| 1. |
- Adner, Mikael, et al.
(författare)
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Budesonide Prevents Cytokine-Induced Decrease of the Relaxant Responses to Formoterol and Terbutaline, but Not to Salmeterol, in Mouse Trachea
- 2010
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Ingår i: Journal of Pharmacology and Experimental Therapeutics. - : American Society for Pharmacology & Experimental Therapeutics (ASPET). - 1521-0103 .- 0022-3565. ; 333:1, s. 273-280
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Tidskriftsartikel (refereegranskat)abstract
- During asthma exacerbations, increased airway inflammation may impair the effects of beta(2)-adrenoceptor (beta(2)AR) agonists. It is unclear whether this impairment is prevented by inhaled glucocorticoids (GCs). We have investigated the relaxation of carbachol-contracted mouse tracheal segments to the beta(2)AR agonists formoterol, terbutaline, and salmeterol. The segments were pre-exposed for 4 days to the proinflammatory cytokines tumor necrosis factor alpha (100 ng/ml) and interleukin-1 beta (10 ng/ml) with or without the GC, budesonide (1 mu M). Formoterol and terbutaline induced greater maximal relaxation (R-max)than salmeterol. The cytokines decreased R-max of all beta(2)AR agonists, whereas budesonide had no effect. However, after concomitant treatment with cytokines and budesonide, the R-max values of formoterol and terbutaline were not impaired, whereas budesonide did not prevent the decrease in the R-max of salmeterol. A similar pattern was observed for cAMP production by the agonists. In tracheal smooth muscle, beta(2)AR mRNA was not affected by the cytokines but increased with budesonide. However, the cytokines markedly increased cyclooxygenase (COX)-2 mRNA expression, which may lead to heterologous desensitization of beta(2)AR. It is noteworthy that the cytokine-induced increase of COX-2 was blocked by concomitant budesonide suggesting that heterologous desensitization of beta(2)AR by the cytokines may be prevented by budesonide treatment. Budesonide prevented cytokine-induced impairment of the tracheal relaxation and beta(2)AR/cAMP signaling for formoterol but not for salmeterol. This suggests that differences exist between formoterol and salmeterol in beta(2)AR coupling/activation and/or signal transduction upstream of cAMP. These results imply that maximal bronchodilator effects of formoterol, but not of salmeterol, are maintained by budesonide treatment during periods with increased inflammation, such as asthma exacerbations.
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| 2. |
- Borde, Annika, 1979, et al.
(författare)
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Increased water transport in PDMS silicone films by addition of excipients
- 2012
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Ingår i: Acta Biomaterialia. - : Elsevier BV. - 1742-7061 .- 1878-7568. ; 8:2, s. 579-588
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Tidskriftsartikel (refereegranskat)abstract
- The development of new adhesive wound care products intended for an application over a prolonged time requires good water transporting properties of the adhesive for the maintenance of a suitable environment around the wound. The ability of polydimethylsiloxane (PDMS)-based silicone films to transport water has led to its use in skin pressure-sensitive adhesives and it would be advantageous to find ways for controlling or increasing water transport across PDMS films in order to be able to develop improved skin adhesives. In this study we present a way to increase water transport in such films by the addition of hydrophilic excipients. Three hydrophilic additives, highly water-soluble sucrose and the two superabsorbent polymers (SAP) Carbopol® and Pemulen™, were investigated. The effect of the excipients was characterized by water transport studies, swelling tests, scanning electron microscopy imaging and confocal microscopy. The cross-linked polymers, primarily Pemulen™, were efficient water transport enhancers, whereas sucrose did not show any effect. The effect of the additives seemed to correlate with their water binding capacity. For SAPs the formation of a percolating structure by swollen polymer was also suggested, which enhances water penetration by the higher volume fraction of areas with a higher diffusion constant (swollen SAP), leading to a faster transport through the entire film. © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
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| 3. |
- Engström, Linda, et al.
