Acid Cholesteryl Ester Research Articles

Preparation and characterisation of liquid crystal elastomer films with selective reflectivity

ABSTRACT In this paper, the liquid crystal elastomer films (A’BG series) have been prepared by grafting polymerisation, using the 4-allyloxybenzoic acid cholesteryl ester (MB) as liquid crystal monomer, dodecane-1,12-diyl bis(undec-10-enoate) (MG) as flexible cross-linker and polymethyl hydrosiloxane (containing 35 Si-H) as the main chain. The A’BG series films are cholesteric liquid crystal elastomer films (LCEs) with a liquid crystal region above 100°C. With the crosslinker content decreasing, A’BG-2 and A’BG-3 display selective reflection in UV region and visible region, respectively. The selective reflection wavelength of A’BG-3 occurs blue shift with the temperature increasing. The glass transition temperatures (Tg) of the A’BG series films are 16.4–40.8°C and A’BG series films display shape memory properties near room temperature. The A’BG series elastomer films have a high thermal stability and the temperatures of the 5% mass loss are above 300°C. The backbone siloxane structures in the A’BG series elastomer films are highly stable, and the -COOChol group is relatively easy to decompose.

Kinetics of lipid radical formation in lipoproteins from β-thalassemia: Implication of cholesteryl esters and α-tocopherol

Vascular complications in β-thalassemia are associated with oxidative modification of lipoproteins under high oxidative stress. The lipid components of lipoproteins are oxidized via lipid peroxidation and produce lipid radicals (L•) as the key initial intermediates. Modification of lipid components, therefore, might result in alterations in the rate and products of lipid peroxidation. In this study, the kinetics of L• formation during the 2,2'-Azobis(2-amidinopropane) dihydrochloride (AAPH)- and hemin-induced oxidation of low-density and high-density lipoproteins (LDL and HDL) from β-thalassemia patients and healthy volunteers were investigated using a specific and sensitive fluorescence probe for L•. Kinetic parameters, including initial lag time, propagation rate and total L• production, were calculated by monitoring a fluorescence-active NBD-Pen-L• adduct. Oxidation of thalassemia lipoproteins exhibited a significantly shorter lag time but a slower propagation rate of L• formation when compared with healthy lipoproteins. LDL showed higher resistance to oxidation during the initiation phase but higher L• formation than HDL. Our results indicated that the levels of α-tocopherol determined the initial lag time, whereas the levels of core lipids and cholesteryl esters, especially cholesteryl linoleate (CL), determined the propagation rate and total L• production. The difference in potency of AAPH and hemin supported that hemin preferentially targeted core lipids. Moreover, analysis of 13-hydroxyoctadecadienoic acid cholesteryl ester (13-HODE-CE)/CE ratio indicated that thalassemia lipoproteins have higher susceptibility to oxidation than healthy lipoproteins. In conclusion, our findings suggested that CL and α-tocopherol were implicated in the susceptibility of lipoproteins to lipid peroxidation in physiological and pathological conditions of β-thalassemia.

Synthesis and characterization of cholesteric liquid crystal elastomer films

A series of liquid crystal elastomer films (the PBC series) have been synthesized by grafting liquid crystal (LC) monomer 4-allyloxybenzoic acid cholesteryl ester (MB) and crosslinking agent [1,1'-biphenyl]-4,4'-diyl bis(undec-10-enoate) (MC) onto polymethylhydrosiloxane catalyzed by hexachloroplatinic acid at 60 °C. The PBC series are cholesteric liquid crystal elastomers (LCEs). The glass transition temperatures (Tg) of the PBC series are between 23-33 °C, and the LC range is above 200 °C. The temperatures of 5% weight loss of the PBC series are above 300 °C, which shows good thermal stability. The PBC series display good orientation. PB3C3 shows a good ability of shape recovery above Tg.

