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  • 1
    Electronic Resource
    Electronic Resource
    Desensitization of the epidermal adenylate cyclase system: agonists and phorbol esters desensitize by independent mechanisms
    Amsterdam : Elsevier
    Biochimica et Biophysica Acta (BBA)/Molecular Cell Research 1093 (1991), S. 95-101 
    Details
    ISSN: 0167-4889
    Keywords: (Pig epidermis) ; Adenylate cyclase ; Agonist ; Desensitization ; Phorbol ester
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Medicine , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1016/0167-4889(91)90143-L
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Experimental conditions for the development of persistent otitis media with effusion (1990)
    Springer
    European archives of oto-rhino-laryngology and head & neck 247 (1990), S. 89-92 
    Details
    ISSN: 1434-4726
    Keywords: Otitis media with effusion ; Eustachian tube dysfunction ; Escherichia coli endotoxin ; Animal experiment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The purpose of this study was to investigate sufficient conditions for the development of long-lasting otitis media with effusion (OME) without any organic obstruction of the eustachian tube. Three experimental conditions were employed using 20 adult cats (27 ears). Only tubal ventilatory dysfunction with transection of the tensor veli palatini muscle and excision of the pterygoid hamulus resulted in a small incidence of OME (7.1%), which lasted for 5 weeks. Instillation of Escherichia coli endotoxin into the middle ears formed only a transient OME in 50% of the animals. Combination of these two procedures brought a high incidence of OME (85.7%), most of which lasted for more than 8 weeks. These studies showed that tubal ventilatory dysfunction alone was not a sufficient condition for the development of OME but was important for prolongation of the pathological state of OME. The production of inflammatory exudate was considered to be a trigger for the formation of OME.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00183174
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  • 3
    Electronic Resource
    Electronic Resource
    CRP down-regulates adenylate cyclase activity by reducing the level of phosphorylated IIAGlc, the glucose-specific phosphotransferase protein, in Escherichia coli (1998)
    Springer
    Molecular genetics and genomics 259 (1998), S. 317-326 
    Details
    ISSN: 1617-4623
    Keywords: Key words cAMP level ; Adenylate cyclase ; CRP ; Phosphorylation state ; IIAGlc
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The cellular cAMP level is markedly down-regulated by cAMP receptor protein (CRP) in Escherichia coli. CRP regulates adenylate cyclase both at the level of transcription of its structural gene cya and at the level of enzyme activity. We established a method to determine the phosphorylation state of IIAGlc, the glucose-specific phosphotransferase protein, in intact cells. We found that IIAGlc exists predominantly in the unphosphorylated form in wild-type cells growing in LB medium, while it is largely phosphorylated in crp or cya cells. Disruption of the ptsG gene that codes for the membrane component of the major glucose transporter (IICBGlc), and/or the fruF gene coding for FPr (fructose-specific hybrid phosphotransferase protein), did not affect the phosphorylation state of IIAGlc. When IICBGlc was overproduced in the presence of glucose, the levels of both cAMP and phosphorylated IIAGlc in crp cells were concomitantly decreased to wild-type levels. In addition, when His-90 in IIAGlc was replaced by glutamine, both phosphorylation of IIAGlc and the overproduction of cAMP in crp cells were eliminated. We also found that extracts of crp + cells markedly stimulate dephosphorylation of IIAGlc-P in vitro. We conclude that CRP-cAMP down-regulates adenylate cyclase primarily by reducing the level of phosphorylated IIAGlc. The data suggest that unspecified proteins whose expression is under the control of CRP-cAMP are responsible for this regulation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004380050818
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  • 4
    Electronic Resource
    Electronic Resource
    Endoscopic findings at the pharyngeal orifice of the eustachian tube in otitis media with effusion (1996)
    Springer
    European archives of oto-rhino-laryngology and head & neck 253 (1996), S. 42-44 
