Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Sphingomyelins”

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 37 records · Page 2Linked to original sources
PubMed1976

Properties of a toxin from the sea anemone Stoichacis helianthus, including specific binding to sphingomyelin.

Stoichactis helianthus toxin, a protein derived presumably from the nematocysts, was purified to homogeneity. It has a molecular weight of about 16,000, an isoelectric pH of 9.8, and it contains approximately 3.7% carbohydrate. It is powerfully hemolytic for erythrocytes derived from a variety of animal species, those of the cat being the most sensitive and those of the guinea pig the most resistant. The toxin is lytic also for rabbit blood platelets, and it destroys cultured fibroblasts but is inactive for several kinds of bacterial protoplasts and spheroplasts. The hemolytic activity is specifically inhibited by sphingomyelin, and it is proposed that this phospholipid is the constituent of the membrane which functions as receptor for the toxin. Supporting evidence includes the findings that enzymes known to destroy sphingomyelin (a) prevent erythrocyte membranes from inhibiting hemolysis, and (b) render erythrocytes resistant to lysis by the toxin. The mechanism underlying hemolysis may involve translocation of membrane sphingomyelin by virtue of a specific affinity of the coelenterate protein for this phospholipid.

Animals↗
PubMed1979

Free ceramide, sphingomyelin, and glucosylceramide of isolated rat intestinal cells.

Free ceramide, glucosylceramide, and sphingomyelin were isolated from mature cells of adult rat small intestine. Free ceramide and ceramide cleaved from sphingomyelin by enzymatic hydrolysis were fractionated by thin-layer chromatography on borate-impregnated silica gel plates. Sphingoid bases were characterized by gas-liquid chromatography of aldehydes formed upon periodate oxidation. Fatty acids were quantified as methyl esters. Ceramide structures were confirmed by direct-inlet mass spectrometry. Free ceramide was found to contain two major long-chain bases in nearly equal quantity: sphingosine, mainly linked to palmitic acid, and 4D-hydroxysphinganine associated with C20 to C24 fatty acids, 22% being hydroxylated. Sphinganine occurred as a minor component linked to nonhydroxy fatty acids. Sphingomyelin contained the three long-chain bases and 63% of its ceramide was N-palmitoyl-sphingosine. Mass spectrometry of glucosylceramide confirmed 4D-hydroxyshingamine as the major sphingoid base associated preferentially with longer chain hydroxy fatty acids.

Animals↗
PubMed2026

Targeting CD44 reverses sphingomyelin-induced oligodendrocyte maturation arrest in acid sphingomyelinase deficiency.

Loss-of-function mutations in the smpd1 gene cause acid sphingomyelinase deficiency (ASMD). Early neurodegeneration and lethality characterize its infantile neurovisceral form (type A). While neuronal dysfunction was traditionally considered the primary driver of the pathology, recent evidence suggests that dysmyelination and microgliosis are not merely secondary features. Specifically, myelin debris undermines the protective role of microglia, contributing to neuroinflammation and neuronal death. Herein, we examined central myelin and oligodendrocyte lineage progression in ASM knockout mice. We show that early-onset dysmyelination results from compromised oligodendrocyte maturation driven by aberrant sphingomyelin-mediated signaling. Transcriptomic profiling revealed that mature oligodendrocytes in these mice retain a gene expression signature similar to oligodendrocyte precursor cells, indicating a differentiation arrest. The cell adhesion molecule CD44 remained significantly upregulated in mature ASMko oligodendrocytes. Pharmacological inhibition of CD44 with verbascoside rescued oligodendroglial maturation in primary culture. Verbascoside administration in vivo restored myelin integrity and improved motor behavior. These findings establish that sphingomyelin homeostasis is critical for oligodendrocyte maturation and identify myelin defects as both primary pathological triggers and therapeutic targets for ASMD with neurologic symptoms.

Animals↗
PubMed1977

The relationship of amniotic fluid insulin levels and the lecithin-sphingomyelin ratio.

Amniotic fluid insulin levels and the lecithin-sphingomyelin ratio were determined in 62 samples of 33 insulin-dependent diabetic patients from the 29th to the 44th week of gestation inclusive and in 42 samples of 38 gestational diabetic patients from the 35th to the 43rd week of gestation inclusive. (Gestational age was measured by ultrasonography.) The level of insulin in the amniotic fluid did not appear to affect the lecithin-sphingomyelin ratio.