Synthesis and properties of L(AS)3-type low-molecular-mass organic gelators based on citryl aromatic amino acid cholesteryl ester

Three types of L(AS)3 gelators have been synthesized by the reaction of phenylalanine, tyrosine and tryptophan，whose amino were protected and reacted with cholesterol under the condition of citric acid as a linker, respectively. The synthetic gelators performed strong gelation ability in cyclohexane and isopropanol. The structure, thermal stability and mechanical properties of the gels were observed; the gel formation mechanism was analyzed with XRD and SEM and the results showed that the hydrogen bonding and the π-π interaction force remarkably increased due to the existence of a great deal of amide bonds, ester bonds and aromatic rings in gelators. The gels are packed in a layered structure and are stable against temperature change. Among three gelators, citric acid tyrosine cholesterol ester displays a good gel-solution conversion under trifluoroacetic acid-triethylamine simulation in isopropanol. The study is expected to have application in the detection of organic amines in the field of sensing.

Fatty acids in multiple circulating lipid fractions reflects the composition of liver triglycerides in humans

Fatty acids (e.g. 16:1n-7) and desaturase indices (e.g. stearoyl-CoA desaturase, SCD) in plasma cholesteryl esters (CE) and phospholipids (PL) are used as biomarkers of dietary fat quality and lipid metabolism and are associated with disease outcomes. Endogenously produced circulating fatty acids are believed to reflect composition of the liver, yet little data exist to support such relationship. We investigated associations between circulating fatty acids and fatty acids within the liver. Liver biopsies and blood were collected from n=60 patients with non-alcoholic fatty liver disease. Fatty acids in CE, PL and triglycerides (TG) in plasma and liver were analyzed using gas chromatography. Associations were assessed using Spearman rank correlations. Overall, fatty acids and desaturase indices in plasma PL and TG showed moderate-strong correlations with fatty acids and desaturase indices in corresponding lipid fractions in liver. For plasma CE, 16:1n-7 and SCD were correlated with 16:1n-7 and SCD in liver CE. Noteworthy, fatty acids in plasma CE and PL also showed moderate-strong correlations with fatty acids in liver TG (e.g. r=0.82-0.87 for 16:1n-7 and r=0.77 for SCD). We demonstrate that fatty acids in circulating lipid fractions, including CE, TG and PL, reflects the composition of liver TG in humans, suggesting that circulating fatty acids might be useful biomarkers for the fatty acid composition of the liver. As liver tissue is rarely available in cohort studies, our findings could enhance our understanding of plasma fatty acids as markers of hepatic lipid metabolism and their links to metabolic diseases.

Regular Dietary Intake of Palmitate Causes Vascular and Valvular Calcification in a Rabbit Model.

Aims: Palmitic acid (PA) and oleic acid (OA) are two main dietary fatty acids. Dietary intake of PA has been associated with cardiovascular disease risk, and the effect of OA remains uncertain. Our study aimed to assess the effect of a short-term intake of lard, as source of PA and OA, on aorta and aortic valve.Methods and Results: Rabbits were fed with two lard-enriched diets, containing either elevated levels of PA or of both PA and OA as compared to chow diet. After 16 weeks of each diet, calcification was observed in the aortic intima and in the aortic valve. The extent of calcification did not differ between the two diets. In contrast, rabbits fed chow diet did not develop any calcification. In blood, PA enrichment resulted in decreased lymphocyte and monocyte counts and increased levels of hemoglobin and haematocrit. Levels of the calcification inhibitor fetuin-A were also diminished, whereas creatinine levels were raised. Of note, none of the diets changed cholesterol levels in LDL or HDL. Comprehensive quantitative lipidomics analysis identified diet-related changes in plasma lipids. Dietary PA enrichment led to a drop of polyunsaturated fatty acids (PUFA), in particular of linoleic acid in cholesteryl esters, triglycerides and diacylglycerols (DAG). Ratios of PA to 18-carbon PUFA in DAG were positively correlated with the extent of aortic valve calcification, and inversely with monocyte counts. PA content in blood correlated with aorta calcification.Conclusions: Regular dietary PA intake induces vascular and valvular calcification independently of traditional risk factors. Our findings raise awareness about PA-rich food consumption and its potential deleterious effect on cardiovascular health.

