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PubMed2003

[Study on the association of lecithin cholesterol acyltransferase gene polymorphisms with the lipid metabolism in coronary atherosclerotic heart disease].

OBJECTIVE: To examine the distribution of 3 polymorphisms of lecithin cholesterol acyltransferase gene in Chinese population and the association of these polymorphisms with lipid metabolism in patients with atherosclerotic heart disease (CHD). METHODS: Genotypes and frequencies of 3 sites were examined by PCR-restriction fragment length polymorphism technique in 209 unrelated normal control individuals and 203 CHD patients. RESULTS: The observed allele frequencies conform well to Hardy-Weinberg equilibrium. The frequency of 608T allele was significantly higher in controls than that in patients (P=0.034). Compared with the CHD patients without 608T, the CHD patients with 608T exhibited a significant increase in plasma HDL-C concentration (P=0.015). 911T/C and 1188C/T polymorphisms were not found in either group. CONCLUSION: 608T polymorphism of LCAT gene was associated with higher plasma HDL-C level in CHD patients, while 911T/C and 1188C/T polymorphisms maybe very rare in Chinese population.

Alleles↗
PubMed2002

[Analysis of lecithin-cholesterol acyltransferase cDNA and protein sequence from tree shrew].

OBJECTIVE: To acquire cDNA sequence of lecithin-cholesterol acyltransferase (LCAT) from tree shrew and analyze the sequence structure. METHODS: The first strand cDNA was acquired by reverse transcription using mRNA from tree shrew liver as template. By the method of SMART RACE PCR, tree shrew LCAT cDNA was acquired and deduced its amino acids sequence. The sequence and structure of tree shrew LCAT cDNA and amino acid were analyzed and predicted by the molecular software. RESULTS: Tree shrew LCAT cDNA is composed of 1,340 bp, including 2 bp 5' untranslated region (5' UTR), 1,320 bp open reading frame (ORF) which encodes protein precursor of 440 amino acids (24 amino acids signal peptide and 416 amino acids mature peptide), and 18 bp 3' untranslated region (3'UTR). The stop codon is TAA and there is a poly (A) signal sequence AATAAA and a 25 bp poly (A) tail. Tree shrew LCAT cDNA sequence has been accepted by GenBank as a new gene, accession number AF272861 and its homology with human and baboon was 90% and 89%, respectively. CONCLUSION: The sequence of LCAT cDNA in tree shrew has high identity with that of human and other experimental animal species.

Amino Acid Sequence↗
PubMed1976

Local anesthetic inhibition of pancreatic phospholipase A2 action on lecithin monolayers.

Using quantitative data previously reported for the penetration of local anesthetics into lecithin monolayers, the effects of surface and subphase concentrations of anesthetics on the inhibition of pancreatic phospholipase A2 action on didecanoyl phosphatidylcholine monolayers was investigated. Inhibition as a function of subphase concentration of anesthetic was in the order: dibucaine greater than tetracaine greater than butacaine greater than lidocaine = procaine. Inhibition as a function of surface concentration showed no obvious correlation; procaine inhibited at a very low surface concentration, followed by lidocaine at a somewhat higher concentration, and tetracaine, butacaine and dibucaine only at rather high concentrations. Ultraviolet difference spectroscopy indicated an interaction between lidocaine and enzyme in the subphase. Fluorescence studies showed that lidocaine is a competitive inhibitor of enzyme-lipid interface interaction. It is proposed that the more surface-active anesthetics inhibit by surface effects while the less surface-active anesthetics (lidocaine and procaine) inhibit by interaction with the enzyme in the subphase, which prevents enzyme penetration at the monolayer interface.

4-Aminobenzoic Acid↗
PubMedDate not supplied

Spectral properties of fluorescent dyes in lecithin vesicles. Probes for the structure of lipid bilayer membranes and for membrane potentials.

