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  • 1
    Electronic Resource
    Electronic Resource
    Relative growth and maturation of axon size and myelin thickness in the tibial nerve of the rat (1990)
    Springer
    Acta neuropathologica 79 (1990), S. 364-374 
    Details
    ISSN: 1432-0533
    Keywords: Peripheral nerve morphometry ; Axons ; Myelin ; Growth changes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Morphometric observations have been made on the medial plantar division of the tibial nerve (MPD) and on the motor branches of the tibial nerve to the calf muscles (MBC) in rats ranging in age from weaning (3 weeks) to 12 months. Axon size, assessed by measurements of circumference and cross-sectional area, increased rapidly until 3 months with further slight increases between 3 and 9 months and a slight fall between 9 and 12 months. Axon size distributions were unimodal throughout in the MPD but bimodal for the MBC except at 3 weeks. Distributions of myelin thickness were bimodal throughout for both nerves. Scatter plots of g ratios (axon diameter: total fibre diameter) confirmed the presence of two fibre populations: a group of small fibres with relatively thin myelin sheaths, and a group of larger fibres within which sheath thickness was relatively less on the larger than on the smaller axons. These two fibres populations were less easily separable in the MBC than in the MPD nerves. These results document morphometrically the normal growth changes in the rat tibial nerve and also provide control data for the analysis of the effects of experimental procedures on the growth and maturation of peripheral nerve fibres.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00308712
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  • 2
    Electronic Resource
    Electronic Resource
    Relative growth and maturation of axin size and myelin thickness in the tibial nerve of the rat (1990)
    Springer
    Acta neuropathologica 79 (1990), S. 375-386 
    Details
    ISSN: 1432-0533
    Keywords: Peripheral nerve ; Morphometry ; Diabetes mellitus ; Hypomyelination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The relative changes in the growth and maturation of axon size and myelin thickness were studied in the medial plantar division of the tibial nerve in the lower leg and in the motor branches of the tibial nerve to the calf muscles in rats in which diabetes mellitus had been induced with streptozotocin at the time of weaning. Observations were made at 6 weeks and 3, 6, 9 and 12 months of diabetes for comparison with age-matched controls. Similar changes were observed in both nerves. Growth in body weight and skeletal growth was severely retarded from the time of induction of diabetes but at the 6-week stage axon size was not reduced, suggesting that neural growth may initially be relatively protected. At later stages axon size was consistently reduced in the diabetic animals as compared with the controls and showed an absolute reduction at 12 months, as compared with 9 months, that was greater than in the controls. Myelin thickness became reduced earlier and was more severely affected than axon size so that the fibers were relatively hypomyelinated. The myelin changes were greater in larger than in smaller fibers. The index of circularity of axons was reduced in the diabetic nerves. These results show that induction of diabetes in prepubertal rats produces effects on peripheral nerve fibers which differ from those resulting from diabetes induced in adult animals. The effects also differ between large and small nerve fibres. These observations may explain some of the disparate findings obstained in previous studies on experimental diabetes in rats.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00308713
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  • 3
    Electronic Resource
    Electronic Resource
    Colocalization of cholinesterases with β amyloid protein in aged and Alzheimer's brains (1993)
    Springer
    Acta neuropathologica 85 (1993), S. 362-369 
    Details
    ISSN: 1432-0533
    Keywords: β Amyloid ; Acetylcholinesterase ; Butyrylcholinesterase ; Diffuse plaques ; Preamyloid deposits
