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PubMed1981

Lipid fluidity in lung surfactant: monolayers of saturated and unsaturated lecithins.

Monolayers of saturated or unsaturated lecithins (PCs) could be compressed to near-zero surface tension (gamma) when they were below the gel-to-liquid crystalline transition temperature (Tc) of the PC, whereas, when above Tc, they collapsed at gamma of 15-23 mN X m-1. Thus PCs with ordered, but not necessarily saturated, chains are required to achieve low gamma. At 37 degrees C the minimum gamma reached by monolayers containing dipalmitoyl PC (DPPC; Tc = 41 degrees C) plus 1-stearoyl-2-oleoyl PC (SOPC; Tc = 6 degrees C) depended on the proportions of the two lipids and the compression rate. When compressed at 1 cm2 X s-1, monolayers of mixtures containing less than 50% SOPC were capable of achieving gamma less than 9 mN X m-1. When the proportion of unsaturated lecithin was high (70%), compression at 1 cm2 X s-1 was insufficient to form a monolayer capable of reaching a very low surface tension. Exclusion of fluid lipid during compression could account for these observations.

Membrane Fluidity↗

PubMed1985

An approach using lecithin treatment for olivopontocerebellar atrophies.

A therapeutic trial with two different lecithins, with 32 and 7% phosphatidylcholine respectively, was performed for 3 months on 11 patients with clinical diagnosis of dominant, recessive and sporadic olivopontocerebellar atrophies. The correlation between plasma choline levels and the clinical picture shows a clinical worsening with very high choline levels and a slight improvement with smaller increases of plasma choline levels. The possible role in these disorders of phosphatidylcholine and linoleic acid - both present in lecithin - is discussed, with relationship to these findings.

Adult↗

PubMed1978

Lecithin: cholesterol acyltransferase activity in patients with chronic liver diseases and positive LP-X tests.

Lecithin: cholesterol acyltransferase activity has been measured in serum from patients with various liver disorders and positive LP-X tests and from healthy subjects. Statistical analysis indicated that lecithin: cholesterol acyltransferase activity provided no help in the discrimination between the persons of both groups although the mean activities differed significantly.

Chronic Disease↗

PubMed1987

Essential fatty acids in serum lecithin of children with atopic dermatitis and in umbilical cord serum of infants with high or low IgE levels.

The fatty acid composition of serum lecithin from children with atopic dermatitis (AD) was found to be abnormal, characterized by significantly increased proportion of linoleic acid and reduced levels of metabolites of this fatty acid. The levels of linoleic acid in umbilical cord serum lecithin were significantly higher in babies with high serum IgE than in those with low or non-demonstrable serum IgE. Since elevated cord serum IgE is strongly associated with development of atopic disease the results suggest that fatty acid changes may be a basic feature of AD. Immunologic dysfunction in patients with AD may possibly partly be a consequence of the fatty acid abnormality.

Child↗

PubMed1994

Epidermal growth factor stimulation of lecithin release by human amnion.

Lecithin release from human amnion disks was assayed in basal conditions as well as under epidermal growth factor administration. The tissue responded to the peptide by increasing the phospholipid release. A significant effect was observed only after 30 min of treatment. A possible role of epidermal growth factor-induced amniotic lecithin release in fetal lung maturation as well as in the mechanism of delivery is discussed.

Amnion↗

PubMed1989

Studies on amniotic prolactin: chromatographic pattern and correlation with the lecithin content.

We have measured the concentrations of prolactin and lecithin in the amniotic fluid from 20 normal pregnant women in the 2nd and 3rd trimester. Prolactin is present totally as a low-molecular-weight form, 'little' prolactin, and appears to correlate negatively with lecithin during the 2nd and positively during the 3rd trimester. On the basis of these results and of the information that prolactin is present as high-molecular-weight isohormones in maternal blood, it is argued that amniotic prolactin is synthesized 'in situ' and that different mechanisms are involved in the regulation of prolactin production.

