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  • 1
    ISSN: 1520-5010
    Quelle: ACS Legacy Archives
    Thema: Medizin
    Materialart: Digitale Medien
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  • 2
    ISSN: 1520-5010
    Quelle: ACS Legacy Archives
    Thema: Medizin
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    ISSN: 1520-5126
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
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  • 4
    ISSN: 1520-5126
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Archives of toxicology 63 (1989), S. 238-243 
    ISSN: 1432-0738
    Schlagwort(e): 1,2,2-Trimethylpropyl dimethylphosphinate ; Analysis ; Soman simulant ; Pharmacokinetics ; Soman ; Partition coefficients
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The soman simulant 1,2,2-trimethylpropyl dimethylphosphinate (PDP) antagonizes the therapeutic complications due to persistence of the nerve agent 1,2,2-trimethylpropyl methylphosphonofluoridate (soman) in rats. Using [13D]PDP or 1,2-dimethylpropyl dimethylphosphinate as an internal standard, we developed a gas chromatographic procedure for the analysis of PDP in aqueous solution and in blood samples. This procedure was used to investigate the pharmacokinetics of PDP in anaesthetized rats at intravenous doses of 2.0 and 0.6 mg/kg. The blood concentrations measured over a 420-min period can be described by a two-compartment open model with a rapid distribution phase (t1/2 = 4.3 min) and a rather slow elimination phase (t ss 1/2 = 2–3 h). The kinetics are approximately linear with dose. Under “steady state conditions”, PDP distributes evenly over the central and peripheral compartment (V dss = l.1–1.5 1.kg−1). At most 0.7% of intact PDP is renally excreted, which indicates that it is extensively metabolized. Since the partition coefficients (20° C) over n-octanol and water of PDP and soman are in the same range, i.e., 12 and 60, respectively, the much more rapid decrease in blood levels of C(±)P(−)-soman compared to PDP must be due to metabolic pathways of soman which are not available for PDP. At comparable doses, the blood level of PDP is initially 1 order of magnitude higher than that of C(±)P(−)-soman. This ratio increases in the course of 420 min to 4 orders of magnitude. Therefore, the kinetic conditions for which soman simulants were designed, i.e., to displace soman from reversible binding sites by means of a “mass effect”, are clearly fulfilled. However, hitherto unidentified effects other than competition between PDP and C(±)P(−)-soman for binding sites may also contribute to the beneficial effects of PDP pretreatment in soman intoxication.
    Materialart: Digitale Medien
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  • 6
    ISSN: 1432-0738
    Schlagwort(e): Key words Sulphur mustard  ;  Adducts  ;  Haemoglobin ; LC tandem MS  ;  Multiple reaction monitoring
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract As part of a program to develop methods for the verification of alleged exposure to sulphur mustard, we synthesized and characterized three amino acid adducts presumably formed by alkylation of haemoglobin: 4-(2-hydroxyethylthioethyl)-l-aspartate, 5-(2-hydroxyethylthioethyl)-l-glutamate and N1- and N3-(2-hydroxyethylthioethyl)-l-histidine. Suitable derivatization methods for GC/MS analysis were developed for these adducts as well as for the cysteine and the N-terminal valine adduct. Incubation of human blood with [35S]sulphur mustard in vitro followed by acidic hydrolysis of isolated globin and derivatization with Fmoc-Cl afforded three major radioactive peaks upon HPLC analysis, one of which coeluted with the synthetic Fmoc derivative of N1/N3-(2-hydroxyethylthioethyl)-l-histidine. After pronase digestion of globin the adducts of histidine, glutamic acid, aspartic acid, cysteine and N-terminal valine could be tentatively identified and quantitated. Final identification was obtained from GC/MS analysis. The most abundant adduct, N1/N3-(2-hydroxyethylthioethyl)-l-histidine, could not be sensitively analysed by GC/MS. A convenient LC-tandem MS procedure was developed for this compound, enabling the detection of exposure of human blood to 10␣μM sulphur mustard in vitro.
    Materialart: Digitale Medien
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  • 7
    ISSN: 1432-0738
    Schlagwort(e): Key words Chemical warfare agents ; LC tandem MS ; Multiple reaction monitoring ; O-isopropyl methylphosphonic acid ; Sarin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract A convenient and rapid micro-anion exchange liquid chromatography (LC) tandem electrospray mass spectrometry (MS) procedure was developed for quantitative analysis in serum of O-isopropyl methylphosphonic acid (IMPA), the hydrolysis product of the nerve agent sarin. The mass spectrometric procedure involves negative or positive ion electrospray ionization and multiple reaction monitoring (MRM) detection. The method could be successfully applied to the analysis of serum samples from victims of the Tokyo subway attack and of an earlier incident at Matsumoto, Japan. IMPA levels ranging from 2 to 135 ng/ml were found. High levels of IMPA appear to correlate with low levels of residual butyrylcholinesterase activity in the samples and vice versa. Based on our analyses, the internal and exposure doses of the victims were estimated. In several cases, the doses appeared to be substantially higher than the assumed lethal doses in man.
