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  • 1
    ISSN: 1432-1076
    Keywords: Reduced nicotinamide adenine dinucleotide (NADH) dehydrogenase ; Respiratory chain ; Mitochondrial myopathies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We describe eight children with complex I deficiency, four of them with an isolated, the other four with an additional deficiency of complex IV. Clinical, chemical and morphological findings were compared from patients with isolated and combined deficiency. In both groups, the age of onset of symptoms was between the 1st day and the 4th month of life. Clinical and biochemical heterogeneity were observed. We found no correlation between residual activity of complex I in muscle, blood lactate level, and severity of clinical symptoms. Newborns presenting with severe lactic acidosis and children with later onset myopathy were seen in both groups. The group with combined complex I deficiency showed a more severe clinical course. By light microscopy ragged red fibres were only found in two patients with combined deficiency. However, by electron microscopy structural alterations of the mitochondria were observed in six out of seven muscle specimens.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Biochemical and Biophysical Research Communications 59 (1974), S. 1278-1285 
    ISSN: 0006-291X
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: Exogenously added glycerophosphatides, specifically radioactively labelled either in the 1 or in the 2 position, were used to investigate the occurrence and properties of phospholipase A1 in plasma membranes prepared from neuronal- and glial-enriched fractions of rabbit brain. Phospholipase A1 activity was maximal at pH values ranging between 8.0 and 9.0 for the plasma membranes of both cell types. The enzyme activity was most abundant in the microsomal fraction, with a neurondglial ratio of about 2. The plasma membranes displayed about half the enzymic activity of the microsomal fraction, whereas only small amounts of phospholipase A1 were present in the neuronal and glial mitochondria. Investigations on the substrate specificity showed a different pattern for the enzyme of neuronal and glial origin. The release of labelled fatty acids from phosphatidylcholine by the neuronal plasma membrane phospholipase A1 decreased with increasing degree of unsaturation of the fatty acids at the 1 position. The presence of plasmalogens and plasmalogen precursors in the incubation mixture appreciably inhibited the hydrolysis of the corresponding diacyl compounds.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 23 (1974), S. 0 
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: —The activity of phospholipase A1 (phosphatide acylhydrolase, EC 3.1.1.4) was measured against phosphatidylcholine, -ethanolamine and -serine, specifically labelled with different fatty acids at either the 1 or 2 position, during experimental allergic encephalomyelitis in rats. In the acute stage of the disease there was a significant increase in enzyme activity in comparison to that from the control animals. The enhanced phospholipase A1 activity was of the-same order of magnitude for all 1,2-diacyl-glycerophospholipids investigated. The phospholipase A1-catalysed release of labelled fatty acids from molecular species of phosphatidylcholine decreased slightly with increasing degree of unsaturation of the fatty acids at the 1-position. The Km-values of the highly purified enzyme were not altered by the demyelinating disorder. The phospholipase A1 activity returned to the control level in the recovery stage.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: —1,2-Diacyl-, 1-alk-1′-enyl-2-acyl-and 1-alkyl-2-acyl-sn-glycero-3-phosphorylcholine, specifically labelled with different fatty acids at the 2 position, were prepared enzymically using the acyltransferase system of rabbit sarcoplasmic reticulum. The substrates were submitted to hydrolysis by mitochondrial phospholipase A2 (phosphatide acyl-hydrolase, EC 3.1.1.4) obtained from normal and from rat brain afflicted with EAE. In the acute stage of the disease an increase of approximately 25 per cent in phospholipase A 2 activity could be observed in comparison to that from the control animals for all investigated substrates. Phospholipase A2 obtained from normal rat brains and from those afflicted with EAE had a higher affinity for 1,2-diacyl-sn-glycero-3-phosphorylcholine when compared to the corresponding alkyl acyl- and alkenyl acyl-analogues. Choline plasmalogen was cleaved more slowly than the corresponding alkyl acyl derivative. The enzyme activity returned to the control level in the recovery stage of the demyelinating disease.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract— Glial cells isolated from rabbit cerebral cortex contained approximately one-third more phospholipids per unit protein than the neuronal cell bodies. The pattern of individual phospholipids was rather similar in both cell types. The incorporation of intracisternally administered 32P into neuronal and glial phospholipid classes of rabbit brain was studied at intervals ranging from 5 to 60min. In general, for all investigated phospholipids the incorporation of the label was somewhat faster in neurons than in glial cells. Phosphatidylinositol showed the fastest and ethanolamine plasmalogen the slowest incorporation of 32P in both neurons and glial cells. A lag phase of about 10 min could be observed before labelling of the glial phosphatidylcholine, phosphatidylethanolamine, ethanolamine plasmalogen, phosphatidylserine and sphingomyelin had occurred. Among the neuronal phospholipids a lag phase was found only for the labelling of the ethanolamine plasmalogen. Norepinephrine increased the incoropration of 32P into phosphatidylinositol of both glia and neurons but had no effect on the specific radioactivity of ethanolamine plasmalogen and sphingomyelin. Labelling of phosphatidylcholine was slightly inhibited in both cell types by the administration of norepinephrine.