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  • 2005-2009
  • 1995-1999  (12)
  • 1980-1984  (1)
  • Chemistry  (7)
  • acetylHmb  (2)
  • fibril formation  (2)
  • in situ neutralisation  (2)
  • milk secretion  (2)
Materialart
Erscheinungszeitraum
Jahr
Schlagwörter
  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Journal of mammary gland biology and neoplasia 1 (1996), S. 307-315 
    ISSN: 1573-7039
    Schlagwort(e): Feedback inhibition ; pulse-chase protocol ; autocrine mechanism ; milk secretion
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Extracellular storage allows biologically-active substances in milk to influence mammary function. Among these factors is one which regulates the rate of milk secretion acutely according to frequency or completeness of milk removal in each mammary gland. The active factor in goat's milk has been identified by screening milk constituents for their ability to inhibit milk constituent secretion in tissue and cell culture bioassays, and found to be a novel milk protein. The proteins identified by bioassayin vitro, also inhibited milk secretion in lactating goats in a reversible, concentration-dependent manner. This protein, termed FIL (feedback inhibitor of lactation), acts by reversible blockade of constitutive secretion in the mammary epithelial cell. As the inhibitor is synthesized in the same epithelial cells, feedback inhibition is, therefore, an autocrine mechanism. FIL's unusual mechanism of action also influences other aspects of mammary function. Acute disruption of mammary membrane trafficking is associated with downregulation of prolactin receptors and followed by a decrease in epithelial cell differentiation. Thus, in addition to acutely-regulating milk secretion, FIL may induce the adaptation in mammary cell differentiation which actsin vivo to sustain the secretory response to a sustained change in milk removal. In the long term, matching of milk output to demand is achieved by a change in mammary cell number. This developmental response is also local in nature. Whether it too is due to autocrine modulation by FIL of mechanisms influencing cell proliferation or survival, or elicited by another milk-borne factor, remains to be determined.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Journal of mammary gland biology and neoplasia 1 (1996), S. 123-134 
    ISSN: 1573-7039
    Schlagwort(e): Mammary gland ; hormones ; growth hormone ; prolactin ; autocrine control ; milk secretion
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Milk secretion is regulated by a complex interaction of galactopoietic hormones which is not yet fully understood. Recent studies have demonstrated that this systemic control is modulated within the mammary gland by local mechanisms responsive to the frequency and completeness of milk removal. New insights into the endocrine and local (paracrine and autocrine) regulation of milk secretion have come from the adaptation of traditional endocrinological techniques to take advantage of new molecular tools, and from technical advances in other fields. This paper reviews recently developed animal models for the study of milk secretion and describes their application to provide new information into the roles of two key galactopoietic hormones, growth hormone and prolactin, and the modulation of their actions by local, intramammary mechanisms.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    ISSN: 1573-3904
    Schlagwort(e): amyloid ; circular dichroism ; ‘difficult sequence’ ; in situ neutralisation ; N-(2-hydroxy-4-methoxybenzyl) ; tetramethylfluoroformamidinium hexafluorophosphate
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A peptide corresponding to residues 106–126 of the human prion protein (PrP) possesses the neurotoxic and amyloidogenic properties of the infectious form of the parental protein. This peptide is now identified as a ‘difficult sequence’ and synthesis using conventional manual Fmoc chemistry was unsuccessful with acylation terminating at a central core of hydrophobic amino acids. The use of tetramethylfluoroformamidinium hexafluorophosphate and 1-methyl-2-pyrrolidone as anti-aggregatory agents in the coupling steps improved the synthesis but still resulted in an incomplete peptide. The incorporation ofN-(2-hydroxy-4-methoxybenzyl)protection at glycine residues 119 and 124 enabled synthesis of the full length peptide in low yield. Synthesis using Boc chemistry within situ neutralisation gave the full length peptide in high yield.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    ISSN: 1573-3904
    Schlagwort(e): amyloid ; circular dichroism ; 'difficult sequence' ; in situ neutralisation ; N-(2-hydroxy-4-methoxybenzyl) ; tetramethylfluoroformamidinium hexafluorophosphate