The Effect of the Applied Temperature on the Maximum Refleactive Wavelength in Chiral Liquid Crystal Polymers

The liqud crystals (LCs) monomers 4-(Undecenoic-1-yloxybenzoyloxy)-4’-cyanobenzene e M1 and 5-{4-[4-(4-undecyloxy) biphenyl] -oxycarbonyl} pentanoic acid cholesteryl ester M2 are synthesized. The liquid crystals polymer was synthesized by nematic and chiral LC monomers. The property of the LC materials are detected by POM and DSC. The bandgaps of the LC polymer are influenced by the change of temperature. The effect of temperature on the reflective wavelength is decreased from 513nm to 394nm with temperature increased. The chiral LC polymer is a one dimension photonic materials. The optical and thermal property of the CLCs polymer is controlled by the out field, and widely used for display, smart windows and chiral liquid crystal laser etc.

Synthesis and Characterization of Chiral azo LCPs

Precursor polymer MP series were synthesized by 4-allyloxybenzoic acid cholesteryl ester (M) and 4- hydroxyphenyl 4- (propionyloxy) benzoate (P). We obtained novel themotropic side-chain liquid crystal polymer MPZ series by esterification between MP series and 4-((4-ethoxyphenyl) diazenyl) benzoic acid (Z). Differential scanning calorimetry (DSC) was used to measure the thermal properties of those polymers, and the mesogenic properties were characterized by polarized optical micrograph (POM), DSC and X-Ray. MP series exhibited yellow, green, blue and purple Grandjean textures. MPZ series also showed colorful Grandjean textures. They exhibited thermotropic liquid crystal properties in a broad mesogenic region.

Abstract 364: An NPC1 and NPC2 Independent Pathway Mediates Trafficking of Cholesterol From Lysosomes to the Extracellular Matrix

We previously reported that cholesterol-enriched macrophages deposit cholesterol into the extracellular matrix and this process depends on ABCA1 and ABCG1. The extracellular cholesterol deposits can be mobilized by HDL, or ApoA-I, the latter dependent on ABCA1-mediated lipidation of ApoA-I. The objective of the current study was to determine the effects of other genes and inhibitors that affect cellular cholesterol trafficking on the deposition of extracellular cholesterol. We used a monoclonal antibody that labels cholesterol microdomains to detect the extracellular cholesterol deposits. Progesterone and U18666A previously were shown to induce accumulation of cholesterol within lysosomes, and we found that these agents also blocked macrophage deposition of extracellular cholesterol. Brefeldin A, an inhibitor of golgi and vesicular trafficking, inhibited extracellular cholesterol deposition. On the other hand, vacuolin, an agent that inhibits the fusion between autophagosomes and lysosomes and thereby induces cellular accumulation of autophagosomes, did not inhibit extracellular cholesterol deposition. To examine the effect of mutant genes known to affect cholesterol trafficking, we examined mutant cultured fibroblasts that were cholesterol-enriched by incubation with LDL plus the LXR agonist, T0901317. Like macrophages, normal cholesterol-enriched fibroblasts deposited extracellular cholesterol that was dependent on ABCA1, because ABCA1-deficient fibroblasts did not deposit extracellular cholesterol. While progesterone and U18666A inhibited fibroblast extracellular cholesterol deposition, surprisingly, fibroblasts deficient in NPC1 or NPC2, which also abnormally accumulate cholesterol within lysosomes during cholesterol enrichment, nevertheless, deposited extracellular cholesterol similar to normal fibroblasts. That lysosomal hydrolysis of LDL cholesteryl ester is involved in extracellular cholesterol deposition was shown by substantially reduced extracellular cholesterol deposition by fibroblasts lacking acid cholesteryl ester hydrolase. Our findings indicate that a pathway not dependent on NPC1 or NPC2 mediates trafficking of cholesterol from lysosomes to the extracellular space.

Exploring unsaturated fatty acid cholesteryl esters as transdermal permeation enhancers.

