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  • 1
    Electronic Resource
    Electronic Resource
    Determining specific biomass activity in anaerobic wastewater treatment processes (1992)
    Springer
    Bioprocess and biosystems engineering 8 (1992), S. 55-60 
    Details
    ISSN: 1432-0797
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract An experimental method for the measurement of specific gas production rate was developed and tested with biomass samples taken from anaerobic fluidized bed reactors, operating with a variety of carriers with molasses, condensate from cellulose production and brewery wastewater as feeds. The method is based on reactor sampling and offline gas volume measurement during a known time interval. Important factors are biomass and liquid sampling under oxygen-free conditions, using the liquid from the reactor as substrate, providing sufficient mixing and maintaining the physical integrity of the biomass. The method was developed in such a way that small samples (20 ml) were taken under anaerobic conditions (poising agent) for short-term (2–3 min.) gas rate measurements in a small fluidized bed (25 ml) batch reactor with U-tube. Biomass content was measured by an instrumental nitrogen method (Dumas), followed by weight determination of the carrier. The gas rates measured with the test system, and their dependence on substrate concentration, were in good agreement with those directly measured from the continuous fluidized bed reactor. Additions of molasses and acetate to the sample proved that the influence of concentration on the biomass activity can be obtained only by operating the continuous reactor at the concentration levels of interest. Comparison between the reactors showed large differences in the specific activity and the total reactor activity. It was found when comparing two reactors, that the values of the specific and the total activities permitted the calculation of the relative biomass quantities. In this way the influence of the carrier-type could be evaluated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00369264
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  • 2
    Electronic Resource
    Electronic Resource
    Mechanism of action of the nonlipophilic antiallergic drug eclazolast (REV 2871) in the inhibition of mediator release in a mast cell model (1999)
    Springer
    Inflammation research 48 (1999), S. 569-574 
    Details
    ISSN: 1420-908X
    Keywords: Key words: RBL-2H3 — Exocytosis — Eclazolast — Calcium — Antiallergic
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. Objective and Design: In this study, we compared eclazolast with other lipophilic antiallergic drugs, relating to effects on signal transduction pathways, leading to inhibition of exocytosis in a rat basophilic leukemia cell (RBL-2H3). ¶Materials and Methods: Effects of the drugs on mediator release (β-hexosaminidase, arachidonic acid metabolites) after FcεRI activation in RBL-2H3 cell were quantified. Furthermore, effects of the drugs on cellular signalling (Ca2+ influx, intracellular Ca2+ concentration, inositol 1,4,5-trisphosphate (IP3) concentration) were assayed. Effects of the drugs on bilayer and cell membranes have been recorded. ¶Results: It is shown that eclazolast down-regulates IP3 levels. In contrast to lipophilic drugs, eclazolast does not affect artificial bilayers and erythrocyte membranes, and there is no effect on thapsigargin induced Ca2+ influx. The effect of eclazolast was highly dependent on the antigen concentration with which the cells were triggered. ¶Conclusions: The mechanism of action of eclazolast is deviant from lipophilic antiallergic agents. It inhibits exocytosis by intracellularly affecting only direct FcεRI linked processes and not through inhibition of Ca2+ influx channels, as found for membrane disturbing lipophilic drugs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s000110050505
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  • 3
    Electronic Resource
    Electronic Resource
    Relation between effects of a set of anti-allergic drugs on calcium pathways and membrane structure in Fc∈RI activated signal transduction (1996)
    Springer
    Inflammation research 45 (1996), S. 564-573 
    Details
    ISSN: 1420-908X
    Keywords: RBL-2H3 ; Fc∈RI ; Membrane ; Protein tyrosine phosphorylation ; Calcium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The antigen induced stimulation of mast cells by aggregation of Fc∈RI receptors activates a signal transduction cascade leading to release of mediators of inflammation like histamine, arachidonic acid metabolites and cytokines. In this study we investigated a series of structurally related anti-allergic drugs, containing a common lipophilic diphenylmethyl piperazinyl tail and head groups that differ in lipophilicity. Effects of these drugs on various steps of the signal transduction cascade was investigated to gain insight into the mechanism of action of these drugs. It appeared that addition of the drugs to resting cells induced changes in the tyrosine phosphorylation of cellular proteins. The most active anti-allergics in inhibiting exocytosis, AL3264 and oxatomide, also induced the largest changes in phosphorylation. The effects of the drugs on tyrosine phosphorylation after cell activation was complex. Additionally, Ca2+ fluxes were investigated. Ca2+ efflux from the cells was negligibly influenced by the active drugs. However, the drugs inhibited influx from extracellular Ca2+, which was correlated with the effects of the drugs on inhibition of exocytosis and on membrane stabilization induced by the drugs, measured as haemolysis of erythrocytes. It is concluded that inhibition of Ca2+ influx is the major mechanism with which these drugs inhibit exocytosis and that for this effect drug-membrane interactions, possibly affecting the function of membrane embedded proteins, are of importance. Possible mechanisms including drug-membrane interactions, phosphorylation and inhibition of Ca2+ influx are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02342228