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract A peptide corresponding to residues 106-126 of the human prion protein (PrP) possesses the neurotoxic and amyloidogenic properties of the infectious form of the parental protein. This peptide is now identified as a 'difficult sequence' and synthesis using conventional manual Fmoc chemistry was unsuccessful with acylation terminating at a central core of hydrophobic amino acids. The use of tetramethylfluoroformamidinium hexafluorophosphate and 1-methyl-2- pyrrolidone as anti-aggregatory agents in the coupling steps improved the synthesis but still resulted in an incomplete peptide. The incorporation of N-(2-hydroxy-4-methoxybenzyl) protection at glycine residues 119 and 124 enabled synthesis of the full length peptide in low yield. Synthesis using Boc chemistry with in situ neutralisation gave the full length peptide in high yield.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    International journal of peptide research and therapeutics 6 (1999), S. 289-293 
    ISSN: 1573-3904
    Schlagwort(e): Aβ(1–40) ; acetylHmb ; circular dichroism ; electron microscopy ; fibril formation ; secondary structure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Modifications to secondary structure and fibril formation caused by multiple acetylHmb backbone amide protection of Alzheimer's disease Aβ(1–40) were investigated using circular dichroism spectroscopy and electron microscopy. Penta(acetylHmb) Aβ(1–40) was observed to have a reduced ability to form α-helix and β-sheet structures under the same solution conditions as the native peptide, with α-helical propensity being reduced more significantly than β-sheet propensity. Further, acetylHmb backbone protection was found to alter Aβ(1–40) interaction with SDS-micelles by preventing α-helix formation. Aβ fibril formation, a characteristic property of this peptide, was also not observed for penta(acetylHmb) Aβ(1–40).
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    International journal of peptide research and therapeutics 6 (1999), S. 289-293 
    ISSN: 1573-3904
    Schlagwort(e): Aβ(1-40) ; acetylHmb ; circular dichroism ; electron microscopy ; fibril formation ; secondary structure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Modifications to secondary structure and fibril formation caused by multiple acetylHmb backbone amide protection of Alzheimer's disease Aβ(1-40) were investigated using circular dichroism spectroscopy and electron microscopy. Penta(acetylHmb)Aβ(1-40) was observed to have a reduced ability to form α-helix and β-sheet structures under the same solution conditions as the native peptide, with α-helical propensity being reduced more significantly than β-sheet propensity. Further, acetylHmb backbone protection was found to alter Aβ(1-40) interaction with SDS-micelles by preventing α-helix formation. Aβ fibril formation, a characteristic property of this peptide, was also not observed for penta(acetylHmb)Aβ(1-40).
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1999 (1999), S. 1479-1488 
    ISSN: 1434-1948
    Schlagwort(e): Phosphorus heterocycles ; Cations ; Tungsten complexes ; Coordination modes ; Phosphaalkenes ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The 1,1,3-tris(diisopropylamino)diphosphirenium salt 1 reacts with lithium aluminium hydride leading to the P-hydrogeno-C-phosphinophosphaalkenes 2, which on treatment with a catalytic amount of BF3·OEt2 afford the 1,3-bis(diisopropylamino)-1H-diphosphirene 3. The corresponding η1-coordinated 1H-diphosphirene 6 can be prepared by treatment of 2 or 3 with one equivalent of [W(CO)5(thf)]. Alternatively, the diphosphirenium salt 1 reacts with an excess of [W(CO)5(thf)], affording the corresponding η1-coordinated diphosphirenium salt complex 4, which is converted into the P-hydrogenophosphaalkene complex 5 with lithium aluminium hydride. The dinuclear tungsten complexes 7 and 8 are obtained by treatment of the free 1H-diphosphirene 3 with two equivalents of [W(CO)5(thf)] or one equivalent of [W(CO)4(thf)2], respectively. Compound 6 reacts with two equivalents of hydrogen chloride, giving the 1-chloro-3-diisopropylamino-1H-diphosphirene 9, which can be subsequently converted into the 1-diisopropylamino-, 1-azido, or 1-phenyl-3-diisopropylamino-1H-diphosphirenes 6, 10 and 11 by nucleophilic substitution with diisopropylamine, azidotrimethylsilane or sodium tetraphenylborate, respectively. The [η2-(3-diisopropylaminodiphosphirenylium salt)·W(CO)5] complexes 12a-c can be prepared by reaction of 9 with silver trifluoromethanesulfonate, aluminium or gallium trichloride or, alternatively, by treatment of 6 with two equivalents of trifluoromethanesulfonic acid. Reaction of 12a with diisopropylamine, water, bis(triphenylphosphoranylidene)ammonium chloride or tetrabutylammonium fluoride gives the corresponding 1H-diphosphirene complexes 6, 13, 9, or 14, respectively. Compound 12a also reacts with one or two equivalents of [W(CO)5(thf)], leading to the di- and tri-nuclear complexes 15and 16, respectively.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 8
