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PubMed1994

Phospholipid analysis of alveolar macrophages and bronchoalveolar lavage fluid following bleomycin administration to rabbits.

Changes in the lipid metabolism of the lung during pulmonary injury were investigated by quantitative and qualitative analysis of phospholipids in pulmonary surfactant and alveolar macrophages (AM) obtained from rabbits that had been given a single transtracheal injection of bleomycin hydrochloride (BLM) 0, 7, 14, 21, and 28 days previously. BLM treatment increased the phospholipid content of both bronchoalveolar lavage (BAL) supernatant fluids and BAL cells. Furthermore, the proportion of phosphatidylcholine (PC) showed an increase in BAL cells during the development of pulmonary injury, and BLM treatment appeared to cause transformation of AM to foamy AM. Lipid analyses of the foamy AM revealed that their phospholipid content was increased, and that the percentage of PC with palmitic acid was elevated. Thus it appears that accumulation of phospholipids derived from pulmonary surfactant contributes to the increase in phospholipids and PC in BAL cells. These findings indicate that BLM treatment produces an alteration in the amount and composition of AM phospholipids, and also in BAL supernatant fluids.

Animals↗
PubMed1990

Histological, ultrastructural and chromatographical discrimination of phospholipids in meningiomas.

Phospholipids in meningiomas were studied by light and electron microscopy, and by high-performance liquid chromatography. They were microscopically demonstrated in six of the ten cases by Sudan III staining after the fixation with potassium dichromate. However, the conventional ultrastructural fixation with glutaraldehyde and osmium tetroxide failed to confirm phospholipids, as most of them were dissolved during dehydration. In contrast, the specimens pretreated with tannic acid before osmication ultrastructurally retained phospholipids which were represented by multilamellar bodies or ribbon-like rings. Both were found in 23 of the 30 cases within the cytoplasm, among the plasma membranes and in the extracellular matrices. The outermost lamella or ribbon showed a direct continuity from the neighbouring plasma membranes of the cytoplasm or the mitochondria. The multilamellar bodies showed an overall distribution, while the ribbon-like rings were predominantly distributed around the psammoma bodies. Precipitation of hydroxyapatite crystals within the ribbon-like rings resulted in matrix minerals of psammoma bodies. Chromatographical analyses of meningiomas disclosed phospholipids including phosphatidyl ethanolamine, phosphatidyl choline, phosphatidyl serine, sphingomyelin and phosphatidyl inositol in that order. Psammomatous meningiomas contained a higher percentage of phosphatidyl serine than non-psammomatous tumors. Ultrastructural study of synthetic phospholipids adequately treated with tannic acid showed that the multilamellar bodies were similar to phosphatidyl choline, while the ribbon-like rings were similar to phosphatidyl serine. The role of phospholipids in meningiomas is discussed.

Adult↗
PubMed1988

IgG but not IgM anti-phospholipid antibody binding is temperature dependent.

We examined the effect of temperature on the measurement of enzyme-linked immunosorbent assay (ELISA)-defined human polyclonal antiphospholipid antibody. Both IgG and IgM antibodies were easily demonstrable when sera were incubated on phospholipid-coated ELISA plates at 4-22 degrees C. When incubations were done at 37-45 degrees C IgG antibody binding markedly decreased but IgM antibody binding did not. Warming the phospholipid-coated ELISA plate alone, the serum alone, the buffer alone, or the blocking reagent alone had no effect. When the antigen content of the wells was increased fourfold the effect of warming still occurred. The effect of warmth was reversible and was seen with affinity-purified antibody as well as with whole serum. Phospholipid vesicles in suspension, however, absorbed antibody in a dose-dependent fashion at 4, 22, and 42 degrees C. These results indicate that antibody binding to phospholipid is temperature dependent when phospholipid is adherent to the solid phase. Whether the change in IgG-phospholipid interaction results from a change in antigen or in antibody remains unknown.

Antigen-Antibody Reactions↗
PubMed1992

Phospholipid binding of antiphospholipid antibodies and placental anticoagulant protein.

