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At least 235 records · Page 13Linked to original sources
PubMed1995

Zinc deficiency and activities of lipogenic and glycolytic enzymes in liver of rats fed coconut oil or linseed oil.

In previous studies, zinc-deficient rats force-fed a diet with coconut oil as the major dietary fat developed a fatty liver, whereas zinc-deficient rats force-fed a diet with linseed oil did not. The present study was conducted to elucidate the reason for this phenomenon. In a bifactorial experiment, rats were fed zinc-adequate or zinc-deficient diets containing either a mixture of coconut oil (70 g/kg) and safflower oil (10 g/kg) ("coconut oil diet") or linseed oil (80 g/kg) ("linseed oil diet") as a source of dietary fat, and activities of lipogenic and glycolytic enzymes in liver were determined. In order to ensure adequate food intake, all the rats were force-fed. Zinc-deficient rats on the coconut oil diet developed a fatty liver, characterized by elevated levels of triglycerides with saturated and monounsaturated fatty acids. These rats also had markedly elevated activities of the lipogenic enzymes acetyl-CoA carboxylase, fatty acid synthase (FAS), glucose-6-phosphate dehydrogenase (G6PDH), 6-phosphogluconate dehydrogenase (6PGDH), and citrate cleavage enzyme, whereas activities of malic enzyme and glycolytic enzymes were not different compared with zinc-adequate rats on the coconut oil diet. In contrast, rats receiving the linseed oil diet had similar triglyceride concentrations regardless of zinc status, and activities of lipogenic enzymes and glycolytic enzymes were not different between the two groups. Zinc-deficient rats fed either type of dietary fat exhibited statistically significant correlations between activities of FAS, G6PDH, 6PGDH and concentrations of saturated and monounsaturated fatty acids in liver.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Effects of salmon oil and corn oil on plasma lipid level and hepato-biliary cholesterol metabolism in rats.

The aim of this work was to compare the effects of n-3 and n-6 fatty acids on plasma lipid level and hepato-biliary cholesterol metabolism by studying rats fed semi-synthetic diets enriched with either 10% salmon oil, 10% corn oil, or a blend of 6% corn oil and 4% salmon oil. After 4 weeks of feeding, a drop in plasma lipid level was noted in the salmon oil group in comparison to the control group, whereas no change was observed in the corn oil group. An increase in production of cholesterol ester by the liver was recorded in the salmon oil group with a marked enhancement in acyl-CoA:cholesterol acyltransferase (ACAT: EC 2.3.1.26) activity and hepatic cholesterol concentration. Corn oil did not affect either ACAT activity or hepatic cholesterol storage. All bile parameters (flow, bile salts, phospholipids, cholesterol) increased in the salmon oil group, but the molar ratio of cholesterol participation in the bile secretion decreased. These changes in bile composition, as well as in hepatic metabolism of cholesterol, may help to explain the hypolipidemia following the intake of fish oil.

Animals↗
PubMed2006

Accelerated atherosclerosis in apolipoprotein E-deficient mice fed Western diets containing palm oil compared with extra virgin olive oils: a role for small, dense high-density lipoproteins.

To test the hypothesis that extra virgin olive oils from different cultivars added to Western diets might behave differently than palm oil in the development of atherosclerosis, apoE-deficient mice were fed diets containing different cultivars of olive oil for 10 weeks. Female mice were assigned randomly to one of the following five groups: (1-4) fed chow diets supplemented with 0.15% (w/w) cholesterol and 20% (w/w) extra virgin olive oil from the Arbequina, Picual, Cornicabra, or Empeltre cultivars, and (5) fed a chow diet supplemented with 0.15% cholesterol and 20% palm oil. Compared to diets containing palm oil, a Western diet supplemented with one of several varieties of extra virgin olive oil decreased atherosclerosis lesions, reduced plaque size, and decreased macrophage recruitment. Unexpectedly, total plasma paraoxonase activity, apoA-I, plasma triglycerides, and cholesterol played minor roles in the regulation of differential aortic lesion development. Extra virgin olive oil induced a cholesterol-poor, apoA-IV-enriched lipoparticle that has enhanced arylesterase and antioxidant activities, which is closely associated with reductions in atherosclerotic lesions. Given the anti-atherogenic properties of extra virgin olive oil evident in animal models fed a Western diet, clinical trials are needed to establish whether these oils are a safe and effective means of treating atherosclerosis.