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The colocalization of β amyloid protein with the enzymes acetyl- and butyrylcholinesterase was assessed using immunocytochemistry for β amyloid protein and a sensitive histochemical technique for cholinesterases. In non-demented aged and Alzheimer's disease brains, double-stained sections for cholinesterases and thioflavin-S showed that all thioflavin-S-positive plaques were also positive for cholinesterases, indicating the presence of these enzymes in all plaques with β-pleated amyloid protein. When amyloid angiopathy was present, cholinesterases were also observed in amyloid-laden vessels walls. Comparison of series of adjacent sections alternatively stained for acetylcholinesterase, β amyloid protein and butyrylcholinesterase, as well as by double histo-immunocytochemical staining, showed either cholinesterase in a proportion of the preamyloid diffuse plaques. These data indicate that cholinesterases are associated with the amyloid protein from very early stages, when the β-pleated structure is being formed. Novel functions attributed to acetyl- and butyrylcholinesterase, such us their proteolytic activity either by themselves or in association with heparan sulfate proteoglycans, may play a role in the aggregation or the consolidation processes taking place at the early stages of diffuse plaque formation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00334445
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  • 4
    Electronic Resource
    Electronic Resource
    Cholinesterases colocalize with sites of neurofibrillary degeneration in aged and Alzheimer's brains (1994)
    Springer
    Acta neuropathologica 87 (1994), S. 284-292 
    Details
    ISSN: 1432-0533
    Keywords: Acetylcholinesterase ; Butyrylcholinesterase ; Tau protein ; Tangle ; Degenerated neurites
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Acetylcholinesterase and butyrylcholinesterase have been associated with structures undergoing neurofibrillary degeneration, as well as with all types of senile plaques, in non-demented aged and Alzheimer's brains. At the electron microscope level, the reaction product of both enzymes, appeared to decorate paired helical filaments, straight filaments and βA4 amyloid fibrils. Recent studies showed that cholinesterases were associated with amyloid at early stages, e.g., in diffuse plaques. In the present study, the interrelationship of cholinesterases to structures undergoing neurofibrillary degeneration was analyzed further. Tau immunoreactivity was compared to the staining pattern observed with the two esterases. Double protocols consecutively performed on the same sections, and counterstaining with thioflavin-S, confirmed the presence of cholinesterases in all structures with neurofibrillary degeneration. The conclusion that cholinesterases consistently colocalize with both neurofibrillary bundles and βA4 amyloid fibrils at all stages of their accumulation, allows us to speculate on the possible role that these enzymes may play in either the formation or the consolidation of fibrillary aggregates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00296744
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  • 5
    Electronic Resource
    Electronic Resource
    Cholinesterases colocalize with sites of neurofibrillary degeneration in aged and Alzheimer's brains (1994)
    Springer
    Acta neuropathologica 87 (1994), S. 284-292 
    Details
    ISSN: 1432-0533
    Keywords: Key words: Acetylcholinesterases – Butyrylcholinesterase – Tau protein – Tangle – Degenerated neurites
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. Acetylcholinesterase and butyrylcholinesterase have been associated with structures undergoing neurofibrillary degeneration, as well as with all types of senile plaques, in non-demented aged and Alzheimer's brains. At the electron microscope level, the reaction product of both enzymes, appeared to decorate paired helical filaments, straight filaments and βA4 amyloid fibrils. Recent studies showed that cholinesterases were associated with amyloid at early stages, e.g., in diffuse plaques. In the present study, the interrelationship of cholinesterases to structures undergoing neurofibrillary degeneration was analyzed further. Tau immunoreactivity was compared to the staining pattern observed with the two esterases. Double protocols consecutively performed on the same sections, and counterstaining with thioflavin-S, confirmed the presence of cholinesterases in all structures with neurofibrillary degeneration. The conclusion that cholinesterases consistently colocalize with both neurofibrillary bundles and βA4 amyloid fibrils at all stages of their accumulation, allows us to speculate on the possible role that these enzymes may play in either the formation or the consolidation of fibrillary aggregates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00296744
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  • 6
    Electronic Resource
    Electronic Resource
    Productivities of microbial decomposers during early stages of decomposition of leaves of a freshwater sedge (1995)
    Oxford, UK : Blackwell Publishing Ltd
    Freshwater biology 34 (1995), S. 0 
    Details
    ISSN: 1365-2427
