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- Basun, H, et al.
(författare)
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Plasma levels of Abeta42 and Abeta40 in Alzheimer patients during treatment with the acetylcholinesterase inhibitor tacrine
- 2002
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Ingår i: Dementia and geriatric cognitive disorders. - : S. Karger AG. - 1420-8008 .- 1421-9824. ; 14:3, s. 156-160
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Tidskriftsartikel (refereegranskat)abstract
- Deregulation of amyloid precursor protein (APP) processing with increased production of amyloid β-peptide (Aβ) is considered to be a key pathogenic event in Alzheimer’s disease (AD). It has been suggested that stimulation of the muscarinic M<sub>1</sub> receptor subtype affects APP processing and leads to a change in Aβ concentration. To test the hypothesis that treatment with a cholinesterase inhibitor could change the levels of Aβ in plasma, we measured Aβ42 and Aβ40 plasma levels in AD subjects before tacrine treatment and at weeks 2 and 6 of treatment. Treatment with tacrine had no statistically significant effect on plasma Aβ42 and Aβ40 either at 2 weeks or at 6 weeks of administration compared to baseline levels. Plasma Aβ42 and Aβ40 levels showed large subject-to-subject variation but small variation within the same patient over the 3-sample interval. After 2 weeks of treatment with tacrine, there was a strong negative correlation between tacrine concentration and levels of Aβ42 (r = –0.64; p = 0.01) and Aβ40 (r = –0.55; p = 0.04). However, after 6 weeks there was no correlation between plasma concentrations of tacrine and Aβ42 (r = 0.33; p = 0.34) or Aβ40 (r = –0.22; p = 0.54) levels in plasma. After 2 weeks of treatment with an acetylcholinesterase inhibitor, we found a correlation between higher drug concentrations and lower β-amyloid levels. This might indicate an effect on APP metabolism with an increased α-cleavage. But after 6 weeks of drug treatment, there was no obvious drug effect on β-amyloid concentrations. This finding may indicate that compensatory mechanisms have started at 6 weeks and that no long-term effect on key pathological features in AD is to be expected by an inhibition of acetylcholinesterase.
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- Roegner, C., et al.
(författare)
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Transport of Recently Settled Soft-Shell Clams (Mya Arenaria L.) in Laboratory Flume Flow
- 1995
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Ingår i: Journal of Experimental Marine Biology and Ecology. - 0022-0981. ; 187:1, s. 13-26
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Tidskriftsartikel (refereegranskat)abstract
- A laboratory flume was used to examine the retention of juvenile soft-shell clams (2 wk postsettlement) in sediment when exposed to flow. Clams resisted erosion until the initiation of sediment transport, after which they were rapidly advected from sections of test substrate. Comparisons between living and killed clams indicated that burrowing behavior was instrumental for maintaining position in flow I the critical erosion velocity for sediment movement. The ability of low density, shallow-burrowing juvenile bivalves to avoid transport as bedload or resuspended particles is probably minimal during erosional periods, despite that fact that the position of larger, deeper living individuals may be unaffected, In energetic regimes, infaunal recruitment patterns can be dominated by hydrodynamic forces affecting juveniles.
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