We evaluated the interaction of antiphospholipid antibodies (aPL) with placental anticoagulant protein I (PAP I), a calcium-dependent phospholipid binding protein which may act as a natural anticoagulant. Clotting assays showed additive prolongation of clotting times with aPL and PAP I. ELISA and vesicle phospholipid binding studies showed PAP I inhibition of aPL binding to phospholipid but no inhibition of PAP I-phospholipid binding by aPL. aPL and PAP I interact additively in anticoagulant activity in in vitro clotting systems and compete for phospholipid in ELISA system. These data support the hypotheses that aPL and PAP I may recognize similar phospholipid epitopes and that in vivo interaction may occur.

Annexins↗
PubMed1990

Effect of acute thioacetamide administration on rat brain phospholipid metabolism.

Brain phospholipid composition and the [32P]orthophosphate incorporation into brain phospholipids of control and rats treated for 3 days with thioacetamide were studied. Brain phospholipid content, phosphatidylcholine, phosphatidylethanolamine, lysolecithin and phosphatidic acid did not show any significant change by the effect of thioacetamide. In contrast, thioacetamide induced a significant decrease in the levels of phosphatidylserine, sphingomyelin, phosphatidylinositol and diphosphatidylglycerol. After 75 minutes of intraperitoneal label injection, specific radioactivity of all the above phospholipids with the exception of phosphatidylethanolamine and phosphatidylcholine significantly increased. After 13 hours of isotope administration the specific radioactivity of almost all studied phospholipid classes was elevated, except for phosphatidic acid, the specific radioactivity of which did not change and for diphosphatidylglycerol which showed a decrease in specific radioactivity. These results suggest that under thioacetamide treatment brain phospholipids undergo metabolic transformations that may contribute to the hepatic encephalopathy induced by thioacetamide.

Alanine Transaminase↗
PubMed1985

Thermotropic behavior of retinal rod membranes and dispersions of extracted phospholipids.

High sensitivity, differential scanning calorimetry studies of bovine retinal rod outer segment (ROS) disk membranes and aqueous dispersions of the extracted ROS phospholipids have been performed. ROS disk membranes were found to exhibit a broad peak of excess heat capacity with a maximum at less than about 3 degrees C, ascribable to a gel-to-liquid crystalline phase transition of a fraction of the phospholipids. A similar thermotropic transition was observed for aqueous dispersions of the total extracted and purified ROS phospholipids. Comparison of the results obtained for the dispersion of total ROS phospholipids to those of the purified head group fractions suggests that the thermotropic behavior reflects a gel-to-liquid crystalline transition, leading to lateral phase separation, involving those phosphatidylcholine (PC) molecules containing saturated fatty acyl chains, possibly together with the highest melting ROS phosphatidylethanolamine (PE) and phosphatidylserine (PS) components. The interpretation of the thermal behavior of the ROS disk membranes depends on whether the transition is assumed to derive from the ROS PC and/or PE/PS fractions, and whether the transbilayer arrangement of the ROS phospholipids is assumed to be symmetric or asymmetric. The calorimetric data can be simply explained in terms of an asymmetric distribution of the major ROS disk membrane phospholipids (G.P. Miljanich et al., J. Membrane Biol. 60:249-255, 1981). In this case, the transition would arise from the PE/PS fractions in the outer ROS disk membrane monolayer, and the anticipated transition from the PC in the inner monolayer would be broadened due to interaction with cholesterol. For the ROS membranes at higher temperatures, two additional, irreversible transitions are observed at 57 and 72 degrees C, corresponding to the thermal denaturation of opsin and rhodopsin, respectively.

Animals↗
PubMedDate not supplied

Effects of phospholipase inhibitors and calcium antagonists on the changes in myocardial phospholipids induced by isoproterenol.

