Search PubMed⌕ Search

Biomedical subjects

S Salvati

Publications and source records attributed to S Salvati.

31 records · Page 2Linked to original sources
PubMed1990

Lipid profile of rat myelin subfractions.

Myelin from adult rat brains was separated on a discontinuous sucrose gradient into three subfractions. Analysis of "light", "heavy" and "membrane fraction" lipid classes was performed by HPTLC and densitometry while fatty acid composition was determinated by GLC. The more interesting results observed are: i) the "membrane fraction" resembles in its lipid and fatty acid composition other cell membranes (particularly oligodentrocytes); ii) "light" and "heavy" myelin are quite similar between them but the former has a higher content of sphingomyelin, a lower hydroxy/nonhydroxy cerebrosides ratio and a lower content of monoenoic fatty acids than the "heavy" subfraction. The results obtained could explain the different structures observed in each myelin subfraction since fatty acid composition, hydroxy fatty acids, sphingomyelin and cholesterol play a key role in the stability and structure of membranes.

Animals↗
PubMed1990

Lipid changes in central nervous system membranes in experimental allergic encephalomyelitis (EAE).

Lipid composition of myelin fractions isolated from Lewis rats during the early stage of the development of experimental allergic encephalomyelitis (EAE) were determined by high-performance thin layer chromatography (HPTLC). When comparing the myelin fractions of EAE-affected animals with those of controls, the main differences were observed in the light fraction, where a decrease in the percentage of phospholipids (PH) relative to the total lipids was observed. These findings give further support that the light myelin fraction being the most sensitive at the onset of clinical symptoms must play a key role in demyelinating process.

Animals↗
PubMed1990

Biochemical changes in central nervous system membranes in chronic-relapsing experimental allergic encephalomyelitis.

Biochemical studies of myelin fractions were undertaken on Lewis rats during various time-points in the development of chronic-relapsing experimental allergic encephalomyelitis (CR-EAE). Lipid and protein composition of myelin fractions obtained by sucrose density gradient centrifugation at 10, 19, 24, and 66 d postinduction (pi) were determined by high-performance thin-layer chromatography (HPTLC) and sodium dodecyl sulfate-polyacrilamide gel electrophoresis (SDS PAGE), respectively. When comparing the myelin fractions of CR-EAE affected animals with those of controls, main differences were observed at 10 d pi. These changes were particularly evident in the light myelin fraction, where a decrease in the percentage of phosphatidylethanolamine and small basic protein relative to the total lipids and proteins of the fraction were observed. At 19 and 24 d pi no biochemical differences were present in both fractions. At 66 d pi, differences in the lipid composition were observed again only in the light myelin fraction. These findings suggest that the light myelin fraction is the most sensitive, particularly at the early stages of the disease, and must play a key role in demyelinating processes.

Animals↗
PubMed1989

Analysis of brain and myelin lipids by high-performance thin layer chromatography and densitometry.

We have developed a simple method involving high-performance thin layer chromatographic separation of total brain and myelin lipids. Only two solvent systems consisting of chloroform: methanol:acetic acid and water at different concentrations were needed. The plate was then stained with three sequential procedures to visualize phospholipids, cholesterol and galactolipids. Densitometric procedure at each step of staining was utilized to obtain quantitative analysis of brain and myelin samples.

Animals↗
PubMed1986

Biochemical changes in central nervous system membranes in experimental allergic encephalomyelitis.

Biochemical and morphological studies of myelin subfractions were undertaken on Lewis rats during the early stage of the development of experimental allergic encephalomyelitis (EAE). Myelin subfractions, obtained by sucrose density gradient centrifugation at 10 days post-induction, were subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis and assayed for 2':3'-cyclic nucleotide 3'-phosphodiesterase (CNPase) activity. Aliquots were processed for electron microscopic analysis. When comparing the myelin subfractions of EAE-affected animals with those of controls, differences were observed only in the light fractions, i.e., a decrease in the specific activity of CNPase and in the percentage of basic proteins relative to the total proteins of the fraction. This decrease was also evident in the basic protein/proteolipid protein ratio which is frequently used in the literature. In addition, electron microscopic observations demonstrated strong differences in the morphology of the same fraction. These findings suggest that the light fraction is the most sensitive in the early stages of the disease and must play a key role in demyelinating processes.

