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PubMed1983

Short-term regulation of fatty acid synthesis in isolated alveolar type II cells from adult rat lung. Effects of free fatty acids and hormones.

We measured the total rate of fatty acid synthesis in alveolar type II cells freshly isolated from the lungs of adult rats. The rate of incorporation of 3H from 3H2O into cellular fatty acids was linear during 3-hr incubations and was very brisk [18 ng-atoms 3H/10(6) cells/hr +/- 2 (mean +/- SD, n = 23)]. When the nutrient medium (Minimum Essential Medium) was supplemented with various hormones or free fatty acids, the long-chain fatty acids (C14-C20) caused a decrease in the rate of 3H incorporation to a variable degree depending on the species of fatty acid. Stearate (10(-4) M) and palmitate (10(-4) M) caused the greatest inhibition of de novo cellular fatty acid synthesis, followed by myristate, arachidonate, and oleate. Insulin (10(-7) M), glucagon (10(-8) M), terbutaline (10(-5) M), 8-bromo-cyclic AMP (10(-3) M), the essential fatty acid linoleate (10(-4) M), and the medium-chain-free fatty acids laurate and octanoate (10(-4) M) did not alter the rate of fatty acid synthesis in type II cells. We demonstrated that the alveolar type II cell is a major lipogenic cell type in the rat. We also demonstrated that the availability of preformed fatty acids in the extracellular milieu is one factor regulating the rate of fatty acid synthesis in these cells.

Animals↗
PubMed1996

Carotenoids and their fatty-acid esters in banana peel.

In relation to banana ripening, banana peel was examined for carotenoid pigments by a combination of alumina column chromatography and high-performance liquid chromatography (HPLC). Carotenoids and their fatty-acid esters were first separated by an alumina column into five fractions, of which each was further subfractionated by HPLC with different kinds of solvent. The carotenoid content of the banana peel was in the range of 3-4 micrograms per gram as lutein equivalent. The ingredients of the carotenoids were ascertained to consist of lutein, beta-carotene, alpha-carotene, violaxanthin, auroxanthin, neoxanthin, isolutein, beta-cryptoxanthin and alpha-cryptoxanthin. Most of the oxygenated carotenoids were found to occur in the esterified form, mainly with myristate, and to a lesser extent with laurate, palmitate or caprate.

Carotenoids↗
PubMed2000

Novel inhibitors of the condensing enzymes of the type II fatty acid synthase of pea (Pisum sativum).

The type II fatty acid synthases (FASs) of higher plants (and Escherichia coli) contain three condensing enzymes called beta-ketoacyl-ACP synthases (KAS), where ACP is acyl-carrier-protein. We have used novel derivatives of the antibiotic thiolactomycin to inhibit these enzymes. Overall de novo fatty acid biosynthesis was measured using [1-(14)C]acetate substrate and chloroplast preparations from pea leaves, and [1-(14)C]laurate was used to distinguish between the effects of the inhibitors on KAS I from those on KAS II. In addition, the activities of these enzymes, together with the short-chain condensing enzyme, KAS III, were measured directly. Six analogues were tested and two, both with extended hydrocarbon side chains, were found to be more effective inhibitors than thiolactomycin. Incubations with chloroplasts and direct assay of the individual condensing enzymes showed that all three compounds inhibited the pea FAS condensing enzymes in the order KAS II > KAS I > KAS III. These results demonstrate the general activity of thiolactomycin and its derivatives against these FAS condensation reactions, and suggest that such compounds will be useful for further detailed studies of inhibition and for use as pharmaceuticals against Type II FASs of pathogens.

3-Oxoacyl-(Acyl-Carrier-Protein) Synthase↗
PubMed2000

Effects of milk diets containing beef tallow or coconut oil on the fatty acid metabolism of liver slices from preruminant calves.

