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  • 1990-1994  (15)
  • Analytical Chemistry and Spectroscopy  (9)
  • Oligodendrocyte  (4)
  • mass spectrometry
  • 1
    Electronic Resource
    Electronic Resource
    Electrolyte-induced demyelination in rats (1994)
    Springer
    Acta neuropathologica 88 (1994), S. 287-292 
    Details
    ISSN: 1432-0533
    Keywords: Blood-brain-barrier ; Central pontine myelinolysis ; Electrolyte-induced demyelination ; Oligodendrocyte ; Pathogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The blood-brain barrier (BBB) was studied in rats with electrolyte-induced demyelination (EID), an experimental model for central pontine myelinolysis. Intravenously injected peroxidase was extravasated at 3 h post hypertonic saline injection (PHS) into regions frequently involved in EID. Increased pinocytotic activity and focal interendothelial gaps were seen at 3 h PHS and less frequently at 48 h PHS. Measurement of total cerebral water content revealed an increase during the hyponatremic phase. This was followed by a marked increase at 3 h PHS with continued increment at 48 h PHS. Intracellular edema with accumulation of fluid within neurites and astrocytic processes was noted during the hyponatremic phase, whereas extracellular edema developed after hypertonic saline injection. The implications of disrupted BBB and its role in the pathogenesis of EID are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00310371
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  • 2
    Electronic Resource
    Electronic Resource
    Electrolyte-induced demyelination in rats (1994)
    Springer
    Acta neuropathologica 88 (1994), S. 293-299 
    Details
    ISSN: 1432-0533
    Keywords: Blood-brain barrier ; Central pontine myelinolysis ; Electrolyte-induced demyelination ; Oligodendrocyte
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract This study presents the electron microscopic evolution of lesions in electrolyte-induced demyelination (EID) in rats, a lesion which bears striking histological and clinical similarity to central pontine myelinolysis. The earliest change was observed during the hyponatremic phase and consisted of minimal intracellular edema present throughout the brain. Following the injection of hypertonic saline, additional changes were observed which were restricted to sites previously reported to be frequently involved in EID. Early dilatation of the inner tongue of oligodendrocyte cytoplasm in myelinated nerve fibers was observed at 3h post hypertonic saline injection (PHS). This was followed, at 48h PHS, by the appearance of degenerative changes consistent with dying oligodendrocytes. Well-delineated, vacuolar and spongy lesions, seen by light microscopy, were present by 48h PHS at the same sites as above. Electron microscopically, this appearance was found to be due to striking intramyelinic edema. By 96h PHS, macrophages containing myelin and other cellular debris were frequently present at these sites. Concomitantly, myelin sheaths underwent vesicular disruption and disintegration. This sequence of events suggest a lesion of the oligodendrocyte-myelin complex, secondary to initial blood-brain barrier damage and edema.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00310372
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    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Electrolyte-induced demyelination in rats (1994)
    Springer
    Acta neuropathologica 88 (1994), S. 287-292 
    Details
    ISSN: 1432-0533
    Keywords: Key words Blood-brain-barrier ; Central pontine ; myelinolysis ; Electrolyte-induced demyelination ; Oligodendrocyte ; Pathogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The blood-brain barrier (BBB) was studied in rats with electrolyte-induced demyelination (EID), an experimental model for central pontine myelinolysis. Intravenously injected peroxidase was extravasated at 3 h post hypertonic saline injection (PHS) into regions frequently involved in EID. Increased pinocytotic activity and focal interendothelial gaps were seen at 3 h PHS and less frequently at 48 h PHS. Measurement of total cerebral water content revealed an increase during the hyponatremic phase. This was followed by a marked increase at 3 h PHS with continued increment at 48 h PHS. Intracellular edema with accumulation of fluid within neurites and astrocytic processes was noted during the hyponatremic phase, whereas extracellular edema developed after hypertonic saline injection. The implications of disrupted BBB and its role in the pathogenesis of EID are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00310371
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Electrolyte-induced demyelination in rats (1994)
    Springer
    Acta neuropathologica 88 (1994), S. 293-299 
    Details
    ISSN: 1432-0533
    Keywords: Key words Blood-brain barrier ; Central pontine ; myelinolysis ; Electrolyte-induced demyelination ; Oligodendrocyte
