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  • 1990-1994  (20)
  • Cell & Developmental Biology  (16)
  • Organic Chemistry  (4)
  • Ethanol
  • 1
    Electronic Resource
    Electronic Resource
    Design and Synthesis of Novel Opiate Antagonists with LH-Stimulating Properties (1990)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 73 (1990), S. 326-336 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Opiate antagonists stimulate the release of LH and might, therefore, contribute to an innovative therapy for the treatment of numerous clinical syndromes characterized by hypofunction of the HHG axis. The purpose of this work was to design and synthesize pure opiate antagonists useful for this therapy. Me, Et, Pr, and PhCH2 groups were introduced at the crucial 14β-position of morphines and morphinans via a hetero-Diels-Alder key step starting from thebaine derivative 1 and tested for opiate antagonism and LH-stimulating activity. Me-, Et-, and Pr-substituted compounds 11a-c were stronger antagonists than naltrexone, whereas Pr and PhCH2 substituents in 11c, 11d, 9d, 9d3, 9d4, and 9d5 led to orally active LH stimulators. Based on our finding that the μ-antagonists 12 and 11b5 showed no LH stimulation, we conclude that a combination of both μ-and χ-antagonism is necessary for potent LH stimulation.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19900730212
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  • 2
    Electronic Resource
    Electronic Resource
    Reorganization of cytoskeletal and junctional proteins during cochlear hair cell degeneration (1991)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 18 (1991), S. 215-227 
    Details
    ISSN: 0886-1544
    Keywords: guinea pig ; organ of Corti ; cytokeratins ; actin ; cingulin ; phalangeal scar ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Experiments were carried out to elucidate changes in cytoskeletal elements and intercellular junctions in the organ of Corti, when hair cells degenerate and phalangeal scars form. Hair cell damage was induced by exposing guinea pigs to high intensity noise. The spatial and temporal changes in the organization of micro-filaments, intermediate filaments, and tight junction-specific proteins were investigated using scanning and transmission electron microscopy and histochemistry. The results show that microfilaments, cytokeratins, adherens junctions, and tight junctions rearrange their distribution in damaged areas. From the temporal sequence of these changes it appears that phalangeal scars develop simultaneous with hair cell degeneration, and that the integrity of the luminal membranes in the organ of Corti is not interrupted. Each scar is formed by two supporting cells which expand and invade the sub-apical region of the dying hair cell. This region becomes cytokeratin-positive. The two supporting cells meet at the mid-line of the scar, where a new junctional complex is formed. The junctional complex consists of tight junction and adherens-type junction, but desmosomes are absent.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970180307
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  • 3
    Electronic Resource
    Electronic Resource
    Metabolic regulation in mammalian sperm: Mitochondrial volume determines sperm length and flagellar beat frequency (1991)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 19 (1991), S. 180-188 
    Details
    ISSN: 0886-1544
    Keywords: spermatozoa ; cilia and flagella ; mechanochemical transduction ; dynein ; cell motility ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In the absence of glycolytic support, mammalian sperm derive their energy for motility from a densely packed array of mitochondria at the base of the flagellum known as the midpiece. Using data on the morphometric dimensions of over 200 mammalian species, we found that an allometric relationship exists between midpiece length (Lm) and flagellum length (Lf). Specifically, the length of the midpiece varies approximately as the 3/2 power of the flagellar length although the proportionality constant is different for eutherian and marsupial sperm. In contrast, when we corrected for the fraction of the midpiece that was taken up by mitochondria, a single linear correlation between mitochondrial volume and flagellar length for all mammals was found. These allometric relationships were used along with basic flagellar hydrodynamic theories to establish a unifying equation that predicted flagellar frequencies for any mammalian sperm between 40 μm and 200 μm in length. These findings imply that, at least in mammals, the mechanisms for energy production and dissipation in sperm flagella are highly conserved.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970190306
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  • 4
    Electronic Resource
    Electronic Resource
    Growth factors and wound repair (1991)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 46 (1991), S. 1-2 
    Details
    ISSN: 0730-2312
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcb.240460102
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  • 5
    Electronic Resource
    Electronic Resource