Animals↗
PubMed1998

Effect of the long-term feeding of dietary lipids on the learning ability, fatty acid composition of brain stem phospholipids and synaptic membrane fluidity in adult mice: a comparison of sardine oil diet with palm oil diet.

The effect of 12 month feeding of 5% palm oil or sardine oil diet on the maze-learning ability, fatty acid composition of brain stem phospholipids and synaptic membrane fluidity in mice was studied. The time required to reach the maze exit and the number of times that a mouse strayed into blind alleys in the maze were measured three times every 4 days. The time and number of mice fed on the sardine oil diet were less than those of animals fed on the palm oil diet in the first and second trials. The results of fatty acid composition analysis of brain stem phosphatidylethanolamine showed that the percentage of docosahexaenoic acid (22:6, n-3; DHA) was higher, but the arachidonic acid (20:4, n-6; AA) and docosatetraenoic acid (22:4, n-6; DTA) were lower in the sardine oil diet fed-mice than in the palm oil diet fed-animals. Moreover, the microviscosity of the synaptic plasma membrane in the sardine oil diet group was lower than that in the palm oil diet group. These results suggest that the adult mice fed on the sardine oil diet for a long period maintain higher levels of docosahe xaenoic acid in brain phospholipids, synaptic membrane fluidity and maze-learning ability than animals fed on the palm oil diet.

Animals↗
PubMed1999

Modulation of the regression of atherosclerosis in the hamster by dietary lipids: comparison of coconut oil and olive oil.

The Golden Syrian hamster (Mesocricetus auratus) has been shown to be a useful model of both human lipoprotein metabolism and the development of atherosclerosis. We report the effects of dietary lipids on the progression and regression of atherosclerosis in this model. In the first study, hamsters fed on coconut oil (150 g/kg diet) and cholesterol (30 g/kg diet) developed lipid-rich lesions in the ascending aorta (0.28 (SD 0.14) mm2) and aortic arch (0.01 (SD 0.01) mm2) after 4 weeks that continued to progress over the next 8 weeks (0.75 (SD 0.41) mm2 and 0.12 (SD 0.11) mm2 for the ascending aorta and aortic arch respectively). Removal of cholesterol from the diet halted this progression. Furthermore, in animals fed on olive oil in the absence of added cholesterol, plasma LDL-cholesterol concentrations were lower (P < 0.05) and the extent of atherosclerotic lesions was reduced (P < 0.001 for both regions of the aorta) compared with animals fed on coconut oil (with no added cholesterol). In a second study, animals were fed on the atherogenic diet for 10 weeks, transferred to diets containing either coconut oil (150 g/kg diet) or olive oil (150 g/kg diet) without added cholesterol and monitored for up to 16 weeks. In the ascending aorta, lesion size doubled in animals fed on coconut oil but stabilized in those fed on olive oil. In the aortic arch, lesion size decreased linearly (P < 0.05, P < 0.001 for coconut oil and olive oil respectively) with the greatest reduction being seen in the olive-oil-fed animals (P < 0.05). Again, progression and regression of atherosclerosis appeared to reflect the relative concentrations of LDL-cholesterol and HDL-cholesterol in the plasma. We conclude that the male Golden Syrian hamster represents a useful model of dietary induced regression as well as progression of atherosclerosis.

Analysis of Variance↗
PubMed2005

Quantitation of short-chain glycerol-bound compounds in thermoxidized and used frying oils. A monitoring study during thermoxidation of olive and sunflower oils.