Coconut oil (CO) induces a triacylglycerol infiltration in the hepatocytes of preruminant calves when given as the sole source of fat in the milk diet over a long-term period. Metabolic pathways potentially involved in this hepatic triacylglycerol accumulation were studied by in vitro methods on liver slices from preruminant Holstein x Friesian male calves fed a conventional milk diet containing CO (n 5) or beef tallow (BT, n 5) for 19 d. Liver slices were incubated for 12 h in the presence of 0.8 mm-[14C]oleate or -[14C]laurate added to the medium. Fatty acid oxidation was determined by measuring the production of CO2 (total oxidation) and acid-soluble products (partial oxidation). Production of CO2 was 1. 7-3.6-fold lower (P 0.0490) and production of acid-soluble products tended to be lower (P = 0.0625) in liver slices of CO- than BT-fed calves. Fatty acid esterification as neutral lipids was 2.6- to 3. 1-fold higher (P = 0.0088) in liver slices prepared from calves fed the CO diet compared with calves fed the BT diet. By contrast with what occurs in the liver of rats fed CO, the increase in neutral lipid production did not stimulate VLDL secretion by the hepatocytes of calves fed with CO, leading to a triacylglycerol accumulation in the cytosol. It could be explained by the reduction of fatty acid oxidation favouring esterification in the form of triacylglycerols, in association with a limited availability of triacylglycerols and/or apolipoprotein B for VLDL packaging and subsequent secretion.

Analysis of Variance↗
PubMed1975

Purified liver microsomal cytochrome P-450. Electron-accepting properties and oxidation-reduction potential.

The reduction of highly purified cytochrome P-450 from rabbit liver microsomes under anaerobic conditions requires 2 electrons per molecule. Similar results were obtained with dithionite, NADPH in the presence of NADPH-cytochrome P-450 reductase, or a photochemical system as the electron donor, with CO or other ligands, with substrate or phosphatidylcholine present, after denaturation to form cytochrome P-420, or with cytochrome P-450 partially purified from rat or mouse liver microsomes. The reduced cytochrome P-450 donates 2 electrons to dichlorophenolindophenol or to cytochrome c. Reoxidation of reduced cytochrome P-450 by molecular oxygen restores a state where 2 electrons from dithionite are required for re-reduction. Although these unexpected findings indicate the presence of an electron acceptor in addition to the heme iron atom, significant amounts of non-heme iron, other metals or cofactors, or disulfide bonds were not found, and free radicals were not detected by electron paramagnetic resonance spectrometry. Resolution of the cytochrome with acetone and acid yielded the apoenzyme, which did not accept electrons, and ferriprotoporphyrin IX, which accepted a single electron. A reconstituted hemoprotein preparation with the spectral characteristics of cytochrome P-420 accepted as much as 0.7 extra electron equivalent per heme. The midpoint oxidation-reduction potential of purified cytochrome P-450 from rabbit liver microsomes at pH 7.0 is -330 mv, and with CO present this value is changed to about -150 mv. The oxidation-reduction potential is unaffected by the presence of phosphatidylcholine or benzphetamine, a typical substrate. Laurate, aminopyrine, and benzphetamine undergo hydroxylation in the presence of chemically reduced cytochrome P-450 and molecular oxygen. Neither NADPH nor the reductase is required for substrate hydroxylation under these conditions.

Anaerobiosis↗
PubMedDate not supplied

Estimation of absorption enhancement by medium-chain fatty acids in rat large intestine.

