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  • Chemistry  (99)
  • Life and Medical Sciences  (20)
  • Inorganic Chemistry  (7)
  • 1985-1989  (119)
  • 1989  (119)
  • 1
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The determination of pipecolic acid in serum or plasma by positive chemical ionization gas chromatography/mass spectrometry is assessed. This quantitative method involves stable isotope dilution and cation-exchange solid-phase extraction. Several derivatives of pipecolic acid and its octadeuterated analogue were investigated for their mass spectrometric characteristics. The beptafluorobutyric methyl ester derivatives afford optimal resolution on gas chromatography of biological extracts. Moreover, the derivatizing reagent (methanolic HCl) allows a combined elution and derivatization. Selected ion monitoring is performed on the [M + H]+ ions of both analyte and internal standard, at m/z 340 and 348, respectively. Serum or plasma samples from healthy subjects and patients suspected of peroxisomal diseases have been examined.
    Additional Material: 4 Ill.
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  • 2
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Letters Edition 27 (1989), S. 361-367 
    ISSN: 0887-6258
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 5 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 1324-1329 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 8 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 12 (1989), S. 540-543 
    ISSN: 0935-6304
    Keywords: High performance liquid chromatography, HPLC ; Adsorption HPLC system ; Partition reverse phase HPLC system ; Valproic acid, VPA ; Antiepileptic drugs, AEDs ; O-p-Nitrobenzil-N,N′-diisopropylisourea, PNBDI ; Enzyme immunoassay, EMIT ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A sensitive and specific method for the determination of valproic acid in plasma has been developed. After the proteins in the plasma have been precipitated with a saturated solution of ammonium sulfate in 1N HCl, the valproic acid, together with the internal standard, is extracted from the plasma with dichloromethane.An aliquot of the organic solution is taken for derivatization of the valproic acid and the internal standard with O-p-nitrobenzyl-N,N′-diisopropylisourea.Separation is carried out by HPLC using two chromatographic systems: an adsorption system with a μ Porasil column, hexane-chloroform (94:6) as mobile phase, and caproic acid as internal standard and a partition reverse phase system comprising a μ Bondapak TM/C18 column, acetonitrile/methanol/0.0035 M phosphate buffer (60:10:30), and caprylic acid as internal standard. UV detection is at 254 nm.This method, developed in both systems, permits the determination of plasma levels of valproic acid in the reported range of 50-100 μg/mL. With adequate sensitivity, specificity, precision, and accuracy.The plasma levels of valproic acid may be determined by this method without interference from the commonest antiepileptic drugs. Good correlation is obtained with the enzymatic immune analytic method: EMIT.
    Additional Material: 7 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 12 (1989), S. 604-607 
    ISSN: 0935-6304
    Keywords: Capillary gas chromatography ; Two-phase acylation ; Aziridine ; 2-Chloroethylamine ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The determination of small, water soluble amines such as aziridine and 2-chloroethylamine, in drug substances at trace levels is described. After removal of the bulk of the drug substance by extraction or precipitation, derivatization with acid chlorides is performed. In a two-phase (water-organic solvent) system, this derivatization reaction is accomplished almost simultaneously with the extraction of the product to the organic layer. The organic layer is analyzed by gas chromatography using on-column injection and selective detection. Detection limits are approx. 0.2 mg/kg for aziridine and approx. 0.5 mg/kg for 2-chloroethylamine.
    Additional Material: 6 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 38 (1989), S. 1745-1759 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A series of imide end-capped oligoesters were prepared by reacting a number of hydroxylterminated poly(diethyleneglycol terephthalate) oligomers (X̄n ranging from 1 to 20) with N-(4-chlorocarbonylphenyl)maleimide and N-(4-chlorocarbonylphenyl)nadimide. All the oligomers were characterized by vapor pressure osmometry, 1H- and 13C-NMR and GPC. The thermal properties were also investigated and a correlation of the thermal behavior with molecular weight and the type of reactive end groups was established. Molecular models were also synthesized and characterized to obtain reliable analytical data for the determination of the oligomers composition.
