Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    The contribution of arachidonic acid to the aetiology and pathophysiology of focal brain oedema; studies using an infusion oedema model (1991)
    Springer
    Acta neurochirurgica 113 (1991), S. 57-68 
    Details
    ISSN: 0942-0940
    Keywords: Blood brain barrier ; cerebral blood flow ; intracranial pressure ; arachidonic acid ; brain oedema ; evoked potential
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Arachidonic acid solution (2 to 15 mg/ml) was infused into the right forebrain white matter of anaesthetised cats over three hours to evaluate its contribution to the genesis and pathophysiology of vasogenic brain oedema. The 0.6 ml infusion increased local white matter water content by a mean of 11.3 ml/100 g tissue but did not increase cortical water content. Histological studies revealed local expansion and trabeculation of the white matter with aggregations of granulocytic neutrophils in the venules and perivenular brain. The adjacent cortical cytoarchitecture was normal. The white matter around the infusion site was stained lightly and over a variable area (15–20 mm2) by intravenously administered Evans Blue dye 2%. Regional cerebral blood flow (rCBF) adjacent to the frontal infusion did not change significantly during the period of infusion and remained similar to rCBF in the contralateral hemisphere. Following the arachidonic acid infusion regional CBF CO2 reactivity was normal and three was no asymmetry of either cortical somatosensory evoked potential (SEP) or motor evoked potential (MEP) waveforms. The increase in brain water content and changes in the ICP and ICP related biodynamics (pressure-volume index, lumped craniospinal compliance and CSF outflow resistance) were similar to those seen following infusion of 0.6 ml saline. These studies suggest that free intraparenchymal arachidonic acid, at concentrations exceeding those occurring in most neuropathological conditions, can increase the normal brain parenchymal capillary permeability but does not disrupt focal cerebrovascular and electrophysiological function. The clinical implications of these findings are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01402116
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Neuropathological and neurophysiological effects of interstitial white matter autologous and non-autologous protein containing solutions: Further evidence for a glioma derived permeability factor (1993)
    Springer
    Acta neurochirurgica 120 (1993), S. 164-174 
    Details
    ISSN: 0942-0940
    Keywords: Brain edema ; blood brain barrier ; serum protein ; evoked potential ; glioma ; cerebral blood flow ; permeability factor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The feline infusion model of brain edema was used to evaluate the pathophysiological effects of 0.6ml infusions of autologous serum protein (66%), human serum protein (66%), human glioma cyst fluid and a tissue culture medium (TCM) on the structure and function of the forebrain white matter. These infusions increased local white matter water content by between 10.8 and 12.5 ml/100 g brain and were associated with moderate increases in ICP and CSF outflow resistance and a significant decrease in lumped craniospinal compliance. Cortical somatosensory potentials, motor evoked potentials, EEG and local cerebral blood flow (rCBF) at normocapnia were generally unchanged by the various infusions. All infusates except the 66% autologous serum protein infusion impaired rCBF CO2 reactivity. Histologically all infusates caused marked extracellular edema. The autologous serum protein infusion caused no additional histological changes whereas the glioma cyst infusates caused profound endothelial and astrocytic swelling, focal endothelial necrosis, basement membrane disruption, perivascular microglial reaction and pavementation and perivascular migration of polymor-phonuclear leukocytes. Similar but less marked changes were seen after infusion of human serum protein whilst the TCM produced only minimal changes. The intensity and extent of Evans Blue extravasation into the forebrain white matter was greatest with glioma cyst infusates and with all infusions reflected the extent to microvascular changes. These studies show that products derived from gliomas cause additional damage to the blood-brain-barrier than that caused by non-autologous serum proteins. These results add further support for the existence of glioma derived permeability factors (GDPF), but suggest neither serum proteins nor glioma derived compounds in the white matter interstitium significantly influence local electrophysiological function. Some limitations of the infusion edema model when using non-autologous infusions and difficulties quantitating brain dysfunction are emphasised.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02112037
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    The role of sea-salts in enhancing and mitigating surface water acidity (1995)
    Springer
    Water, air & soil pollution 85 (1995), S. 553-558 
    Details
    ISSN: 1573-2932
    Keywords: Sea-salts ; acidification ; Scottish catchments ; aluminium ; salmonids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Enhancement of the acidity of fresh waters due to sea-salt “episodes” has been reported in western regions of Scotland, Ireland and Norway and eastern regions of Canada and the United States of America. In all cases these short-term pH depressions have been ascribed to cation-exchange processes in catchment soils whereby sodium ions displace acidic cations (H+, Al3+) resulting in a lowering of the Na/Cl ratio in run-off water. Studies of sea-salt episodes in different catchment types of similar sensitivity in Scotland show significant variations in chemical responses, especially in terms of acidification status. Catchments with high background salt content, in a low sulphur deposition area, show only a small increase in acidity with negligible aluminium release and most of the sodium retention matched by Ca and Mg release. Catchments in intermediate deposition areas, with low background salt levels, exhibit smaller sodium retention with increased leaching of acidity and labile aluminium. High non-marine S deposition sites, with intermediate background salt levels, reveal high levels of acidity and aluminium leaching associated with some calcium leaching and evidence of Mg retention. Mitigation of acidification occurs at sites with high background sea-salt levels (eg north west Scotland) where acidic deposition is selectively retained in catchment soils. Non-marine sulphate values in run-off are therefore much lower (often producing negative values) than those predicted from current S deposition values. Consequently such sites are presently producing false exceedances of freshwater Critical Loads when current S deposition values are used. Future reductions in S deposition will probably affect the adsorption characteristics at these sites with consequent effects on sulphate leaching.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00476887
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    The consequences of liming a highly acidified catchment in central Scotland (1995)
    Springer
    Water, air & soil pollution 85 (1995), S. 1015-1020 
    Details
    ISSN: 1573-2932
    Keywords: acidification ; liming ; catchment ; fish ; Scotland
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Research during the mid 1980s identified acidified, forested catchments in central Scotland whose hydrochemistry was not capable of supporting native fish populations. Calcium concentrations were around 20 μeq l−1, less than the suggested critical value of 50 μeq l−1, with hydrogen concentrations around 70 μeq l−1, greater than the critical value of about 30 μeq l−1. Limestone was applied by aerial application to the source areas of selected streams in 1990 with around 5% (15 ha) of the total catchment area of 270 ha treated at 10 tonnes ha−1. Stream monitoring, carried out over the period 1989–1995, showed an immediate response to liming followed by a progressive decline. Calcium values were elevated to 〉150 μeq l−1 and hydrogen concentrations reduced to 20 μeq l−1, reverting in time towards pre-liming values. Although salmonid survival was improved during low flow conditions in summer, only a few fry survived to the autumn as acid episodes increased, and these were subsequently lost from the system during the winter period. Budget calculations indicated losses of around 30% of the applied calcium during the first four years. Studies on the vegetation and soils revealed a greater than expected penetration of calcium to depth (10–20 cm) in the soil profile. Results suggest that source area liming at this rate has had minimal effects on the vegetation and by increasing the proportion of the catchment limed to 15% could have a much greater success in reducing the frequency of biologically damaging episodes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00476963
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...