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract This study presents the electron microscopic evolution of lesions in electrolyte-induced demyelination (EID) in rats, a lesion which bears striking histological and clinical similarity to central pontine myelinolysis. The earliest change was observed during the hyponatremic phase and consisted of minimal intracellular edema present throughout the brain. Following the injection of hypertonic saline, additional changes were observed which were restricted to sites previously reported to be frequently involved in EID. Early dilatation of the inner tongue of oligodendrocyte cytoplasm in myelinated nerve fibers was observed at 3   h post hypertonic saline injection (PHS). This was followed, at 48   h PHS, by the appearance of degenerative changes consistent with dying oligodendrocytes. Well-de- lineated, vacuolar and spongy lesions, seen by light microscopy, were present by 48   h PHS at the same sites as above. Electron microscopically, this appearance was found to be due to striking intramyelinic edema. By 96   h PHS, macrophages containing myelin and other cellular debris were frequently present at these sites. Concomitantly, myelin sheaths underwent vesicular disruption and disintegration. This sequence of events suggests a lesion of the oligodendrocyte-myelin complex, secondary to initial blood-brain barrier damage and edema.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00310372
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    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Structural analysis of bovine pancreatic thread protein (1990)
    Springer
    The protein journal 9 (1990), S. 623-632 
    Details
    ISSN: 1573-4943
    Keywords: Pancreatic thread protein ; primary structure ; mass spectrometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Pancreatic thread protein (PTP) forms double helical threads in the neutralpH range after purification, undergoing freely reversible,pH-dependent globule-fibril transformation. The purified bovine PTP consists on SDS gels of two carbohydrate-free polypeptide chains (Grosset al., 1985). Plasma desorption mass spectrometry and amino acid sequence analysis now confirm that bovine PTP contains two disulfide-bonded polypeptides, an A chain of 101 amino acid residues with a molecular weight of 11,073 and a B chain of 35 residues with a molecular weight of 3970. The intact protein exhibits a molecular weight of 15,036, agreeing 〉99.9% with the molecular weight calculated from the sequence. The B chain sequence was determined by gas-phase Edman degradation of the intact polypeptide. The A chain sequence was determined from overlapping peptides generated by cleavage at lysyl, tryptophanyl, and aspartyl-prolyl residues. Based upon the bovine PTP cDNA structure, the two chains of the protein result from cleavage of a single polypeptide with removal of a dipeptide between the NH2-terminal A chain and COOH-terminal B chain. Comparison of bovine PTP with other proteins reveals significant structural relatedness with the single-chain homologues from human and rat pancreas and with the motif associated with Ca2+-dependent carbohydrate recognition domains. The physiological role of PTP has not yet been resolved. The protein is present in very high concentration in pancreatic secretion and it has been detected in brain lesions in Alzheimer's disease and Down syndrome and in regenerating rat pancreatic islets. The present results provide a firm protein base for ongoing molecular, physical-chemical, and structure-function studies of this unusual protein.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01025016
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    Paper (German National Licenses)
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  • 6
    Electronic Resource
    Electronic Resource
    Determination of an organotin stabilizer in a rigid poly(vinyl chloride) plastic by on-line supercritical fluid extraction and chromatography with formic acid modified carbon dioxide and flame ionization detection (1993)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 16 (1993), S. 198-202 
    Details
    ISSN: 0935-6304
    Keywords: Supercritical fluid chromatography ; Supercritical fluid extraction ; Poly(vinyl chloride) ; Dimethyltin mercaptide ; Formic acid ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240160316
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  • 7
    Electronic Resource
    Electronic Resource
    Importance of quality control in a gas chromatographic method to characterize crude oilsMany of the details in this paper were presented as a poster at the Tenth International Symposium on Capillary Chromatography, Riva del Garda, Italy, May 22-25, 1989. (1994)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 463-468 
    Details
    ISSN: 0935-6304
