| 1. |
- Ahlen, K., et al.
(författare)
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Platelet-derived growth factor-BB modulates membrane mobility of ß1 integrins
- 2004
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Ingår i: Biochemical and Biophysical Research Communications - BBRC. - : Elsevier BV. - 0006-291X .- 1090-2104. ; 314:1, s. 89-96
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Tidskriftsartikel (refereegranskat)abstract
- Platelet-derived growth factor (PDGF)-BB elicits a migratory response including reorganization of the actin cytoskeleton in different cell types. Here we have investigated the effects of PDGF-BB stimulation on ß 1 integrin containing focal adhesions in human diploid fibroblasts adhered to collagen type I. Stimulation with PDGF-BB dissociated focal adhesions and relocated ß1 integrins from focal adhesions to the periphery of the cells. These changes were rapid and transient in character. Relocation of ß1 integrins was prevented by inhibitors of phosphoinositide-3-kinase and protein kinase C. PDGF-BB stimulated fibroblasts exhibited an increased diffusion coefficient of cell surface ß1 integrins as determined by fluorescence recovery of photobleaching. The cell surface expression of ß1 integrins was not changed after stimulation with PDGF-BB. Our data suggest that PDGF-BB increases the dynamic properties of cell-surface ß1 integrins, which most likely are important for the migratory response elicited by PDGF-BB. © 2003 Elsevier Inc. All rights reserved.
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| 2. |
- Ammoun, Sylwia, et al.
(författare)
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Distinct Recognition of OX1 and OX2 Receptors by Orexin Peptides
- 2003
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Ingår i: Journal of Pharmacology and Experimental Therapeutics. - : American Society for Pharmacology & Experimental Therapeutics (ASPET). - 0022-3565 .- 1521-0103. ; 305:2, s. 507-514
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we have compared the abilities of orexin-A and orexin-B and variants of orexin-A to activate different Ca(2+) responses (influx and release) in human OX(1) and OX(2) receptor- expressing Chinese hamster ovary cells. Responses mediated by activation of both receptor subtypes with either orexin-A or -B were primarily dependent on extracellular Ca(2+), suggesting similar activation of Ca(2+) influx as we have previously shown for orexin-A and OX(1) receptors. Amino acid-wise truncation of orexin-A reduced its ability to activate OX(1) and OX(2) receptors, but the response mediated by the OX(2) receptor was more resistant to truncation than the response mediated by the OX(1) receptor. We also performed a sequential replacement of amino acids 14 to 26 with alanine in the truncated orexin-A variant orexin-A(14-33). Replacement of the same amino acids produced a fall in the potency for each receptor subtype, but the reduction was less prominent for the OX(2) receptor. The most marked reduction was produced by the replacement of Leu20, Asp25, and His26 with alanine. Interestingly, extracellular Ca(2+) dependence of responses to some of the mutated peptides was different from those of orexin-A and -B. The mutagenesis also suggests that although the determinants required from orexin-A for binding to and activation of the receptor are highly conserved between the orexin receptor subtypes, the OX(2) receptor requires fewer determinants. This might in part explain why orexin-B has the affinity and potency equal to orexin-A for this subtype, although it has 10- to 100-fold lower affinity and potency for the OX(1) receptor.
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| 3. |
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| 4. |
- Gloris, M, et al.
(författare)
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Proton-induced production of residual radionuclides in lead at intermediate energies
- 2001
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Ingår i: NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT. - : ELSEVIER SCIENCE BV. ; 463:3, s. 593-633
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Recension (övrigt vetenskapligt/konstnärligt)abstract
- Integral excitation functions for the production of residual nuclides are basic quantities for the calculation of radioactive inventories of spallation targets in spallation neutron sources and in accelerator-driven devices for energy amplification or for
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| 5. |
- Holmqvist, Bo, et al.
(författare)
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The early ontogeny of neuronal nitric oxide synthase systems in the zebrafish.