Three fluorescent dyes (a merocyanin, a cyanin and a modified umbeliferon) have been incorporated into vesicles from three different lecithins. Their absorption spectrum, emission spectrum and fluorescence polarization in the lipid vesicles has been studied and compared with the spectral properties in homogeneous organic solutions. The reactivity of lipid bound dyes with reagents in the aqueous phase was investigated. The location of various dyes in the lipid membrane and their use as indicators of phase transitions or membrane potentials are discussed.

Fluorescent Dyes↗
PubMed1992

Inhibition of lecithin:cholesterol acyltransferase activity by synthetic phosphatidylcholine species containing eicosapentaenoic acid or docosahexaenoic acid in the sn-2 position.

Phospholipids isolated from the plasma of monkeys fed a diet enriched in fish oil were poor substrates for cholesteryl ester (CE) synthesis by the lecithin:cholesterol acyltransferase (LCAT) reaction relative to those from animals fed a lard containing diet when the phospholipids were used for the preparation of recombinant particles by cholate dialysis (Parks, J. S., B. C. Bullock, and L. L. Rudel. 1989. J. Biol. Chem. 264: 2545-2551). The purpose of the present study was to directly test the influence of eicosapentaenoic acid (20:5 n-3) and docosahexaenoic acid (22:6 n-3) in the sn-2 position of phosphatidylcholine (PC) on the activity of LCAT. PC species containing 1-palmitoyl-2-oleoyl PC (POPC), 1-palmitoyl-2-linoleoyl PC (PLPC), 1-palmitoyl-2-arachidonoyl PC (PAPC), 1-palmitoyl-2-eicosapentaenoyl PC (PEPC), or 1-palmitoyl-2-docosahexaenoyl PC (PDPC) were purchased or synthesized and made into recombinant particles of uniform size and composition with [14C]cholesterol and apoA-I using the cholate dialysis procedure. The recombinant particles (PC:cholesterol:apoA-I molar ratio = 42:1.9:1) exhibited the following order of reactivity towards purified human LCAT in vitro: POPC greater than PLPC greater than PEPC = PAPC greater than PDPC. The apparent Vmax/Km for recombinant particles containing PEPC and PDPC was 17% and 7% that of particles containing POPC, respectively. There was a linear decrease in CE formation when the percentage of PEPC or PDPC was increased from 0 to 100% relative to POPC in recombinant particles with a constant PC:cholesterol:apoA-I molar ratio, suggesting that the PEPC and PDPC were competitive inhibitors of the LCAT reaction.(ABSTRACT TRUNCATED AT 250 WORDS)

Chromatography, High Pressure Liquid↗
PubMedDate not supplied

A comparison of two commercially irradiated Trypticase Soy Agars containing lecithin and polysorbate 80.

Gamma-radiation sterilized Trypticase Soy Agar containing lecithin and polysorbate 80 (TSA++) (Becton Dickinson Microbiology Systems, Cockeysville, MD) and irradiated TSA++ (Adams Scientific, West Warwick, RI) were tested by a quantitative spread plate method. Four bacteria Bacillus subtilis ATCC 6633, Pseudomonas aeruginosa ATCC 10145, Staphylococcus aureus ATCC 25923, Streptococcus pyogenes ATCC 19615 and the yeast Candida albicans ATCC 10231 were tested in two separate experiments using different lots of media. A strain of Aspergillus niger ATCC 16404, was tested by a qualitative streak plate method. The Becton Dickinson Microbiology Systems (BDMS) irradiated TSA++ overall recovered a greater number of organisms than the Adams Scientific TSA++ in both experiments and allowed for the earlier recovery of S. pyogenes ATCC 19615. The growth of A. niger ATCC 16404, was comparable on both media. Efficacy of the media to neutralize 1, 2 and 3% phenol as well as 0.001, 0.01 and 0.1% benzalkonium chloride (BC) solutions was done by a disk diffusion method using 2 gram-positive and 4 gram-negative bacteria. Both media showed complete neutralization of the 0.001 and 0.01% BC solutions and partial neutralization of the 0.1% BC solution. The BDMS TSA++ showed better neutralization of the 2 and 3% phenol solutions than the Adams Scientific TSA++. This data indicates that not all irradiated TSA++ media perform in an equivalent manner.

