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  • 1
    ISSN: 1438-3888
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Material flux rates in an intertidal mussel bed were measured synchronously over two tidal cycles in June 1989 with Benthic Ecosystem Tunnels and a double lane flume. The tunnels enclosed the near bottom water, whereas the flume canalized the total water column. One tunnel was set up in a mussel bed and another one in an adjacent sand bottom as a control. The flume enclosed a mussel lane and a sand lane. In the tunnel and in the flume the mussel bed revealed ammonium and phosphate discharge. At the same time, phytoplankton, dominated byPhyaeocystis globosa, was taken up intensively. These flux rates showed the same tendency but they were higher in the flume than in the tunnel. Different tendencies and flux rates for oxygen and particulate organic matter (POC, PN) were found in flume and tunnel. These differences demonstrate the importance of water column processes regarding the material exchange of a mussel bed. Tunnels enclose smaller bodies of water and are therefore expected to detect even small effects of the benthos on the passing water. In flumes, benthic influence may be diluted over the entire water column but conditions are more natural. The use of flumes is restricted to shallow waters while tunnels have the potential to be used at any depth.
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    European archives of oto-rhino-laryngology and head & neck 208 (1974), S. 89-96 
    ISSN: 1434-4726
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Nach lokaler Applikation von Tetracyclin an 10 Tieren und nach parenteraler Applikation an 10 Tieren wurde die Verteilung im Innenohr nach Gefriertrocknung und Methacrylateinbettung unter dem Fluorescenzmikroskop studiert. Im Falle der parenteralen Verabreichung sahen wir eine diffuse Verteilung des Tetracyclins über allen Windungen. Im Vergleich zur lokalen Applikationsform war die Fluorescenz nur gering. Im Falle der lokalen Verabreichung wurden vorwiegend in der 1. Windung extrem hohe Tetracyclinkonzentrationen gefunden, hier einerseits vorwiegend in der Basilarmembran, im Corti-Organ, der Lamina spir. ossea, dem Limbus spir. und der Reissner-Membran, andererseits dem Lig. spir. einschließlich der Stria vascularis. Das Vorherrschen der Tetracyclinfluorescenz in der Basalwindung stimmt mit den basalen Haarzellschäden überein, die wir nach lokaler Applikation gefunden haben. Es konnte gezeigt werden, daß Tetracyclin vorwiegend vom runden Fenster ausgeht und zunächst seine höchste Konzentration in der Sc. tymp. in der Basalwindung erreicht. In der Sc. tympani breitet es sich helicotremawärts aus. Gleichzeitig ist in der stark fluorescierenden 1. Windung bereits ein übertritt in die Sc. vestib. und Sc. media derselben Windung zu beobachten. Eine frühzeitige Elimination des Tetracyclins kann entlang den Venolen der tympanalen Wand, der knöchernen Wandung des Modiolus und der Pars ossea der Lamina spir. beobachtet werden. Nerv und Nervenscheiden kommen nach unseren Beobachtungen als wesentliche Abtransportwege nicht in Betracht. Die nach parenteraler Applikation im Bereich des zentralen Nervensystems festgestellte Tetracyclinfluorescenz war sowohl in den Kurz- als auch in den Langzeitversuchen nur sehr gering, was auf eine schlechte Liquorgängigkeit des von uns verwendeten Präparates hinweist.
