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  • 1985-1989  (17)
  • Analytical Chemistry and Spectroscopy  (15)
  • BALB/cJ mice  (2)
  • 1
    ISSN: 1432-2072
    Schlagwort(e): Ethanol self-administration ; Operant behavior ; C57BL/6J mice ; BALB/cJ mice ; Fixed-ratio schedules ; Behavior genetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Previous studies of ethanol reinforcement in BALB/cJ and C57BL/6J mice have shown that over a range of concentrations oral ethanol appeared to serve as a reinforcer only for the C57BL/6J mice. In the previous studies BALB/cJ mice maintained rates of responding for ethanol that only slightly exceeded the rates maintained by the vehicle, water. However, the quantity of ethanol consumed with the continuous reinforcement schedule (fixed ratio one) may have led to pharmacologically significant effects, given the high sensitivity to ethanol of this genotype. The present study tested whether and to what extent ethanol would maintain responding under increasing fixed ratio size in these two strains of mice at ethanol concentrations of 0%, 8%, and 16% (w/v). For the C57BL/6J mice, as fixed-ratio size increased from 1 to 2, 4, and 8, there were almost directly proportional increases in response rate at ethanol concentrations of 8% and 16% (w/v), but not at 0%. Post-session blood ethanol levels confirmed intake of pharmacologically significant quantities. The volume consumed per unit of body weight decreased as fixed-ratio size increased. For the BALB/cJ mice, at no condition did ethanol maintain responding at levels that significantly exceeded vehicle maintained responding. BALB/cJ mice did not differ from C57BL/6J mice as fixed-ratio size was increased during vehicle conditions. These results, along with earlier findings, demonstrate that ethanol can serve as a reinforcer for C57BL/6J mice but not in BALB/cJ mice over a range of schedule conditions. They further support the conclusion that genotype is an important determinant of ethanol reinforced behavior.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Behavior genetics 17 (1987), S. 439-451 
    ISSN: 1573-3297
    Schlagwort(e): oral self-administration ; operant behavior ; C57BL/6J mice ; BALB/cJ mice ; alcohol ; behavior genetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Psychologie
    Notizen: Abstract By the use of operant conditioning procedures, we determined whether mice from two strains, C57BL/6J and BALB/cJ, differ in ethanol-reinforced behavior. To establish ethanol as a reinforcer, drinking was induced by feeding mice prior to the 30-min experimental session. Initially mice received water and then a series of increasing ethanol concentrations (1, 2, 4, and 8%, w/v) in response to a lever press. The volume of liquid consumed per unit of body weight remained relatively constant across concentrations, and thus the amount of ethanol consumed (g/kg) increased with increases in ethanol concentration. At all concentrations the C57BL/6J mice drank larger volumes than the BALB/cJ mice. After shifting the time of feeding from before to after the session, the consumption of 8% ethanol declined 56% for the C57B/6J mice and 81% for the BALB/cJ mice. To determine if ethanol was serving as a reinforcer, behavior and intake were then compared during ethanol and water availability. The ethanol consumption of the C57BL/6J mice markedly exceeded the water consumption and resulted in blood ethanol levels of 199 ±27 mg/dl. These levels significantly exceeded the 8% ethanol intake of the BALB/cJ mice, while 0% intake was low and not significantly different between strains. The 8% ethanol drinking of the BALB/cJ mice did not differ from their water drinking. Thus, ethanol was established as a positive reinforcer for C57BL/6J mice but not for BALB/cJ mice.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 193-204 
    ISSN: 0887-6134
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A method which involves the use of tandem mass spectrometry (MS/MS) for the identification of drug metabolites has been demonstrated with a triple quadrupole mass spectrometer. The method is based on the fact that metabolites usually retain various substructures of the original drug molecule. MS/MS is capable of rapidly identifying molecules with characteristic substructures without prior separation. It is shown that this method makes it possible to postulate possible drug metabolite structures rapidly and systematically without the use of standards. The MS/MS method, as it was applied to the identification of the metabolites of a new antiepileptic drug, zonisamide, is discussed. In this case it was possible to identify isomeric metabolites due to their differences in vaporization times off the probe and their different daughter spectra. The complementary uses of the neutral loss and parent scans for the determination of the site of metabolism is demonstrated. A new figure of merit, the limit of identification, is introduced. The amount of the epoxide metabolite of carbamazepine necessary for its reliable identification in urine was shown to be 0.4 ng/μl. The application of various techniques to confirm preliminary findings with this MS/MS method are described.
