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  • 1
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Biopolymers 37 (1995), S. 67-88 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Since its initial discovery in 1982, growth hormone-releasing factor (GRF) has been the subject of intense investigation. This interest was prompted by the potential application of GRF for Stimulating growth in dwarf humans and for performance enhancement in livestock. Substantial research has been focused upon the development of potent, long-acting analogs as therapeutics. Herein is described a summary of the cumulative efforts of various laboratories endeavoring in this quest. The rationale utilized in GRF analog development is discussed: (1) determination of bioactive core. (2) evaluation of secondary structure, and (3) elucidation of degradation pathways (chemical and enzymatic). Using this information, several series of linear (unnatural and natural sequence) and cyclic GRF analogs were designed, synthesized, and evaluated. Stimulated by the constraints of commercial production, innovative, alternative methods of synthesis were explored: solid-phase, solution-phase, enzymatic, and recombinant. To date, the most promising candidate for drug development is [His1, Val2, Gln8, Ala15, Leu27]-hGRF(1-32)-OH. This natural sequence analog, consisting of rodent and human sequences, incorporates the bioactive core, preferred secondary structure, resistance to chemical and enzymatic degradation: with the added benefit of amenability to large-scale recombinant synthesis. © 1994 John Wiley & Sons, Inc.
    Additional Material: 9 Ill.
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  • 2
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Biopolymers 43 (1997), S. 339-366 
    ISSN: 0006-3525
    Keywords: growth factor receptors ; tyrosine kinase ; transforming growth factor - α ; epidermal growth factor ; neurotrophin ; nerve growth factor ; insulin growth factor ; insulin ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The focus of this review is the relationship between the three-dimensional structure of ligands of the various members of the growth factor receptor tyrosine kinase superfamily and their interaction with the cognate receptor. Particular attention is given to the transforming growth factor - α, epidermal growth factor (EGF); nerve growth factor, neurotrophin; and insulin-like growth factor - 1 (IGF-1), insulin systems since these have been extensively studied in recent years. The three receptor types, which bind these ligands, are the epidermal growth factor receptor family (erb B receptors), the neurotrophin or Trk receptor family, and IGF-1/insulin receptors, respectively, and represent three distinct members of the tyrosine kinase superfamily. For each of these, formation of the ligand-receptor complex initiates the signal transduction cascade through autophosphorylation by the intracellular tyrosine kinase domain. The extracellular portion of the receptor that contains the ligand binding domain in these systems varies significantly in organization in each case. For the EGF receptor system, ligand binding induces homo- and heterodimerization of the receptor leading to activation of the intracellular kinase. For the Trk receptor system, homodimerization of receptors has been shown to occur, although a second receptor, p75, is also required for high affinity binding of neurotrophins and for enhanced sensitivity of tyrosine kinase activation at low ligand concentrations. The IGF-1 and insulin receptors exist as covalent cross-linked dimers where each monomer is composed of two subunits.The aim of this review is also to discuss the mechanism of ligand-receptor interaction for each of these cases; however, since no structural information is yet available for the ligand-receptor complex, the discussion will largely be centered on the molecular requirements of ligand binding. As these receptors are activated through the ligand binding site on the extracellular domain, this represents a possible target for pharmacological intervention by inhibition or stimulation of this portion of the receptor. Thus from a drug design perspective, the focus of this review is to discuss progress in the development of agonists or antagonists of the ligand for these receptors. © 1998 John Wiley & Sons, Inc. Biopoly 43: 339-366, 1997
    Additional Material: 18 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 35 (1997), S. 1105-1124 
    ISSN: 0887-624X
    Keywords: liquid crystalline ; epoxy ; kinetic ; curing ; smectic ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The curing kinetics of a system containing 4,4′-diglycidyloxy-α-methylstilbene (DOMS) and different functionality amines, N-ethylaniline (NEA), aniline, benzenesulfonamide (BSA), and sulfanilamide (SAA), have been studied by differential scanning calorimetry (DSC) under isothermal conditions. The phase transformations during curing of the systems have been monitored by a crosspolarized optical microscope equipped with a hot-stage and photo detector. It has been found that the growth of a nematic liquid crystal structure does not cause a discrepancy from the autocatalytic model for the reactions between aniline and epoxy. There is no liquid crystalline structure formed for the systems containing NEA or BSA, which follow the autocatalytic kinetic models within the temperature range of 120-150°C. For the curing reactions between DOMS and SAA, there is a big deviation from the autocatalytic model when the liquid crystals transfer from a nematic structure to a smectic structure. Unlike the usual decrease of reaction rate resulting from diffusion in a heterogeneous reaction, the reaction rate is enhanced. A modified kinetic model has been constructed for this reaction system by introducing a pseudoconcentration term caused from the liquid crystalline structure formation. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 1105-1124, 1997
    Additional Material: 14 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 1457-1471 
    ISSN: 0887-624X
    Keywords: epoxy ; catalyst ; liquid crystalline ; kinetic ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Tetraalkylphosphonium-Tetrafluoroborate-Tetrafluoroboric Acid was used as a catalyst in the curing of a liquid crystalline epoxy. Under some conditions the Tetraalkylphosphonium-Tetrafluoroborate-Tetrafluoroboric Acid actually retarded the reaction. An extensive experimental and kinetic analysis is presented anda mechanism for the reaction retardation is proposed. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1457-1471, 1998
    Additional Material: 16 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 43 (1997), S. 157-165 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A semibatch flow scheduling strategy proposed by Teymour and Ray (1989, 1996) is evaluated for a polymerization reaction conducted in a pilot-plant reactor. The reaction used is the free radical terpolymerization of styrene, α-methyl styrene, and acrylic acid monomers initiated by an organic peroxide initiator and carried out in the presence of a reactive glycol ether solvent. This strategy was tested in both single batch and sequential semibatch modes. The process was shown to produce polymer of constant molecular weight properties and composition as inferred from acid number and monomer conversion measurements. This process could be used for obtaining polymer products from a semibatch reactor that are of comparable quality to CSTR products. Results indicate success of this process at meeting this objective; however, practical considerations relating to agitation and temperature control need to be properly addressed to ensure this success.