Major short-chain glycerol-bound compounds were investigated in olive oil (OO) and conventional sunflower oil (SO) during thermoxidation at 180 degrees C for 5, 10, and 15 h. These compounds included methyl heptanoate (C7:0), methyl octanoate (C8:0), methyl 8-oxo-octanoate (8-oxo-C8:0), methyl 9-oxononanoate (9-oxo-C9:0), dimethyl octanodiate (C8:0 diester), and dimethyl nonanodiate (C9:0 diester), which were analyzed by GC after derivatization of triacylglycerols to fatty acid methyl esters. An acceptable linear correlation (r = 0.967) was found between the total content of these compounds and the total content of polar compounds, suggesting that quantitation of the major short-chain glycerol-bound compounds provides a good indication of the total alteration level of oils heated at frying temperature. Samples with levels of polar compounds around 25% on oil showed total contents within 2-3 mg/g of oil. To determine the content of these compounds in used frying oils, 10 samples from restaurants and fried-food outlets in Spain were analyzed. Results showed total levels between 2.13 and 7.56 mg/g of oil in samples with contents of polar compounds ranging from 18.8 to 55.5% on oil. Samples with levels of polar compounds of approximately 25% showed total contents of the short-chain compounds similar to those found in the thermoxidized oils, that is, within 2-3 mg/g of oil.

Chromatography, Gas↗
PubMed1986

Controlled evaluation of fat intake in the Mediterranean diet: comparative activities of olive oil and corn oil on plasma lipids and platelets in high-risk patients.

Activities of low-fat diets with olive oil or corn oil on lipids and platelets were studied in 23 middle-aged patients with high atherosclerosis risk for 8 wk. The olive oil diet had a polyunsaturated-saturated ratio of 0.33 vs 1.28 for the corn oil diet. Plasma total cholesterol was reduced with corn oil, but high-density lipoprotein cholesterol levels were lower with corn oil and unchanged or raised by olive. Plasma apolipoprotein B levels were equally reduced by both diets; apolipoprotein AI and the apo AI:B ratio rose only with olive oil. Plasma-glucose levels were lowered significantly with olive oil. Changes in platelet function were characterized by a reduced sensitivity to arachidonic acid (particularly with corn oil) and to collagen (particularly with olive). An olive oil diet with a moderate fat intake (about 30% of total calories) leads to favorable plasma lipoprotein and platelet changes.

Adult↗
PubMed1993

Different clearance of intravenously administered olive oil and soybean-oil emulsions: role of hepatic lipase.

The elimination of two intravenously administered fat emulsions consisting of either 20% (wt:vol) soybean oil or 17% olive oil plus 3% soybean oil was studied in six normolipidemic young men according to a randomized crossover protocol. Slower elimination was found with the olive oil emulsion. A significantly lower maximal removal capacity (K1) and fractional catabolic rate (K2) were measured with olive oil emulsion (P < 0.05). Removal of olive oil emulsion was inversely related to hepatic lipase activity (r = -0.85; P < 0.05). Removal of soybean-oil emulsion was related to the initial plasma triglyceride concentration (r = -0.84; P < 0.05) but not to lipolytic activity. In vivo apolipoprotein C-II binding was similar for both emulsions. Therefore, hepatic lipase activity is more important in the elimination of olive oil emulsions than soybean-oil emulsions. The faster elimination of soybean-oil emulsions suggests an additional elimination pathway, such as the reticuloendothelial system.

Adult↗
PubMed1995

Lipoprotein concentrations in normolipidemic males consuming oleic acid-rich diets from two different sources: olive oil and oleic acid-rich sunflower oil.