The intrinsic protective barrier property of skin, one of the major challenges in the design of transdermal drug delivery systems, can be overcome through the use of chemical permeation enhancers (CPEs). Herein, we explore the potential of unsaturated fatty acid (UFA) esters of cholesterol (Chol) viz., oleate, linoleate and linolenate, as transdermal CPEs using tenofovir (TNF) as a model drug. All Chol UFA esters at 1% w/w were found to be more effective enhancers when compared to their respective parent fatty acids (FAs) and saturated FA counterparts. Cholesteryl linolenate (Chol-LLA) showed the most superior performance (enhancement ratio (ER)=3.71). The greatest ER for Chol-LLA (5.93) was achieved at a concentration of 2% w/w. The histomorphological and transepithelial electrical resistance (TEER) evaluations supported the results of the permeability studies. These findings showed no significant loss in the integrity of the epidermis, with drug and enhancer treatment having temporary effects on the barrier property of the epidermis. Chol UFA esters can therefore be considered as new CPEs for exploitation in topical formulations for various classes of drugs.

Effect of a 2-y dietary and physical activity intervention on plasma fatty acid composition and estimated desaturase and elongase activities in children: the Physical Activity and Nutrition in Children Study

Background: Evidence on the effects of lifestyle interventions on plasma fatty acid composition in children is limited.Objective: We investigated the effects of a dietary and physical activity intervention on plasma fatty acid composition of cholesteryl esters (CEs) and phospholipids and estimated desaturase and elongase activities in children.Design: We conducted a 2-y controlled dietary and physical activity intervention based on Finnish nutrition and physical activity recommendations in a population sample of 506 children aged 6–8 y. We assessed plasma fatty acid composition by gas chromatography and estimated desaturase and elongase activities as the ratio of product fatty acids to precursor fatty acids. We analyzed data by using linear mixed models adjusted for age and sex.Results: The proportion of total polyunsaturated fatty acids (PUFAs) in CEs tended to increase in the intervention group compared with the control group (P = 0.007 for group × time interaction). The proportion of total PUFAs in phospholipids (P = 0.019 for group × time interaction) and the proportion of linoleic acid in CEs (P = 0.038 for group × time interaction) decreased in the control group. The proportion of α-linolenic acid in CEs (P < 0.001 for group × time interaction) increased and in phospholipids (P = 0.015 for group × time interaction) tended to increase in the intervention group. The proportion of stearic acid in CEs decreased in the intervention group (P = 0.001 for group × time interaction). The proportion of oleic acid in CEs (P = 0.002 for group × time interaction) increased and in phospholipids (P = 0.023 for group × time interaction) tended to increase in the control group. Estimated elongase activity in CEs decreased in the control group (P = 0.050 for group × time interaction). Intervention had no effect on estimated desaturase activities.Conclusions: Dietary and physical activity intervention had a beneficial effect on plasma fatty acid composition in children by preventing the decrease in the proportion of total PUFAs and linoleic acid and by increasing the proportion of α-linolenic acid. This study was registered at clinicaltrials.gov as NCT01803776.

The ACBP gene family in Rhodnius prolixus: Expression, characterization and function of RpACBP-1

The acyl-CoA-binding proteins (ACBP) constitute a family of conserved proteins that bind acyl-CoA with high affinity and protect it from hydrolysis. Thus, ACBPs may have essential roles in basal cellular lipid metabolism. The genome of the insect Rhodnius prolixus encodes five ACBP genes similar to those described for other insect species. The qPCR analysis revealed that these genes have characteristic expression profiles in insect organs, suggesting that they have specific roles in insect physiology. Recombinant RpACBP-1 was able to bind acyl-CoA in an in vitro gel-shift assay. Moreover, heterologous RpACBP-1 expression in acb1Δ mutant yeast rescued the multi-lobed vacuole phenotype, indicating that RpACBP-1 acts as a bona fide acyl-CoA-binding protein. RpACBP-1 knockdown using RNAi caused triacylglycerol accumulation in the insect posterior midgut and a reduction in the number of deposited eggs. The amount of stored triacylglycerol was reduced in flight muscle, and the incorporation of fatty acids in cholesteryl esters was increased in the fat body. These results showed that RpACBP-1 participates in several lipid metabolism steps in R. prolixus.