    Details
    ISSN: 1434-4726
    Keywords: Endoscopy ; Eustachian tube ; Otitis media with effusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Transnasal endoscopy of the pharyngeal orifice of the eustachian tube was performed on 155 ears with otitis media with effusion (77 ears of children, 78 ears of adults). In children, blockage of the orifice by mucopurulent nasal discharge was the most frequent finding (72.7%), followed by compression of the orifice by the adenoid tissue (52.0%), hypertrophy of the peritubal tonsil (16.9%), and edema around the orifice, especially at its posterior lip (10.4%). In adults, the most frequent abnormal finding was edema of the orifice (26.9%), followed by blockage of the orifice by mucopurulent nasal discharge (23.1 %), and atrophy of the orifice (10.3%). In 39.7% of cases findings were normal. Thus, main pathological findings associated with tubal dysfunction involved inflammation in the nasopharynx.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00176702
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  • 5
    Electronic Resource
    Electronic Resource
    Direct measurement of middle ear pressure through the eustachian tube (1987)
    Springer
    European archives of oto-rhino-laryngology and head & neck 243 (1987), S. 378-381 
    Details
    ISSN: 1434-4726
    Keywords: Middle ear pressure ; Otitis media with effusion ; Eustachian tube
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We report a method for measuring middle ear pressure through the eustachian tube. We used a 1-mm-diameter micro-tip catheter pressure transducer (Mikro-tip) and inserted this into the tympanic cavity through the eustachian tube. In preliminary studies, we measured four normal ears, two ears with tubal dysfunction, one ear with a dry perforation and 13 ears with otitis media with effusion (OME). Among those ears with OME, three showed negative middle ear pressure, three slight positive pressure and one normal pressure. These findings suggest that our transtubal method is reliable and useful for measuring middle ear pressure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00464646
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  • 6
    Electronic Resource
    Electronic Resource
    Protein kinase C-dependent modulation of stimulatory guanine nucleotide binding protein of fetal rat skin keratinocytes (1995)
    Springer
    Archives of dermatological research 288 (1995), S. 24-30 
    Details
    ISSN: 1432-069X
    Keywords: Key words G-protein ; Adenylate cyclase ; Phorbol ; esters ; Densensitization ; Keratinocytes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Although the protein kinase C (PKC) activator, phorbol 12-myristate 13-acetate (PMA) has been known to induce heterologous desensitization of the epidermal adenylate cyclase, the precise mechanism of PMA action remains unknown. Effects of PMA on the receptor-G-protein-adenylate cyclase system of fetal rat skin keratinocytes (FRSK) were investigated. Choleratoxin catalysed the ADP ribosylation of 45 kDa and 52 kDa membrane proteins and islet activating protein (IAP) catalysed the ADP ribosylation of a 40 kDa membrane protein. Incubation of FRSK with PMA decreased the cholera toxin-catalysed ADP ribosylation of the membrane protein, but not the IAP-catalysed ADP ribosylation. The effect of PMA on the cholera toxin-catalysed ADP ribosylation was inhibited by the PKC inhibitor, H-7 (1-(5-isoquinolinesulfonyl)-2-methyl piperazine dihydrochloride). 1-Oleoyl-2-acetylglycerol (OAG), a membrane-permeable diacylglycerol analogue, also decreased the cholera toxin-catalysed ADP ribosylation, but 4- O -methyl PMA, a very weak PKC activator, had no effect. Keratinocytes are known to express the guanine nucleotide binding proteins, Gsα, Gi2α and Gi3α. Immunoblot analysis of the PMA-treated FRSK showed no detectable difference in the amount of Gsα, Gi2α, Gi3α or the β subunit of the G-protein. PMA significantly decreased the β-adrenergic adenylate cyclase response and cholera toxin-induced cyclic AMP accumulation, while it markedly increased forskolin-induced cyclic AMP accumulation. These results indicate that phorbol esters affect the stimulatory guanine nucleotide binding protein (Gs) of FRSK via a PKC-dependent pathway.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004030050018
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