The effects on plasma lipid concentrations of two oleic acid-rich diets, prepared with two different plant oils--olive oil and sunflower oil high in monounsaturated fatty acids (MUFAs)-- were compared with a National Cholesterol Education Program (NCEP) I diet. Twenty-one healthy, normolipidemic, young males consumed an NCEP-I diet (30% of energy as fat) during a 25-d period. Subjects were then assigned to two 4-wk study periods, according to a randomized, crossover design. Group one was placed on an olive oil-enriched diet (40% fat, 22% MUFAs), followed by a 4-wk period of a sunflower oil-enriched diet (40% fat, 22% MUFAs). In group two, the order of the diets was reversed. Both MUFA dietary periods resulted in an increase in high-density-lipoprotein (HDL) cholesterol (7% for the olive oil diet and 4% for the sunflower oil diet) and in apolipoprotein (apo) A-I (9% for both) compared with the NCEP-I diet. Low-density-lipoprotein (LDL) cholesterol and apo B concentrations (x +/- SEM) were lower (P < 0.05) during the sunflower oil diet (2.40 +/- 0.11 mmol/L, 0.85 +/- 0.04 mg/L) than during the olive oil diet (2.64 +/- 0.15 mmol/L, 0.93 +/- 0.05 mg/L). No significant differences were observed in these variables between the sunflower oil and NCEP-I (2.48 +/- 0.13 mmol/L, 0.89 +/- 0.04 mg/L) diets.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Effects of a monounsaturated rapeseed oil and a polyunsaturated sunflower oil diet on lipoprotein levels in humans.

The effects of high oleic acid rapeseed oil compared with polyunsaturated fats on serum lipoprotein levels are largely unknown. Therefore, we fed 30 women and 29 men a baseline diet rich in saturated fat, which was followed by a diet rich in high oleic and low erucic acid rapeseed oil (total energy content of fat, 38%; saturates, 12.4%; monounsaturates, 16%; n-6 polyunsaturates, 6%; and n-3 polyunsaturates, 2%) and one rich in sunflower oil (total energy content of fat, 38%; saturates, 12.7%; monounsaturates, 10%; n-6 polyunsaturates, 13%; and n-3 polyunsaturates, 0%). The oils were incorporated into mixed natural diets that were dispensed in a random order for 3.5 weeks each in a blinded crossover design. The diet composition was confirmed by analysis of duplicate diets. Both test diets reduced serum total cholesterol (TC) and low density lipoprotein (LDL) cholesterol levels from baseline, the monounsaturated rapeseed oil diet more than the polyunsaturated sunflower oil diet (TC: -15% versus -12%, p less than 0.01; LDL cholesterol: -23% versus -17%, p less than 0.01). Very low density lipoprotein (VLDL) cholesterol and total, VLDL, and LDL triglyceride levels were lower during the sunflower oil diet compared with the rapeseed oil diet. Total high density lipoprotein (HDL) cholesterol levels remained unchanged by both diets. The consumption of rapeseed oil resulted in a more favorable HDL2 to LDL cholesterol ratio (0.43 +/- 0.19 versus 0.39 +/- 0.18, p less than 0.01) and an apolipoprotein A-I to B ratio (3.0 +/- 1.4 versus 2.4 +/- 1.6, p less than 0.001) than did the sunflower oil.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

Effect of fish oil and coconut oil on antioxidant defence system and lipid peroxidation in rat liver.

Diets high in fish oil containing polyunsaturated fatty acids of the n-3 family, have been suggested to decrease the risk of cardiovascular disease. However these lipids are highly susceptible to oxidative deterioration. In order to investigate the influence of n-3 fatty acids on oxidative status, the effect of feeding rats with fish oil or coconut oil diets was studied by measuring different parameters related to an oxidative free radical challenge. Synthetic diets containing 15% (w/v) fish oil or coconut oil were used to feed growing rats for 4 weeks. As compared to control diet, the fish oil containing diet produced a significant decrease of cholesterol and triglyceride concentration in serum, however there was a significant increase in lipid peroxidation products. In addition, in fish oil fed animals, there was also a decrease in vitamin E and A concentration. Furthermore, the rate of lipid peroxidation in isolated microsomes was three fold higher in rats fed fish oil as compared to rats with coconut oil diet. No significant differences between the two experimental groups were observed in superoxide dismutase (SOD) and phospholipid hydroperoxide glutathione peroxidase (PHGPX) activities. However, there was a decrease in glutathione peroxidase (GPX) activity. These results suggest that fish oil feeding at an amount compatible with human diet, although decreasing plasma lipids, actually challenge the antioxidant defence system, thus increasing the susceptibility of tissues to free radical oxidative damage.