To investigate the change in myocardial phospholipids after the administration of isoproterenol and its prevention by pretreatment with phospholipase inhibitors and calcium antagonists, we determined the phospholipid species in the heart of female Wistar rats. Isoproterenol (40 mg/kg) was administered 24 h before excising the heart, and chlorpromazine, mepacrine (phospholipase inhibitors), nifedipine, verapamil (calcium antagonists) and propranolol (beta-adrenoceptor blocker) were injected intraperitoneally 30 min prior to isoproterenol administration. The phospholipid species were quantified using silica gel precoated thin-layer rods and the hydrogen flame ionization method. Isoproterenol induced significant increases in heart/body weight ratio, myocardial protein/heart weight ratio and lysophosphatidylcholine (LPC), and significant decreases in myocardial total phosphorus, creatine kinase (CK) activity, phosphatidylethanolamine and phosphatidylcholine (PC). The significant decrease in PC and increase in LPC indicated the degradation of myocardial phospholipids. Pretreatment with nifedipine (30 mg/kg), verapamil (50 mg/kg) or propranolol (20 mg/kg) completely prevented the occurrence of myocardial injury through the preservation of myocardial phospholipid composition, total phosphorus, CK activity and heart/body and protein/heart weight ratios. On the other hand, chlorpromazine (30 mg/kg) and mepacrine (50 mg/kg) partially prevented myocardial damage through the preservation of myocardial phospholipid composition, total phosphorus and CK activity. Results suggest that not only calcium influx but also phospholipase activation plays an important role in the development of myocardial injury induced by isoproterenol.

Animals↗
PubMed1984

Co-isolation of proteolipids and calcium-phospholipid-phosphate complexes.

This study demonstrates that calcium-phospholipid-phosphate complexes (CPLX) and calcifiable proteolipid are associated in vivo by establishing that they can be co-isolated from calcified bacteria. Both of these membrane constituents, which support apatite formation in vitro, have been isolated independently from Bacterionema matruchotii. However, isolation of proteolipid was preceded by demineralization in 2N formic acid, thereby dissociating bound Ca, whereas isolation of CPLX included sonication of calcified bacteria in 2:1:1.5 chloroform:methanol:Tris buffer, thereby dissociating any protein. Co-isolation is possible by demineralizing the calcified bacteria with 50 mM phthalic acid, pH 5.5, followed by extraction with 2:1 chloroform:methanol, and precipitation of crude phospholipid with acetone. CPLX and proteolipid are present in all Sephadex LH-20 chromatographic fractions of the crude phospholipid and of diethyl ether precipitates of the crude phospholipid. CPLXs contain protein:phospholipid:Ca:Pi but differ in relative composition from each other and from independently isolated CPLX. The Ca:phospholipid:Pi molar ratio of diethyl ether precipitable proteolipid-CPLX is most similar to previously published values for CPLX. The protein content of CPLX accounts for all of the proteolipid apoprotein in each Sephadex LH-20 fraction.

Actinomycetaceae↗
PubMed1977

The in vivo incorporation of [32P]-labeled orthophosphate into pyrophosphatidic acid and other phospholipids of Cryptococcus neoformans through cell growth.

Cryptococcus neoformans was cultured in a liquid medium containing [32P]-orthophosphate and harvested at various stages of cell growth. An aliquot of the [32P]-labeled cells was transferred to a nonradioactive medium, and the culture was continued again for some hours. The [32P]-radioactivity composition and the phosphorus composition of individual phospholipids relative to the total phospholipid through the incubation periods were estimated. Although levels of major phospholipids remained constant throughout the cell growth, the distribution pattern of the [32P]-radioactivity of individual phospholipids changed remarkably along with the progress of cell growth. The changing patterns of the specific radioactivities of individual phospholipids through the growth phase demonstrated that phosphatidic acid was one of the most active metabolites in phospholipids and that pyrophosphatidic acid was also metabolically active.

Cryptococcus↗
PubMed1979

Phospholipid exchange between subcellular organelles of rabbit lung.