    Zusätzliches Material: 12 Ill.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 2 (1988), S. 275-276 
    ISSN: 0951-4198
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Physik
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 3 (1989), S. 293-294 
    ISSN: 0951-4198
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Physik
    Notizen: The ion PhSiH2- undergoes a number of fragmentations upon collisional activation, including losses of H·, H2 (mainly to form PhSi-), and SiH2, together with formation of HSi-. The ion/molecule chemistry of PhSiH2- is characteristic of silyl anion systems and bears no analogy to that of benzyl anion reactions; for example with N2O and CO2 it forms Ph(H)2SiO- as the sole ionic product, while with CS2 it yields Ph(H)2SiS-.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 6
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The electron ionization spectra of all of the positional isomers of myo-inositol monophosphate and of myo-inositol 1,2-cyclic phosphate were obtained by gas chromatography/mass spectrometry of the pertrimethylsilyl derivatives. The fragmentation pattern of pertrimethylsilyl myo-inositol-1-phosphate was studied using deuterium labeling. The phosphate moiety was found to direct fragmentation to produce fragment ions of useful intensity with specific carbon retention. The spectrum of pertrimethylsilyl myo-inositol-1,4-bisphosphate is also described. An electron impact gas chromatographic/mass spectrometric method for myo-inositol-1-phosphate has been developed, which has a sensitivity to a level of 0.1 pmol. The positive and negative ion fast atom bombardment spectra of myo-inositol hexakis(disodium phosphate) and myo-inositol hexakis(dihydrogen phosphate) are described. The lesser-phosphorylated inositol polyphosphates were also studied, including inositol pentakis and inositol tetrakis(dihydrogen phosphates) as well as D-myo-inositol-1,4,5-trisphosphate and D-myo-inositol-1,4-bisphosphate from human red blood cells. The sensitivity of fast atom bombardment for the measurement of the latter two substances allows their detection to a level of about 10 nmol. The fast atom bombardment spectrum of synthetic myo-inositol 1,2-cyclic phosphate revealed variable amounts of a dimer produced during its preparation.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 3 (1989), S. 151-152 
    ISSN: 0951-4198
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Physik
    Notizen: Ab initio calculations indicate that the ion [ONCO]- is linear, whereas [HNNCO]- is effectively coplanar. The ions may be formed by collisional activation of deprotonated hydroxy and aminocarbamates. The characteristic fragmentations of [ONCO]- and [HNNOO]- are losses of O and NH respectively.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 8
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 3 (1989), S. 10-11 
    ISSN: 0951-4198
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Physik
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 9
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 24 (1989), S. 875-884 
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Under electron ionization (EI) conditions, porphyrins yield unusually high intensities of doubly charged molecular and fragment ions. These doubly charged ions offer unique opportunities for the structure elucidation of porphyrins by tandem mass spectrometry (MS/MS). First, they fragment to a greater extent than the corresponding singly charged ions under both EI/MS and EI/MS/MS conditions. Second, doubly and singly charged porphyrin ions often fragment via different pathways, and can therefore yield different structural information. This paper describes several ways in which analyses of doubly charged porphyrin ions with a triple quadrupole tandem mass spectrometer can be useful in structure elucidation of porphyrins. The effect of the metal atom on the fragmentation of metalloporphyrins in an EI source is demonstrated by correlating the extent of doubly charged fragment ion formation to a stability index. Doubly charged porphyrin ions are shown to yield predominantly doubly charged daughter ions upon collisionally activated dissociation (CAD), and are also shown to fragment to a greater extent than corresponding singly charged porphyrin ions. Advantages and disadvantages of doubly charged porphyrin ion MS/MS for structure elucidation are discussed.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
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  • 10
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 23 (1988), S. 327-333 
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The unimolecular fragmentation reactions of 28 protonated nitroarenes, occurring on the metastable ion time-scale, are reported. In addition, the collision-induced fragmentation of the same species have been studied at 10 eV and at 50 eV collision energy. When an OH, COOH or NH2 substituent is ortho to the nitro function, the dominant fragmentation involves loss of H2O, for both unimolecular and collision-induced reactions. When there is an electron-releasing substituent ortho or para to the litro group, loss of OH is the dominant fragmentation reaction both on the metastable ion time-scale and for ions activated by collision. When the electron-releasing substituent is meta to the nitro group, loss of NO2 is the dominant low-energy unimolecular fragmentation reaction while loss of HNO2 is the most important fragmentation for ions activated by 50 eV collisions. Elimination of NO from [MH]+ occurs to a significant extent in the unimolecular fragmentation of protonated nitrobenzene and those protenated nitrobenzenes containing electron- attracting substituents. In the collision-induced dissociation of these species loss of HNO2 occurs at the expense of loss of NO. The results are consistent with protonation predominantly at the nitro group. The results are discussed in terms of the use of neutral loss scans in tandem mass spectrometry to monitor complex mixtures for nitroarenes.
    Zusätzliches Material: 3 Tab.
    Materialart: Digitale Medien
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