Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “PHOSPHOLIPIDS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 901 records · Page 50Linked to original sources
PubMed1991

Reactivity patterns of anti-phospholipid antibodies in systemic lupus erythematosus sera in relation to erythrocyte binding and complement activation.

We studied 51 sera from patients with systemic lupus erythematosus to determine the relationship of their anti-phospholipid activity to their anti-erythrocyte and complement activation properties. Forty-nine per cent of the sera had anti-phospholipid activity as demonstrated by ELISA using a panel of anionic phospholipids, and most of these also bound to neutral phospholipids, albeit to a lesser extent. A cellular radioimmunoassay was used for the detection of immunoglobulin and C3 binding to normal erythrocytes (intact, enzyme-treated or glutaraldehyde-fixed) following incubation with patient sera. The levels of IgG anti-phospholipid correlated with hypocomplementaemia and with immunoglobulin binding (paralleled by a deposition of C3 fragments) to the three types of erythrocytes, although most strongly to fixed cells. Immunoglobulin binding to intact erythrocytes correlated primarily with reactivity against neutral phospholipids. The specificity for phospholipid epitopes of immunoglobulin adsorbed onto erythrocytes was confirmed by acid elution followed by testing in ELISA. These data suggest that some anti-phospholipid antibody subsets may bind to erythrocytes in vivo, thus accounting for the observed association of these antibodies with positive direct antiglobulin tests.

Antibodies, Antinuclear↗
PubMed1978

The indispensability of phospholipid and ubiquinone in mitochondrial electron transfer from succinate to cytochrome c.

The indispensability of phospholipid and ubiquinone (Q) in mitochondrial electron transfer was studied by depleting phospholipid and Q in succinate-cytochrome c reductase and then replenishing the depleted enzyme. More than 90% of phospholipid and Q was removed by repeated ammonium sulfate-cholate fractionation. The depleted succinate-cytochrome c reductase showed no enzymatic activity for succinate leads to c or QH2 leads to c and yet retained most of the succinate leads to Q activity. All enzymatic activity was restored upon the addition of Q and phospholipid. Restoration required the addition of Q prior to the addition of phospholipid. Reversing the addition sequence or addition of a mixture of phospholipid and Q resulted only in a small restoration of activities. The conditions for restoration are given in detail. Removal of phospholipid from succinate-cytochrome c reductase resulted in reduction of cytochrome c1 in the absence of exogenous electron donor. Replenishing the preparation with phospholipid brought about the reoxidation of cytochrome c1 in the absence of electron acceptor or oxygen.

Animals↗
PubMed1989

[Fixation effect of phospholipids using tannic acid. Part 1: Artificial lung surfactant].

In order to study the preservation of phospholipids in specimens for electron microscopic study, two procedures were compared; routine double fixation with glutaraldehyde followed-by osmium tetroxide and fixation with a mixture of tannic acid-glutaraldehyde followed by osmium tetroxide, utilizing both glass slide smear and ultrathin section methods, using artificial lung surfactant (mainly composing of phospholipids). The following results were obtained. (1) In routine double fixation with glutaraldehyde-osmium tetroxide, although the lamellar structure, mainly composed of phospholipids, was often visualized, prefixation with mixed tannic acid-glutaraldehyde always resulted in a lamellar structure with a regular periodicity and good contrast. (2) The saturated phospholipid was better preserved with acetone dehydration than with alcohol dehydration. (3) Depending on the outcome of the first fixation, there was extensive loss of phospholipids during the process due to alcohol dehydration and propylene infiltration. (4) When the specimens were fixed with osmium tetroxide prior to tannic acid treatment, the multilamellar structure of the bilayer was usually irregular. Moreover, if the specimens were fixed with osmium tetroxide without tannic acid, phospholipid preservation was not good. From the above results, it became, apparent that prefixation by a mixture of tannic acid-glutaraldehyde followed by osmium tetroxide postfixation and dehydration by acetone was the most appropriate method for preserving saturated phospholipids and thus a stable ultrastructure of phospholipids an lamellar will obtained.