Cross‐Sectional Associations of Food Consumption with Plasma Fatty Acid Composition and Estimated Desaturase Activities in Finnish Children

Plasma fatty acid (FA) composition is known to be an indicator of dietary fat quality, but the associations of other dietary factors with plasma FA composition remain unknown in children. We investigated the cross-sectional associations of food consumption with the proportions of FA and estimated desaturase activities in plasma cholesteryl esters (CE) and phospholipids (PL) among children. The subjects were a population sample of 423 children aged 6–8 years examined at baseline of The Physical Activity and Nutrition in Children (PANIC) Study. We assessed food consumption by food records and plasma FA composition by gas chromatography. We used linear regression models adjusted for age, sex, physical activity and total energy intake to analyze the associations. A higher consumption of vegetable oil-based margarine (fat 60–80 %) was associated with a higher proportion of linoleic and α-linolenic acids in plasma CE and PL. A higher consumption of high-fiber grain products was related to a lower proportion of oleic acid in CE and PL. The consumption of candy was directly associated with the proportion of palmitoleic and oleic acid in plasma CE. The consumption of vegetable oil-based margarine was inversely associated with estimated stearoyl-CoA-desaturase activity in plasma CE and PL and the consumption of candy was directly related to it in plasma CE. The results of our study suggest that plasma FA composition is not only a biomarker for dietary fat quality but also reflects the consumption of high-fiber grain products and foods high in sugar among children.

N-6 and N-3 Fatty Acid Cholesteryl Esters in Relation to Fatal CHD in a Dutch Adult Population: A Nested Case-Control Study and Meta-Analysis

BackgroundDietary polyunsaturated fatty acids (PUFA) are inversely related to coronary heart disease (CHD) in epidemiological studies. We examined the associations of plasma n-6 and n-3 PUFA in cholesteryl esters with fatal CHD in a nested case-control study. Additionally, we performed a dose-response meta-analysis of similar prospective studies on cholesteryl ester PUFA.MethodsWe used data from two population-based cohort studies in Dutch adults aged 20–65y. Blood and data collection took place from 1987–1997 and subjects were followed for 8–19y. We identified 279 incident cases of fatal CHD and randomly selected 279 controls, matched on age, gender, and enrollment date. Odds ratios (OR) were calculated per standard deviation (SD) increase of cholesteryl ester PUFA.ResultsAfter adjustment for confounders, the OR (95%CI) for fatal CHD per SD increase in plasma linoleic acid was 0.89 (0.74–1.06). Additional adjustment for plasma total cholesterol and systolic blood pressure attenuated this association (OR:0.95; 95%CI: 0.78–1.15). Arachidonic acid was not associated with fatal CHD (OR per SD:1.11; 95%CI: 0.92–1.35). The ORs (95%CI) for fatal CHD for an SD increase in n-3 PUFA were 0.92 (0.74–1.15) for alpha-linolenic acid and 1.06 (0.88–1.27) for EPA-DHA. In the meta-analysis, a 5% higher linoleic acid level was associated with a 9% lower risk (relative risk: 0.91; 95% CI: 0.84–0.98) of CHD. The other fatty acids were not associated with CHD.ConclusionIn this Dutch population, n-6 and n-3 PUFA in cholesteryl esters were not significantly related to fatal CHD. Our data, together with findings from previous prospective studies, support that linoleic acid in plasma cholesteryl is inversely associated with CHD.