    Notes: Summary After local application of tetrac.ycline to 10 animals, and after parenteral administration to 10 animals, the distribution process in the inner ear after dryfreezing and an embedding in synthetic resin, was studied under a fluorescence microscope. In the case of local administration extremely high tetracycline concentrations were found especially in the first turn, here mainly in the basilar membrane, the organ of corti and also in Reissner's membrane and the Lamina spiralis. The predominance of fluorescence in the basal turn correlates with the hair cell damages we have seen after local application. It could be demonstrated, that tetracycline, starting at the round window, firstly reaches its highest concentration in the Sc. tympani of the first turn. In the Sc. tympani it spreats towards the helicotrema. At the same time, in the highly fluorescing first turn, a passage into the Sc. vestibuli can be noticed. An early elimination of tetracycline on different ways could be observed. 1. Via the venules of the tympanal wall, the wall of modiolus and the Pars ossea of the Lamina spiralis. 2. Both nerve and nerve paths can, in our opinion, not be considered as an important transportation medium. The tetracycline fluorescence, after parenteral application, observed around the central nerve system, was of such little significance both in short-time and long-time experiments, that we were lead to the assumption that the preparation used by us, does not have the ability so well, penetrate into the liquor.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    European archives of oto-rhino-laryngology and head & neck 208 (1974), S. 203-220 
    ISSN: 1434-4726
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die vorliegende Arbeit befaßt sich mit der Untersuchung einiger stressbedingter Lärmreaktionen. Es wurden Änderungen der Konzentration der freien Fettsäuren im Blut und des Adhäsivitäts- und des Aggregationsvermögens der Thrombocyten festgestellt. Erste signifikante TA- und FFA-Erhöhungen traten bei einem Schwellenwert von 110 dB auf. Die Parameter zeigten sich außerdem abhängig von der Beschallungsdauer und dem Zeitpunkt der Blutentnahme nach Beschallungsende. Darüber hinaus konnte eine Abhängigkeit von Klimafaktoren nicht ausgeschlossen werden. Die FFA erwiesen sich als empfindlicher Indikator für den Ablauf lärmbedingter ergotrop-vegetativer Reaktionen. In vielen Fällen wurde eine Korrelation zwischen FFA und Adhäsivitätserhöhung aufgezeigt und anhand der einschlägigen Literatur diskutiert. Davon abweichende Befunde in Form sogenannter paradoxer Reaktionen lassen auf das vorübergehende Überwiegen gegenregulatorischer Mechanismen schließen. Auf eine mögliche Beeinflussung der Innenohrdurchblutung durch die im großen Kreislauf beobachteten rheologischen Veränderungen wird hingewiesen. Schließlich konnten analoge Befunde anhand einiger klinischer Fälle von akutem Hörsturz, fluktuierendem Gehör und M. Monière erhoben werden.
    Notes: Summary Some stress-induced noise reactions were investigated. Changes in the concentration of free fatty acids in the blood and in the ability of adhesion and aggregation of thrombocytes were found. Significant increases in TA and FFA were first observed at a level of 110 dB SPL. Values depended also on the duration of noise exposure and the time after cessation of the noise at which the blood sample was drawn. An additional dependence on climatic factors could not be excluded. The FFA turned out to be a sensitive indicator for the time course of noise-induced ergotropic autonomic reactions. In many instances, a correlation was found between the changes in FFA and the increases in adhesions, a fact that is being discussed, based upon the pertinent literature. Opposite findings, i.e., paradoxic reactions, indicated a transitory prevalence of counter-reacting regulatory mechanisms The possibility that the inner-ear blood supply may be influenced by the rheological changes in the general circulation is being discussed. Finally, similar findings were made in some clinical cases of acute hearing loss, fluctuant hearing loss, and Meniere's disease.
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    European archives of oto-rhino-laryngology and head & neck 209 (1975), S. 263-270 