Fixatives↗
PubMed1986

Effect of phospholipids on the catalytic subunits of the mitochondrial F0.F1-ATPase.

Beef heart mitochondrial F0.F1-ATPase was reconstituted into phospholipid liposomes using the octylglucoside solubilization, discontinuous sucrose gradient centrifugation procedure described in the preceding manuscript (Laird, D., Smith Eble, K., and Cunningham, C. (1986) J. Biol. Chem. 261, 14844-14850). The influence of individual phospholipids (phosphatidylcholine (PC), phosphatidylethanolamine (PE), and diphosphatidylglycerol (DPG)) on the kinetic parameters related to ATPase activity were investigated. The specific activities for the PC, PE, and DPG reconstituted preparations were 9.8, 6.8, and 7.6 mumol of ATP hydrolyzed per min/mg of protein, respectively. The F0.F1-DPG complex demonstrated a 40% decrease in the Km for ATP. Both the F0.F1-PC and the F0.F1-PE complexes exhibited Ki values for adenyl-5'-yl imidodiphosphate and guanyl-5'-yl imidodiphosphate approximately 2.5 times lower than those obtained in the absence of exogenous phospholipid. The F0.F1-DPG complex displayed Ki values 11.7- and 1.8-fold lower for adenyl-5'-yl imidodiphosphate and guanyl-5'-yl imidodiphosphate, respectively, as compared to the lipid-depleted enzyme. The phospholipids with which F0.F1 were reconstituted also influenced the ATP-induced decrease in the fluorescence of enzyme-associated aurovertin. The rate of the ATP-elicited decrease in aurovertin fluorescence was accelerated in the presence of all three phospholipids with DPG having the most dramatic effect; the t1/2 for maximal decrease in aurovertin fluorescence was 4.3 s for lipid-deficient enzyme and 0.48 s with the F0.F1-DPG complex. The effects of phospholipids on these parameters associated with the catalytic center of the ATPase suggest that phospholipids can modulate catalytic events occurring in F1. In the intact mitochondrion the primary role of phospholipids may be to stabilize conformations of the enzyme consistent with its range of activities.

Animals↗
PubMed1985

Effect of netilmicin on the phospholipid composition of subcellular fractions of rat renal cortex.

The purpose of this study was to determine the subcellular site(s) of the renal cortical phospholipidosis induced by aminoglycosides. For this purpose we injected male Sprague-Dawley rats s.c. with netilmicin, containing tracer quantities of [3H]netilmicin, at 100 mg/kg/day for 2 days; control rats were injected with saline. Twenty-four hours after the second injection of drug the rats were sacrificed and the renal cortex was fractionated by differential ultracentrifugation and Percoll gradient density techniques to obtain purified lysosomes, mitochondria, microsomes, brush border membranes and basolateral membranes. The total phospholipid content of the renal cortex was 300 +/- 5 nmol/mg of protein in control rats and 340 +/- 5 nmol/mg of protein in netilmicin-injected rats. The total phospholipid content of the lysosomal fraction of netilmicin rats, which was enriched in myeloid bodies and [3H]netilmicin, was 91% greater than that of control rats and reflected significant increases of phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine and phosphatidylinositol. This pattern is identical to that reported previously for the rat renal cortical phospholipidosis induced by aminoglycosides. The total phospholipid contents of the mitochondrial, microsomal, brush border membrane and basolateral membrane fractions of netilmicin-injected rats were higher by approximately 10% than the respective fractions of control rats and each fraction exhibited a significant increase of one or more of the four phospholipids elevated in the renal cortical homogenate and in the lysosomal fraction. The data indicate that the myeloid body is the primary source of the lysosomal phospholipidosis induced by netilmicin which provides support for the hypothesis that the lysosomal phospholipidosis is secondary to aminoglycoside-induced inhibition of phospholipid degradation. In addition the findings of increased phospholipid content and altered phospholipid composition of the other subcellular fractions raise the possibility that aminoglycoside antibiotics cause a more generalized disturbance of phospholipid metabolism characterized by altered synthesis as well as degradation in renal proximal tubular cells.