A soluble protein fraction (PLEP) prepared from rabbit lung can catalyze the exchange of phospholipids between subcellular organelles of the lung and between these subcellular organelles and synthetic liposomes. Phospholipid exchange between microsomes and synthetic liposomes and between mitochondria and synthetic liposomes was stimulated 8-fold and 2.5-fold, respectively, in the presence of the protein fraction. Lung exchange protein could also catalyzed phospholipid exchange between subcellular organelles of the liver and synthetic liposomes. Phospholipid transfer between microsomes and lamellar bodies of the lung was stimulated 2-fold by the exchange protein. Both radiolabeled phosphatidylcholine (PC) and phosphatidylinositol (PI) were transferred from 32P-labeled microsomes to lamellar bodies, but the exchange protein exhibited no transfer activity for phosphatidylglycerol (PG) and that for phosphatidylethanolamine (PE) was insignificant compared to the transfer activity for phosphatidylcholine and phosphatidylinositol. While the physiological role of the phospholipid exchange proteins in the lung is unknown, it is possible that they participate in the distribution of the newly synthesized phospholipids from the site of synthesis to lamellar bodies and other membrane compartments of cells.

Animals↗
PubMed1979

Incorporation of deuterium-labeled cis- and trans-9-octadecenoic acids in humans: plasma, erythrocyte, and platelet phospholipids.

The objective of this study was to follow the uptake and distribution of oleic and elaidic acids into human erythrocytes, platelets, and plasma phospholipids. The use of dual and triple labeling methodology permitted a precise comparison of elaidic and oleic acid utilization. Elaidic acid (EI) was selectively concentrated in all the plasma phospholipids except for lysophosphatidylcholine. Three times more elaidic than oleic acid (OI) accumulated in the 1-acyl position of phosphatidylcholine, as determined by hydrolysis with phospholipase A2. Rapid incorporation and removal of elaidate were observed for all samples. These results support the concept that enzymes responsible for acylation of phospholipids are sensitive to double bond configuration and the physical properties of the fatty acid moieties. Labeled fatty acid levels in red cell and platelet phospholipids were much lower than for plasma phospholipids, indicating a relatively slow rate for the in vivo incorporation of fatty acids into blood cell membrane phospholipids. No isotope effect was found when oleic acid labeled with deuterium on the double bond was used.

Adult↗
PubMed1984

Incorporation of fatty acids into phospholipids in L cells stimulated by antibody.

Binding antibodies to surface membranes stimulated incorporation of fatty acids (FA) into phospholipids of L cells. Antibodies stimulated at least a 3.4-fold greater incorporation of arachidonic acid into phosphatidylinositol than into any other class of phospholipid when compared on a molar basis (p less than 0.003). This enhanced incorporation was selective, depending on the character of the FA, because antibodies stimulated the incorporation of arachidonic acid at least 2.4-fold more than oleic acid, palmitic acid or stearic acid (p less than 0.001). Surprisingly, an antibody-stimulated incorporation of palmitic acid into sphingomyelin (SM) was at least 2.2-fold greater than that into any other class of phospholipid (p less than 0.001) and the antibody-stimulated incorporation of palmitic acid into SM was at least 60-fold greater than that of arachidonic acid, stearic or oleic acid (p less than 0.001). Nontoxic doses of ethylenediamine tetraacetic acid (EDTA), dexamethasone, 4-bromophenacylbromide and indomethacin inhibited the antibody-stimulated incorporation of arachidonic acid into cellular phospholipids, principally phosphatidylinositol (PI), and similarly inhibited the antibody stimulation of DNA synthesis. We conclude that when antibody binds to surface antigens on L cells, a rapid and selective incorporation of fatty acids into certain cellular phospholipids occurs, possibly mediated by calcium-dependent phospholipases. Degradation products of arachidonic acid, i.e., prostaglandins, may be important in these antibody stimulation events, as well. These early changes in phospholipid metabolism may serve as an important signal or mechanism for the subsequent stimulation of DNA synthesis in L cells.

Animals↗
PubMed1984

The composition of cardiac phospholipids in rats fed different lipid supplements.