Amniotic Fluid↗
PubMed1977

The fatty acid composition of sphingomyelin from adult human cerebral white matter and changes in childhood, senium and unspecific brain damage.

A micromethod for the investigation of the fatty acid composition of sphingomyelin in presented. In the cerebral white matter of 17 normal adult brains, analyzed for reference, the predominant fatty acids are C 18:0 and C 24:1. Our results are in agreement with those of other authors. Short chained fatty acids are relatively increased in young children; this shift is typical of "immature" myelin. Similar changes are described here in old persons and cases of non-specific brain damage associated with demyelination (autolysis, chronic uremia, juvenile chorea). Sphingomyelin fatty acid composition can be considered a sensitive measure of both disturbed myelination and demyelination.

Adolescent↗
PubMed1977

The effect of phosphatidylcholine to sphingomyelin mole ratio on the dynamic properties of sheep erythrocyte membrane.

Sheep red blood cells are shown to incorporate phosphatidylchline when incubated in human plasma in the presence of EGTA. This treatment results in up to a 5-fold increase in mol ratio of phosphatidylcholine to sphingomyelin. By replacing EGTA with Ca+ the increase of phsphatidylcholine content is completely inhibited, due to the activation of the membrane bound lecithinase which rapidly degrades the incorporated phosphatidylcholine. Analogous treatments of the isolate membranes resulted in similar phosphatidylcholine incorporation but in the presence of Ca+ a residual phosphatidylcholine uptake was still oberved. These results suggest that in the isolated membranes small amounts of phosphatidylcholine can be incorporated into an additional region which is unavailable for the membrane lecithinase. The increase in the phosphatidylcholine to sphingomyelin mol ratio in sheep red blood cells is concomitant with an increase in lipid fluidity, as well as increase in osmotic fragility9

Animals↗
PubMed1979

Mixed micelles of sphingomyelin and phosphatidylcholine with nonionic surfactants. Effect of temperature and surfactant polydispersity.

Mixed micelle formation of the polydisperse nonionic surfactant Triton X-100 as well as its homogeneous analogue, p-(1,1,3,3-tetramethylbutyl)-phenoxynonaoxyethylene glycol (OPE-9), with bovine brain sphingomyelin or dipalmitoyl phosphatidylcholine has been characterized by column chromatography on 6% agarose. At 40 degrees C, mixtures of OPE-9 and either sphingomyelin or dipalmitoyl phosphatidylcholine give a narrow size distribution for mixed micelles. A this temperature the size distribution of Triton X-100-containing mixed micelles is complicated because of the polydispersity of the oxyethylene chains. At 20 degrees C narrow size distributions are observed for mixed micelles of sphingomyelin/Triton X-100 and sphingomyelin/OPE-9 up to at least 0.06 mol fraction of lipid. For dipalmitoyl phosphatidylcholine this is observed only with OPE-9. At intermediate mol fractions of lipid (around 0.25), two populations of mixed micelles exist for sphingomyelin/Trition X-100, sphingomyelin/OPE-9, and dipalmitoyl phosphatidylcholine/OPE-9. At high mol fractions of lipid only one population of mixed micelles again exists. At 20 degrees C, sphingoymelin forms a clear solution with Triton X-100 and OPE-9 to a lipid mol fraction of at least 0.46 and 0.67, respectively. Dipalmitoyl phosphatidylcholine forms a clear solution with OPE-9 to a lipid mol fraction of at least 0.57 at the same temperature. Triton X-100 and dipalmitoyl phosphatidylcholine do not form stable, clear solutions at 20 degrees C unless the lipid mol fraction is extremely low. These results show that surfactant polydispersity and temperature are important determinants in the solubilization of lipids by nonionic surfactants. It is also shown that pure surfactant micelles and lipid/surfactant mixed micelles do not co-exist in the same solution.

Chemical Phenomena↗
PubMedDate not supplied

Fatty acid composition of myelin lipids (cerebrosides, sulphatides and sphingomyelin) from normal human sural nerve, and changes in peripheral neuropathy.

