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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of hepato-biliary-pancreatic surgery 2 (1995), S. 249-254 
    ISSN: 1436-0691
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Cancer chemotherapy and pharmacology 38 (1996), S. 203-209 
    ISSN: 1432-0843
    Keywords: Key words Topoisomerase II poisons ; High-dose-chemotherapy ; Topoisomerase II rescue ; Etoposide effect regulation in vivo ; ICRF-187 ; ADR-529 ; Brain tumor model
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The catalytic cycle of topoisomerase II is the target of some of the most successful antitumor agents used today, e.g., etoposide (VP-16), in the treatment of testicular cancer and small-cell lung cancer. The cell kill mediated by topoisomerase II poisons can be antagonized by distinct drug types. Thus, we have demonstrated etoposide antagonism with the type-II anthracycline aclarubicin, the antimalarial drug chloroquine, and the cardioprotective agent ICRF-187. In other setups, combinations of agonist and antagonists have led to high-dose regimens for counteracting drug resistance. Thus, the exploitation of folinic acid rescue for methotrexate toxicity and the use of mesna to protect against cyclophosphamide toxicity have enabled the use of high-dose methotrexate and cyclophosphamide protocols. Using a similar approach, we have studied possible ways to apply antagonists to topoisomerase II poisons. NDF1-hybrid female mice were treated with the various drugs and drug combinations. Lethality (LD10 and LD50 values) was computed by use of the maximum-likelihood method, and the antitumor effect of the drugs was compared in mice inoculated i.p. with either L1210 cells or Ehrlich ascites tumor cells. In addition, the compounds were tested on L1210 cells inoculated intracranially. The toxicity of the various drugs was evaluated by weight and leukocyte counts. ICRF-187 rescues healthy mice from lethal doses of topoisomerase II poisons. In mice the ICRF-187 LD10 was 500 mg/kg. Within a wide nontoxic dose range (50–250 mg/kg) of ICRF-187 we found protection against m-AMSA and etoposide lethality. Thus, the LD10 of etoposide increased from 34 mg/kg for the single agent to 122 mg/kg for its combination with ICRF-187, corresponding to a 3.6-fold etoposide dose escalation. In contrast, ICRF-187 did not protect against lethal doses of the non-topoisomerase II-directed drug paclitaxel. We further investigated the antitumor effect of equitoxic schedules in mice inoculated i.p. with L1210 or Ehrlich ascites tumor cells. The L1210-bearing mice appeared to obtain a larger increase in life span from the etoposide and ICRF-187 combination as compared with etoposide alone, whereas this was not the case in mice inoculated with Ehrlich ascites tumor cells. As the hydrophilic ICRF-187 is not expected to cross the blood-brain barrier, in contrast to the lipophilic etoposide, we investigated the effect of the drug combination in mice inoculated intracranially with L1210 cells. We obtained a significant increase in life span in mice treated with ICRF-187 + etoposide as compared with mice treated with an equitoxic dose of etoposide alone. Thus, there appear to be potential routes by which one can benefit from this antagonism. ICRF-187 is a powerful nontoxic protector against the lethality of the topoisomerase II-directed drugs etoposide and m-AMSA in vivo. A brain tumor model demonstrates the superiority of high-dose etoposide treatment with ICRF-187 protection as compared with etoposide treatment alone. This implies that tumors in the brain can be reached by cytotoxic drug doses and that normal tissues can be protected due to differences in drug transport across the blood-brain barrier. ICRF-187 is therefore a promising lead compound for the development of schedules using high-dose topoisomerase II poisons in the treatment of brain tumors and metastases.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-2013
    Keywords: Key words Weak acid ; Smooth muscle ; pH ; Osmolarity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  In vitro both acetate and hyperosmolarity cause vasodilation, which could be physiologically important during food ingestion and during peritoneal dialysis. The purpose of this study was to investigate the role of the intracellular calcium concentration ([Ca2+]i, measured with fura-2), membrane potential (measured with glass microelectrodes) and intracellular pH [pHi, measured with bis-carboxyethylcarboxyfluorescein (BCECF)] in the vasodilation. Hyperosmolar sodium acetate (30 mM) concentration dependently relaxed noradrenaline-precontracted arteries. This response was associated with hyperpolarization and a fall in [Ca2+]i. In arteries precontracted with 50 mM K+ the relaxation was associated with a decrease of [Ca2+]i but no change in membrane potential. Isoosmolar sodium acetate neither relaxed or affect [Ca2+]i of K+-precontracted arteries, but induced a small relaxation with no reduction in [Ca2+]i in noradrenaline-precontracted arteries. Hyperosmolar acetate caused a transient reduction of pHi that was unrelated to relaxation. It is concluded that the mechanisms responsible for the relaxation to hyperosmolar acetate involve a decrease of [Ca2+]i, which is only partly explained by hyperpolarization and probably a decrease in the sensitivity of the contractile proteins to [Ca2+]i. pHi seems not to play a role in these effects.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1573-5001
    Keywords: 1H ; 13C and 15N assignments ; module-1 ; neural cell adhesion molecule
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1573-5001
    Keywords: 1H and 15N assignments ; module-2 ; neural cell adhesion molecule
