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  • Picea abies  (3)
  • Dental
  • Growth factors
  • Key words Tip link hypothesis
  • Lärmschwerhörigkeit
  • 1
    Electronic Resource
    Electronic Resource
    Physiologische Auswirkungen einer Zerstörung der Tip-Links kochleärer Haarsinneszellen Bedeutung für die lärminduzierte Schädigung des Gehörs (2000)
    Springer
    HNO 48 (2000), S. 383-389 
    Details
    ISSN: 1433-0458
    Keywords: Schlüsselwörter Tip-Link-Hypothese ; Lärmschwerhörigkeit ; Schalltrauma ; Tinnitus ; TTS ; Key words Tip link hypothesis ; Noise-induced hearing loss ; Tinnitus ; TTS
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Abstract Sound overexposure is known to cause damage to cochlear structures and can induce permanent or temporary hearing loss and tinnitus. Perhaps the most sensitive of these structures to sound overexposure are the tip links. In this paper the elecrophysiological effects of pharmacological destruction of the tip links of outer hair cells was investigated. Outer hair cells treated with elastase (20 U/mL) or BAPTA (5 mM) no longer responded to sinusoidal stimuli. In contrast to common belief, transduction channels opened due to loss of tip links. Such opened channels can allow K+ and Ca2+ to enter the cell from the endolymphatic space and could lead to permanent depolarization. This influx of cations caused by loss of tip links, together with the subsequent hair-cell depolarization, might be a source of sensorineural hearing loss and tinnitus associated with acoustic trauma.
    Notes: Zusammenfassung Eine extreme Lärmexposition ist bekannt dafür, Schädigungen des Gehörs hervorzurufen, die sich in permanenter oder temporärer Schwerhörigkeit und Tinnitus manifestieren können. Vor allem die Stereozilien der Haarsinneszellen stellen einen sensiblen Angriffspunkt dar: deren rämliche Ordnung und ihre Verbindungsfilamente (Tip-Links) können zerstört werden. In der vorliegenden Arbeit wurde die Auswirkung einer pharmakologischen Zerstörung der Tip-Links auf das elektrophysiologische Verhalten der Zelle untersucht. Es zeigte sich, dass die behandelten äußeren Haarsinneszellen nicht mehr mechanosensitiv für nasische Stimuli waren, was die Wichtigkeit der Tip-Links bei der Reiztransduktion unterstreicht. Entgegen der allgemeinen Erwartung gingen die mechanoelektrischen Transduktionskanäle aber in einen offenen Zustand über. Durch die permanent offenen Kannäle strömen dauerhaft hauptsächlich K+- und Ca2+-Ionen aus der Endolymphe in die Zelle ein und führen zu einer Depolarisation. Dieser durch den Verlust der Tip-Links verursachte Einstrom von Kationen und die Depolarisation der Zelle können ein Teil der Ursache einer dem Schalltrauma begleitenden Symptomatik wie Innenohrschwerhörigkeit und Tinnitus sein.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001060050585
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Tools for tissue engineering of mineralized oral structures (2000)
    Springer
    Clinical oral investigations 4 (2000), S. 126-129 
    Details
    ISSN: 1436-3771
    Keywords: Key words Tissue engineering ; Growth factors ; Peptides ; Proteins ; Dental
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  This paper presents a short review of three groups of tools which can be or are used for the tissue engineering of mineralized oral structures: growth factor delivery systems (GFDS) and surface bioactivation with covalent bound peptides or with nanomechanically linked proteins. According to the reported personal experience of the authors, GFDS have to face the following challenging issue before being used routinely in dentistry, e.g., as a tool for reparative dentinogenesis or bone healing: adaptation of the GFDS design to the tissue where it will be implanted in order to deliver the right dose of growth factor (GF) at the right time. The bioactivation of surfaces, for example of dental implants, with covalent bound peptides or nanomechanically linked proteins represents a second innovative way to improve dental health in the future. Here we report on the experimental use of cyclic RGD peptides grafted on polymethylmethacrylate to improve osteoblast adhesion. Furthermore, we show the potential advantage of immobilizing and incorporating collagen I on titanium implant surfaces. These techniques or a combination of them will help to create improvements, for example, of dental implants in the near future. They will also help to promote bone and dentin regeneration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s007840050128
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Performance of two Picea abies (L.) Karst. stands at different stages of decline (1988)
    Springer
    Oecologia 75 (1988), S. 25-37 
    Details
    ISSN: 1432-1939
    Keywords: Forest decline ; Carbohydrates ; Picea abies ; Growth ; Leaf area index