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: 1. We examined standing-senescing, standing-dead and recently fallen leaf blades of Carex walteriana in fens of the Okefenokee Swamp to determine the nature of the microbial decomposers in the early stages of decomposition, measuring both standing crops and productivities ([3H]leucineprotein method for bacteria, [14C]acetateergosterol for fungi).2. Fungal standing crops (ergosterol) became detectable at the mid-senescence stage (leaves about half yellow-brown) and rose to 14–31 mg living-fungal C g−1 organic mass of the decaying system; bacterial standing crops (direct microscopy) were ± 0.2 mgC g−1 until the fallen-leaf stage, when they rose to as high as 0.9 mgC g−1.3. Potential microbial specific growth rates were similar between fungi and bacteria, at about 0.03–0.06 day−1, but potential production of fungal mass was 115–512 μgC g−1 organic mass day−1, compared with 0–22 μgC g−1 day−1 for bacteria. Rates of fungal production were about 6-fold lower on average than previously found for a saltmarsh grass, perhaps because much lower phosphorus concentratiofis in the freshwater fen limit fungal activity.4. There was little change in lignocellulose (LC) percentage of decaying leaves, although net loss of organic mass at the fallen, broken stage was estimated to be 59%, suggesting that LC was lost at rates proportional to those for total organics during decay. Monomers of fungal-wall polymers (glucosamine and mannose) accumulated 2- to 4-fold during leaf decay. This may indicate that an increase found for proximate (acid-detergent) lignin could be at least partially due to accumulation of refractory fungal-wall material, including melanin.5. A common sequence in decaying aquatic grasses is suggested: principally fungal alteration of LC during standing decay, followed by a trend toward bacterial decomposition of the LC after leaves fall and break into particles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2427.1995.tb00430.x
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  • 7
    Electronic Resource
    Electronic Resource
    Alzheimer's disease-type neurofibrillary degeneration in verrucose dysplasias of the cerebral cortex (1995)
    Springer
    Acta neuropathologica 90 (1995), S. 356-365 
    Details
    ISSN: 1432-0533
    Keywords: Tangle ; Nodule ; Cortical development ; Ischemia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Verrucose dysplasias, found at autopsy in the cerebral cortex of three elderly individuals (two without neurological disorders and one with motor neuron disease), are shown to present neurofibrillary degeneration of Alzheimer's disease type. This neurofibrillary degeneration immunoreacted with antibodies against abnormally phosphorylated tau (5E2 and AT8), disclosed acetyland butyrylcholinesterase activity, and was consistently stained with thioflavin-S. Cortical dysplasias, found either as isolated verrucose nodules or comprising multiple nodules, contained cell-sparse areas around which a peak of neurofibrillary changes was seen. Cell-sparse areas were sometimes bridged by stripes of neurons and fibers arranged in a radial fashion, and many of these neurons showed neurofibrillary degeneration. Cytoskeletal abnormalities were conspicuous in layers II and III at the external borders of the dysplasias, as well as in neurons located in layers V and VI, and in the white matter beneath layer VI in central zones of each lesion. The morphology of cells undergoing neurofibrillary changes (from early nonfibrillar stages to late extracellular ones) suggests that neurons disturbed in their migration toward the site to which they had been committed may become vulnerable to cytoskeletal changes. Micro-environmental disturbances related to hypoxia-ischemia in the affected cortex are proposed as likely contributing factors for the longterm production of this neurofibrillary degeneration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00315009
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  • 8
    Electronic Resource
    Electronic Resource
    Alzheimer's disease-type neurofibrillary degeneration in verrucose dysplasias of the cerebral cortex (1995)
    Springer
    Acta neuropathologica 90 (1995), S. 356-365 
    Details
    ISSN: 1432-0533