N-6 and n-3 fatty acid cholesteryl esters in relation to incident stroke in a Dutch adult population: A nested case–control study

Background and aimsThere are few prospective studies on fatty acid status in relation to incident stroke, with inconsistent results. We assessed the associations of plasma n-6 and n-3 PUFA in cholesteryl esters with the risk of total stroke and stroke subtypes in Dutch adults. Methods and resultsWe conducted a nested case–control study using data from a population-based cohort study in adults aged 20–65 years. Blood sampling and data collection took place during 1993–1997 and subjects were followed for 8–13 years. We identified 179 incident cases of stroke and 179 randomly selected controls, matched on age, gender, and enrollment date. Odds ratios (OR) with 95% confidence intervals (95%CI) were calculated per standard deviation (SD) increase of PUFA in cholesteryl esters using multivariable conditional logistic regression. Cases comprised 93 ischemic, 50 hemorrhagic, and 36 unspecified strokes. The n-6 PUFA linoleic acid and arachidonic acid contributed ∼55% and ∼6.5% respectively to total plasma fatty acids, whereas the n-3 PUFA alpha-linolenic acid contributed ∼0.5% and eicosapentaenoic acid plus docosahexaenoic acid (EPA-DHA) ∼1.3%. After adjustment for confounders, n-6 and n-3 PUFA were not associated with incident total stroke or stroke subtypes. The OR (95% CI) for total stroke was 0.95 (0.74–1.23) per SD increase in linoleic acid and 1.02 (0.80–1.30) per SD increase in arachidonic acid. ORs (95% CI) for total stroke were 0.94 (0.72–1.21) for alpha-linolenic acid and 1.16 (0.94–1.45) for EPA-DHA. ConclusionIn the present study, plasma n-6 or n-3 fatty acids were not related to incident stroke or stroke subtypes.

Abstract P013: N-6 And N-3 Fatty Acid Cholesteryl Esters In Relation To Fatal Chd In A Dutch Adult Population: A Nested Case-control Study

Aim: Dietary polyunsaturated fatty acids (PUFA) are inversely related to coronary heart disease (CHD) in epidemiological studies. We examined the associations of plasma n-6 and n-3 PUFA in cholesteryl esters with fatal CHD in a nested case-control study. Methods We used data from two population-based cohort studies in Dutch adults aged 20-65 years. Blood sampling and data collection took place from 1987–1997 and subjects were followed for 8–19 years. We identified 279 incident cases of fatal CHD (235 fatal myocardial infarctions and 44 cardiac arrests) and randomly selected 279 controls, matched on age, gender, and enrollment date. Odds ratios (OR) with 95% confidence intervals (95%CI) were calculated per standard deviation (SD) increase of fatty acids in cholesteryl esters using multivariable conditional logistic regression models. Results After adjustment for confounders, the OR (95% CI) for fatal CHD per SD increase in plasma linoleic acid was 0.89 (0.74-1.06). Additional adjustment for plasma total cholesterol and systolic blood pressure attenuated this association (OR: 0.95; 95% CI: 0.78–1.15). Plasma arachidonic acid was not associated with fatal CHD (OR per SD: 1.11; 95% CI: 0.92-1.35). The ORs (95% CI) for fatal CHD for an SD increase in n-3 PUFA were 0.92 (0.74-1.15) for plasma alpha-linolenic acid and 1.06 (0.88-1.27) for plasma EPA-DHA. Conclusion In this Dutch adult population, arachidonic acid and n-3 PUFA in cholesteryl esters were not related to fatal CHD. Our data support findings from previous prospective studies showing a lower proportion of linoleic acid in plasma cholesteryl esters in CHD cases.

Chemical constituents from Bufonis periostracum and their antitumor activity in vitro

Eight compounds were isolated from Bufonis periostracum by repeated column chromatography on silica gel, ODS and Sephadex LH-20 and their structures were characterized as palmitatic acid cholesteryl ester (1), cholesterol (2), 5alpha, 8alpha-epidioxycholesta-6-en-3beta-ol (3), cholest-5-en-3beta, 7beta-diol (4), cholest-7-en-3beta, 5alpha, 6beta-triol (5), 3-octaddecyloxy-1, 2-propanediol (6), isisamide (7) and bufothionine (8) on the base of spectral analysis. Compounds 1-8 were isolated from Bufonis periostracum for the first time and compounds 3, 5, 6, 7 were obtained from Bufo bufo gargarizans and Bufo genus for the first time. The bioassays showed all tested samples displayed no antitumor activity against the cell lines such as A549, BeL 7402, HGC-27 and HL-60, except the control compound bufalin.