The absorption enhancement by the sodium salts of several fatty acids was investigated in rat large intestine for model compounds having a wide range of molecular weight. Sodium caprylate (C8), sodium caprate (C10), sodium laurate (C12), which are categorized in medium-chain fatty acid, and sodium oleate (C18:1), long-chain unsaturated fatty acid, were employed as lipoidal adjuvants. Phenol red (MW=354.4), glycyrrhizin (822.9), fluorescein isothiocyanate-dextran-4 (FD-4, 4400), FD-10 (9400) and FD-40 (38900) were selected as model compounds for the assessment of the enhancing effect of the lipoidal adjuvants. The absorption of phenol red was promoted at the highest level, about 20 times higher by C12 and C18:1 than the control. The absorption rate - time profiles calculated by deconvolution method showed that C12 takes effect most rapidly and efficiently. In the case of glycyrrhizin, four adjuvants including C12 showed almost the same improvement of the absorption, about 30-40 times larger than the control. C8 and sodium citrate did not significantly enhance the absorption of those model compounds. For FD-4, FD-10 and FD-40, C10, C12 and C18:1 revealed almost the same enhancing effect and the absorption of FD-4, FD-10 and FD-40 was enhanced about 80 times, 1000-1800 times and about 200 times, respectively, larger than the control. The enhancement ratio, the ratio of AUC with adjuvant to AUC of control, suggests that these lipoidal adjuvants would improve most efficiently the absorption of the compound having the molecular weight of around 10000. Furthermore, C12 was suggested to be an effective adjuvant for the compounds with the wide range of molecular weight.

Adjuvants, Pharmaceutic↗
PubMed1975

[Tin-organic compounds and their biocidal properties].

The authors studied the disinfecting action of the vapour of tributyltin oxide in the aerosol chamber and came to the conclusion that the tin-organic compounds possessed a wide buicidal action, still inadequately used in practice. The mentioned vapour served as a disinfectant only in the presence of water vapour. Tribytyltin oxide (0.15% concentration) displayed an ovicidal action on the ova of Ascaris suum. Tributyltin laurate produced a good insecticidal effect on Musca domestica.

Animals↗
PubMedDate not supplied

Preparation of uniform titanium dioxide (TiO2) polystyrene-based composite particles using the glass membrane emulsification process with a subsequent suspension polymerization.

Uniform titanium dioxide (TiO(2))-polystyrene-based composite particles were prepared using the glass membrane emulsification process followed by a subsequent suspension polymerization. The oil phase, consisting of anatase TiO(2) fine powder, monomers, methyl laurate as the hydrophobic additive, Disperbyk-180 and the poly(styrene-co-2-ethyl hexylacrylate) were emulsified through the membrane pores into the aqueous phase containing stabilizers to form a (solid-in-oil)-in-water (S/O/W) emulsion of monomer droplets. The suspension polymerization was carried out at 343 K for 24 h under a nitrogen atmosphere. An SPG membrane with a pore size of 5.25 microm was employed and 20-25 microm TiO(2)-polystyrene based composite particles were obtained depending on the composition of polymerizing oil phase. The effects of the co-monomer, 2-ethylhexyl acrylate and the cross-linking agent, divinyl benzene on the dispersion stability of TiO(2) in the oil phase, the surface feature of the particle and the encapsulation loading were investigated in this study. The membrane emulsification process was capable of preparing the composite particles with approximately 5 wt% of TiO(2) encapsulated, which accounts for with at least 85 wt% of TiO(2) in the oil phase.

Drug Compounding↗
PubMed1992

Preparation and in vitro antiviral activity of liposomes of lipophilic esters of acyclovir.

The long chain acyclovir such as the acyclovir laurate and acyclovir palmitate were prepared directly from acyclovir by application of the usual esterification methods with appropriate acyl chlorides. The lipophilic prodrugs were found to be retained easier by liposomes whereas acyclovir escaped readily from liposomes. When assayed in African green monkey cell cultures against herpes simplex virus type I strain, the acyclovir palmitate liposomes proved to be more active compared with the parent drug and its liposome, suggesting an enhanced compatibility between the ester and liposomal lipids and an increased uptake of encapsulated prodrug by infected cells.

Acyclovir↗
PubMed1992

Identification of rabbit cytochromes P450 2C1 and 2C2 as arachidonic acid epoxygenases.