Fatty acids of cerebrosides, sulphatides and sphingomyelin from normal human sural nerve, by comparison with brain, show a diminution of long-chained fatty acids as well as unsaturated fatty acids. The findings in brachial plexus are intermediate. In cases of peripheral neuropathy from various causes sphingomyelin fatty acid composition reveals pronounced loss of long-chained fatty acids, a phenomenon that is probably unspecific and may be associated with all forms of demyelination. Problems associated with the limited amount of nervous tissue available from biopsy specimens are discussed.

Adult↗
PubMed1978

Sphingomyelinase activity levels in human peripheral blood leukocytes, using [3H]sphingomyelin as substrate: study of heterozygotes and homozygotes for Niemann-Pick disease variants.

Patients and heterozygous carriers of Niemann-Pick disease types A and B as well as the primary (genetic) sea-blue histiocyte syndrome were investigated for their leukocyte sphingomyelinase activity. In parallel, glucocerebrosidase activity was determined in all cases studied. [3H]Sphingomyelin and [14C]glucocerebroside served as substrates for sphingomyelinase and glucocerebrosidase activity measurements, respectively. Conditions for these enzymes' assays are discussed. Sphingomyelinase activity was completely absent in three cases of Niemann-Pick disease type A and significantly diminished in one patient with Niemann-Pick disease type B and two with the sea-blue histiocyte syndrome. Sphingomyelinase activity in obligatory heterozygotes of all variants investigated represented about 40 to 70% of normal activity. Nevertheless, some overlapping with normal values occasionally occurred. Interestingly, glucocerbrosidase activity was elevated in patients with Niemann-Pick disease variants.

Glucosylceramidase↗
PubMed1976

[Adult Niemann-Pick disease: a 26 years follow-up. Report of a case with isolated visceral involvement, excess of tissue sphingomyelin, and deficient sphingomyelinase activity (author's transl)].

The case report of Niemann-Pick disease, in a 26 years old woman whose first symptoms appeared when she was 17 months old, is described. The disease, involving considerable hepatosplenomegaly and pulmonary infiltration, was diagnosed by the presence of lipid laden macrophages (resembling foam cells, sea blue histiocytes and kidney intermediate forms) in the bone marrow, liver and kidney, and an excess of tissue sphingomyelin and cholesterol, and a decrease in sphingomyelinase in circulating leucocytes. The results of ultrastructural, histochemical and biochemical studies on hepatic and renal lipids are reported. The relationship of the case to the sea blue histiocyte syndrome is discussed.

Adult↗
PubMed1977

Nine cases of sphingomyelin lipidosis, a new variant in Spanish-American Children. Juvenile variant of Niemann-Pick Disease with foamy and sea-blue histiocytes.

We describe nine Spanish-American children from five families with an unusual hereditary lipid storage disease. The family origins were in two small southern Colorado towns. The clinical course varied, but all of the children were found to bruise easily and to have splenomegaly, while most had hepatomegaly. Post-natal jaundice and hepatitis occurred in four. Impairment of vertical gaze and intellectual and neurologic deterioration occurred in most of the patients, with the onset of the disease, usually in childhood. The bone marrow in all patients examined contained both foamy and sea-blue histiocytes. Sphingomyelinase levels in skin fibroblast cultures were greatly decreased in seven of the eight cases evaluated. It is believed that these patients have a sphingomyelin lipidosis and represent a variant of the Niemann-Pick disease. Clinical and enzymatic findings are compared with those of other cases in the literature.

Adolescent↗
PubMed1975

Transversal and longitudinal lecithin-sphingomyelin ratios in amniotic and lung fluids of fetal lambs.

Lecithin-sphingomyelin (L/S) ratios were measured in both amniotic and in lung fluids of fetal lambs. Around Day 130 of fetal age sudden increase of L/S ratio appeared in lung fluid. The amniotic L/S ratio increased only slowly as a consequence of which false negative values were obtained. A respiratory distress syndrome is to be expected when the lung fluid shows a L/S ratio less than 2. The L/S ratio of lung fluid is preferable to amniotic L/S ratio. In comparison with those of amniotic fluid the L/S ratios of lung fluid were significantly higher. Lung fluid secretion was measured daily. Large differences were seen among the lambs. Two days before delivery a striking decrease in the quantity of lung fluid production was noticed in all aminals.