Acetylglucosaminidase↗
PubMed1987

Activation of human endothelial cell-type plasminogen activator inhibitor (PAI-1) by negatively charged phospholipids.

The endothelial cell-type plasminogen activator inhibitor (PAI-1) may exist in an inactive, latent form that can be converted into an active form upon treatment of the protein with denaturants, such as sodium dodecyl sulfate, guanidine HCl, or urea. The present paper demonstrates that latent PAI-1 can be activated by lipid vesicles containing the negatively charged phospholipids phosphatidylserine (PS) or phosphatidylinositol. The presence of a net negative charge on the phospholipid headgroup is essential for activation, since lipid vesicles consisting exclusively of zwitterionic phospholipids, such as phosphatidylcholine and phosphatidylethanolamine, do not activate PAI-1. In the presence of PS vesicles, PAI-1 inhibited tissue-type plasminogen activator 50-fold more effectively than in the absence of phospholipids, whereas sodium dodecyl sulfate enhanced PAI-1 activity by 25-fold. In mixed phospholipid vesicles containing PS and phosphatidylcholine in various molar ratios, the extent of PAI-1 activation was directly related to the PS content of the phospholipid membrane. Ca2+ ions interfered with the inhibitory activity of PS-activated PAI-1, suggesting that Ca2+ ions may regulate PAI-1 activity in the presence of negatively charged phospholipids. An important consequence of these findings is that, as in blood coagulation, negatively charged phospholipids may play an important regulatory role in controlling the fibrinolytic system by activating an inhibitor of tissue-type plasminogen activator.

Calcium Chloride↗
PubMed1986

Influence of sterol structure on phospholipid phase behavior as detected by parinaric acid fluorescence spectroscopy.

Phospholipid-sterol interactions were investigated using parinaric acid fluorescence spectroscopy. Cholesterol and cholesterol analogues which were modified in the sterol nucleus or side chain were added at 50 mol % to multilamellar vesicles of model phospholipids selected to be representative of major components in an LM cell plasma membrane. These included sphingomyelins and saturated and monounsaturated phosphatidylcholines and phosphatidylethanolamines. Based on the changes in cis-parinaric acid steady-state fluorescence polarization observed with addition of sterol, 50 mol % cholesterol abolished the phase transition of all the model phospholipids. Dihydrocholesterol and trans-22-dehydrocholesterol behaved like cholesterol in the two systems studied. 24-Methylcholesterols interacted well with all phospholipids except phosphatidylethanolamine which contained an unsaturated fatty acid. 24-Alkyl,trans-22-dehydrocholesterols abolished the phase transition in only two systems: sphingomyelins and phosphatidylcholines possessing relatively short saturated acyl chains. Since steady-state anisotropy is a function of fluorescence lifetime, rotational diffusion rates, and limiting anisotropy, we determined these parameters for two of the phospholipid systems. The results show that steady-state anisotropy values for phospholipid-sterol interactions correlate closely with limiting anisotropy and to a lesser extent with rotational relaxation time. The behavior of the sterols in the model phospholipids are used to interpret 1) fluorescence polarization measurements made with phospholipids extracted from LM cell plasma membranes, and 2) changes in membrane lipid composition which accompany growth of LM cells on various sterols.

Animals↗
PubMed1985

Assembly of the intrinsic factor X activating complex--interactions between factor IXa, factor VIIIa and phospholipid.

The activation of blood coagulation factor X by factor IXa is strongly stimulated by the non-enzymatic cofactors phospholipid, Ca2+ and activated factor VIII. In this paper we present a method by which we were able to determine binding affinities of factor IXa for phospholipids (either in the absence or presence of factor VIIIa) from kinetic measurements of factor X activation. It is shown that rates of factor X activation in the presence of phospholipids can be saturated with an excess factor VIIIa at limiting amounts of factor IXa and vice versa. Our data indicate that the enzymatic unit in the intrinsic factor X activator is a 1:1 stoichiometrical complex of factor IXa and factor VIIIa bound to phospholipid. Titrations with factor IXa at fixed concentrations of phospholipid and factor X show that the apparent dissociation constant of factor IXa for phospholipid is lowered from 10(-6) M to 10(-8) M by the presence of factor VIIIa. We conclude, that in analogy with the role of factor Va in prothrombin activation, phospholipid-bound factor VIIIa functions as a high-affinity binding site ("receptor") for factor IXa in the intrinsic factor X activating complex. Therefore, factor VIIIa increases the observed Vmax of factor X activation by 1) enhancing the kcat of the reaction and 2) increasing the amount of phospholipid-bound factor IXa that participates in factor X activation.

