquinone (1 .4-7.7%) and epoxy-alpha-tocopherolquinones (4.3-34.8%). The results indicate a very high susceptibility of alpha-tocopherol to capture peroxyl radicals upon oxidation, leading to the formation of polar tocopherol oxidation products. Both alpha-tocopherolquinone and epoxy-alpha-tocopherolquinones were not stable upon prolonged heating and were further degraded to other unknown oxidation products. The kinetics of alpha-tocopherol oxidation were significantly influenced by the triolein/tripalmitin ratio. By increasing the level of triacylglycerol unsaturation the rate of alpha-tocopherol recovery after heating increased significantly from 2.2 to 44.2% whereas in the meantime triacylglycerol polymerization increased from 0 to 3.7%.

Chromatography, High Pressure Liquid↗
PubMed1988

The partitioning of fatty acid and cholesterol between core and surfaces of phosphatidylcholine-triolein emulsions at pH 7.4.

Fatty acids are important intermediate molecules in lipid metabolism. During lipolysis of intracellular lipid droplets or plasma triacylglycerol-rich lipoproteins, fatty acids are generated and may transiently accumulate. We therefore studied the distribution of both fatty acid and free cholesterol between the core and surface of phosphatidylcholine-triolein emulsions at pH 7.4. Nine emulsion systems containing 0.8 to 6.6% cholesterol and 0.16 to 1.02% oleic acid were formed, and core and surface phases were isolated. Phospholipid distributes only to the surface phase. The distribution coefficient of cholesterol surface to core was 23.9 +/- 3.6 S.D., i.e., there was approx. 24-times more cholesterol per unit mass in the surface than in the core phase. This distribution was unchanged by the presence of different quantities of fatty acid in the emulsion particles. The apparent distribution coefficient of fatty acid in surface to core was about 10 at low cholesterol contents and fell to about 7 at high cholesterol contents. However, when the apparent distribution coefficient of fatty acid was related only to the phospholipid component of the surface, the apparent distribution coefficient was constant at about 12.3 +/- 1.1 S.D. Since the fatty acid in the surface phase is about half ionized the true distribution coefficient of unionized fatty acids is about 6.2. The results indicate that fatty acids partition into the phospholipid domains of the surface and not into cholesterol domains and the distribution of fatty acids into surface phospholipid domain is not affected by cholesterol content.

Algorithms↗
PubMed1995

The influence of cholesteryl ester content on hepatocyte triolein emulsion uptake.

When triolein emulsions are enriched with cholesteryl oleate they are more readily removed by primary rat hepatocytes and HepG2 cells via an apolipoprotein E-responsive pathway. The increment in the cholesteryl ester does not appreciably change the size of the emulsion or its affinity for the apo E protein. The cholesteryl ester enriched-emulsion demonstrates increased apo E-mediated HepG2-binding as well as endocytosis. The higher the content of cholesteryl ester of the particle, the greater was both the binding and the endocytosis. The increased endocytosis was associated with increased degradation of the apo E. Cholesteryl linoleate and palmitate produced the same effects as the oleate. Lecithin-cholesterol acyltransferase additions were also able to increase the HepG2 uptake of the emulsion. The data indicates that the increment in cholesterol ester occurring during maturation of plasma triacyglycerol-rich particles facilitates hepatic remnant assimilation by an apo E-dependent pathway.

Animals↗
PubMed1994

The condensing effects of egg lecithin and cholesterol on triolein monolayers are inhibited by substitution of one saturated acyl chain in the triacylglycerol.

Previous work showed that the clearance from plasma of chylomicron-like emulsions injected intravenously was affected by the acyl chains of the constituent triacylglycerols. Compared with emulsions containing triolein (OOO) as the only triacylglycerol, clearances were decreased by a single saturated chain in emulsions containing 1,3-dioleoyl-2-stearoyl-sn-glycerol (OSO), 1,2-dioleoyl-3-stearoyl-sn-glycerol (OOS) or 1-stearoyl-2,3-dioleoyl-sn-glycerol (SOO). The differences in clearance may reflect physical differences at the oil-water interface related to chain interactions of the triacylglycerol structures with other lipid components. In the present work lipid monomolecular films at the air-water interface were used to establish the capacity of OOO to interact with the pure synthetic triacylglycerols OOS and SOO, and the capacity of OOS and SOO to co-exist in monolayers of lecithin and of cholesterol was compared with OOO. Substituting one oleoyl chain by a stearoyl chain induced a 20% condensation in monomolecular films of the pure triacylglycerols. Mixtures of OOO with either pure egg yolk phosphatidylcholine or cholesterol also showed substantial condensing effects. In contrast substituting one oleoyl chain by a stearoyl chain substantially lessened the condensing effects. At surface pressures above the collapse pressure of the pure triacylglycerols, substantially more OOO than OOS or SOO was retained in mixed monolayers with phosphatidylcholine. These differences could underlie the effects on metabolism of saturated chains in emulsion triacylglycerols.

Chemical Phenomena↗
PubMed1996

Stereoselectivity of lipases in supercritical carbon dioxide. I. Dependence of the regio- and enantioselectivity of porcine pancreas lipase on the water content during the hydrolysis of triolein and its partial glycerides.

The stereoselectivity of porcine pancreas lipase (PPL) was investigated during the enzymatic hydrolysis of triolein and its partial glycerides in the presence of supercritical carbon dioxide (SCCO2) as reaction medium. The water content of the immobilized lipases was varied. The partial glycerides were separated into mono- and diglycerides by TLC, converted to their 3,5-dinitrophenylurethane derivatives and subsequently resolved into sn-1,2 and sn-2,3 enantiomers (estimation of dioleins) or into sn-1 and sn-3 enantiomers (estimation of monooleins) by HPLC on a chiral stationary phase (Sumichiral OA-4100). In all reactions under the conditions employed, PPL revealed a distinct preference for the sn-3 position of the glycerol. However, the stereoselectivity depends on the reaction time, the substances initially used and the enzyme water content. It seems that the effect of the enzyme water content on the activity and selectivity of porcine pancreas lipase in SCCO2 is based on a modification of the "micro-environment' of the enzyme by the solution of CO2 in water, causing a decrease of the pH value.

Animals↗
PubMed1993

Stable self-sustained potential oscillations across a membrane filter impregnated with triolein.

When applying constant electric current, periodic self-sustained potential oscillations with high stability are observed across a membrane filter impregnated with triolein, placed between KCl and NaCl aqueous solutions. Stability, reproducibility and controllability of the oscillation are much improved by the application of constant electric current compared with those obtained without application of electric current. Relations among value of electric current, base potential and period of the oscillations are studied, and it is concluded that the oscillation period can be controlled by base electric potential. Effects of temperature on the oscillations are investigated, and it is shown that Arrhenius plots for both base conductance and conductance amplitude of each oscillation fitted well to an individual straight line and that values of activation energies are similar to those of bulk salt solutions. From all data obtained it is suggested that the oscillations occur as a result of rhythmic repetition of opening and closing of hole(s) in the membrane, which is due to breakdown and restoration of a part of the membrane.

Cellulose↗