Amniotic Fluid↗
PubMed1979

The affinity of cholesterol for phosphatidylcholine and sphingomyelin.

Erythrocyte ghosts were incubated with sonicated vesicles and the uptake of cholesterol by vesicles allowed to proceed to equilibrium. The experiments were carried out for a series of phospholipids at different temperatures. The equilibrium partition of cholesterol between ghosts and single shelled vesicles provided a measure of the relative affinities of cholesterol for the different phospholipids studied. It was found that the affinity of cholesterol for dipalmitoyl phosphatidylcholine was the same as that for N-palmitoyl sphingomyelin both at temperatures above and below the gel to liquid crystalline transition temperature of these phospholipids.

Cholesterol↗
PubMed1976

Study of the long chain bases of sphingomyelin of Entomophthora coronata.

Sphingomyelin was isolated from a strain of Entomophthora coronata, a fungus pathogenic for humans. After hydrolysis, the long chain bases were converted to their dinitrophenyl (N2pH) derivatives and the aldehydes prepared by oxidizing these compounds with periodic acid. The aldehydes were studied by gas chromatography. Twelve different aldehydes were identified, the chain distributiion ranging from C14 to C17. The prominent chains were unsaturated. Straight and branched chains were found. The most abundant parent base which formed 52% of the total aldehyde was a 1,3-dihydroxy-2-aminohexadecene.

Aldehydes↗
PubMed1977

Accurate photodensitometric measurement of the lecithin: sphingomyelin ration after elimination of the acidic phospholipids from extracts of amniotic fluid specimens.

Treatment of human amniotic fluid lipids dissolved in a chloroform/methanol (9:1, v/v) mixture by batchwise addition of diethylaminoethyl cellulose in a dry state proved to be an easy and rapid procedure for the removal of the acidic phospholipids which may interfere in the photodensitometric evaluation of the lecithin: spingomyelin ratio on a thin-layer chromatogram. This method was used for the measurement of the lecithin: sphingomyelin ratio in a series of normal and abnormal pregnancies. Ratios higher than expected from gestational age were observed in stressed pregnancies. A significant elevation of the ratio was also observed under treatment by dexamethasone.

Amniotic Fluid↗
PubMed1977

Cholesterol ester accumulation in cultured aortic smooth muscle cells. Induction of cholesterol ester retention by chloroquine and low density lipoprotein and its reversion by mixtures of high density apolipoprotein and sphingomyelin.

Accretion of cholesterol ester was studied in rat aortic smooth muscle cells in culture. Confluent multilayers of smooth muscle cells were exposed to human low density lipoprotein (LDL) and chloroquine and this treatment resulted in a very marked increase in cellular cholesterol ester. The degree of enrichment in cholesterol ester was related inversely to the cell density in the petri dish and was maximal in 48 h. The morphological changes after 48 h incubation with chloroquine and LDL consisted of accumulation of numerous membrane-bound inclusions containing electron-dense and electron-lucent material, some of which resembled secondary lysosomes. These changes resembled some of the changes observed in human and experimental atheromatosis. Similar inclusions were seen also in cultured human skin fibroblasts which accumulated large amounts of cholesterol ester during 48 h incubation with LDL and chloroquine. Removal of the accumulated cellular cholesterol ester was studied in the two cell types and it was markedly enhanced in the presence of lipoprotein-deficient serum and high density apolipoprotein-sphingomyelin mixture. The morphological findings after 24 h of post incubation revealed the presence of empty vacuoles, membrane whorls and cytoplasmic lipid droplets. The present results indicate that aortic smooth muscle cells in culture can serve as a good model to study the role of the lysosomal system in atherogenesis.

Adult↗
PubMed1976

Biosynthesis of sphingomyelin in rat liver endoplasmic reticulum.

Rat liver microsomal sphingomyelin synthetase (CDPcholine: N-acylspingosine choline phosphotransferase (EC 2.7.8.3)) has been shown to be markedly stimulated by ATP and pantothenic acid derivatives such as CoA, pantethine, pantetheine and 4'-phosphopantetheine.

Animals↗