    ISSN: 1434-4726
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die Bedeutung der Thrombocytenadhäsivität und -aggregation (TA) für die Frühphase der Thrombose und für das Entstehen degenerativer Gefäßwandprozesse kann heute als erwiesen angesehen werden. Im Zusammenhang damit verdienen die Plasmalipide besondere Beachtung. Von ihnen stellen die Freien Fettsäuren (FFA) einen feinen Indicator für die adrenerge Reaktionsbereitschaft des Organismus dar und darüber hinaus für den Ablauf streßbedingter Kreislaufreaktionen. In der vorliegenden Studie wurden 65 klinische Fälle von Innenohrfunktionsstörungen auf TA und FFA untersucht, wobei nur zwischen Hörstürzen (n=28) einerseits und Funktionsstörungen verschiedener Symptomatik (n=37) andererseits unterschieden wurde. Bei dieser noch vorläufigen Statistik zeigte sich, daß 64% der Hörstürze vorwiegend mittelgradig erhöhte, 84% der 37 untersuchten Funktionsstörungen verschiedener Symptomatik gering bis hochgradig erhöhte Adhäsivitäten aufwiesen. Die FFA-Konzentrationen waren in ca. 90% der 23 untersuchten Fälle von Innenohrfunktionsstörungen erhöht. Auffällig ist, daß die gemessenen Adhäsivitäten und Serum-FFA-Konzentrationen mit den hohen Werten vergleichbar sind, die bei atheromatösen Gefäßprozessen, bei Venenthrombosen, Herz- und Cerebralinfarkten, der intermittierenden cerebrovasculären Insuffizienz und bei durch Mikroembolien bedingten flüchtigen Sehstörungen beschrieben werden. Wenn auch der hohe Prozentsatz an FFA-Erhöhungen bei strengster Einhaltung der Ruhebedingungen zum Zeitpunkt der Blutentnahme sicher unter dem gemessenen Wert liegen dürfte, so weist er doch auf einen gesteigerten Sympathicotonus bei der Mehrzahl der untersuchten Patienten hin. Die klinischen Erfolge, die bei rechtzeitigem Einsatz zahlreicher teils aggregations-und adhäsivitätshemmender, teils lipidsenkender Mittel erreicht werden, sprechen ebenfalls für den Ablauf streßbedingter Kreislaufreaktionen und das Bestehen atheromatöser beziehungsweise thrombembolischer Gefäßprozesse bei zahlreichen akuten oder intermittierenden Innenohrfunktionsstörungen.
    Notes: Summary The significance of platelet adhesiveness and aggregation in the early phase of thrombosis as well as in the development of degenerative vascular wall processes has today become an established fact. In this connection the plasmalipids are of special interest, of which the free fatty acids (FFA) represent a sensitive indicator both for the adrenergic reactivity of the organism and the process of stress-conditioned circulatory reactions. In the present study 65 clinical cases with functional disorders of the internal ear were examined regarding to the platelet adhesiveness and FFA, differentiating only between sudden loss of hearing (n=28) and functional disorders of different symptomatology (n=37). Our preliminary statistics showed in 64% of the patients with a sudden loss of hearing mainly an average, and in 84% of the 37 examined functional disorders of different symptomatology a slight to a high increase in the adhesiveness. The FFA-concentrations increased in approximately 90% of the 23 examined cases with functional disorders of the internal ear. It is remarkable, that the measured adhesiveness and serum-FFA-concentrations are comparable to the high values obtained from atheromatous vascular processes, venous thrombosis, cardial and cerebral infarctions, intermittent cerebrovascular insufficiency as well as from transient impaired vision caused by microembolism. Even if the high percentage in the FFA-increase, under strictest observance of the patient's resting position at the time of the blood withdrawal, is presumably much below the measured value, it still indicates an increased tonus of the sympathetic nervous system in the majority of the examined patients. The clinical satisfactory results obtained after timely applications of numerous agents inhibiting aggregation and adhesiveness, as well as reducing the lipids, also indicate a process of stress-conditioned circulatory reactions and the existence of atheromatous respectively thrombo-embolic vascular processes in a number of acute or intermittent functional disorders of the internal ear.