2',3'-Cyclic-Nucleotide Phosphodiesterases↗
PubMed1984

Morphological and biochemical changes in myelin subfractions of developing rats fed microbial lipids.

Morphological, biochemical, and physicochemical studies of myelin subfractions were undertaken on the progeny of Sprague-Dawley rats fed diets containing lipids either extracted from yeasts grown on n-alkanes or from margarine. Myelin subfractions obtained from pooled brain homogenates of littermates by sucrose density gradient centrifugation at 7, 14, and 21 days postnatally were subjected to electron microscopy, sodium dodecylsulfate polyacrylamide gel electrophoresis and assayed for 2', 3' cyclic nucleotide 3'-phosphohydrolase activity (CNPase; EC 3.1.4.37). Additionally, surface pressure measurements were made of lipid monolayers derived from myelin subfractions, which were subsequently injected with myelin basic proteins. The myelin subfractions of test animals, when compared with those of controls, show an earlier increase in the specific activity of CNPase, the earlier appearance of low-molecular-weight proteins, and an increase in the affinity of basic proteins for lipids derived from the myelin light fraction. This biochemistry suggests the presence of a more mature myelin between 7 and 14 days in the experimental group. The morphological studies, however, do not seem to concur with the biochemical data. The observed changes are discussed in relation to the influence of dietary lipids on myelinogenesis.

2',3'-Cyclic-Nucleotide Phosphodiesterases↗
PubMed1982

Effects of dietary phospholipids and odd-chain fatty acids on the behavioural maturation of mice.

Five groups of female mice were fed from day 14 of pregnancy and throughout lactation on synthetic diets differing only in the lipid component, which constituted 10% of the diet and was derived from (a) the lipid fraction extracted from yeast grown on n-alkanes, (b) commercial soya lecithin, (c) fatty acids isolated from yeast lipids (off-chain fatty acids), (d) lipids extracted from yeast grown on glucose or (e) margarine (8%), corn oil (1%) and the unsaponifiable fraction (1%) from yeast grown on n-alkanes. A control diet (9% margarine and 1% corn oil) was fed to a sixth group of pregnant mice and to the offspring of all the groups from weaning to 60 days after birth. A battery of behavioural tests was performed on the offspring of the six groups between days 1 and 16 after birth (reflex activities), between days 2 and 21 (locomotor activity) and at 60 days of age (avoidance learning). An acceleration of postnatal behavioural maturation was evident in the pups of animals fed lipids from yeast grown on n-alkanes and of those fed soya lecithin, indicating the involvement of phospholipids and odd-chain fatty acids in the aspects of development studied.

Animals↗
PubMed1981

Ontogenetic alterations of the cerebral cortex in rat caused by a diet containing a lipid fraction extracted from yeast (Candida lipolytica) grown on N-alkanes.

Several ontogenetic aspects of the cerebral cortex were studied in rats whose mothers were fed on a diet, the lipid fraction of which was extracted from yeast (Candida lipolytica) grown on N-alkanes, during part of pregnancy and throughout lactation. Measures of the heights of some cortical regions and specific layers, the maturation of mean cell volumes and of the cell/gray coefficient, especially in layers I, IV and VI, show that the diet affects cerebral cortex ontogeny. These effects on brain ontogeny and on intrinsic and extrinsic neuron connections may explain the electrophysiological and behavioural alterations observed in previous studies.

Alkanes↗
PubMedDate not supplied

Diet, lipids and brain development.

Brain development is a sequential anatomical process characterised by specific well-defined stages of growth and maturation. One of the fundamental and necessary events in the normal development of the central nervous system in vertebrates is the formation of a myelin sheath. It is becoming more evident that this process is influenced by dietary lipids. A number of findings have indicated that the administration of a diet deficient in essential fatty acids during development causes hypomyelination in the rat brain. Our studies have shown that lipids can also play a role in accelerating myelinogenesis in the brain of rats whose mothers had been fed, during pregnancy and lactation, a lipid fraction extracted from yeast grown on n-alkanes. Further studies have shown that accelerated myelinogenesis is connected to a precocious appearance of behavioural reflexes. Thus, the use of particular lipids in human nutrition must be carefully screened for possible effects on brain development.

Animals↗