    Keywords: Key words Tangle ; Nodule ; Cortical development ; Ischemia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Verrucose dysplasias, found at autopsy in the cerebral cortex of three elderly individuals (two without neurological disorders and one with motor neuron disease), are shown to present neurofibrillary degeneration of Alzheimer's disease type. This neurofibrillary degeneration immunoreacted with antibodies against abnormally phosphorylated tau (5E2 and AT8), disclosed acetyl- and butyrylcholinesterase activity, and was consistently stained with thioflavin-S. Cortical dysplasias, found either as isolated verrucose nodules or comprising multiple nodules, contained cell-sparse areas around which a peak of neurofibrillary changes was seen. Cell-sparse areas were sometimes bridged by stripes of neurons and fibers arranged in a radial fashion, and many of these neurons showed neurofibrillary degeneration. Cytoskeletal abnormalities were conspicuous in layers II and III at the external borders of the dysplasias, as well as in neurons located in layers V and VI, and in the white matter beneath layer VI in central zones of each lesion. The morphology of cells undergoing neurofibrillary changes (from early non-fibrillar stages to late extracellular ones) suggests that neurons disturbed in their migration toward the site to which they had been committed may become vulnerable to cytoskeletal changes. Micro-environmental disturbances related to hypoxia-ischemia in the affected cortex are proposed as likely contributing factors for the long-term production of this neurofibrillary degeneration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00315009
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  • 9
    Electronic Resource
    Electronic Resource
    Seed dispersal and seedling emergence in an old field community in central New York (USA) (1986)
    Springer
    Oecologia 70 (1986), S. 92-99 
    Details
    ISSN: 1432-1939
    Keywords: Seed dispersal ; Emergence ; Old field communities ; Solidago spp. ; Asteraceae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Seed dispersal and seedling emergence of common taxa growing in a Solidago-dominated old field in central New York (USA) were monitored from May 1982 to June 1984. Over 3.5x104 seeds per m2 were captured on seed traps in each of the two years, with peaks occuring in July (due to Hieracium) and in November (due to Solidago). About 4.0x103 seedling/m2 emerged beneath the intact community in each of the two years. Although seedlings emerged predominantly in the early spring, a secondary peak occurred in September and October when many seedlings of introduced grasses appeared. Two additional aspects of the reproductive biology of the major taxa were related to the seasonal timing of seed dispersal: As the date of peak seed dispersal (among taxa) became progressively later in the season, (1) the duration of dispersal increased from about one week to about one-half year, and (2) the delay between the peak of seed dispersal and the peak of seedling emergence increased from a few days to about one-half year.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00377115
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  • 10
    Electronic Resource
    Electronic Resource
    Bacterial populations in replicate marine enrichment cultures: assessing variability in abundance using 16S rRNA-based probes (1999)
    Springer
    Hydrobiologia 401 (1999), S. 69-75 
    Details
    ISSN: 1573-5117
    Keywords: microcosms ; bacterial populations ; 16S rRNA oligonucleotide probes ; lignin ; coastal seawater
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Most studies of marine bacterial communities focus on functional attributes of the community, rather than on population or community structure, at least in part, because of the difficulty in enumerating individual species within complex communities. Here, we describe a study in which populations of three bacterial species were followed over time in replicate marine enrichment cultures using 16S rRNA-based oligonucleotide probes. Three identical enrichment microcosms were established with lignin-rich pulp mill waste as a sole carbon source, inoculated with coastal seawater, and transferred at two-week intervals. Population levels were assessed throughout a six-week period using species-specific 16S rRNA-based oligonucleotide probes directed toward three bacterial species that were numerically important (and culturable) members of the enrichments. Substantial differences in the population levels of each bacterial species were found among the triplicate incubations, despite the fact that the enrichments were inoculated and treated identically. Stochastic differences in the composition of the inoculum and/or ecological interactions within the enrichment replicates may have been important in determining final population levels. Functional ability, assessed as rates of degradation of a synthetic lignin preparation, were fairly similar among the three replicate enrichments (within 70%), despite the substantial differences in population levels of the representative lignin-degrading species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003771318693
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