Blood Coagulation Factors↗
PubMed1984

Adrenocorticotropic hormone-mediated changes in rat adrenal mitochondrial phospholipids.

We examined the subcellular localization of ACTH (adrenocorticotropic hormone)-induced changes in adrenal phospholipids using dexamethasone-treated rats. In adrenal mitochondrial fraction, ACTH significantly enhanced both concentrations and contents of phosphatidylinositol (37%), phosphatidylcholine (22%), and phosphatidylethanolamine (20%). Other mitochondrial phospholipids including cardiolipin did not change upon administration of ACTH. In adrenal plasma membrane, endoplasmic reticulum, and peroxisomes, no increase in phospholipids was observed. The ACTH-induced increases in mitochondrial phosphatidylinositol, phosphatidylcholine, and phosphatidylethanolamine were specific to adrenal among tissues tested. These changes were observed specifically in cortical cells rather than medulla. Nonsteroidogenic ACTH fragments and related peptides were unable to induce the change in adrenal mitochondrial phospholipids. From the dose-response profile with ACTH, the changes in mitochondrial phospholipids were closely related to ACTH-dependent stimulation of steroidogenesis. Furthermore, in vitro treatment with cyclic AMP enhanced both concentrations and contents of mitochondrial phosphatidylinositol, phosphatidylcholine, and phosphatidylethanolamine similar to those by the in vivo administration of ACTH. Both in vivo and in vitro experiments revealed that the hormone-induced changes in mitochondrial phospholipids were sensitive to a protein-synthesis inhibitor, cycloheximide. However, aminoglutethimide and cytochalasin B, which strongly inhibited the hormone-induced formation of corticosterone, did not affect the increases in mitochondrial phospholipids. These results suggest that the hormone-induced increases in these phospholipids occur between ACTH-mediated ribosomal protein synthesis and corticosterone formation.

Adrenal Glands↗
PubMed1980

Studies on drug-induced lipidosis: subcellular localization of phospholipid and cholesterol in the liver of rats treated with chloroquine or 4,4'-bis (diethylaminoethoxy)alpha, beta-diethyldiphenylethane.

Administration of chloroquine or 4,4'-bis(diethylaminoethoxy)alpha, beta-diethyldiphenylethane (DH) to rats in oral doses of 100 mg/kg for 7 days causes phospholipid and cholesteryl ester accumulation in liver. To further characterize this drug-induced lipidosis, we have isolated and characterized the lipids of subcellular fractions from control rats and rats treated with chloroquine, DH, and Triton WR-1339. The phospholipid content of liver is increased 1.5-fold by chloroquine or DH treatment but is unaffected by Triton WR-1339. Acid phosphatase is increased by treatment with these three agents. Chloroquine and DH cause a shift of acid phosphatase from the light mitochondrial fraction (L) to the heavy mitochondrial fraction (M). Multilamellar bodies, an ultrastructural hallmark of chloroquine and DH-induced lipidosis, were isolated in a highly-purified form from the M fraction of chloroquine- or DH-treated rats. They are highly enriched in acid phosphatase indicating their lysosomal origin. In addition, they contain large amounts of phospholipid, cholesterol, and cholesteryl ester and are the sole site of bis(monoacylglycero)phosphate and the enzyme which catalyzes its synthesis from phosphatidylglycerol. Analysis of the phospholipid content of the respective control and drug-treated liver fractions shows that the entire excess phospholipid content of chloroquine- or DH-treated liver can be accounted for by the drug-induced multilamellar bodies. Triton WR-1339-induced lysosomes, which were isolated for comparison, also contain bis(monoacyglycero)phosphate and bis(monoacyglycero)phosphate synthetase. However, they differ from the drug-induced lysosomes in that their sphingomyelin content is much higher and their total phospholipid and phosphatidylinositol content much lower. The multilamellar bodies are the principal intracellular site of accumulation of chloroquine and DH, respectively. Increased delivery of phospholipid to lysosomes and decreased lysosomal catabolism of phospholipid are the factors which are thought to cause this experimental lipidosis. High levels of phosphatidylinositol in the multilamellar body may be in part responsible for the increased content of bis(monoacyglycero)phosphate since it has been identified as an acyl donor in bis(monoacylglycero)phosphate synthesis.