Changes in dietary lipid intake are known to alter the fatty acid composition of cardiac muscle of various animals. Because changes in cardiac muscle membrane structure and function may be involved in the pathogenesis of arrhythmia and ischemia, we have examined the effects of dietary lipid supplements on the phospholipid distribution and fatty acid composition of rat atria and ventricle following 20 weeks feeding of diets supplemented with either 12% sunflower-seed oil or sheep fat. Neither lipid supplement produced significant changes in the proportions of cholesterol, total phospholipids or phosphatidylcholine, phosphatidylethanolamine or diphosphatidylglycerol,--the phospholipid classes that together account for more than 90% of the total phospholipids of rat cardiac muscle. Significant changes were found in the profiles of the unsaturated fatty acids of all 3 phospholipid components of both atria and ventricle. Although similar, the changes between these tissues were not identical. However, in general, feeding a linoleic acid-rich sunflower seed oil supplement resulted in an increase in the omega-6 family of fatty acids, whereas feeding the relatively linoleic acid-poor sheep fat supplement decreased the level of omega-6 fatty acids but increased the levels of the omega-3 family, resulting in major shifts in the proportions of these families of acids. In particular, the ratio of arachidonic acid: docosahexaenoic acid (20:4,omega-6/22:6,omega-3), which is higher in all phospholipids of atria than ventricle, is increased by feeding linoleic acid, primarily by increasing the level of arachidonic acid in the muscle membranes.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Determination of the phospholipid composition of trout gill by Iatroscan TLC/FID: effect of thermal acclimation.

The phospholipid composition of gill tissue from thermally acclimated rainbow trout, Salmo gairdneri, was determined by Iatroscan analysis following an initial development of the chromarods in a non-polar solvent to remove neutral lipids. Standard curves for all phospholipids, although linear through most of the concentration range tested (1-40 micrograms), extrapolated to negative intercepts on the ordinate, indicating a decline in sensitivity at low phospholipid levels. In addition, the concentration dependence of the Iatroscan response varied by nearly 6-fold among phospholipids. Of the major phospholipids, only lysophosphatidylcholine could not be quantitated accurately because of the presence of an interfering peak. Quantitation by Iatroscan yielded results which, in general, agreed well (within 5%) with results obtained by an independent phosphate analysis. Only in the case of phosphatidylinositol (PI) did the two analytical methods differ significantly; proportions of PI were 55% higher when determined by Iatroscan as opposed to phosphate analysis. Gill tissue from 5 C-acclimated trout possessed higher proportions of phosphatidylethanolamine than tissue from 20 C-acclimated trout. The Iatroscan provided a rapid and reliable means of quantitating the proportions of all the major phospholipids of trout gill, although there are some limitations to the general applicability of the technique.

Acclimatization↗
PubMed1995

Role of cyclic adenosine monophosphate in phospholipid synthesis in Mycobacterium smegmatis ATCC 607.

The present study was undertaken to examine the influence of intracellular levels of cyclic AMP on phospholipid synthesis in Mycobacterium smegmatis ATCC 607. The cyclic AMP levels were modulated by growing cells in the presence of activator (forskolin) and inhibitor (atropine) of adenylate cyclase, the synthesizing enzyme of cyclic AMP. Forskolin-grown cells exhibited a 1.4-fold increase in the level of cAMP while a similar decrease (1.8-fold) was seen with atropine-grown cells. These altered levels of cAMP in turn affected the total content, composition and synthesis of phospholipids. Total phospholipid content increased and decreased in cells grown in the presence of forskolin and atropine, respectively. These observations were further supported by alterations in [14C]acetate incorporation as well as in activities of glycerol kinase and glycerol-3-phosphate acyltransferase, the key enzymes of phospholipid synthesis. Protein phosphorylation mechanism seems to be involved in phospholipid metabolism as the activities of protein kinase increased and decreased in cells grown in forskolin or atropine cells. Our results demonstrate a correlation between phospholipid synthesis and intracellular levels of cAMP in M. smegmatis.

Adenylyl Cyclase Inhibitors↗
PubMed1993

Influence of dietary egg and soybean phospholipids and triacylglycerols on human serum lipoproteins.