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 42 (1998), S. 587-596 
    ISSN: 0021-9304
    Schlagwort(e): gene therapy ; immunoisolation ; human growth hormone ; β-glucuronidase ; factor IX ; Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: Microencapsulation of recombinant “universal” cells with immunoprotective membranes is an alternate approach to somatic gene therapy. Therapeutic gene products secreted by these cells can be delivered to different patients without immunosuppression or genetic modification of the host's cells. The encapsulation of different mammalian cell types (epithelial cells, fibroblasts, and myoblasts) is compared among three alginate-based microcapsules: (1) calcium-linked alginate microcapsules with a solubilized core and a poly-L-lysine-alginate-laminated surface; (2) barium-linked alginate beads with a gelled core; and (3) a hybrid formulation of barium-linked alginate beads with a poly-L-lysine-alginate-laminated surface. The mechanical stability of the different microcapsule types, as measured with a cone-and-plate shearing apparatus, was superior in the two barium-linked alginate beads. All cell types maintained high viability (65-90%) in culture after encapsulation. The recombinant gene products secreted by these cells (human growth hormone MW = 22,000, human factor IX MW = 57,000, and murine β-glucuronidase MW = 300,000) were able to traverse the three microcapsule types at similar rates. Cell numbers within the microcapsules increased twofold to 〉 20-fold over 4 weeks, depending on the cell type. Epithelial and myoblast cell numbers were not affected by microcapsule formulation; however, fibroblasts proliferated the most in the calcium-linked alginate spheres. These results show that for culturing fibroblasts in a mechanically stable environment the classical calcium-linked microcapsules are adequate. However, where mechanical stability is a more critical requirement, the solid barium-linked gelled beads are more appropriate choices. © 1998 John Wiley & Sons, Inc. J Biomed Mater Res, 42, 587-596, 1998.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 9
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Cell Biochemistry and Function 1 (1983), S. 55-63 
    ISSN: 0263-6484
    Schlagwort(e): Carbon tetrachloride ; liver damage ; promethazine ; free radicals ; lipid peroxidation ; hepatoprotective agents ; Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The effects of promethazine (PM) on different aspects of the hepatotoxic action of CCl4 in the rat were investigated with the objective of finding rapid and reliable indicators of hepatoprotective effects. The study was based on definitive histological assessment of liver damage caused by CCl4 in the presence and absence of PM: PM (78 μmol kg-1, i.p.) protected against CCl4-induced hepatic necrosis 24 h after a low dose of CCl4 (1.3 mmol kg-1) but not against a higher dose (13.0 mmol kg-1). The large increases in plasma activities of GOT, GPT and LDH produced by dosing with CCl4 were partially inhibited by the administration of PM. PM and CCl4 caused a synergistic and long-lasting decrease in body temperature (2-3°C for 8-10 h). Modifying the toxicity with PM, together with a low dose of CCl4, helped to minimize secondary effects of CCl4, to clarify the sequence of toxic events, and to assess the sensitivity of some standard tests of hepatotoxicity. Simultaneous measurement of over 20 commonly used biochemical screening tests in individual animals 3 or 6 h after treatment permitted direct correlation of a wide variety of concentrations, activities and effects. For example, liver CHCl3 concentrations (as a measure of CCl4 metabolism) correlate strongly with increases in diene conjugation of microsomal lipids (as a measure of CCl4-induced lipid peroxidation); malonaldehyde production appears to be less sensitive as a measure of lipid peroxidation in vivo than diene conjugation. The changes induced in each parameter and the correlations between them are discussed with reference to the overall nature of the hepatotoxic reaction and its modification by PM.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 10
    ISSN: 0044-8249
    Schlagwort(e): Carbonsäuren ; Clathrate ; Kristall-Engineering ; Wasserstoffbrücken ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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