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  • 4
    Electronic Resource
    Electronic Resource
    Inhibition of mediator release in RBL-2H3 cells by some H1-antagonist derived anti-allergic drugs: Relation to lipophilicity and membrane effects (1995)
    Springer
    Inflammation research 44 (1995), S. 92-97 
    Details
    ISSN: 1420-908X
    Keywords: RBL-2H3 ; Exocytosis ; Lipophilicity ; DSC ; Membrane
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In a model for mucosal mast cells (RBL-2H3 cells) a set H1-antagonist derived anti-allergic drugs containing a diphenylmethyl piperazinyl moiety was examined for their ability to inhibit release of the mediatorβ-hexosaminidase. Cells were activated with antigen or the calcium ionophore A23187, whether or not in combination with the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA). Oxatomide, hydroxyzine and cetirizine inhibit the antigen inducedβ-hexosaminidase release. The release triggered by A23187, whether or not in combination with TPA is hardly influenced by the compounds. A biphasic dependence of the inhibition of exocytosis in RBL cells on lipophilicity is observed with the optimum at log P is 5–6. The extremely lipophilic compounds meclozine and buclizine are not active in this model. pH dependence of the effect of the drugs shows that especially the uncharged species are active in inhibiting exocytosis. The investigated compounds show an effect on phase transitions in L-α-phosphatidylcholine dipalmitoyl liposomes as assayed with differential scanning calorimetry (DSC). For the less extremely lipophilic compounds the induced changes in the phospholipid membranes increased with lipophilicity. The relation between structural features of the drug and the interaction with phospholipids is discussed in view of the DSC results. We conclude that location of the active drugs at the membrane or the membrane/protein interface is important for the inhibiting activity on exocytosis. This could affect several membrane related processes, which are abundant in the early phases of the IgE-mediated signal transduction process.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01793220
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  • 5
    Electronic Resource
    Electronic Resource
    Abstracts of papers Medicinal chemistry meeting (1989)
    Springer
    Pharmacy world & science 11 (1989), S. M1 
    Details
    ISSN: 1573-739X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02196049
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  • 6
    Electronic Resource
    Electronic Resource
    Degradation products of the promethazine radical cation (1985)
    Springer
    Pharmacy world & science 7 (1985), S. 121-124 
    Details
    ISSN: 1573-739X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The degradation products of the promethazine radical cation, generated from promethazine with horseradish peroxidase/H2O2, have been investigated. Several products have been identified which resulted from fission of the bond between the two ethanamine carbon atoms of the N10 side chain. The main product (approx. 90%) was identified as 10-formyl-5-oxophenothiazine. The likely structure of three minor products was also elucidated. The degradation of the promethazine radical cation is different from that of radical cations derived from the propanamine side chain containing phenothiazine drugs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01968714
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  • 7
    Electronic Resource
    Electronic Resource
    Abstracts of Dutch PH.D. Theses (1981)
    Springer
    Pharmacy world & science 3 (1981), S. 598-601 
    Details
    ISSN: 1573-739X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02193225
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  • 8
    Electronic Resource
    Electronic Resource
    De rol van singulet zuurstof bij de fotosensibiliserende werking van furocoumarinen (1981)
    Springer
    Pharmacy world & science 3 (1981), S. 641-647 
    Details
    ISSN: 1573-739X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02193236
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  • 9
    Electronic Resource
    Electronic Resource
    Adsorption toxischer Schocks auf verschiedenartigen Trägermaterialien in anaeroben Biofilm-Fließbettreaktoren (1992)
    Weinheim : Wiley-Blackwell
    Chemie Ingenieur Technik - CIT 64 (1992), S. 878-878 
    Details
    ISSN: 0009-286X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cite.3306409164
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