    Molecular physiology of amylin (1994)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 55 (1994), S. 19-28 
    Details
    ISSN: 0730-2312
    Keywords: amylin ; calcitonin ; CGRP ; cAMP ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Amylin is a 37-amino acid peptide first isolated, purified, and characterized from the amyloid deposits in the pancreases of type 2 diabetics. It is synthesized and secreted primarily from pancreatic beta cells along with insulin. The ability of amylin to potently reduce insulin-stimulated incorporation of glucose into glycogen in skeletal muscle requires both an intact 2Cys-7Cys disulfide bond and a COOH-terminal amide. Amylin has structural and functional relationships to two other messenger proteins, calcitonin and CGRP. Amylin has relatively potent calcitonin-like activity on bone metabolism and weaker CGRP-like activity on the vasculature. CGRP is a slightly weaker agonist than amylin for metabolic responses. Although rat calcitonins are weak, teleost fish calcitonins are very potent agonists for amylin's metabolic effects. This group of peptides appears to act on a family of related G protein-coupled receptors; several variant calcitonin receptors have recently been cloned and expressed. These receptors appear to be coupled to adenylyl cyclase in many instances; recent evidence supports the view that amylin's effects on skeletal muscle occur, at least in large part, through activation of the cAMP pathway. © 1994 Wiley-Liss, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcb.240550004
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  • 6
    Electronic Resource
    Electronic Resource
    Substrates and signalling complexes: The tortured path to insulin action (1992)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 48 (1992), S. 12-18 
    Details
    ISSN: 0730-2312
    Keywords: tyrosine kinases ; phosphatidylinositol kinases ; insulin receptor ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: In the last few years several potential substrates of the insulin receptor tyrosine kinase have been identified, purified, and their cDNAs isolated. These putative substrates include: (1) pp15, a fatty acid-binding protein; (2) pp120, a plasma membrane ecto-ATPase; (3) pp42, a MAP serine/threonine kinase; (4) pp85, a subunit of the Type 1 phosphatidylinositol kinase; and (5) pp185, a phosphatidylinositol kinase binding protein. Although the tyrosine phosphorylation of several of these substrates correlates with the signalling capabilities of various mutant receptors, the role of these substrates in mediating any one of insulin's many biological responses is still unknown. In addition, recent data indicate that the tyrosine phosphorylation of pp42 may in fact be due to autophosphorylation, thereby removing it from the list of putative substrates of the insulin receptor kinase. Finally, the present review discusses the question of whether signalling occurs as a result of the tyrosine phosphorylation of substrates or via the formation of signalling complexes.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcb.240480104
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  • 7
    Electronic Resource
    Electronic Resource
    Ambident reactivity of aryloxide ions towards 1,3,5-trinitrobenzene, low-temperature characterization of the elusive Oxygen-bonded σ-complexes by 1H and 13C NMR spectroscopy (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 71-82 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The ambident reactivity of phenoxide ion towards 1,3,5-trinitrobenzene (TNB) was re-examined by means of a novel reaction system(CD3CN-glyme-d10) which allows the investigation of species formed at low temperatures (-40°C), contrasting with previous studies in dimethyl sulfoxide (DMSO) at ambient temperature. The new method coupled with 400 MHz NMR spectroscopy has allowed the definitive observation of both O- and C-bonded phenoxide σ-complex adducts for the first time, confirming the formation of the former through kinetic control and of the latter through thermodynamic control. The corresponding O-bonded σ-adduct in the TNB-mesitoxide system (whereC-bonded σ-adduct formation is not possible but where there is competing nitro group displacement) has also been characterized by 1H and 13C NBR. Another O-bonded aryloxide adduct characterized is that from the reaction of TNB with3,5-di-tert-butylphenoxide; in this system there is also competing NO2 displacement. Stereoelectronic factors in the O-bonded σ-adducts and aryl ethers are discussed.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610060202
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  • 8
    Electronic Resource
    Electronic Resource
    Rat RIβ isoform of type I regulatory subunit of cyclic adenosine monophosphate-dependent protein kinase: cDNA sequence analysis, mRNA tissue specificity, and rat/mouse difference in expression in testis (1990)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 26 (1990), S. 129-133 
    Details
    ISSN: 1040-452X
