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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    European archives of oto-rhino-laryngology and head & neck 220 (1978), S. 299-301 
    ISSN: 1434-4726
    Keywords: Fluorocarbon ; O2-Solubility ; Perfusion ; Cochlea ; Guinea pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Because oxygen is at least ten times as soluble in fluorocarbon liquids as in plasma or saline, we investigated the principle possibility of perilymphatic perfusion of the cochlea with perfluortributylamin. Our experiments show that fluorocarbons in spite of the excellent O2-solubility in it are not suitable for the perilymphatic perfusion due to their physical properties (density 1.91 g/ml, non-solubility in water, necessity and difficulties of emulsification).
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    European archives of oto-rhino-laryngology and head & neck 224 (1979), S. 257-265 
    ISSN: 1434-4726
    Keywords: Guinea pig ; Cochlear aqueduct ; Round window membrane ; Cerebrospinal fluid ; Perilymph ; Protein concentration ; Electrophysiology ; Histology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary To prevent the perilymph (guinea pig) from contamination with CSF during the sampling the aqueductus cochleae (AC) was blocked by injection of tissue adhesive into the meningeal aperture. The control of an exact blockage of AC was carried out by examination of perilymph-outflow after opening the cochlea (injection of fluorescein-Na into the CSF-space), analysis of perilymphprotein-concentration, macroscopic and microscopic examination of the temporal bones. In all cochleae we have found the same morphological structures, notwith-standing whether the AC was blocked (for a time from 30 min to 7 weeks) or not: The cochlear aqueduct is filled with a mesh of mesenchymal tissue, which grows more dense towards the cochlear aperture and continues into the round window membrane. From scala tympani the AC is always limited by one layer of cells forming a sort of membrane (under light microscope). It seems possible that CSF moves in the inner of the round window membrane between AC and subepithelian space of middle ear mucosa, whereas perilymph of scala tympani is not in direct contact with the flow of CSF. The scala tympanic side of the round window membrane may be a big area for diffusion and there also may be an exchange between CSF and perilymph. The outflow of CSF into the cochlea after experimental opening of the cochlea is an artifact, caused by damage of pressure equilibration between CSF-space and cochlea. 30 min and 5–7 weeks after blockage no morphological and electrophysiological alterations from those of the control ears were to be seen. The protein concentration, however, increased significantly 5–7 weeks after blockage from normally about 200 mg/100 ml to almost the double especially in the scala tympani (see Table 1).
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    European archives of oto-rhino-laryngology and head & neck 238 (1983), S. 77-85 
    ISSN: 1434-4726
    Keywords: Total activity of LDH ; Perilymph ; Sources of error and purity testing ; Plasma ; Cerebrospinal fluid ; Guinea pig ; Noise exposure ; LDH-Gesamtaktivität ; Perilymphe ; Fehlerquellen und Reinheitskontrolle ; Plasma ; Liquor cerebrospinalis ; Meerschweinchen ; Schallbelastung
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die Gesamtaktivität der Laktatdehydrogenase (LDH) von Perilymphe (PL) der Scala tympani und Scala vestibuli, arteriellem Blutplasma und Liquor cerebrospinalis (CSF) unbelasteter und schallbelasteter Meerschweinchen wurde unter besonderer Berücksichtigung der wesentlichen Fehlerquellen untersucht. Zur Reinheitskontrolle der PL-Proben dienten simultane Protein- und Elektrolytbestimmungen (Tabelle 1). Die LDH-Aktivität wurde fluorimetrisch bestimmt. Es zeigte sich, daß zwischen PL, CSF und Plasma erhebliche LDH-Aktivitätsunterschiede bestehen (Tabelle 2). Die mittlere Aktivität ist in der PL 3–4mal höher als im CSF und nur etwa halb so hoch wie im Plasma. Zwischen PL der Scala tympani und Scala vestibuli ergab sich kein signifikanter Unterschied. Die häufigsten LDH-Werte der einzelnen Flüssigkeiten (Abb. 2) liegen etwas unter den arithmetischen Mittelwerten. Unmittelbar (≤60 min) nach 10minütiger Breitbandbelastung mit 140 dB SPL lagen die Mittelwerte der PL beider Schneckenskalen etwas höher als beim unbelasteten Tier (Tabelle 3). 18 h nach Belastungsende zeigte sich nur in der PL der Scala vestibuli eine etwas höhere Aktivität. Die Unterschiede konnten statistisch nicht gesichert werden. Die LDH-Werte von CSF und Plasma blieben sowohl ≤60 min als auch 18 h nach Schallbelastung unverändert.
    Notes: Summary The total activity of lactate dehydrogenase (LDH) of perilymph (PL), plasma, and cerebrospinal fluid (CSF) of unexposed and sound-exposed guinea pigs was examined with due consideration of the principal sources of error. To test the purity of PL samples, protein, potassium, and sodium were determined simultaneously (Table 1). The LDH was analysed fluorometrically. It was found that there are considerable differences in the LDH activities of PL, CSF, and plasma (Table 2). The mean activity of PL was three to four times higher than that of CSF and only about half that of plasma. No significant difference was found between the PL in scala tympani and scala vestibuli. The most frequent LDH values of the individual fluids (Fig. 2) were somewhat lower than the mean values calculated. Immediately (≤60 min) after exposing the animals to wide-band noise at an intensity of 140 dB SPL for 10 min, the mean PL values of the scala tympani and scala vestibuli were found to be somewhat higher than in unexposed animals (Table 3). Eighteen hours after the exposure, slightly higher activity was only detectable in PL of the scala vestibuli. The differences were not found to be significant. The LDH values of CSF and plasma remained unchanged both ≤60 min and 18 h after noise exposure.
    Type of Medium: Electronic Resource
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