- 2004
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Ingår i: Journal of Experimental Biology. - : The Company of Biologists. - 1477-9145 .- 0022-0949. ; 207:Pt 6, s. 923-935
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Tidskriftsartikel (refereegranskat)abstract
- To examine a putative role for neuronal nitric oxide synthase (nNOS) in early vertebrate development we investigated nNOS mRNA expression and cGMP production during development of the zebrafish Danio rerio. The nNOS mRNA expression in the central nervous system (CNS) and periphery showed a distinct spatio-temporal pattern in developing zebrafish embryo and young larvae. nNOS mRNA expression was first detected at 19 h postfertilisation (h.p.f.), in a bilateral subpopulation of the embryonic ventrorostral cell cluster in the forebrain. The number of nNOS mRNA-expressing cells in the brain slowly increased, also appearing in the ventrocaudal cell cluster from about 26 h.p.f., and in the dorsorostral and hindbrain cell cluster and in the medulla at 30 h.p.f. A major increase in nNOS mRNA expression started at about 40 h.p.f., and by 55 h.p.f. the expression constituted cell populations in differentiated central nuclei and in association with the proliferation zones of the brain, and in the medulla and retina. In parts of the skin, nNOS mRNA expression started at 20 h.p.f. and ended at 55 h.p.f. Between 40 and 55 h.p.f., nNOS mRNA expression started in peripheral organs, forming distinct populations after hatching within or in the vicinity of the presumptive swim bladder, enteric ganglia, and along the alimentary tract and nephritic ducts. Expression of nNOS mRNA correlated with the neuronal differentiation pattern and with the timing and degree of cGMP production. These studies indicate spatio-temporal actions by NO during embryogenesis in the formation of the central and peripheral nervous system, with possible involvement in processes such as neurogenesis, organogenesis and early physiology.
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| 6. |
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| 7. |
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| 8. |
- Macher, M.-B., et al.
(författare)
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Hydrogenation of palm oil in near-critical and supercritical propane
- 2001
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Ingår i: European Journal of Lipid Science and Technology. - 1438-7697 .- 1438-9312. ; 103:2, s. 81-84
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Tidskriftsartikel (refereegranskat)abstract
- Palm oil was hydrogenated in a single-phase mixture with propane and hydrogen. This was done in a small (0.5 ml), continuous fixed-bed reactor, using a 1% Pd/C catalyst. Temperature (65-135 °C), H2/TG ratio (4-50 mol/mol) and residence time (0.2-2.0 s) were varied systematically to assess the iodine value (IV) as a function of these three variables. The substrate concentration was 1 wt-%. The IV was dependent mainly on temperature and residence time. At 120 °C and a residence time of 2.0 s, full hydrogenation was achieved. The trends observed indicate that this is possible even at lower temperatures, if the residence time is increased further. Unexpectedly, the hydrogen concentration (i.e. the H2/TG ratio) was of minor importance, which can be a sign of either H2-saturation of the catalyst or a phase-split of the reaction mixture with resulting mass transport limitations for the hydrogen. Unfortunately, the catalyst showed strong signs of deactivation very early in the experiments, possibly due to impurities in the feedstock and/or to coke formation.
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| 9. |
- Macher, M.-B., et al.
(författare)
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Triacylglycerol analysis of partially hydrogenated vegetable oils by silver ion HPLC
- 2001
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Ingår i: Journal of Separation Science. - 1615-9306 .- 1615-9314. ; 24:3, s. 179-185
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Tidskriftsartikel (refereegranskat)abstract
- A fast and reliable method was developed for the analysis of positional and geometrical triacylglycerol isomers in partially hydrogenated vegetable oils. A binary gradient of heptane/acetonitrile was employed in silver ion HPLC with evaporative light scattering detection. Good resolution of native and partially hardened oils was achieved within 22 min for palm oil and within 60 min for rapeseed oil. Initial stability problems were found to be caused by decreasing acetonitrile concentration in the solvent mixture, due to selective evaporation of acetonitrile. By tightening the bottle caps and plugging the usual ventilation inlets, this could be prevented; the system then became very stable. A complementary system (heptane/acetone) was used to confirm the absence of 1,2-elaidin-3-palmitin in the hydrogenated samples. This system shows better resolution in the more saturated region (up to three double bonds). However, for less saturated species, peak-split problems occurred (e.g. for triolein), and the elution strength of acetone was not sufficient for the elution of the most polyunsaturated triacylglycerols of rapeseed oil. This would have required a ternary gradient with an additional, stronger solvent, e.g. acetonitrile. Hence, the original heptane/acetonitrile system was retained as the method of choice. It is sufficiently fast and accurate over a wide range of unsaturation to make it suitable for hydrogenation process control, especially of continuous processes with rapidly changing product composition.
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