Agar↗
PubMed2003

Differential expression of the enzyme that esterifies retinol, lecithin:retinol acyltransferase, in subtypes of human renal cancer and normal kidney.

PURPOSE: Retinoids, a group of compounds, including vitamin A (retinol), and related metabolites, have been shown to regulate the growth and differentiation of many types of cells. IFN-alpha and either 13-cis-retinoic acid or liposomal all-trans retinoic acid have been used in the treatment of patients with metastatic renal cell carcinoma. We knew that samples from renal cell carcinomas contained greatly reduced levels of retinol and retinyl esters relative to samples from normal human kidney. This prompted us to examine the levels of LRAT (lecithin:retinol acyltransferase) protein in various subtypes of human kidney cancers relative to normal human kidney by immunohistochemistry. EXPERIMENTAL DESIGN: We examined 31 partial or radical nephrectomy specimens diagnosed with kidney tumors between 1997 and 1998. Representative paraffin-embedded tissue blocks from each tumor, with each containing adjacent nonneoplastic renal parenchyma, were used for immunohistochemical analysis with affinity purified antibodies to human LRAT protein. RESULTS: LRAT protein was detected at high levels in the epithelial cells in the tubules and the lining of Bowman's capsule in the glomeruli of normal, nonneoplastic kidney sections. Among the 31 tumors, there were 13 cases of conventional (clear cell) renal cell carcinoma (RCC; including 2 multilocular cystic RCCs), 7 papillary RCC, 6 chromophobe RCC, 1 RCC, unclassified, and 4 renal oncocytoma. All tumors showed diffuse immunoreactivity for LRAT. In each case, the staining was uniform throughout the tumor, with only minimal variation in the staining intensity between different areas. All 4 renal oncocytomas, 2 of 6 chromophobe RCCs, 1 conventional (clear cell) carcinoma, 1 RCC, unclassified, and 2 conventional RCCs, which were of the multilocular cystic-type stained strongly (3+) for LRAT. In contrast, the remaining conventional RCCs and the papillary RCC samples stained much less intensely for LRAT. Of the 10 tumors that stained 3+ for LRAT in the study, 9 were either benign tumors or tumors with low malignant potential. CONCLUSIONS: These data show that LRAT expression is higher in renal tumors with an indolent biological behavior. Additional studies will ascertain if LRAT possesses any prognostic or therapeutic role in renal cancer.

Acyltransferases↗
PubMed2003

Role of lipases, lecithin:cholesterol acyltransferase and cholesteryl ester transfer protein in abnormal high density lipoprotein metabolism in insulin resistance and type 2 diabetes mellitus.

Dyslipidaemia, hallmarked by low HDL cholesterol and high plasma triglycerides, is a feature of insulin resistance and type 2 diabetes mellitus. These lipoprotein abnormalities represent major cardiovascular risk factors in these conditions. Among other factors, lipoprotein lipase (LPL), hepatic lipase (HL), lecithin:cholesterol acyltransferase (LCAT) and cholesteryl ester transfer protein (CETP) play an important role in an abnormal HDL metabolism in insulin resistance and type 2 diabetes mellitus. LPL hydrolyses lipoprotein triglycerides, thus providing lipids for HDL formation. In insulin resistant states, a decreased post-heparin plasma LPL activity contributes to a low HDL cholesterol, whereas an increased activity of HL reduces HDL particle size by hydrolysing its triglycerides and phospholipids. High HL activity coincides with low HDL cholesterol. The esterification of free cholesterol by LCAT increases HDL particle size. Subsequent CETP action results in transfer of cholesteryl esters from HDL towards triglyceride-rich lipoproteins. This cholesteryl ester transfer process results in lower HDL cholesterol and indirectly decreases HDL size. Plasma cholesterol esterification is unaltered or increased, whereas cholesteryl ester transfer is enhanced in type 2 diabetes mellitus, abnormalities which are probably related to the degree of hypertriglyceridaemia. It is plausible that a low LPL activity contributes to premature atherosclerosis as observed in insulin resistance and type 2 diabetes mellitus, but the effects of high HL activity and altered plasma cholesterol esterification on atherosclerosis development are uncertain. Since the cholesteryl ester transfer process between lipoproteins provides a metabolic intermediate between low HDL cholesterol and high plasma triglycerides, hypertriglyceridaemia-associated accelerated transfer of cholesteryl ester out of HDL may be pathogenetically involved in the development of cardiovascular disease in insulin resistance and type 2 diabetes mellitus.