    Keywords: Capillary GC ; Petroleum crude oil ; Condensates ; Carbon number distribution ; Pseudocomponents ; Quality control ; Quality assurance ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A quality control scheme has been developed to achieve reproducible capillary GC characterization of crude oils and petroleum condensates. The method uses an internal standard to quantify the amount of non-eluted material in the crude oil sample. Correlation between the gas chromatographic results and actual distillation was 2 %. After repeated use, however, weekly analysis of the same standard crude oil did not give the correct composition. This was a result of discrimination, which worsened with time, as a result of leaks in the septum or the graphite ferrules. More reproducible results were obtained by performing frequent analyses of quality control samples to ensure that the gas chromatographic system was operating properly. The use of quality control charts was a convenient way of ensuring correct operation and identifying the need for corrective action on the gas chromatographic system.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240170613
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  • 8
    Electronic Resource
    Electronic Resource
    A comparison of formic acid and formamide as modifiers of supercritical carbon dioxide compatible with flame lonization detection (1993)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 16 (1993), S. 130-134 
    Details
    ISSN: 0935-6304
    Keywords: Supercritical fluid chromatography ; Packed columns ; Modifiers ; Formic acid ; Formamide ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240160216
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  • 9
    Electronic Resource
    Electronic Resource
    Analysis of effector cell-derived lyso platelet activating factor by electron capture negative ion mass spectrometry (1991)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 20 (1991), S. 545-552 
    Details
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Quantification of 1-O-alkyl-2-lyso-sn-3-glycero-phosphocholine (lysoPAF) and determination of the different molecular species released by cells has been hampered by the molecules's lack of intrinsic bioactivity, unavailability of a suitable internal standard, and reliance on derivatives requiring electron impact techniques. We have synthesized trideuterated internal standards (labeled on the terminal carbon of the alkyl chain) for both C16:0 and C18:0 lysoPAF. Using these standards, we isolated and quantified lysoPAF released from A23187-stimulated human neutrophils and rat alveolar macrophages. Extracted lysoPAF was purified by solid-phase extraction and thin-layer chromatography. The polar phosphorylcholine group was removed with 29 M HF or phospholipase C. The two free hydroxyl groups were derivatized with pentafluorobenzoyl chloride. The resultant bis-pentafluorobenzoyl derivative, analyzed by gas chromatography/electron capture negative ion mass spectrometry, underwent substantial fragmentation. Lowering of the ion source temperature resulted in a dramatic increase in signal-to-noise ratio, with the vast majority of the ion current carried in the molecular anion. Stimulated neutrophils released 16.3 and 10.2 ng/106 cells of C16:0 lysoPAF and C18:0 lysoPAF, respectively. Rat macrophages synthesized 15.9 ng/106 cells of C16:0 lysoPAF, but C18:0 lysoPAF was variably detected at low levels. We conclude that use of the bispentafluorobenzoyl ester derivative of lysoPAF allows facile quantification of this autacoid metabolite in biological matrices.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200200907
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  • 10
    Electronic Resource
    Electronic Resource
    An evaluation of tandem mass spectrometry in drug metabolism studiesA preliminary account of this work was presented at the 2nd European Tandem Mass Spectrometry meeting held at the University of Warwick, UK, on 19-22 July 1992. (1993)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 22 (1993), S. 388-394 
    Details
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The use of precursor ion and constant neutral loss scanning as a means of rapidly detecting drug metabolites is evaluated. Four clinically useful drugs, namely (i) cyclophosphamide, (ii) mifentidine, (iii) cimetropium bromide and (iv) haloperidol, were subjected to microsomal incubations to afford phase I metabolites. Aside from a minor clean-up procedure involving zinc sulfate precipitation of microsomal proteins and solid-phase extraction of metabolites using a Sep-pak C-18 cartridge, the mixtures were analysed directly by fast atom bombardment tandem mass spectrometry. It is demonstrated that such screening strategies are important in detecting novel metabolites. However, there are some problems associated with only using such methods, including (i) the possibility of not detecting metabolites that undergo unusual collision-induced dissociation fragmentation pathways, (ii) the non-detection of metabolites that have undergone metabolic change at unusual sites of reactivity, and (iii) production of artifacts derived from the parent drug by the primary ionization process. Examples are discussed that highlight both the strengths and weaknesses of such an approach.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200220705
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