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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 13 (1969), S. 182-193 
    ISSN: 1432-0533
    Keywords: Neurochemistry ; Hexosamine ; Leucodystrophies ; Demyelination ; Lipidoses, Cerebral
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Während der ersten 6 Monate der Formalinfixierung sinkt der Gehalt an Lipid-Hexosamin (LHA) in der grauen und weißen Hirnsubstanz etwa um 20%. Das Rest-Hexosamin (RHA) sinkt in der weißen Substanz nicht weiter ab, steigt aber in der grauen Substanz. Die Bestimmung von LHA und RHA nach sechsmonatiger Fixation reicht für quantitative biologische und pathologische Untersuchungen aus. Während der Hirnentwicklung kommt es zu einem Anstieg und späteren Abfall des RHA in der grauen und weißen Substanz. Höchstwerte werden in der weißen Substanz früher als in der grauen erreicht. LHA und RHA waren normal in grauer und weißer Substanz bei Entmarkungsprozessen nicht-metabolischer Genese. Erhöhter LHA-Gehalt wurde in der weißen Substanz von metachromatischer Leukodystrophie, Tay-Sachsscher Erkrankung und einigen anderen Leukodystrophien gefunden. RHA-Anstieg ging konstant mit einem LHA-Anstieg in der weißen, nicht aber in der grauen Substanz, either.
    Notes: Summary During the first six months of formalin fixation LHA values decrease about 20% in both grey and white matter. RHA does not decrease in the white matter but increases in the grey matter. Determination of LHA and RHA after six months of fixation is accurate enough for quantitative biological and pathological studies. During development there is an increase and subsequent fall in RHA in grey and in white matter. Maximum values are reached earlier in white than in grey matter. LHA and RHA were normal in grey and white matter in demyelinating conditions of non-metabolic origin. Increased LHA values were observed in white matter of metachromatic leucodystrophy, Tay-Sachs disease, and some other leucodystrophies. RHA increase invariably was co-occurring with LHA increase in the white matter but not so in the grey matter.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Oecologia 95 (1993), S. 122-133 
    ISSN: 1432-1939
    Keywords: Sargassum patens ; Halichoeres tenuispinus ; Competition ; Predation ; Macrofauna
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The possibility that resource limits constrain the growth of mobile epifaunal populations associated withSargassum patens plants was investigated by placing plants and associated animals into field microcosms which excluded fish predators, and then comparing faunal abundance and size-structure changes in different microcosm treatments with field populations. Four different micrososm treatments were set up: two treatments containing defaunated plants inoculated with caprellid amphipods, and two control treatments with natural faunas. The estimated secondary production of faunas enclosed in all microcosm treatments rapidly settled on a constant value (5 mg/day) which was similar to that determined in experiments conducted in Western Australia using the same microcosms but for faunas associated with a seagrass rather than a macroalga. These results support the hypothesis that the secondary production of epifaunal communities associated with macrophytes is constrained by quantifiable food resource ceilings. Predation by the most common fish species in the area, the wrasseHalichoeres tenuispinis, did not appear to alter macrofaunal production in theS. patens bed; however, it did greatly affect the faunal size-structure by eliminating most of the larger animals. The majority of epifaunal animals ≥ 2.0 mm sieve-size were consumed byH. tenuispinis, while negligible numbers of 0.5-mm sieve-size animals were captured. We postulate that food resource ceilings and predatory size-selectivity are widespread phenomena, affecting epifaunal populations at a variety of locations. Predation is predicted to generally increase rather than decrease faunal abundance because the consumption of each large invertebrate by a predator frees sufficient resources to feed several smaller individuals.
    Type of Medium: Electronic Resource
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