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    European archives of oto-rhino-laryngology and head & neck 214 (1976), S. 109-124 
    ISSN: 1434-4726
    Keywords: O2 supply ; Intracochlear O2 pressure ; Cochlea circulation ; Abnormal vascular plexus ; pO2 and pH2 needle electrodes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The local partial pressure of oxygen (pO2) and the rate of hydrogen elimination were measured in the three scalae of the basal turn of 28 Guinea-pig cochleae under conditions of normoxia, hyperoxia and hypercapnia and with acoustical stimulation with the needle electrodes developed by Baumgärtl and Lübbers. In the scala tympani a pO2 decrease from the round window toward Corti's organ was registered and pO2 values of over 100 mm Hg were measured near the membrane of the round window and of 10–40 mm Hg near the basilar membrane depending on how deeply the electrode penetrated into the scala tympani. The pO2 profiles were changed or reversed when the animal breathed a mixture of 95% oxygen and 5% carbon dioxide and when the round window membrane was covered with agar-agar or paraffine and exteriorly flooded with nitrogen. Acoustical stimulation with a white noise of 85 dB caused a considerable pO2 drop in the perilymph of the scala tympani while in the endolymph of the scala media we observe only a slight decrease. Intravenous application of dextran of low viscosity leads to a pO2 increase when the original oxygen value in the scala tympani was low. The half-life of hydrogen in the scala tympani amounts to about 4 min. The results permit the conclusion that, in the area of the cochlear basis, Corti's organ receives its oxygen supply via the capillary system as well as via the membrane of the round window.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    European archives of oto-rhino-laryngology and head & neck 221 (1978), S. 269-284 
    ISSN: 1434-4726
    Keywords: Intracochlear pO2 ; Inner ear microcirculation ; Sympathectomy ; Exposure to loud sounds ; Microcoaxial needle electrodes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Oxygen partial pressure (pO2) profiles and microcirculatory parameters were recorded in vivo under standardized conditions in the three scalae of the cat's cochlea after unilateral excision of the upper cervical sympathetic nerve. Experiments were performed both under rest conditions and during exposure to loud sounds. pO2 and pH2 were polarographically measured using microcoaxial needle electrodes with sputtered reference elements according to Baumgärtl and Lübbers (1975). The tip diameter of the complete probe was 0.3–0.7 μm. The oxygen pressure field of the three scalae of the basal winding was recorded through the round window membrane during continuous advance of the needle (150 μm/min). Temporal pO2 changes as well as microcirculatory parameters were measured in the scala media after the electrode was fixed in position. Starting out from the air values at the surface of the round window membrane, pO2 decreased continuously from more than 100 Torr during insertion towards the basilar membrane, where it averaged 25 Torr. When the needle had penetrated the basilar membrane and entered the endolymphic space, an increased pO2 of 35–40 Torr was recorded. After penetrating Reissner's membrane, a slightly decreased pO2 was measured in the scala vestib. Aside from the oxygen reaching the cochlea through the round window, the capillaries of the round window membrane were found to contribute to the oxygen saturation of the perilymph near the window. Under rest condition, unilateral upper cervical sympathectomy did not noticeably influence the oxygen pressure field in the three cochlear scalae. After exposure to loud sounds, however, endolymphic pO2 decreased less and recovered quicker on the sympathectomized side than on the intact one. Ventilation of the animals with pure oxygen or gas mixtures of high CO2-O2 concentrations increased the pO2 level within 1 min. The increase was more pronounced in the endolymphic space than in the other cochlear scalae and also the pO2 decrease in the scala media was particularly distinct in the cat. Under exposure to loud sounds the influence of the sympathetic nerve on the intracochlear pO2 was found to depend on the aortic blood pressure. The advantageous effect of sympathectomy was particularly visible at a low aortic pressure but less distinct at a higher one. In some cases, a long-lasting pO2 decrease was noticed in the endolymphic space even after short (1–2 s) exposure to noise. The hydrogen exchange rate recorded in the endolymphic space after exposure to loud sounds (noise of 115 dB) using the hydrogen clearance method was distinctly delayed and, consequently, the capillary blood flow was diminished. Unilateral acute upper cervical sympathectomy favorably influenced the peripheral circulation during exposure to loud sounds by increasing the blood flow (reduced half life period). The experiments showed that unilateral acute upper cervical sympathectomy did not considerably influence the endolymphic pO2 under rest condition, whereas an advantageous effect on the endocochlear pO2 and blood flow was noticed under exposure to loud sounds. Moreover, there was indication of a correlation between sympathetic effect and mean aortal blood pressure.
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    European archives of oto-rhino-laryngology and head & neck 240 (1984), S. 295-310 
    ISSN: 1434-4726
    Keywords: Inner ear function ; Autoregulation cochlear blood flow ; Cochlear microcirculation ; Hydrogen-clearance-measurements ; Polaro-graphic microanalysis ; Aortic blood pressure ; Blood gases analysis ; Cats
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary To study the autoregulative capabilities of the cochlear vessels, hydrogen clearance (HC) measurements were carried out by means of various blood pressure levels in hemorrhagic hypotension. H2-sensitive platinum — needle electrodes were applied and a polarographic microanalysis method was used. The measurements were performed in the scala media of anesthetized cats during measuring of blood pressure and blood gases. The statistical analysis of the experimental data shows that the relationship between the HC and aortic blood pressure represents a regression line. According to the regression line the half-life time of HC was delayed for 0.7 min, when the blood pressure was reduced by 10 mm Hg (40–150 mm Hg blood pressure range). This corresponds to a cochlea flow rate of 0.3 ml/100 g/min. By mean aortic blood pressure of 40 mm Hg, the speed of H2 exchange still remains about 50% of the initial clearance. This indicates that the cochlear vessels have autoregulative capability. This autoregulative capability differs from the saturation curves of most autoregulated blood flow in the brain, heart and kidney vessels. These findings are in accordance with the observations of other authors. As our experimental data show, and as long as an analogy can be drawn between man and cat, it is hardly possible to explain that the fall of the blood pressure alone could lead to a disturbance of the oxygen supply to the inner ear, as often discussed in certain inner-ear dysfunctions.