    Materialart: Digitale Medien
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  • 8
    ISSN: 1432-0738
    Schlagwort(e): C(±)P(±)-Soman ; Toxicokinetics ; 2-(o-cresyl)-4H-1∶3∶2-benzodioxaphosphorin-2-oxide ; CBDP ; Carboxylesterase ; Rat ; Guinea pig ; Marmoset
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Pretreatment of rats and guinea pigs with the specific carboxylesterase inhibitor 2-(o-cresyl)-4H-1 ∶ 3 ∶ 2-benzodioxaphosphorin-2-oxide (CBDP) reduces the LD50 of the nerve agent C(±)P(±)-soman in these species to the same range as in primates. This suggests that such CBDP-pretreated animals can be used in investigations that are relevant for prophylaxis and therapy of intoxication with C(±)P(±)-soman in primates including humans. In order to test this hypothesis we have studied the toxicokinetics of the toxic C(±)P(−)-isomers of soman in artificially respirated and CBDP-pretreated rats and guinea pigs at intravenous doses corresponding to 6 × LD50. A comparison of the areas under the curve (AUCs) of the blood levels of C(±)P(−)-soman in pretreated and non-pretreated animals at the same absolute dose shows extreme nonlinearity with dose, indicating that CBDP occupies highly reactive binding sites which are no longer available for sequestration of the soman isomers. The AUCs of C(±)P(−)-soman at equitoxic doses of 6× LD50 are reduced by pretreatment with CBDP from 1683 to 464 ng.min.ml−1 in rats and from 978 to 176 ng.min.ml−1 in guinea pigs, which is in the range of the AUC in non-pretreated marmosets at an equitoxic dose (419 ng.min.ml−1). The blood levels of the C(±)P(−)-isomers in marmosets and CBDP rats are rather similar during the first 7 min, but persist in CBDP rats for 2 h longer at toxicologically relevant levels than in marmosets. The levels of C(±)P(−)-soman in CBDP-pretreated guinea pigs are substantially lower than in marmosets for an initial period of 80 min. Nevertheless, they drop below toxicologically relevant levels approximately 50 min later than in marmosets. Evidently, one should be cautious in considering CBDP, pretreated rats and guinea pigs as substitute primates.
    Materialart: Digitale Medien
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  • 9
    ISSN: 1432-0738
    Schlagwort(e): Key words Physiologically based model  ;   C(±)P(±)-soman  ;  Stereoisomers  ;  Toxicokinetics  ;   Guinea pig
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract A physiologically based model was developed which describes the in vivo toxicokinetics of the highly reactive nerve agent C(±)P(±)-soman at doses corresponding to 0.8–6 LD50 in the atropinized guinea pig. The model differentiates between the summated highly toxic C(±)P(−)-soman stereoisomers at supralethal doses and the individual nontoxic C(±)P(+)-isomers. Several toxicant-specific parameters for the soman stereoisomers were measured in guinea pig tissue homogenates. Cardiac output and blood flow distribution were measured in the atropinized, anesthetized, and artificially ventilated guinea pig. The model was validated by comparison of the time courses for the blood concentrations of the two pairs of stereoisomers in the guinea pig after i.v. bolus administration with the blood concentrations predicted by the model. The predictions put forward for the summated C(±)P(−)-isomers are in reasonable agreement with the experimental data obtained after doses corresponding to 2 and 6 LD50. In view of large differences in the rates of hydrolysis of the C(±)P(+)-isomers, these two isomers had to be differentiated for satisfactory modeling of both isomers. In order to model the toxicokinetics of C(±)P(−)-soman at a dose of 0.8 LD50, the almost instantaneous elimination of the C(+)P(−)-isomer at that dose had to be taken into account. The sensitivity of the predictions of the model to variations in the parameters has been studied with incremental sensitivity analysis. The results of this analysis indicate that extension to a model involving four individual stereoisomers is desirable in view of large differences in the biochemical characteristics of the two C(±)P(−)- and C(±)P(+)-isomers.
    Materialart: Digitale Medien
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  • 10
    Digitale Medien
    Digitale Medien
    Springer
    Archives of toxicology 49 (1982), S. 175-183 
    ISSN: 1432-0738
    Schlagwort(e): Acetylcholinesterase ; Methamidophos ; Phosphoramidates ; Reactivation ; Inhibition ; Oximes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Reactivation of electric eel acetylcholinesterase (AChE) inhibited by MeO(NH2)P(O)SMe (methamidophos) and by MeS(NH2)P(O)SMe was studied at pH 7.5 and 25° C. The former inhibited enzyme shows a rather rapid spontaneous reactivation (t1/2=3.7 h); this reactivation is accelerated by 1 μM of the bispyridinium oximes TMB4 and obidoxime, and, to a lesser extent, by the monopyridinium oximes P2S and its 1-benzyl analogue (benzyl-P2A). The latter inhibited enzyme shows rapid aging (t1/2=0.6 h). Reactivation with 1 mM of the bispyridinium oximes is incomplete and reactivation with 1 mM of the monopyridinium oximes proceeds very slowly. These large differences between the properties of the two inhibited enzymes indicate that the methylthio group is the leaving group during inhibition of AChE by methamidophos. Additional support is afforded by the observation of induced aging of the former inhibited enzyme by thiourea. Upon comparison of the reactivation of AChE inhibited by methamidophos with that of AChE inhibited by an N-methyl analogue, cruf ornate, and an N,N-dimethyl analogue, tabun, it appears that the rate of spontaneous reactivation decreases with increasing alkylation of the P-NH2 group. Whereas benzyl-P2A is somewhat less active than P2S for reactivation of AChE inhibited by methamidophos, it is superior to P2S for reactivation of AChE inhibited by crufomate and also superior to P2S and to the bispyridinium oximes for AChE inhibited by tabun.
    Materialart: Digitale Medien
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