    Keywords: Kinase isoforms ; Protein kinase A ; cAMP ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: A rat complementary DNA (cDNA) for the RIβ isoform of type I cyclic adenosine monophosphate (cAMP)-dependent protein kinase regulatory subunit was cloned and sequenced and was found to contain the entire protein coding and 3′-untranslated regions, with a single (ATTAAA) poly-adenylation site. The largest open reading frame was preceded by a short outof-phase open reading frame, which is not seen in the corresponding mouse RIβ cDNA due to a single base substitution. The rat RIβ cDNA clone was 2,374 bases long and detected a rat mRNA of approximately 2.8 kilobases. Rat RIβ mRNA was abundant in adult rat brain and testis but was undetectable in other rat tissues. The rat RIβ cDNA also detected RIβ mRNA in mouse brain, but not mouse testis, from 10-week-old BALB/c or 10- and 6-week-old Swiss Webster mice. Thus, despite a 96% nucleotide identity in the coding region of RIβ in rat vs. mouse, there are at least two differences in these closely related species. First, there is a short open reading frame, which precedes the coding region in the rat but not the mouse. Second, unlike the mouse testis, the rat testis contains abundant levels of RIβ mRNA.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080260206
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  • 9
    Electronic Resource
    Electronic Resource
    Galactosyltransferase activity is restricted to the plasma membranes of equine and bovine sperm (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 28 (1991), S. 74-78 
    Details
    ISSN: 1040-452X
    Keywords: Galactosyltransferase ; Sperm-egg binding ; Fertilization ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: β1, 4-Galactosyltransferase (GalTase) is localized to the plasma membrane of mouse sperm, in which it mediates the binding of sperm to glycoconjugate residues in the egg zona pellucida. In this study, the presence and subcellular distribution of sperm GalTase were determined in two other mammalian species that yield sufficient sperm for subecellular fractionation. Equine and bovine semen were collected, and the plasma membranes (PM), outer acrosomal membranes (OAM), and inner acrosomal membranes (IAM) were sequentially removed. The purities of the isolated membrane preparations were determined by transmission electron microscopy and found to be ≥90%, 96%, and 98% for equine PM, OAM, and IAM, respectively, and ≥80%, 94%, and 97% for bovine PM, OAM, and IAM, respectively. GalTase activity was assayed under optimal conditions in all membrane preparations and was preferentially localized to the isolated PM both in equine and in bovine spermatozoa. The selective localization of GalTase to the sperm PM in two other species suggest that it may serve as a generalized gamete receptor during initial sperm-egg binding in mammals.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080280112
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  • 10
    Electronic Resource
    Electronic Resource
    Evidence for the presence of an integrin cell adhesion receptor on the oolemma of unfertilized human oocytes (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 31 (1992), S. 215-222 
    Details
    ISSN: 1040-452X
    Keywords: RGD ; α5 ; Immunobeads ; Integrins ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The Arg-Gly-Asp peptide (RGD), contained in several extracellular matrix proteins such as fibronectin, laminin, vitronectin, and collagen, is a tripeptide that plays a role as a recognition sequence in many cell-to-cell and cell-to-matrix adhesion mechanisms, through its interaction with several receptors of the integrin family. We previously described the ability of the oolemma of hamster oocytes to bind GRGDTP coupled to the surface of activated immunobeads and demonstrated that RGD-containing oligopeptides inhibit the adhesion of human and hamster spermatozoa to zona-free hamster oocytes and their subsequent penetration. In the present experiments, we show, utilizing immunobeads coated with an RGD-containing peptide (PepTiteTM 2000), that the oolemma of unfertilized human eggs is also able to recognize this adhesion sequence. The binding of PepTiteTM 2000-coated immunobeads to the oolemma was inhibited by the oligopeptide GRGDTP as well as by fibronectin and laminin. When immunobeads were prepared with a PepTiteTM concentration of 10 μg/ml, GRGDTP 150 μg/ml, laminin 80 μg/ml, and fibronectin 60 μg/ml inhibited bead rosetting on the egg surface. These data suggest that a specific binding moiety for RGD is present on the human egg surface. The binding of fibronectin to the oolemma was also demonstrated by the rosetting of immunobeads coupled with antifibronectin antibody to human oocytes after their exposure to 1 mg/ml free fibronectin. Such binding of fibronectin to the oolemma could be inhibited by coincubation with a monoclonal antibody directed against the cell adhesion fragment of fibronectin. In addition, oolemmal rosetting of immunobeads coupled with a monoclonal antibody directed against the α5 subunit, usually part of the fibronectin receptor VLA 5 (α5β1), provided additional evidence that a putative fibronectin receptor is present on the oolemma of human eggs.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080310309
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