Amniocentesis↗

PubMed1982

Relative fatty acid composition of serum lecithin in the second half of the normal pregnancy.

Fasting vein blood samples from 21 apparently normal pregnant women were collected in 4-week intervals from the 24th week of gestation until delivery. The relative fatty acid composition of serum lecithin was analyzed by gas-liquid chromatography. Palmitic acid increased successively concomitant with a decrease in stearic acid which indicates that serum lecithin is predominantly synthesized along pathway I. Linoleic acid decreased successively parallel to an increased incorporation of longer polyunsaturated fatty acids and non-essential monoenoic (palmitoleic and oleic) acids. The increased incorporation of longer polyunsaturated fatty acids is suggested to be associated with the increased activity of the deacylation-reacylation cycle. The increase of nonessential monoenoic fatty acids is suggested to be associated with a reduced de novo incorporation of linoleic acid.

Adult↗

PubMed1980

Lecithin Content of amniotic fluid in twin pregnancies with and without long-term tocolytic therapy.

During the period from January 1973 to October 1979, 55 transabdominal amniocenteses were performed on 40 twin pregnancies and the lecithin content of the amniotic fluid obtained was established in order to determine the fetal lung maturity. The lecithin determination was performed densitometrically according to Kynast and Saling. Through long-term tocolysis in twins the surfactant production rate is delayed in each phase of the pregnancy, whereas in a collective without long-term tocolysis one can reckon with sufficient fetal lung maturity from the 35th week onwards.

Adrenergic beta-Agonists↗

PubMed1980

Lecithin: cholesterol acyltransferase activity, HDL-cholesterol and apolipoprotein A in serum of patients undergoing chronic haemodialysis.

In comparison with a control group, significantly lower lecithin:cholesterol acyltransferase activities and HDL-cholesterol values were found in the serum of patients undergoing chronic haemodialysis, while apolipoprotein A concentration remained unchanged. Reduced activity of lecithin:cholesterol acyltransferase is an indication of the abnormal cholesterol metabolism in haemodialysed patients and could be, in addition to other factors, an explanation for the high incidence of cardiovascular diseases in this patient group.

Apolipoproteins↗

PubMed1978

Lung lecithin synthesis in primates as related to respiratory distress syndrome.

Lecithin is synthesized de novo in the lung by two biochemical pathways, choline incorporation and phosphatidylethanolamine methylation. These studies in the Macaca mulatta fetus and neonate have demonstrated the relative contributions of the two pathways and the timing in monkey gestation of increased pulmonary lecithin production.

Amniotic Fluid↗

PubMed1999

Linkage of a candidate gene locus to familial combined hyperlipidemia: lecithin:cholesterol acyltransferase on 16q.

Familial combined hyperlipidemia (FCHL) is a common lipid disorder characterized by elevated levels of plasma cholesterol and triglycerides that is present in 10% to 20% of patients with premature coronary artery disease. To study the pathophysiological basis and genetics of FCHL, we previously reported recruitment of 18 large families. We now report linkage studies of 14 candidate genes selected for their potential involvement in the aspects of lipid and lipoprotein metabolism that are altered in FCHL. We used highly polymorphic markers linked to the candidate genes, and these markers were analyzed using several complementary, nonparametric statistical allele-sharing linkage methodologies. This current sample has been extended over the one in which we identified an association with the apolipoprotein (apo) AI-CIII-AIV gene cluster. We observed evidence for linkage of this region and FCHL (P<0.001), providing additional support for its involvement in FCHL. We also identified a new locus showing significant evidence of linkage to the disorder: the lecithin:cholesterol acyltransferase (LCAT) locus (P<0.0006) on chromosome 16. In addition, analysis of the manganese superoxide dismutase locus on chromosome 6 revealed a suggestive linkage result in this sample (P<0.006). Quantitative traits related to FCHL also provided some evidence of linkage to these regions. No evidence of linkage to the lipoprotein lipase gene, the microsomal triglyceride transfer protein gene, or several other genes involved in lipid metabolism was observed. The data suggest that the lecithin:cholesterol acyltransferase and apolipoprotein AI-CIII-AIV loci may act as modifying genes contributing to the expression of FCHL.