Animals↗
PubMed1989

Effects of fish oil and corn oil diets on prostaglandin-dependent and myelopoiesis-associated immune suppressor mechanisms of mice bearing metastatic Lewis lung carcinoma tumors.

The effects of a fish oil diet on the myelopoietic and immunological parameters of normal mice and of mice bearing metastatic Lewis lung carcinoma (LLC-C3) tumors were compared to the effects of a corn oil or a mixed-fat rodent chow diet. This was studied soon after tumor appearance, on Day 17, when immune suppression was mediated by prostaglandin E2 (PGE2)-producing suppressor cells, and late in tumor development, on Day 28 when immune suppression was associated with myelopoiesis and the appearance of bone marrow-derived suppressor cells whose activity was not dependent on PGE2. Feeding a fish oil diet from Days 10 to 17 of tumor growth partially restored splenic T-cell blastogenesis, reduced spleen cell secretion of PGE2, and alleviated splenic suppressor activity. When fed from Days 21 to 28 of tumor growth, a fish oil diet neither restored T-cell blastogenesis nor alleviated suppressor cell activity. The fish oil diet increased the frequency of myeloid progenitor cells in normal mice and in mice bearing small or large tumors. Concurrently, the fish oil diet stimulated the appearance of bone marrow-derived suppressor cells. When administered after the establishment of palpable primary tumors, a fish oil diet also increased the formation of pulmonary lung nodules. In contrast to the fish oil stimulation of myelopoiesis and the associated suppressor cells, feeding a corn oil diet to tumor-bearing mice during Days 21 to 28 after tumor implantation reduced myelopoiesis and the presence of the associated bone marrow suppressor cells. These data show that a fish oil diet can minimize the immune suppression in tumor bearers when suppression is mediated by PGE2-producing suppressor cells, but can also induce myelopoietic stimulation leading to the appearance of bone marrow-derived suppressor cells and increased tumor metastasis.

Animals↗
PubMed1994

The effect of zinc deficiency on erythrocyte membrane lipids of force-fed rats receiving a diet containing coconut oil or fish oil.

In the present study, the effect of zinc deficiency on erythrocyte membrane lipids of force-fed rats that received either a diet with coconut oil and safflower oil (86:14, w/w) or a diet with fish oil and safflower oil (91:9, w/w) was investigated. Zinc deficiency caused in the rats fed both types of dietary fat an increase in the amounts of total phospholipids and individual phospholipid classes in erythrocyte membranes. In the rats fed the coconut oil diet, zinc deficiency caused an increase in the proportion of docosahexaenoic acid (22:6) in phosphatidylcholine (PC), diacyl phosphatidylethanolamine (PE), phosphatidylserine (PS), and in total erythrocyte membrane fatty acids. In contrast, in the rats fed the fish oil diet, zinc deficiency caused an increase in the proportion of docosahexaenoic acid only in PC, but not in the other phospholipids. However, in these rats, changes in the ratio between eicosapentaenoic acid (20:5) and the n-3 fatty acids with 20 and 22 carbon atoms were observed in PC, diacyl PE and plasmalogen PE. The most pronounced changes in fatty acid composition due to zinc deficiency in the rats fed both types of fat occurred in PC. There was a relationship between the changes in the composition of plasma total fatty acids and the changes in fatty acid composition of erythrocyte membrane PC caused by zinc deficiency in the rats fed both types of dietary fat. The amount of cholesterol was similar in all treatment groups. However, zinc-deficient rats fed the coconut oil diet-but not those fed the fish oil diet-had an increased ratio between total phospholipids and cholesterol. Thus, the study shows that the effect of zinc deficiency on erythrocyte membrane lipids is to some degree similar for rats fed a coconut oil diet and rats fed a fish oil diet, and to some degree different.