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Journal of bioenergetics and biomembranes 27 (1995), S. 543-554 
    ISSN: 1573-6881
    Keywords: Oxidative phosphorylation ; respiration ; ATP ; fluxes ; Metabolic Control Analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract Strains carrying deletions in theatp genes, encoding the H+-ATPase, were unable to grow on nonfermentable substrates such as succinate, whereas with glucose as the substrate the growth rate of anatp deletion mutant was surprisingly high (some 75–80% of wild-type growth rate). The rate of glucose and oxygen consumption of these mutants was increased compared to the wild-type rates. In order to analyze the importance of the H+-ATPase at its physiological level, the cellular concentration of H+-ATPase was modulated around the wild-type level, using genetically manipulated strains. The control coefficient by the H+-ATPase with respect to growth rate and catabolic fluxes was measured. Control on growth rate was absent at the wild-type concentration of H+-ATPase, independent of whether the substrate for growth was glucose or succinate. Control by the H+-ATPase on the catabolic fluxes, including respiration, was negative at the wild-type H+-ATPase level. Moreover, the turnover number of the individual H+-ATPase enzymes increased as the H+-ATPase concentration was lowered. The negative control by the H+-ATPase on catabolism may thus be involved in a homeostatic control of ATP synthesis and, to some extent, explain the zero control by the H+-ATPase onE. coli growth rate.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Mental health services research 1 (1999), S. 125-157 
    ISSN: 1573-6636
    Keywords: Psychotherapy ; pharmacotherapy ; child ; adolescent ; mental health
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Decades of intervention research have produced a rich body of evidence on the effects of psychotherapies and pharmacotherapies with children and adolescents. Here we summarize and critique that evidence. We review findings bearing on the efficacy of psychosocial treatments and medications under controlled experimental conditions. We also report evidence, where available, on the effectiveness of both classes of treatment with clinically referred youth treated in real-world clinical contexts. In general, the large body of evidence on efficacy contrasts sharply with the small base of evidence on effectiveness. Addressing this gap through an enriched research agenda could contribute importantly to linking scientific inquiry and clinical practice—to the benefit of both ventures. This is one element of a multifaceted agenda for future research and for synthesis of research, which will require the interplay of multiple disciplines related to child and adolescent mental health.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Biopolymers 43 (1997), S. 303-322 
    ISSN: 0006-3525
    Keywords: peptide binding ; antigen presentation ; class II histocompatibility glycoproteins ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The immune system has evolved complex mechanisms for the recognition and elimination of pathogens. CD4+ helper T lymphocytes play a central role in orchestrating immune responses and their activation is carefully regulated. These cells selectively recognize short peptide antigens stably associated with membrane-bound class II histocompatibility glycoproteins that are selectively expressed in specialized antigen presenting cells. The class II - peptide complexes are generated through a series of events that occur in membrane-bound compartments within antigen presenting cells that, collectively, have become known as the class II antigen processing pathway. In the present paper, our current understanding of this pathway is reviewed with emphasis on mechanisms that regulate peptide binding by class II histocompatibility molecules. © 1997 John Wiley & Sons, Inc. Biopoly 43: 303-322, 1997
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 58 (1998), S. 191-195 
    ISSN: 0006-3592
    Keywords: control analysis ; Lactococcus lactis ; gene expression ; flux ; oligonucleotide ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In this article, we review some of the expression systems that are available for Metabolic Control Analysis and Metabolic Engineering, and examine their advantages and disadvantages in different contexts. In a recent approach, artificial promoters for modulating gene expression in micro-organisms were constructed using synthetic degenerated oligonucleotides. From this work, a promoter library was obtained for Lactococcus lactis, containing numerous individual promoters and covering a wide range of promoter activities. Importantly, the range of promoter activities was covered in small steps of activity change. Promoter libraries generated by this approach allow for optimization of gene expression and for experimental control analysis in a wide range of biological systems by choosing from the promoter library promoters giving, e.g., 25%, 50%, 200%, and 400% of the normal expression level of the gene in question. If the relevant variable (e.g., the flux or yield) is then measured with each of these constructs, then one can calculate the control coefficient and determine the optimal expression level. One advantage of the method is that the construct which is found to have the optimal expression level is then, in principle, ready for use in the industrial fermentation process; another advantage is that the system can be used to optimize the expression of different enzymes within the same cell. © 1998 John Wiley & Sons, Inc. Biotechnol Bioeng 58:191-195, 1998.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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