Modified Low Density Lipoproteins Decrease the Activity and Expression of Lysosomal Acid Lipase in Human Endothelial and Smooth Muscle Cells

Lysosomal acid lipase (LAL), the only lysosomal enzyme involved in the hydrolysis of LDL-cholesteryl esters, is a key regulator of cellular cholesterol and fatty acid homeostasis and its deficiency contributes to the pathophysiology of various diseases. In this study, we questioned whether oxidized or glycated LDL, a common occurrence in atherosclerosis and diabetes, affect the activity and expression of LAL in vascular endothelial cells (EC) and smooth muscle cells (SMC). LAL activity and expression were assayed in cultured human EC and SMC exposed to oxidized LDL (oxLDL), (±)9-hydroxyoctadecadienoic acid-cholesteryl ester (HODE), glycated LDL (gLDL), or native LDL (nLDL) as control, in the presence or absence of LXR or PPAR-gamma agonists. We found that LAL activity and expression were significantly down regulated by oxLDL and HODE in EC, and by gLDL in SMC. The LXR agonist T0901317 reversed the decreased LAL expression in modified LDL- or HODE-exposed EC (P<0.001) and in gLDL-exposed SMC, whereas PPAR-gamma agonist rosiglitazone induced a low effect only in EC. In conclusion, modified LDL down regulates LAL expression in human EC and SMC by a process involving the LXR signaling pathway. This is the first demonstration that modified LDL modulate LAL expression, in a cell specific manner.

Dietary polyunsaturated fatty acids and adaptation to chronic hypoxia alter acyl composition of serum and heart lipids

The effects of dietary supplementation with fat of different fatty acid profile and chronic intermittent hypoxia (CIH) on the fatty acid composition of serum and heart lipids were analysed. Adult male Wistar rats were fed a standard non-fat diet enriched with 10 % of lard, fish oil (n-3 PUFA) or maize oil (n-6 PUFA) for 10 weeks. After 4 weeks on the diets, each group was divided in two subgroups, either exposed to CIH in a barochamber (7000 m, twenty-five exposures) or kept at normoxia. In normoxic rats, the fish oil diet increased the level of conjugated dienes. The n-6:n-3 PUFA ratio in serum TAG, phospholipids (PL), cholesteryl esters (CE) and heart TAG, PL and diacylglycerols (DAG) followed the ratio in the fed diet (in the sequence maize oil>lard>fish oil). In heart TAG, PL and DAG, 20 : 4n-6 and 18 : 2n-6 were replaced by 22 : 6n-3 in the fish oil group. The main fatty acid in CE was 20 : 4n-6 in the lard and maize oil groups whereas in the fish oil group, half of 20 : 4n-6 was replaced by 20 : 5n-3. CIH further increased 20 : 5n-3 in CE in the fish oil group. CIH decreased the n-6:n-3 PUFA ratio in serum CE, heart TAG, PL and DAG in all dietary groups and stimulated the activity of catalase in the maize and fish oil groups. In conclusion, PUFA diets and CIH, both interventions considered to be cardioprotective, distinctly modified the fatty acid profile in serum and heart lipids with specific effects on conjugated diene production and catalase activity.

Research of Tribological Properties of Mineral Motor Oil with Cholesteryl Stearate Additive

Results of tribological research of mineral motor oil with and without twisted nematic liquid crystal additive (stearic acid cholesteryl ester) are presented in the article. Experimental research was performed by means of a “fixed segment – rotating roller” tribometer according to the central three-factor second-order rotatable factorial design. The following parameters were accepted as controllable factors: contact pressure (3.32–6.68 MPa), concentration of liquid crystal in lubricant (0.16–1.84 ) and the average height of surface roughness of contacting surfaces of roller and segment (2.5–37.5 μm). The friction coefficient and friction zone temperature were served as output parameters. Regression equations describing the friction process were obtained and tribological efficiency of liquid crystal additive was established.