Acyltransferases↗
PubMed1983

Binding to phospholipid protects factor VIII from inactivation by human antibodies.

The addition of purified factor IXa and phospholipid to factor VIII concentrate protected the VIII:C from inactivation by human antibodies. This protective effect was shown to be due largely to the phospholipid. Addition of phospholipid alone gave substantial protection against even high-titer antibodies, as shown by measurements of thrombin generation and VIII:C assays. Increasing concentrations of phospholipid led to significant reductions in the amount of VIII C:Ag detected by an IRMA method, up to 70% of the original VIII C:Ag being "lost" at the highest concentration of phospholipid. These results indicate that phospholipid binding plays an important part in the procoagulant activity of factor VIII and that human antibodies to VIII:C are directed largely at the phospholipid binding site. The addition of phospholipid to factor VIII concentrates could have important clinical applications in the treatment of hemophiliacs with antibodies to factor VIII.

Antibodies↗
PubMed1981

Regulation of activated protein C by protein S. The role of phospholipid in factor Va inactivation.

Protein S enhances the rate of Factor Va inactivation by activated Protein C (Walker, F. J. (1980) J. Biol. Chem. 255, 5521-5524). The activity of protein S is saturable, appearing to interact stoichiometrically with activated Protein C. Diisopropylphosphate-modified activated Protein C reversed the effect of Protein S, further indicating that a Protein S-activated Protein C interaction is required for expression of the activity of Protein S. In the absence of phospholipid, Protein S had no effect on the rate of activated Protein C-catalyzed inactivation of Factor Va. The activity of Protein S was only expressed in the presence of phospholipid vesicles, where it appeared to increase the affinity of the inactivation system for phospholipid. Protein S had no effect upon the rate of Factor Va inactivation in the presence of saturating levels of phospholipid vesicles. The effects of Protein S on the kinetics of Factor Va inactivation corresponded with its effect on the interaction between activated Protein C and phospholipid vesicles, measured by light scattering. In the presence of Protein S, the binding of activated Protein C to phospholipid vesicles was enhanced. Protein S had no effect upon the binding on the zymogen (Protein C to phospholipid vesicles). In conclusion, the stimulatory effect of Protein S on the inactivation of Factor Va by activated Protein C can be attributed, in part, to the enhancement of the binding of activated Protein C to phospholipid vesicles.

Blood Coagulation Factors↗
PubMedDate not supplied

[Possible participation of acid phospholipids in the translocation of secreted proteins through the cytoplasmic membrane of bacteria].

The work presents a brief review of data on the interrelation between the biosynthesis and secretion of proteins in bacteria, and between metabolism, composition and physicochemical state of membrane lipids. Based on the analysis of these data in view of the modern ideas of the dynamic character of the membrane lipid structure, a hypothesis concerning the active participation of acid phospholipids in the translocation of protein and phospholipids through the bacterial cytoplasmic membrane is advanced. A new model of the coupled translocation of protein and phospholipids through the membrane is proposed which differs from the previous ones because it accounts not only the role of the secreted protein structure in its translocation through the membrane but assumes an active participation of membranes themselves (specifically phospholipids) in this process. The model assumes the interaction between a signal peptide of the de novo synthesized protein and acid phospholipids of membranes. Such an interaction initiates a transmembrane movement of phospholipids and a coupled translocation of phospholipids and protein, in which phospholipids and proteins secreted favor the movement of each other.

Biological Transport↗
PubMed1981

The role of phospholipid and factor VIIIa in the activation of bovine factor X.