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: —1,2-Diacyl-, 1-alk-1′-eny1-2-acyl- and 1-alky1-2-acyl-sn-glycero-3-phosphorylcholine specifically labelled with different fatty acids at the 2 position, were prepared enzymically using the acyltransferase system of rabbit sarcoplasmic reticulum. The substrates were submitted to hydrolysis by phospholipase A2 (phospholipid acyl-hydrolase, EC 3.1.1.4) obtained from normal and brain tissue affected with subacute sclerosing panencephalitis. In the diseased tissue an increase of phospholipase A2 activity ranging from 46 to 54% could be observed in comparison to the control brain for all substrates investigated. Among the investigated substrates phospholipase A2 had the highest affinity for the 1,2-diacylcompound, whereas alkenylacyl- and alkylacyl-sn-glycero-3-phosphorylcholine were cleaved at almost similar rates. The hydrolysis rate of choline-plasmalogen and the corresponding diacyl compound by the enzyme was greatly influenced by the fatty acid moiety located at the 2 position of the substrates.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 21 (1973), S. 0 
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract— The de novo synthesis of phosphatidylcholine and phosphatidylethanolamine in isolated neuronal and glial cells from adult rabbit brain cortex was investigated in vitro, using labelled phosphorylcholine (phosphorylethanolamine) or cytidine-5′-phosphate choline (cytidine-5′-phosphate ethanolamine), as lipid precursors. Synthesis of phospholipid from phosphorylcholine and phosphorylethanolamine in both fractions was extremely low when compared to that derived from the corresponding cytidine nucleotides. The neuronal cell-enriched fraction was found to possess a much higher rate of synthesis of both lipids from all precursors. Neuronal/glial ratios of about 5–9 were found for the synthesis of phosphatidylcholine and phosphatidylethanolamine from cytidine-5′-phosphate choline and cytidine-5′-phosphate ethanolamine, respectively. Several kinetic properties of the choline-phosphotransferase (EC 2.7.8.2) and ethanolaminephosphotransferase (EC 2.7.8.1) were found to be similar both in neurons and in glia (e.g. Km of cytidine-5′-phosphate ethanolamine, Km of diacyl glycerol, pH optimum, need for divalent cations), but the Km value for cytidine-5′-phosphate choline in glial cells was much lower (2.3 × 10−4m) than in neurons (1 × 10−3m). The Kmfor cytidine-5′-phosphate ethanolamine in both cells was much lower than in whole brain microsomes. It is concluded that the cytidine-dependent enzymic system for phosphatidylcholine and phosphatidylethanolamine synthesis is concentrated mostly in the neuronal cells, as compared to glia.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 28 (1977), S. 0 
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: [Methyl-3H]choline has been injected intraventricularly into adult rabbits, and the rate of synthesis of phosphatidylcholine, choline plasmalogen and sphingomyelin (and their hydrosoluble precursors) in isolated neuronal and glial cells has been investigated. At all time intervals examined, the injected radioactivity was incorporated only into the base moiety of the choline lipids in both cell types. Maximum labelling of the two choline phosphoglycerides occurred in neurons 150 min after administration, whereas the highest specific radioactivity for glial phosphatidylcholine and choline plasmalogen was reached at 6 and 10 h, respectively. At any time interval examined, the neuronal and glial choline plasmalogen displayed a higher specific radioactivity than the corresponding diacyl-derivative. The two phosphoglycerides incorporated the base in both cell populations at a faster rate than did whole brain tissue. Sphingomyelin was labelled in both cells at a low rate and acquired measurable radioactivity levels only after 2 h from isotope administration.Highest levels of radioactivity for phosphorylcholine and cytidine-5′-diphosphocholine were reached in both neurons and glia 1-2 h after administration, but these levels per unit protein were higher in glial than in neuronal cells.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 24 (1975), S. 0 
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract— Adult rabbits were injected intraventricularly with [14C]ethanolamine and the incorporation of the base into the phosphatidylethanolamine and ethanolamine plasmalogen (and their water-soluble precursors) of isolated neuronal and glial cells was investigated. All the radioactivity was incorporated into the base moiety of the ethanolamine lipids for the time intervals examined in both types of cells. In neurons, maximum labelling of the two ethanolamine lipids occurred at 7 h after administration, whereas the highest specific radioactivity for glial phosphatidylethanolamine and ethanolamine plasmalogen was reached at 20 and 36 h, respectively. The two lipids had a faster turnover in neurons than in glia, and in both populations incorporated the base at a faster rate than did whole brain tissue. The maximum incorporation rates for phosphorylethanolamine and CDP-ethanolamine were reached in both types of cell at about 6 h after administration but the content of radioactivity per unit protein for phosphorylethanolamine was much higher in glial than in neuronal cells. It is concluded that the site of most active synthesis of ethanolamine phospholipids in vivo is the neuronal cell, with a possible transfer of intact lipid molecule to the glial compartment.
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