    Notes: Zusammenfassung Zum Studium der autoregulatorischen Fähigkeiten der Cochleagefäße wurden Wasserstoff (H2)-Clearancemessungen bei verschieden hohen Blutdrucken unter den Bedingungen einer haemorrhagischen Hypotension durchgeführt. Dabei kam das polarographische Mikroanalyseverfahren unter Verwendung palladinierter Platin-Nadelelektroden zur Anwendung. Die Messungen erfolgten in der Scala media narkotisierter, assistiert beatmeter Katzen unter Registrierung von Blutdruck und Blutgasen. Die statistische Analyse der Meßergebnisse zeigt, daß zwischen H2-Clearance und aortalem Blutdruck ein linearer Zusammenhang nach Art einer Regressionsgeraden besteht. Entsprechend dieser Geraden bewirkt die haemorrhagische Blutdrucksenkung um 10 mm Hg in dem beobachteten Blutdruckbereich zwischen 150 und 40 mm Hg eine mittlere Verzögerung der H2-Clearance von 0,7 min, was quantitativ einer cochlearen Flußrate von 0,3 ml/100 g/min entspricht. Bei einem mittleren aortalen Blutdruck von 40 mm Hg beträgt die H2-Austauschgeschwindigkeit immer noch ca. 50% der Ausgangsclearance entsprechend einem Blutdruck von 150 mm Hg. Dies ist Ausdruck einer ausgeprägten autoregulatorischen Fähigkeit der Cochleagefäße. Die autoregulatorische Potenz der Cochleagefäße unterscheidet sich jedoch in charakteristischer Weise von den Sättigungskurven der noch extremer autoregulierten Hirn-, Herz- und Nierenkreisläufe. Hierin stimmen unsere Ergebnisse mit den Beobachtungen anderer Autoren (Hultcrantz, Angelborg und Linder, 1977) weitgehend überein. Unsere Untersuchungsergebnisse an der Katze machen, soweit Analogieschlüsse überhaupt möglich sind, es schlecht vorstellbar, daß ein Blutdruckabfall allein Funktionsstörungen des Hörorgans bewirken kann.
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    European archives of oto-rhino-laryngology and head & neck 235 (1982), S. 593-593 
    ISSN: 1434-4726
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The cochlear microcirculation was recorded by hydrogensensitive microelectrodes in rabbits and guinea pigs applying polarographic analysis technique. H2-clearence measurements were carried out and then the hydrogen halfconcentration time was determined from curves representing a qualitative measure for the cochlear microcirculation. The results are discussed and compared with those obtained by other techniques.
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    European archives of oto-rhino-laryngology and head & neck 207 (1974), S. 490-492 
    ISSN: 1434-4726
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Based upon results obtained from extensive examinations, today the significance of thrombocytes, particularly their adhesive and aggregational power, has been recognized to be important in the early state of thrombosis. Therefore, it suggests itself to analize the adhesive power of thrombocytes in a sudden loss of hearing and in Menière's Disease, since the pathogenesis of these illnesses largely remains unsettled, and that at least in case of a sudden loss of hearing thrombotic processes play a part. The fibre test shows in both cases a significant increase in the adhesive power of the thrombocytes. These results are compared with those obtained from Ristow and Breddin using the platelet aggregation test (PAT).
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    European archives of oto-rhino-laryngology and head & neck 216 (1977), S. 519-519 
    ISSN: 1434-4726
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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