Microsomes prepared from COS-1 cells transiently expressing rabbit cytochromes P450 2C1 and 2C2 catalyzed the metabolism of arachidonic acid to predominantly 11,12- and 14,15-epoxyeicosatrienoic acids (EETs) when microsomal epoxide hydrolase activity was inhibited by 0.2 mM 1,2-epoxy-3,3,3-trichloropropane. P450 2C2 catalyzed the formation of 11,12-EET and 14,15-EET at a ratio of 3.0 and also produced 19-hydroxyeicosatetraenoic acid (19-HETE). The 11,12-EET, 14,15-EET, and 19-HETE represented 48.3, 15.9, and 12.8%, respectively, of the total metabolites formed. P450 2C1 produced a similar but distinct ratio of 11,12-EET to 14,15-EET (2.0) and did not produce any detectable 19-HETE. The 11,12-EET and 14,15-EET represented 63.0 and 31.1%, respectively, of the total metabolites formed. The 8,9- and 5,6-EETs were not detected with either enzyme. The ratio of the 11,12-EET to 14,15-EET was 1.5 with P450 2CAA, a P450 arachidonic acid epoxygenase (P450 2CAA) that had an amino-terminal sequence identical to that of P450 2C2 [J. Biol. Chem. 267:5552-5559 (1992)]. P450 2C1, 2C2, and 2CAA metabolized lauric acid. The ratio of omega-1- to omega-hydroxylated laurate was 3.6, 3.4, and 2.4 for P450 2CAA, P450 2C2, and P450 2C1, respectively. Purified P450 2CAA had a slightly greater apparent molecular weight than expressed P450 2C2 on sodium dodecyl sulfate-polyacrylamide gels. The results clearly establish that rabbit P450 2C1 and 2C2 are arachidonic acid epoxygenases, and they suggest that P450 2CAA and 2C2 are very similar but may not be identical isoforms.

Animals↗
PubMedDate not supplied

Proposed mechanisms for the anabolic steroid-induced increase in myocardial susceptibility to ischaemia/reperfusion injury.

UNLABELLED: Androgenic anabolic steroids (AAS) are often used by athletes to enhance athletic performance but are strongly associated with detrimental cardiovascular effects including sudden cardiac death. HYPOTHESIS: AAS use increases myocardial susceptibility to ischaemia/reperfusion injury. METHODS: Rats were trained (swimming) with or without intramuscular injection of nandrolone laurate (0.375 mg/kg). Untrained rats with or without nandrolone served as controls. Hearts were mounted on the Langendorff perfusion apparatus and mechanical function was measured before and after 20-min normothermic global ischaemia. Myocardial tissue samples were collected for determination of tissue cyclic nucleotide and TNFalpha concentrations. RESULTS: Anabolic steroids decreased the rate pressure product (RPP) of the exercise-trained rat heart [34 582 +/- 1 778 mmHg/min vs 28 868 +/- 2 446 mmHg/min for exercise-trained steroid-treated hearts (p < 0.05)]. Reperfusion RPP was lower in both the sedentary, and the exercise-trained, steroid-treated hearts than in their concurrent vehicle-treated controls (18 276 +/- 2 026 mmHg/min vs 12 018 +/- 1 725 mmHg/min for sedentary steroid-treated hearts and, 21 892 +/- 2 912 mmHg vs 12 838 +/- 1 536 mmHg/min for exercise-trained steroid-treated hearts). Myocardial TNFalpha [267.75 +/- 44.25 pg/g vs 190.00 +/- 15.75 pg/g (p < 0.05)] and cAMP concentrations [406.04 +/- 18.41 pmol/g vs 235.6 +/- 43.26 pmol/g (p < 0.05)] were elevated in the steroid-treated hearts when compared with their untreated counterparts. CONCLUSIONS: Supraphysiological doses of anabolic steroids, whether taken during exercise training or under sedentary conditions increase myocardial susceptibility to ischaemia/reperfusion injury in our model. This increased susceptibility may be related to steroid-induced increases in the pre-ischaemic myocardial cAMP concentrations and/or increases in both pre-ischaemic and reperfusion TNFalpha concentrations.