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary This is the first in a series of papers on the growth, photosynthetic rate, water and nutrient relations, root distribution and mycorrhizal frequency of two Norway spruce forests at different stages of decline. One of the stands was composed of green trees only while the other included trees ranging in appearance from full green crowns to thin crowns with yellow needles. In this paper we compare the growth and carbohydrate relations of the two stands and examine relationships among growth variables in ten plots. The declining stand produced 65 percent of the wood per ground area compared with the stand in which all trees were green because its foliage produced less wood at any level of leaf area index. The difference in foliage efficiency between the sites could not be explained by differeneces in climate, competition or stand structure. The declining stand appeared to have lower carbon gain as indicated by a smaller increase in reserve carbohydrates before bud break, and weaker sinks for carbohydrates as indicated by less use of the stored carbohydrates than the healthy stand. Thus, growth reduction was probably related to factors which affect both photosynthesis and, even more, the sinks for carbohydrate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00378810
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Performance of two Picea abies (L.) Karst. stands at different stages of decline (1988)
    Springer
    Oecologia 76 (1988), S. 519-524 
    Details
    ISSN: 1432-1939
    Keywords: Picea abies ; Forest decline ; Xylem flow ; Whole tree transpiration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The water relations of Picea abies in a healthy stand with green trees only and a declining stand with trees showing different stages of needle yellowing were investigated in northern Bavaria. The present study is based on observations of trees differing in their nutritional status but apparently green on both sites in order to identify changes in the response pattern which might be caused by atmospheric concentrations of air pollutants and could lead to the phenomenon of decline. Transpiration was measured as water flow through the hydroactive xylem using an equilibrium mass-flow measurement system. Total tree transpiration was monitored diurnally, from July 1985 until October 1985 at both sites. The relationship between transpiration and meteorological measurements indicated that transpiration was a linear function of the vapor pressure deficit. No differences in transpiration of green trees were observed between the two sites. Canopy transpiration was 57%–68% of total throughfall and 41%–54% of total rainfall. Due to this positive water balance, soil water potential at 10 and 20 cm depths remained close to-0.02 MPa (max.-0.09 MPa) for most of the summer. Soil water potential was correlated with the difference between the weekly precipitation and transpiration. No differences in the water relations of apparently healthy trees in the two P. abies stands were observed. It is concluded that differences between green trees at the two sites in terms of nutrient relations or growth rate cannot be explained by changes in whole-tree transpiration or soil water status.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00397863
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    Performance of two Picea abies (L.) Karst. stands at different stages of decline (1988)
    Springer
    Oecologia 77 (1988), S. 7-13 
    Details
    ISSN: 1432-1939
    Keywords: Forest decline ; Ectomycorrhizas ; Fine roots ; Picea abies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The development of root tips and apparent ectomycorrhizas was compared in the Fichtelgebirge (FRG) over one growing season in two 30-year-old Picea abies stands, both on soils derived from phyllite but showing varying symptoms of decline. Visual symptoms of tree decline reflected a lower relative and absolute mycorrhizal frequency, a lower number of ectomycorrhizas per m2 leaf area and an uneven vertical distribution of root tips and ectomycorrhizas. The number of apparent ectomycorrhizas per ground area was correlated with the amount of magnesium, calcium, and ammonium, and the pH in the free-drainage soil solution, and with the molar calcium to aluminium ratio in mineral soil extracts. The foliage concentrations of magnesium and calcium were correlated with the numbers of apparent ectomycorrhizas per m2 leaf or ground area. These observations were used to formulate testable hypotheses concerning the role of the root system and the soil environment in forest decline.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00380917
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    Paper (German National Licenses)
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