    Additional Material: 5 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 37 (1989), S. 2537-2548 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Miscible blends from plasticized poly(vinyl chloride), and epoxidized natural rubber having 50 mol% epoxidation level were prepared in a Brabender Plasticorder by the melt-mixing technique. Changes in Brabender torque and temperature, density, dynamic mechanical properties, and differential scanning calorimetry of the samples were examined as a function of blend composition. The plasticized poly(vinyl chloride)/epoxidized natural rubber blends behaved as a compatible system at all composition ranges as evident from their single glass-rubber transition temperature (Tg) obtained from dynamic mechanical analysis as well as from differential scanning calorimetry. Profound changes in the nature of the glass-rubber transition were noted with respect to blend composition. The Tg-width values of blends lie between those of plasticized poly(vinyl chloride) and epoxidized natural rubber.
    Additional Material: 8 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 23 (1989), S. 349-356 
    ISSN: 0148-7280
    Keywords: FSH ; ovary ; amphibian ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: In the fully grown Bufo arenarum oocyte, carbohydrate breakdown during the autumn-winter season is accomplished mainly through the glycolytic pathway followed by the krebs cycle. During the breeding season (spring-summer), carbohydrates are used mainly through the pentose phosphate cycle and through the variant of the Krebs cycle known as the glutamic aspartic cycle.The metabolism operating in the oocytes was determined using the following paramenters: 1) the capacity of isolated mitochondria to oxidize citrate and fumarate; 2) the enzymatic activities of phosphofructokinase (PEK) and glucose-6-phosphate dehydrogenase (G-6-PDH); and 3) cirate and ATP compartmentalization.The present paper shows that follicle-stimulating hormone (FSH) would be one of the factors responsible for summer metabolism, since ovary fractios obtained from winter specimens treated with the hormone acquired the metabolic characteristics corresponding to oocytes obtained from breeding-season animals from dose-response, and response in the function of time curves, it could be assumed that the optimum doses and times were 0.1 μg FSH/ml of incubation medium and 30 min treatment, respecitively.The metabolic effect of FSH upon oocytes could be mediaated by the adenylate cyclase cAMP system, since treatment of ovric fractions with cAMP 10-3 M reproduced the effects obtained with the hormone. In addition, 0.02 mg/ml tetracyline proved to block the effect of FSH. A direct metabolic action of FSH on body cavity oocytes (without follicle cells) was observed when submitting these oocytes to the same hormonal treatment.
    Additional Material: 5 Ill.
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  • 9
    ISSN: 0148-7280
    Keywords: galactosyltransferase ; capacitation ; epididymis ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The effects of bovine mammary alpha-lactalbumin on the motility and zona-binding characteristics of mouse sperm were investigated. Two properties of sperm associated with capacitation, hyperactivated motility, and the ability of sperm to bind to the zona pellucida of oocytes were shown to be suppressed by alpha-lactalbumin. These inhibitory effects were not accompanied by changes in the percentage of motile cells or by differences in the velocity parameters of the hyperactivated and non-hyperactivated spermatozoa. Bovine serum albumin prevented and reversed the alpha-lactalbumin-induced suppression of hyperactivation. Sperm-zona pellucida binding was partially restored by lowering the alpha-lactalbumin concentration in the medium in which sperm were allowed to bind to the zona pellucida. The results suggest that mouse sperm are decapacitated by bovine mammary alpha-lactalbumin. The counteracting effect of bovine serum albumin to the suppressive action of alpha-lactalbumin on the flagellum suggests the involvement of a mechanism different from the action of alpha-lactalbumin on the sperm head inhibiting binding to the zona pellucida.
    Additional Material: 8 Ill.
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  • 10
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: It is shown that the demosponge Corallistes sp. (Tetractinomorpha, Lithistida, Corallistidae) collected in the Coral Sea, contains corallistin A (1), the second example, of a free porphyrin from a living organism. The compound proved to be active against the Kb cell line. In contrast with the geoporphyrins which do not bear any O-atom corallistin A (1) carries two carboxylic groups.
    Additional Material: 1 Tab.
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