Carrier Proteins↗
PubMed2003

[Study on supercritical CO2 extraction of lecithin from radix Polygoni Multiflori Preparata by orthogonal design].

OBJECTIVE: To find out the optimal supercritical CO2 fluid extraction process for Radix Polygoni Multiflori Preparata, the extraction process was studied by orthogonal design with the yield of lectithin as index. METHODS: Four factors were chosen in this experiment, including extractor pressure, extractor temperature, separator I pressure and separator I temperature. The ultraviolet visible spectrophotometry was applied for the determination of lecithin in all different experimental conditions. RESULTS: The optimal supercritical CO2 fluid extraction process was: extractor pressure 32 MPa, extractor temperature 50 degrees C, separator I pressure 6 MPa and separator I temperature 55 degrees C. CONCLUSION: Compared with the traditional extraction methods, SFE-CO2 process has the predominance of saving solvent and shortening the technology process, which is exactly suitable for industralization manufacture.

Analysis of Variance↗
PubMed1992

Continuous fluorescence assay for lecithin:cholesterol acyltransferase using a water-soluble phosphatidylcholine.

A water-soluble fluorescent phosphatidylcholine, 1,2-bis[4-(1-pyreno-butanoyl]-sn-glycero-3-phosphocholine (DPybPC) has been used to develop a sensitive, continuous assay for pure lecithin:cholesterol acyltransferase (LCAT) in solution. The monomeric substrate allowed us to examine the reaction of LCAT in the absence of a lipid/water interface in terms of the sensitivity of the enzymatic reaction to anions, ionic strength, apolipoproteins A-I and A-II, and a series of lysophosphatidylcholines and fatty acids. In contrast to the reaction of LCAT with aggregated phosphatidylcholines, the reaction of DPybPC with LCAT was not significantly affected by anions, ionic strength, nor apolipoproteins, indicating that these are only effectors of the interfacial reaction. Lysophosphatidylcholines and fatty acids inhibited LCAT in a chain-length-dependent manner below the critical micellar concentrations of these amphiphiles, indicating that the products of the LCAT reaction can bind to the enzyme and affect its kinetics even in the absence of an interface.

Evaluation Studies as Topic↗
PubMed1978

Emerging treatments: replacement therapy with choline or lecithin in neurological diseases.

This review evaluates the theoretical background and experimental data behind a new development: the replacement therapy of deficient central cholinergic systems with the dietary precursors choline or lecithin. Cholinergic deficiency states are possibly present in five neurological entities: Huntington's chorea, Tardive Dyskinesia, Gilles de la Tourette's disease, Friedreich's ataxia and pre-senile dementia. Preliminary data from various laboratories, including our own, in each of these disorders indicate that some clinical improvement can occasionally be seen, and that this approach deserves further investigation.

Animals↗
PubMed2004

Effect of long-term hemodialysis on plasma lecithin: cholesterol acyltransferase activity and the amounts and compositions of HDL2 and HDL3 in hemodialysis-treated patients with chronic renal failure: a 9-year longitudinal study.