Adult↗

PubMed1973

Plasma lipoproteins in familial lecithin: cholesterol acyltransferase deficiency. Further studies of very low and low density lipoprotein abnormalities.

Plasma lipoproteins of d<1.006 g/ml, d 1.006-1.019 g/ml, and d 1.019-1.063 g/ml from patients with familial lecithin:cholesterol acyltransferase deficiency yielded abnormal subfractions upon being separately filtered through 2% agarose gel. A subfraction that emerged with the void volume and contained unusually large amounts of unesterified cholesterol and phosphatidylcholine was present in each lipoprotein group, and in each group this subfraction was less prominent in the nonlipemic plasma of one patient than in the lipemic plasma of other patients. A subfraction containing smaller lipoproteins also was present in each lipoprotein group. These lipoproteins were of the same size as normal lipoproteins of the corresponding density, but contained abnormally small amounts of cholesteryl ester. The lipoproteins of 1.019-1.063 g/ml contained abnormal components of intermediate molecular weight as well as large and small abnormal components similar to those described previously. The intermediate components were more prominent in the nonlipemic plasma but were easily recognized in the hyperlipemic plasma as a peak of S(f) 20-30 in the analytical ultracentrifuge. Also they could be recognized, upon electron microscopy of the lipoproteins of d 1.019-1.063 g/ml, as particles 340-1000 A in diameter. The data suggest that related large, abnormal particles pervade the patients' very low and low density lipoproteins, and that the large particles are affected by, but are not dependent on, the lipemia that frequently accompanies the disease. The smaller very low and low density lipoproteins appear to be counterparts of lipoproteins present in normal plasma. Their abnormal composition is compatible with the possibility that lecithin:cholesterol acyltransferase normally decreases the triglyceride and phosphatidylcholine and increases the cholesteryl ester of very low density and low density plasma lipoproteins in vivo.

Acyltransferases↗

PubMed1977

The effect of prolactin on the lecithin content of fetal rabbit lung.

1 mg ovine prolactin was injected intramuscularly into rabbit fetuses (24th day of gestation) located in one of the two uterine horns exposed by laparotomy (n = 12). Fetuses in the other uterine horn were injected with an identical volume of vector and served as controls (n = 13). 2 days later the fetuses were removed by a second laparotomy and sacrificed. Analysis of lung tissue composition yielded the following results: (a) the prolactin-treated group of fetuses showed 40% higher total lung phospholipid content (17.0 +/- 0.8 micronmol/g) than the control group (12.2 +/- 0.5 micronmol/g); (b) the prolactin-treated group had a 67% higher lung lecithin content (8.7 +/- 0.8 micronmol/g) than the control group (5.2 +/- 0.4 micronmol/g); (c) dipalmitoyllecithin accounted for 67% of total lung lecithin in the prolactin-treated group and 44% in the control group. These differences were statistically highly significant (P less than 0.001). However, between the prolactin-treated and the control groups, there were no statistically significant differences in body weight and length, lung weight, the ratio of lung weight to body weight, DNA, protein and, water content. These results suggest that prolactin might be a trigger of lung surfactant synthesis in the rabbit fetus.

Animals↗

PubMed1979

Treatment of tardive dyskinesia with lecithin.

Six patients with moderate or severe tardive dyskinesia participated in a 14-day double-blind crossover comparison of placebo with 50 g/day of lecithin. There were no side effects, and Abnormal Involuntary Movement Scale (AIMS) ratings of videotaped examinations indicated significant improvement in the dyskinesias of all subjects during the lecithin trial, even with concomitant administration of a constant dose of neuroleptic medication to five patients.

