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  • Electronic Resource  (2)
  • Adrenergic mechanisms  (1)
  • Electropolymerization  (1)
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  • Electronic Resource  (2)
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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    European archives of oto-rhino-laryngology and head & neck 252 (1995), S. 298-303 
    ISSN: 1434-4726
    Keywords: Nasal mucosa ; Adrenergic mechanisms ; β2-agonist ; β3agonist ; Propranolol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In thiopentone-anesthetized mature pigs (n = 7), local intra-arterial infusion of the β2-adrenoceptor agonists terbutaline and salbutamol and the β3-agonist BRL 37344 induced dose-dependent increases in nasal arterial blood flow (BF) and volume of the nasal mucosa (reflecting capacitance vessel function). Increases were also found in the laser Doppler flowmeter signal, reflecting superficial mucosal BE. In contrast to terbutaline and salbutamol, BRL 37344 showed marked effects on volume. Pretreatment with the β-adrenoceptor blocker propranolol significantly reduced the vasodilatory effects of terbutaline and salbutamol, whereas the BF increase evoked by BRL 37344 was not affected. Exogenous noradrenaline (NA) induced in vitro dose-dependent contractions of human nasal mucosa biopsies obtained from patients with non-allergic chronic rhinitis (n = 21) or non-allergic nasal polyposis (NANP, n = 16). On a molar basis, the contractile effect of NA was significantly greater in nasal mucosa samples without histological abnormalities when compared to biopsies with abundant inflammatory cells and edema within the submucosa. In the presence of propranolol, the vasoconstrictor effect of NA was significantly enhanced in biopsies with abundant inflammatory cells obtained from patients with NANP (P〈0.01). This observation suggests the possible occurrence of a β2 hyper-reactivity in the nasal mucosa of patients with NANP. After precontraction in a Krebs-Ringer solution with 50 nM K+, all nasal biopsies studied showed dose-dependent relaxation to terbutaline, salbutamol and BRL 37344. This relaxant effect was markedly reduced after pretreatment with propranolol. These observations suggest that β2- and β3-adrenergic vasodilatatory mechanisms may be similar in the nasal mucosa of the pig and man.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1572-9001
    Keywords: Electropolymerization ; frontier orbital modeling ; poly(dialkoxybenzene)s ; conductive polymers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A modeling strategy, based on (i) quantum semiempirical calculation of the electronic structure of the successive intermediate oligomers and (ii) evaluation of the activation energy of the successive coupling reactions by use of the frontier orbital model, has been used to study the growth of a wide set of conductive polymers and is illustrated with poly(1,2-dialkoxybenzene) and poly(1,4-dialkoxybenzene) generated by electrochemical oxidation of the corresponding monomer. These monomers have been chosen because they are known to yield polymers of completely different structures. The strategy, which is designed to be as little computer time-consuming as possible, allows us to predict a growth trend in agreement with the structure inferred from spectrochemical experiments. In the case of poly(1,2-dialkoxybenzene) it suggests the formation of a cyclic tetramer as a byproduct detected in small quantities by means of MALDI spectroscopy. This modeling strategy allows one to describe the electronic modifications induced by the growth of a highly conjugated structure. It suggests that oxidation of the successive oligomers at high doping level and quinonic deformation are key factors for the growth of long and regular polymer structures
    Type of Medium: Electronic Resource
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