BACKGROUND: Atherosclerosis was correlated with hemodialysis duration (HD) in chronic renal failure (CRF) patients. Dyslipidemias were identified as atherogenic risk factors. MATERIAL/METHODS: To investigate variations in HDL2 and HDL3 composition and lecithin: cholesterol acyltransferase (LCAT) activity as functions of HD, 20 CRF patients were selected for maintenance hemodialysis during the 9 years from April 1, 1991 to March 31, 2000. Blood samples were drawn four times: 1991 (T0, study begin), 1994 (T1), 1997 (T2), and 2000 (T3). T0 results were taken as references. RESULTS: Triacylglycerol concentrations were 1.12-fold higher at T1 (P<0.01), 1.31-fold at T2, and 1.63-fold at T3 (P<0.001). Increases of 14% and 33% of total cholesterol were noted at T2 (P<0.05) and T3 (P<0.001). Hypertriglyceridemia correlated with HD (r=0.70, P<0.05). LCAT activity decreased by 27%, 39%, and 51% at times T1, T2, and T3, respectively, this activity being negligible in 30% of patients at T2 and 40% at T3. An inverse relationship was noted between LCAT activity and HD (r=-0.80, P<0.001). Increases in HDL2-unesterified cholesterol (UC) and HDL3-UC were obtained at T2 and T3 (P<0.05), and high HDL2-triacylglycerols (TG) and HDL3-TG were noted at T1, T2, and T3 (P<0.001). HDL3-phospholipids (PL) values were diminished by 9% at T1 (P<0.05), 17% at T2, and 19% at T3 (P<0.001). CONCLUSIONS: Long-term hemodialysis aggravates lipid anomalies following CRF. Alterations in HDL composition contribute to the reduced efficacy of reverse cholesterol transport and patients are submitted to a greater risk for atherosclerosis.

Adult↗
PubMed1992

Effect of apoprotein B conformation on the activation of lysolecithin acyltransferase and lecithin: cholesterol acyltransferase. Studies with subfractions of low density lipoproteins.

In order to determine the role of apoprotein (apo) B conformation in the activation of the lysolecithin acyl-transferase reaction, we studied the activation of purified enzyme by various subfractions of low density lipoprotein (LDL), isolated by density gradient centrifugation. The activation of LAT correlated positively with the density of LDL and negatively with cholesterol/protein and triglyceride (TG)/protein ratios. The enzyme activation was also positively correlated with the number of trinitrobenzenesulfonic acid-reactive lysine amino groups, which increased with increasing density of LDL. The immunoaffinity of the LDL subfractions for B1B6, a monoclonal antibody directed to the receptor-binding region of apoB, increased with increasing density, while the affinity toward C1.4, a monoclonal antibody directed to the amino-terminal region of apoB, was not altered. Enrichment of normal whole LDL with TG resulted in a 45% reduction in enzyme activation, a 27% decrease in the number of trinitrobenzenesulfonic acid-reactive lysine groups, and a marked reduction in the immunoaffinity for B1B6. All these parameters reversed to normal when the TG-enriched LDL was treated with milk lipoprotein lipase, which specifically reduced the TG content of LDL. The LDL subfractions also supported cholesterol esterification by the purified enzyme, in parallel with lysolecithin esterification, indicating that apoB can also serve as an activator of the lecithin-cholesterol acyltransferase reaction. These results strongly suggest that the localized conformational change of apoB which occurs during the TG depletion of the precursor particle is critical for its activation of acyltransferase reactions, in a manner analogous to its interaction with the cellular receptors.

1-Acylglycerophosphocholine O-Acyltransferase↗
PubMed2004

[Improvement in quality of life in the elderly. Results of a placebo-controlled study on the efficacy and tolerability of lecithin fluid in patients with impaired cognitive functions].