Human serum lipid and lipoprotein concentrations and compositions were compared in ten healthy middle-aged men consuming phospholipids from egg or from soybean or triacylglycerol mixtures with fatty acid compositions similar to that of the phospholipids. All subjects followed each of the four treatments: egg phospholipids (EP), soybean phospholipids (SP), an oil of fatty acid composition similar to that of EP, and an oil similar in fatty acid composition to SP for six weeks with "wash-out" periods of similar duration between treatment periods. The phospholipids, 15 g/d, and the oils, 12 g/d, which contained approximately equivalent quantities of fatty acids were provided to the subjects in gelatin capsules and were taken before meals. Diet intake was monitored by three-day food records. Serum lipoproteins (Lp) were separated by ultracentrifugation into very low density lipoproteins, low density lipoproteins (LDL), high density lipoproteins (HDL)2 and HDL3. Lp fractions and whole serum were analyzed for triacylglycerols, cholesterol (CH), phospholipids (PL), and protein. HDL cholesterol was determined in whole serum. Cholesteryl esters were determined in some Lp fractions. Lipid compositions of Lp were expressed in mmol/g protein. Apoprotein B was measured in whole serum and in LDL; apoprotein A-I in whole serum and in HDL3. In whole serum, CH and PL were significantly lower after the SP compared to EP treatment periods. CH, but not PL, was lower after SPTG compared to EP. CH in HDL2 was significantly higher after SP compared to SPTG. Also, PL in HDL2 were significantly higher after SP compared to all other treatments and to baseline.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1976

Changes in phospholipids and acyl group composition of rat mammary gland during pregnant, lactating, and post-weaning periods.

The distribution of phospholipids as well as their fatty acid compositions of rat mammary tissues were examined during pregnant, lactating, and post-weaning periods. There was no apparent change in phospholipids and their acyl groups during the early and late pregnant periods. However, tissue phospholipid composition was different during pregnant, early, and late lactating periods. After parturition, there was a marked increase in the proportion of diacyl-glycerophosphorylcholine in the phospholipids of mammary tissue, but this proportion decreased gradually during lactation. The decrease in diacyl-glycerophosphorylcholine during lactation was marked by a corresponding increase in diacyl-glycerophosphorylethanolamie. Although the shorter chain fatty acids of triglycerides were increased during lactation, only a small proportion of these fatty acids was found in the phosphoglycerides. Marked changes in acyl group composition of individual phospholipids are found during these different physiological stages. In general, there was a rapid decrease in 20:4 and an increase in 18:2 in the major phosphoglycerides during parturition. The proportion of 20:4 in the phosphoglycerides remained low throughout the entire lactating period, while that of 18:2 continued to increase 2-3 fold. Most of the changes in acyl group of the phosphoglycerides during lactation returned to normal ca. 10 days after weaning. A possible relationship of the variation of phospholipid and acyl group compositions in mammary tissue to changes in hormonal pattern during different physiological stages is discussed.

Animals↗
PubMed1990

Modification of phospholipid polar head group with monomethylethanolamine and dimethylethanolamine decreases cholesteryl ester and triacylglycerol synthesis in cultured human fibroblasts.

Modification of the phospholipid polar head group was achieved by supplementation of the growth medium of cultured human fibroblasts with the choline analogues monomethylethanolamine (ME) or dimethylethanolamine (DE) at a concentration of 80-200 micrograms/mL for 48 hr. The maximum concentration of phosphatidylmonomethylethanolamine (PME) or phosphatidyldimethylethanolamine (PDE) reached without affecting the phospholipid/protein ratio was about 45% of total phospholipids. Incorporation of oleic acid into cholesteryl esters and triacylglycerols was markedly inhibited after supplementation with ME or DE, and accounted for 60% and 40% of controls, respectively, at 200 micrograms/mL, whereas incorporation into phospholipids was not affected. AcylCoA:cholesterol acyltransferase (ACAT) and diacylglycerol acyltransferase (DGAT) activities measured on cell-free extracts appeared to be decreased also by phospholipid polar head group modification, whereas the overall phospholipid acyltransferase activity remained unchanged. The intracellular content of cholesteryl esters and triacylglycerols, determined by the isotopic equilibrium method with radioactive cholesterol and glycerol, was found to be diminished to 50-60% and 40-50% of controls, respectively, after supplementation with the choline analogues. The study showed that modification of the phospholipid polar head group affects the activity of membrane-bound enzymes involved in the metabolism of neutral lipids.

Acyltransferases↗