The kinetic parameters of bovine factor X activation by bovine factor IXa have been determined in the absence and presence of Ca2+, thrombin-activated bovine factor VIII (VIIIa), and phospholipid (dioleoylphosphatidylcholine/dioleoylphosphatidylserine, 75/25; mol/mol). Factor IXa in the absence of Ca2+, factor VIIIa, and phospholipid is able to catalyze factor X activation. The Km for factor X is 299 microM which is well above its concentration in bovine plasma, about 0.2 microM. The Vmax of factor Xa formation is 0.0022 mol of Xa . min-1 . mol of IXa-1 under these conditions. Addition of Ca2+ has little effect on the kinetic constants of factor X activation by factor IXa. In the presence of 10 mM CaCl2 the Km for factor X is 181 microM, and the Vmax is 0.0105 mol of Xa . min-1 . mol of IXa-1. The presence of 10 microM phospholipid dramatically decreases the Km for factor X to 0.058 microM, and the Vmax becomes 0.0025 mol of Xa . min-1 . mol of IXa-1. The Vmax of factor Xa formation slightly increases when more phospholipid is present in our experiments, and there is a considerable increase of the Km for factor X at higher phospholipid concentrations. Therefore, the Km measured in the presence of phospholipid has to be regarded as an apparent Km. The possible explanations for this phenomenon are discussed. For the complete factor X-activating complex (i.e. factor IXa, factor VIIIa, Ca2+, and 10 microM phospholipid) the Km for factor X is 0.0063 microM, and the Vmax is raised 200,000-fold to 500 mol of Xa . min-1 . mol of IXa-1. In order to exert its stimulating effect on factor X activation factor VIII has to be activated with thrombin. Our results show that factor IXa is an enzyme which can activate factor X at a very low rate. The stimulating effect of phospholipid in factor X activation is mainly due to an effect on the Km for factor X, bringing it within the range of the plasma concentration. The stimulatory effect of factor VIIIa is explained by its 200,000-fold increase of the Vmax of factor Xa formation.

Animals↗
PubMed1983

Increased synthesis and accumulation of phospholipids during differentiation of 3T3-L1 cells into adipocytes.

Conversion of 3T3-L1 preadipocytes to fully developed adipocytes in culture under the influence of dexamethasone, 1-methyl-3-isobutyl xanthine, and insulin offers a unique system to investigate differentiation-related changes in lipid metabolism. Depending on the type of isotopic precursors ([3H2]O, 32Pi, and [1-14C]acetate) used, a 10-170-fold increase in the rate of incorporation into lipid was observed in 3T3-L1 adipocytes which contained 5-10-fold higher amounts of cellular protein/culture than preadipocytes. In preadipocytes and adipocytes, the major lipids synthesized were phospholipids, triglycerides, and fatty acids. The rate of 32Pi incorporation into total lipids was 21-fold higher in adipocytes than that in preadipocytes, and 90% of the total radioactivity in both preadipocytes and adipocytes was contributed by phosphatidylcholine (PC), phosphatidylethanolamine (PE), and phosphatidylinositol (PI). The content of phospholipids was 7-8-fold higher/culture in adipocytes than that in preadipocytes, and 65 and 80% of the total phospholipids of preadipocytes and adipocytes, respectively, were composed of PC and PE. Based on DNA measurements, there was a 3-fold increase in phospholipids and an approximately 3-fold increase in protein/cell. During 3T3-L1 adipose conversion, a detectable increase in cellular protein, triglycerides, and phospholipids was observed on day 3 after induction and, thereafter, these constituents increased continuously up to day 11. Among the different phospholipids of both preadipocytes and differentiating 3T3-L1 cells, PC, PE, and PI exhibited significant changes in their rate of 32Pi incorporation during adipogenesis. While there was a continuous increase in the incorporation of 32Pi into PI, there was preferential incorporation of 32Pi into PC and PE, the significance of which is not clear. The increase in phospholipids and protein content during adipogenesis suggests that phospholipids are required for membrane biosynthesis.