Lecithin, a precursor of the neurotransmitter acetylcholine, has a positive effect on brain and memory functions. In a prospective, randomized, double-blind study, the effect of buerlecithin fluid (BLF) was investigated in comparison with placebo in patients with mild cognitive disorders. A total of 96 ambulatory patients (> 55 years) were admitted to the study. Treatment duration was 84 days. In both treatment groups, a clear improvement in all the cognitive parameters tested was seen. The main target measure, the overall Sandoz Clinical Assessment Geriatric (SCAG) score improved by 18.7 (test substance) and 16.4 (placebo) points (p = 0.1620). A statistically relevant improvement of the secondary target parameter, response in the SCAG score, was achieved with BLF (85.4%) in comparison with placebo (62.5%) (p = 0.018). Furthermore, BLF demonstrated significant superiority in a number of the other target measures. The study also confirmed the very good tolerability of BLF.

Aged↗
PubMedDate not supplied

[Lipid-mobilizing effect of reduced glutathione and its intensifying action on lecithin-cholesterol acyltransferase activity in blood serum of rats].

Effect of reduced glutathione (50 mg/100 g) on lipid distribution between organs (liver and kidney) and lecithin-cholesterol acyltransferase (LCAT) activity in blood serum of rats was investigated. The accumulation of common lipids as a result of speeding up the absorbtion of blood serum unsaturated fatty acids and relative decrease of lipids unsaturation in the liver and lipid content dynamics in kidneys owing to the intensification of two processes in this organ: the transport of polyene fatty acids in composition of blood serum lipoprotein lipids to kidney cells and peroxidation of membrane phospholipids were found out. The activating effect of GSH (in vivo and in vitro) on LCAT activity of rat blood serum was shown. It was summarised that GSH-intensification of blood serum etherification ability may be a basic component of reduced glutathione lipid mobilization effect.

Animals↗
PubMed1992

Lecithin:cholesterol acyltransferase gene expression is regulated in a tissue-selective manner by fibrates.

Plasma lipoprotein metabolism is influenced by several factors that may act by regulating the expression of proteins involved in lipoprotein metabolism, such as lecithin:cholesterol acyltransferase (LCAT). We determined the influence of several hormones and hypolipidemic drugs on hepatic LCAT gene expression and plasma LCAT activity. Liver LCAT mRNA levels were resistant to regulation by the hormones ethinylestradiol, L-thyroxine, hydrocortisone, or by the hypolipidemic drugs probucol, simvastatin, and nicotinic acid. In contrast, hepatic LCAT mRNA levels decreased to 67%, 64%, and 46% of the control levels after treatment with the fibric acid derivatives clofibrate, gemfibrozil, and fenofibrate, respectively. Fenofibrate lowered liver LCAT mRNA levels in a dose-dependent manner, which was paralleled by a decrease in plasma LCAT activity to 54% of the controls at a dose of 0.5% (w/w) in rat chow. The decrease in liver LCAT mRNA levels was maximal after 1 day, whereas the fall in plasma LCAT activity trailed by 2 days. Cessation of treatment with fenofibrate restored liver LCAT mRNA levels to control levels within 1 week. The transcription rate of the LCAT gene decreased by 25% in nuclei isolated from fenofibrate-treated rat liver, thereby indicating that hepatic LCAT gene expression is, at least partly, regulated at a transcriptional level. In contrast to the liver, brain and testis LCAT mRNA levels remained constant after treatment with fenofibrate, indicating that fibrates regulate LCAT gene expression in a tissue-selective manner.

Analysis of Variance↗
PubMed1991

[Myeloperoxidase interaction with mixed monolayers of lecithin and cholesterol].

Interaction between myeloperoxidase and mixtures of lecithin-cholesterol monolayers were investigated. Solubility of the enzyme in 1-octanol or in octanol were tested too. It is shown that myeloperoxidase demonstrates an ability to concentrate on phase limits. The enzyme well dissolves in lipid membrane phases. It is possible to assume that myeloperoxidase penetrates and accumulates in the eye lens.

Adsorption↗