Antipsychotic Agents↗

PubMed1983

Lecithin in the treatment of Gilles de la Tourette's syndrome.

Five patients with Tourette's syndrome were administered a mean dose of 512 mg/kg per day of oral lecithin. None of the patients exhibited sustained clinical improvement in symptom severity. No significant changes in serum prolactin or growth hormone were observed during lecithin administration.

Administration, Oral↗

PubMed1982

Fluctuations of free choline levels in plasma of Alzheimer patients receiving lecithin: preliminary observations.

Plasmas of 12 patients currently taking part in a double-blind trial of lecithin in senile or presenile dementia of Alzheimer type were analysed for plasma choline levels at fixed intervals during lecithin treatment. The values were not maintained at a constant level and showed a decline after one or two months of treatment, often followed by a subsequent rise. Possible explanations for this observation are given, and its significance to the treatment of dementia discussed.

Aged↗

PubMed1980

Choline incorporation into lecithin in response to insulin or dexamethasone in homogeneous cell cultures of rat lung epithelial cells and fibroblasts.

Labeled choline incorporation into adult rat lung alveolar epithelial cells and adult rat lung fibroblasts in monolayer culture was determined after incubation with insulin (Ins) 10 micrograms/ml, Dexamethasone (Dex) 10(-6)M, or no drug (ND). Incubation periods were 1, 3, 4, and 5 hours. The lecithin (phosphatidyl choline - PC) recovered was separated inot disaturated phosphatidyl choline (DSPC) and unsaturated phosphatidyl choline (USPC). Results expressed as specific activity per hour (see Table) indicate that the incorporation of choline into PC and USPC was greater in fibroblasts (F) than in epithelial cells (E) whether ND, Dex or Ins was present. For incorporation into DSPC, there was no difference between E and F whether ND, Dex or Ins was present. There was significant increase in choline incorporation into PC or USPC for both cell types when Ins was present, whereas there was no difference for either cell type when Dex was present. Insulin significantly increased choline incorporation into DSPC in E cells only. Dex was no different from ND in DSPC incorporation in either cell type. We attribute the greater lecithin synthesis of the F cells to a more rapid increase in cellular structural lipids in the fibroblast cell. Dex had no effect on either cell type possibly from the short-term exposure or possibly because the effect of dexamethasone on alveolar epithelial cells is mediated by product(s) from other lung cells, and thus requires a mixed cell culture to have its effect. We suggest that further study of isolated homogeneous cell lines will not be fruitful in the evaluation of mechanisms of acceleration of lung maturation.

Animals↗

PubMed2005

Lecithin organogels as a potential phospholipid-structured system for topical drug delivery: a review.

The purpose of this review is to give an insight into the considerable potential of lecithin organogels (LOs) in the applications meant for topical drug delivery. LOs are clear, thermodynamically stable, viscoelastic, and biocompatible jelly-like phases, chiefly composed of hydrated phospholipids and appropriate organic liquid. These systems are currently of interest to the pharmaceutical scientist because of their structural and functional benefits. Several therapeutic agents have been formulated as LOs for their facilitated transport through topical route (for dermal or transdermal effect), with some very encouraging results. The improved topical drug delivery has mainly been attributed to the biphasic drug solubility, the desired drug partitioning, and the modification of skin barrier function by the organogel components. Being thermodynamically stable, LOs are prepared by spontaneous emulsification and therefore possess prolonged shelf life. The utility of this novel matrix as a topical vehicle has further increased owing to its very low skin irritancy potential. Varied aspects of LOs viz formation, composition, phase behavior, and characterization have been elaborated, including a general discussion on the developmental background. Besides a comprehensive update on the topical applications of lecithin organogels, the review also includes a detailed account on the mechanistics of organogelling.

Administration, Topical↗