Anabolic Agents↗
PubMed1991

Phycochemical investigations on Centroceras clavulatum (Ceramiales, Rhodophyta).

The methanolic extract of a marine red alga Centroceras clavulatum (C. Ag.) Mont., collected from the coast of Karachi, was studied for its fatty acid and sterol compositions. The analysis of fatty acid methyl esters by GC-MS revealed the presence of methyl laurate, tridecylate, myristate, pentadecylate, palmitate, margarate, nonadecylate, arachidate, behenate, tricosanoate and pentacoeanoate among saturated and methyl palmitoleate and heptadecylenate among unsaturated acids. The sterol composition divulged the presence of 22-dehydrocholeaterol, cholesterol, 24-methyl-cholesterol and beta-sitosterol, identified through main spectrometry and 1H-NMR spectroscopy.

Journal Article↗
PubMed1990

Kinetics of the inhibition of hog kidney D-amino acid oxidase by short-, medium- and long-chain fatty acids.

Various fatty acids were studied in vitro as inhibitors of pure hog kidney D-amino acid oxidase by means of a spectrophotometric peroxidase-coupling method using D-methionine as a substrate. All the fatty acids tested behaved as substrate-competitive inhibitors of the enzyme. The affinity of the saturated aliphatic acids for D-amino acid oxidase decreased from pentanoate (5:0; Ki = 220 microM) to laurate (12:0; Ki = 675 microM), then rose to a maximum with stearate (18:0; Ki = 36 microM), suggesting the presence of a site in the active center of the enzyme that accepts long-chain fatty acid alkyl groups. Unsaturation did not further increase the affinity of the fatty acid for this binding site.

Animals↗
PubMed1990

Esterification of retinol in lacrimal gland. Evidence for acyl-CoA:retinol acyltransferase activity.

Vitamin A is stored in cells as long-chain fatty acyl esters of retinol. Esterification in many tissues is catalyzed in part by acyl-CoA:retinol acyltransferase (ARAT). Since the lacrimal gland contains stores of retinyl esters, it was the goal of this study to determine whether the lacrimal gland contains ARAT activity. Rabbit lacrimal gland microsomes incubated with 3H-retinol synthesized retinyl esters. The reaction rate was stimulated 30-fold in the presence of a fatty acyl-CoA generating system, producing a mixture of esters including retinyl laurate, retinyl linoleate, retinyl palmitate, and retinyl stearate as determined by reverse-phase HPLC. Retinyl palmitate was synthesized at 1944 pmole/mg protein/30 min, representing 50% of total ester synthesis, and this activity was directly proportional to microsomal protein concentration. In the presence of 180 microM 3H-retinol and 100 microM palmitoyl-CoA, retinyl palmitate was synthesized at 175-220 pmole/mg/min, and the reaction fit Michaelis-Menten kinetics as a function of retinal concentration (theoretical Vmax = 329.4 pmole/mg/min). Lauroyl CoA and stearoyl CoA, but not linoleoyl CoA, were as effective as palmitoyl CoA as substrates for the reaction. The enzyme activity was inhibited by p-chloromercuriphenyl sulfonic acid and Na-taurocholate. The data show that the lacrimal gland synthesizes retinyl esters and that the characteristics of synthesis are consistent with the presence of acyl-CoA:retinol acyltransferase in lacrimal gland.

Acyl Coenzyme A↗
PubMed1989

[Antiseptic sensitivity of clinical strains of Pseudomonas aeruginosa].