    Additional Material: 13 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 65 (1997), S. 299-304 
    ISSN: 0020-7608
    Keywords: Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In Article I, we showed that the freeon-exchange theory of magnetic coupling is a viable alternative to the widely used spin-exchange theory. In Article II, we are concerned with the symmetric-bridge, molecular magnet, AXB, where A and B are magnetic atoms and X is the bridge. The symmetric-bridge molecular magnet is of particular interest because the major features of its spectrum and its coupling constants are obtained by means of the two-electron, two-site freeon theory. We exhibit one example of ferromagnetic coupling, J〉0 and one of antiferromagnetic coupling, J〈0.   © 1997 John Wiley & Sons, Inc. Int J Quant Chem 65: 299-304, 1997
    Additional Material: 4 Ill.
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  • 7
    ISSN: 1040-0397
    Keywords: Glucose ; Biosensor ; Nafion ; Oxygen dependence ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We have prepared amperometric glucose sensitive electrodes with a composite active layer consisting of Nafion, glucose oxidase, and carbon-supported platinum particles. A particularly advantageous configuration results from the use of such a film on a gas diffusion electrode. We demonstrate that the gas diffusion electrode configuration enables us to supply oxygen from the back of the electrode, thus providing the capability of operating the sensor independent of dissolved oxygen. The insensitivity to solution oxygen concentration has been demonstrated by monitoring the glucose response of the electrode after extensive deoxygenation of solution. Cast composite layers yield mechanically robust coatings with high enzyme loadings, and thus high sensitivity to glucose. The electrode responds rapidly and is stable over a long period (90% activity after more than half a year) when stored in solution. We have optimized the composition of the sensitive layer with respect to Nafion to C/Pt ratio and enzyme loading.
    Additional Material: 7 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Bioluminescence and Chemiluminescence 13 (1998), S. 285-285 
    ISSN: 0884-3996
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: No abstract.
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 60 (1998), S. 560-567 
    ISSN: 0006-3592
    Keywords: phenol degradation ; Pseudomonas putida ; inhibition model ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A semiempirical model, based on the presence of an inhibitory intermediate metabolite excreted to the broth, was developed to better predict the dynamic responses to shock loadings of Pseudomonas putida Q5 degrading phenol. Compared to the Haldane equation, the new model exhibited better prediction capabilities for a broad range of inlet concentration and dilution rate step changes. The experiments were performed at 10° and 25°C and ranged from stable responses to washouts. The time delays observed experimentally were successfully predicted with the dual-inhibition model and a very good agreement with the observed phenol profile also was found in a pulse experiment. A possible intermediate metabolite was detected by HPLC analyses based on the high correlation shown with the predicted inhibitory intermediate metabolite in the model. © 1998 John Wiley & Sons, Inc. Biotechnol Bioeng 60: 560-567, 1998.
    Additional Material: 10 Ill.
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  • 10
    ISSN: 0730-2312
    Keywords: vitamin D3 analogs ; 24-oxo metabolites ; growth inhibition ; differentiation ; apoptosis ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The seco-steroid hormone, 1α,25 dihydroxyvitamin D3 (1α,25(OH)2D3) binds to a specific nuclear receptor that acts as a ligand-inducible transcription factor. The resulting genomic effects include partial arrest in G0/G1 of the cell cycle and induction of differentiation; these effects have been observed in various types of cancer. Recently, we produced enzymatically the natural 24-oxo metabolites of 1α,25(OH)2D3 and two of its potent synthetic analogs (1α,25-(OH)2-16-ene-D3 and 1α,25-(OH)2-20-epi-D3) using a rat kidney perfusion system. We have found that the 24-oxo metabolites of both 1α,25(OH)2D3 and its analogs have either the same or greater antiproliferative activity against various cancer cells as their parental compounds. Notably, two cell lines (DU-145 (prostate cancer) and MDA-MB-436 [breast cancer]) that were extremely resistant to the antiproliferative effects of vitamin D3 analogs displayed greater sensitivity towards the 24-oxo metabolite of the vitamin D3 analog. Similarly, the 24-oxo metabolites had the capacity to induce differentiation and apoptosis and to diminish the proportion of cells in S phase. Most interestingly, while the analog 1α,25(OH)2-20-epi-D3 induced expression of BRCA1 in MCF-7 breast cancer cells; its 24-oxo metabolite dramatically suppressed BRAC1 expression. Thus, we have shown for the first time that the various biological activities produced by the hormone 1α,25(OH)2D3 and some of its analogs may represent a combination of actions by the hormone 1α,25(OH)2D3 and its natural 24-oxo metabolites. J. Cell. Biochem. 66:413-425, 1997. © 1997 Wiley-Liss, Inc.
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