Animals↗
PubMed2003

The determination of water in crude oil and transformer oil reference materials.

The measurement of the amount of water in oils is of significant economic importance to the industrial community, particularly to the electric power and crude oil industries. The amount of water in transformer oils is critical to their normal function and the amount of water in crude oils affects the cost of the crude oil at the well head, the pipeline, and the refinery. Water in oil Certified Reference Materials (CRM) are essential for the accurate calibration of instruments that are used by these industries. Three NIST Standard Reference Materials (SRMs) have been prepared for this purpose. The water in these oils has been measured by both coulometric and volumetric Karl Fischer methods. The compounds (such as sulfur compounds) that interfere with the Karl Fischer reaction (interfering substances) and inflate the values for water by also reacting with iodine have been measured coulometrically. The measured water content of Reference Material (RM) 8506a Transformer Oil is 12.1+/-1.9 mg kg(-1) (plus an additional 6.2+/-0.9 mg kg(-1) of interfering substances). The measured water content of SRM 2722 Sweet Crude Oil, is 99+/-6 mg kg(-1) (plus an additional 5+/-2 mg kg(-1) of interfering substances). The measured water content of SRM 2721 Sour Crude Oil, is 134+/-18 mg kg(-1) plus an additional 807+/-43 mg kg(-1) of interfering substances. Interlaboratory studies conducted with these oil samples (using SRM 2890, water saturated 1-octanol, as a calibrant) are reported. Some of the possible sources of bias in these measurements were identified, These include: improperly calibrated instruments, inability to measure the calibrant accurately, Karl Fischer reagent selection, and volatilization of the interfering substances in SRM 2721.

Journal Article↗
PubMed2002

Effect of dispersing oil phase on the biodegradability of a solid alkane dissolved in non-biodegradable oil.

Acinetobacter sp. CR was grown on a model oil, which consisted of an inert oil matrix of pristane with n-heneicosane dissolved in it as the sole carbon source, in a stirred-tank bioreactor. This bacterium takes up substrates from the oil phase by direct contact with the oil phase. A previously established mathematical model was applied to reveal the effect of agitation conditions on the growth and n-alkane degradation kinetics of the bacterium. Higher impeller speed resulted in both lower microbial growth and lower n-alkane degradation rate of the bacterium, although it increased the specific surface area of the oil, which was measured by a previously developed device. This result was due to the decreased number of cells adhering to the oil surface, i.e., intense agitation inhibited the adhesion of cells to the oil surface. The addition of a surfactant below a critical micelle concentration (CMC) inhibited the degradation of n-heneicosane dissolved in pristane, although the biodegradability of the substrate recovered gradually with the increase in the dose of surfactant over CMC. The results suggest that efforts to increase the specific surface area of the oil phase have the undesirable result of inhibiting oil degradation when the dominant microbial degraders take up substrates in oil by direct contact with the oil.

Acinetobacter↗
PubMed1996

Bottom sediments of the Arabian Gulf--II. TPH and TOC contents as indicators of oil pollution and implications for the effect and fate of the Kuwait oil slick.