MICs, the frequency of clinical and statistic resistance and the antiseptic activity index were studied in complex on out-of-hospital and hospital ecovars of P. aeruginosa. The forms resistant to a number of antiseptics, i.e. chloramine B, chlorhexidine, decamethoxine and dioxidine whose frequency eventually increased were shown to be widely distributed. The antiseptic sensitivity spectrum was more narrow and more heterogeneous than that of other bacteria, the heterogeneity level being dependent on the antiseptic type and bacterial ecovar. The activity of pervomur, phenol, resorcin and boric acid was higher against the clinical strains of P. aeruginosa while iodopyrin, sulfacetamide sodium and dioxidine were less active. The P. aeruginosa strains had natural resistance to cetylpyridinium chloride, rokkal, ethonium, sodium laurate and laurylsulfate and rivanol. It was recommended to assay antiseptic sensitivity of agents causing purulent inflammatory infections and to control circulation of antiseptic resistant variants of bacteria in hospitals.

Anti-Infective Agents, Local↗
PubMed1989

[Inhibition of neutrophil function by solvent of injectable sedatives--effects of propylene glycol, ethanol and benzyl alcohol].

Propylene glycol, ethanol and benzyl alcohol are usually included in the injection solutions of diazepam, flunitrazepam and others as solvents and/or pain relief agents. It was reported that diazepam and flunitrazepam inhibited oxidative burst of human neutrophils to produce O2-, H2O2 and other active oxygen species. However, the present study revealed that the solvents had far more potent inhibitory effects in this regard than diazepam and flunitrazepam themselves. The solvents reversibly inhibited phagocytosis and O2- production by neutrophils, and they were stimulated by both soluble stimulants, phorbol myristate acetate or laurate, and a particulate stimulant, serum opsonized zymosan, in a dose-dependent manner. Benzyl alcohol, which had the most potent effect among the solvents, appeared to inhibit the O2- generating enzyme NADPH oxidase directly, rather than by affecting intracellular calcium mobilization. Thus one should keep in mind such unexpected effects of the solvents included in solutions for injection.

Benzyl Alcohol↗
PubMed1989

Auto-oxidation of Lingula unguis and Siphonosoma cumanense hemerythrins induced by some perturbants.

Auto-oxidation of human adult hemoglobin and Siphonosoma cumanense and Lingula unguis hemerythrins were investigated in the presence and absence of perturbants. In the presence of urea, there were no drastic increases in auto-oxidation rates for the three proteins. In contrast, thiocyanate and laurate enhanced the auto-oxidation rates remarkably. In the presence of thiol reagents such as PCMB and NEM, auto-oxidation rates were enhanced with dissociation into subunit, but not enhanced so much with SH-modification only. Thus oligomerization is probably necessary to protect auto-oxidation.

Animals↗
PubMed1988

Activation by saturated and monounsaturated fatty acids of the O2- -generating system in a cell-free preparation from neutrophils.

Saturated and monounsaturated fatty acids with appropriate chain length such as laurate and oleate activated an O2- -generating enzyme system in a cell-free preparation from porcine neutrophils. The activated preparation catalyzed a stoichiometric conversion of O2 to O2- by utilizing NADPH as the electron donor. The preparation contained both membrane and soluble fractions and, upon separation into subfractions, the O2- -generating activity resided exclusively in the membrane fraction. Polyunsaturated fatty acids including arachidonate also activated the system, but they concurrently stimulated NADPH-independent O2 consuming reactions which yield neither O2- nor H2O2. The amount of such a non-O2- -producing O2 consumption often reached twice as much as that of O2- production. For the activation of the O2- -generating system in the membrane, the presence of the soluble fraction was essential. However, the soluble fraction was no longer effective when once used for the activation, suggesting that the effective component(s) in the fraction was consumed or translocated to the membrane during the activation. When the activated membrane was incubated with delipidated albumin, the activity was lost with concomitant decreases in the amount of membrane-associated fatty acids. The lost activity was restored by the replenishment of the fatty acid in the presence of a fresh soluble fraction. We also found that Ca2+ augmented a non-O2- -producing O2 consumption in the cell-free preparation by unsaturated fatty acids and interfered with the activation of the O2- -generating system, especially that by saturated fatty acids.

4,5-Dihydro-1-(3-(trifluoromethyl)phenyl)-1H-pyraz↗