Acetates↗
PubMed1981

Measurement of "lamellar body phospholipid" in amniotic fluid as a method for assessing fetal lung maturity.

A simple, rapid micro-method, suitable for use in a routine clinical laboratory, is described for isolating a surfactant fraction from 0.1 mL of human amniotic fluid and measuring its phospholipid content. We determined the phospholipid content of this fraction, referred to as "lamellar body phospholipid," in 451 samples of amniotic fluid collected within two days of delivery and related the data to the respiratory performance of the newborn in every case; 112 of the infants were delivered at 28-37 weeks gestation. The incidence of hyaline membrane disease was inversely related to the concentration of lamellar body phospholipid in the amniotic fluid. Eleven of 12 infants with lamellar body phospholipid values less than 25 mg/L and four of 44 infants with lamellar phospholipid values between 25 and 50 mg/L developed hyaline membrane disease or other serious respiratory problems possibly related to lung immaturity, whereas all of 395 infants with lamellar body phospholipid values of 50 mg/L or more were free from respiratory problems of this nature. The incidence of transient tachypnea was greatest when the lamellar body phospholipid value was between 25 and 50 mg/L, suggesting that this condition may be related to a degree of lung maturity.

Amniotic Fluid↗
PubMed1981

The role of phospholipid in the multiple functional forms of brain monoamine oxidase.

The nature of phospholipid requirement and lipid-protein interactions for the multiple functional forms of monoamine oxidase was investigated by rebinding the purified phospholipid to a lipid-depleted brain mitochondrial preparation. It was found that phosphatidylinositol uniquely stimulated the monoamine oxidase A activity to 80% over that in the original intact mitochondria. Other negatively charged phospholipids, although not as potent, could fully or partially reactivate the A or the B activity. Phosphatidylserine was relatively more effective in restoring the B activity. Phosphatidylcholine, a zwitterionic phospholipid, reconstituted 70% of the A activity but did not influence the B. More importantly, efficiency-gradient analyses indicated a distinct nature in the mechanism of lipid-protein interactions for the negatively charged and the zwitterionic phospholipids. The potency of the negatively charged phospholipid decreased sharply with increasing lipid molecules. No further stimulation could be detected when the lipid to protein ratio reached about 30 molecules of the negatively charged phospholipid for 100,000 daltons of membrane protein. The negatively charged phospholipid appeared to bind directly to the monoamine oxidase protein boundary with a high affinity. Phosphatidylcholine might reassociate as the membrane fluid bilayer, which in turn modulated the monoamine oxidase A activity.

Animals↗
PubMed1994

Evaluation of phospholipidic surface coatings ex-vivo.

To evaluate the thromboresistant properties of phospholipidic surface coatings mimicking the lipid surface of blood cells, we studied four different types of phospholipids bound onto PVC tubings in comparison to uncoated as well as heparin bonded controls. The samples analyzed included diacetylenic phospholipid coated as a monomeric treatment (A), diacetylenic phospholipid polymerised prior to being coated (B), and two types of polymeric phospholipids made using methacrylate containing monomers (C and D). A bovine (bodyweight 67 +/- 3 kg) left heart bypass model (pump flow 3.2 +/- 0.1 l/min) was selected and the surfaces were exposed to the blood stream up to 360 min without systemic heparinization. Thereafter another set of samples was exposed to stagnant blood over 20 min. Besides hemodynamic, hematologic and biochemical analyses, the macroscopic appearance of 119 blood exposed surface samples was graded semiquantitatively on a scale of 0 to 10: no macroscopic deposits = grade 0, 1 spot (1 mm diameter) = grade 1, 2 spots = grade 2, 5 or more spots = grade 5, up to 10% of the surface covered with clots = grade 6, 100% covered = grade 10 (P < 0.05 = *): mean grade of deposits was 0.0 +/- 0.0 for segments perfused and 0.0 +/- 0.0 for segments exposed to stagnant blood with surfaces exposing to the blood either heparin, phospholipid A, or phospholipid B (NS). Phospholipids C and D were graded 0.0 +/- 0.0 if perfused and 0.7 +/- 1.2 if exposed to stagnant blood.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