Measurements of total petroleum hydrocarbon (TPH) concentrations in 77 core samples collected in 1992 from the bottom sediments of the Arabian Gulf were used to delineate oil pollution levels and their distribution in the region. Seven chronic moderately (TPH 50-89 microg g(-1)) and heavily (TPH 266-1448 microg g(-1)) polluted areas were identified; three in the northern part of the region and four in the southern part. Oil pollution in these areas was attributed to natural oil seepage, accidental damage to pipelines, accidental spillage from tankers, the Nowruz oil slick, and tanker deballasting. Present-day intermediate (TPH 50-114 microg g(-1)) and high (TPH 200-1122 microg g(-1)) pollution levels were identified in 10 areas. Of these, three polluted areas in the northeastern corner, offshore Saudi Arabia and offshore Bahrain, Qatar and United Arab Emirates are probably directly affected by the Kuwait oil slick. A new scenario is suggested for the movement and fate of the oil slick, in which additional large oil discharges from northern sources, as well as substantial quantities of eroded oiled sediments and oil floating from heavily impacted tidal flats along the Saudi Arabian coastline, serve as sources of oil pollution. A definite relationship exists between the grain-size distribution and the TPH content of bottom sediments, with the highest TPH concentrations in the muddy sediments, suggesting that adsorption onto muds is the primary mechanism of oil pollutant accumulation in the Arabian Gulf. Total organic carbon measurements do not correlate positively with the grain-size distribution and TPH contents of the sediments, and hence cannot be used as indicators for petroleum hydrocarbon pollution in the Arabian Gulf.

Journal Article↗
PubMed2002

K-ras oncogene DNA sequences in pink salmon in streams impacted by the Exxon Valdez oil spill: no evidence of oil-induced heritable mutations.

It was hypothesized in previous studies that the Exxon Valdez oil spill in Prince William Sound, Alaska, induced heritable mutations and resulted in mortality of pink salmon (Oncorhynchus gorbuscha) embryos. In one of these studies, laboratory exposure of pink salmon embryos to crude oil resulted in apparent mutation-induction in exon 1 and exon 2 of the K-ras oncogene, but no fish from the area impacted by the oil spill were analyzed. We assessed K-ras exon 1 and exon 2 DNA sequences in pink salmon from five streams that were oiled and five streams that were not oiled by the Exxon Valdez oil spill in Prince William Sound, and two streams with natural oil seeps and one stream without seeps on the Alaska Peninsula. Of the 79 fish analyzed for exon 1 and the 89 fish analyzed for exon 2, none had the nucleotide substitutions representing the mutations induced in the laboratory study. Other variable nucleotides occurred in similar proportions in oiled and non-oiled streams and probably represent natural allelic variation. These data do not support the hypothesis that heritable mutations in the K-ras gene were induced by the Exxon Valdez oil spill or oil seeps.

Alaska↗
PubMedDate not supplied

Microemulsions of triglyceride-based oils: The effect of co-oil and salinity on phase diagrams.

Microemulsification of triglyceride-based oil is challenging due to the formation of undesirable phases such as macroemulsions, liquid crystals, or sponge phases. This research evaluates the formation of artificial sebum microemulsions using linker molecules, with the addition of co-oil to help enhance sebum solubilization. The microemulsion consists of a lipophilic linker (sorbitan monooleate), a hydrophilic linker (hexylglucocide), a main surfactant (sodium dioctyl sulfosuccinate), a co-oil, and artificial sebum. The effect of adding co-oil to the phase behavior and the microstructure of the resulting microemulsion is described. The effect of several types of co-oil is also studied; the co-oils evaluated here are squalene, squalane, isopropyl myristate, and ethyl laurate. The effect of salinity on the microemulsion phase behavior is also presented. Fish diagrams are obtained by plotting total surfactant/linker concentration as a function of sebum fraction in the oil mixture (co-oil + sebum). Different microemulsion types (Winsor Types I, II, III, and IV) are formed, depending on the total surfactant/linker concentration and the fraction of co-oil in the oil mixture. Winsor Type IV (single-phase) microemulsions are observed at high surfactant/linker concentrations. These single-phase, isotropic, and low-viscous fluids are particularly useful for cleansing and delivery of functional ingredients in skin care products. Salt addition shifts the fish diagram towards more hydrophobic oil systems and higher surfactant/linker concentrations.

Cosmetics↗