(författare)
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Lipopolysaccharide-Induced Fever Depends on Prostaglandin E2 Production Specifically in Brain Endothelial Cells
- 2012
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Ingår i: Endocrinology. - : Endocrine Society. - 0013-7227 .- 1945-7170. ; 153:10, s. 4849-4861
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Tidskriftsartikel (refereegranskat)abstract
- Immune-induced prostaglandin E2 (PGE2) synthesis is critical for fever and other centrally elicited disease symptoms. The production of PGE2 depends on cyclooxygenase-2 and microsomal prostaglandin E synthase-1 (mPGES-1), but the identity of the cells involved has been a matter of controversy. We generated mice expressing mPGES-1 either in cells of hematopoietic or nonhematopoietic origin. Mice lacking mPGES-1 in hematopoietic cells displayed an intact febrile response to lipopolysaccharide, associated with elevated levels of PGE2 in the cerebrospinal fluid. In contrast, mice that expressed mPGES-1 only in hematopoietic cells, although displaying elevated PGE2 levels in plasma but not in the cerebrospinal fluid, showed no febrile response to lipopolysaccharide, thus pointing to the critical role of brain-derived PGE2 for fever. Immunohistochemical stainings showed that induced cyclooxygenase-2 expression in the brain exclusively occurred in endothelial cells, and quantitative PCR analysis on brain cells isolated by flow cytometry demonstrated that mPGES-1 is induced in endothelial cells and not in vascular wall macrophages. Similar analysis on liver cells showed induced expression in macrophages and not in endothelial cells, pointing at the distinct role for brain endothelial cells in PGE2 synthesis. These results identify the brain endothelial cells as the PGE2-producing cells critical for immune-induced fever.
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| 4. |
- Gatchell, Michael, et al.
(författare)
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Commissioning of the DESIREE storage rings - a new facility for cold ion-ion collisions
- 2014
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Ingår i: XXVIII International Conference on Photonic, Electronic and Atomic Collisions (ICPEAC 2013). - : Institute of Physics (IOP). ; 488:1
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Konferensbidrag (refereegranskat)abstract
- We report on the ongoing commissioning of the Double ElectroStatic Ion Ring ExpEriment, DESIREE, at Stockholm University. Beams of atomic carbon anions (C-) and smaller carbon anion molecules (C-2(-), C-3(-), C-4(-) etc.) have been produced in a sputter ion source, accelerated to 10 keV or 20 keV, and stored successfully in the two electrostatic rings. The rings are enclosed in a common vacuum chamber cooled to below 13 Kelvin. The DESIREE facility allows for studies of internally relaxed single isolated atomic, molecular and cluster ions and for collision experiments between cat-and anions down to very low center-of-mass collision energies (meV scale). The total thermal load of the vacuum chamber at this temperature is measured to be 32 W. The decay rates of stored ion beams have two components: a non-exponential component caused by the space charge of the beam itself which dominates at early times and an exponential term from the neutralization of the beam in collisions with residual gas at later times. The residual gas limited storage lifetime of carbon anions in the symmetric ring is over seven minutes while the 1/e lifetime in the asymmetric ring is measured to be about 30 seconds. Although we aim to improve the storage in the second ring, the number of stored ions are now sufficient for many merged beams experiments with positive and negative ions requiring milliseconds to seconds ion storage.
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| 5. |
- Gatchell, Michael, et al.
(författare)
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First results from the Double ElectroStatic Ion-Ring ExpEriment, DESIREE
- 2014
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Ingår i: XXVIII International Conference on Photonic, Electronic and Atomic Collisions (ICPEAC 2013). - : Institute of Physics (IOP). ; 488
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Konferensbidrag (refereegranskat)abstract
- We have stored the first beams in one of the rings of the double electrostatic ion-storage ring, DESIREE at cryogenic and at room temperature conditions. At cryogenic operations the following parameters are found. Temperature; T= 13K, pressure; p <10(-13) mbar, initial number of stored ions; N > 10(7) and storage lifetime of a C-2(-) beam; tau = 450 S.
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| 6. |
- Hartman, Henrik, et al.
(författare)
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First storage of ion beams in the Double Electrostatic Ion-Ring Experiment : DESIREE
- 2013
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Ingår i: Review of Scientific Instruments. - : American Institute of Physics (AIP). - 0034-6748 .- 1089-7623. ; 84:5
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Tidskriftsartikel (refereegranskat)abstract
- We report on the first storage of ion beams in the Double ElectroStatic Ion Ring ExpEriment, DESIREE, at Stockholm University. We have produced beams of atomic carbon anions and small carbon anion molecules (Cn-, n = 1, 2, 3, 4) in a sputter ion source. The ion beams were accelerated to 10 keV kinetic energy and stored in an electrostatic ion storage ring enclosed in a vacuum chamber at 13 K. For 10 keV C2- molecular anions we measure the residual-gas limited beam storage lifetime to be 448 s +/- 18 s with two independent detector systems. Using the measured storage lifetimes we estimate that the residual gas pressure is in the 10-14 mbar range. When high current ion beams are injected, the number of stored particles does not follow a single exponential decay law as would be expected for stored particles lost solely due to electron detachment in collision with the residual-gas. Instead, we observe a faster initial decay rate, which we ascribe to the effect of the space charge of the ion beam on the storage capacity.
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| 7. |
- Hsiao, Meng-Hsuan, et al.
(författare)
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Design and characterization of a novel amphiphilic chitosan nanocapsule-based thermo-gelling biogel with sustained in vivo release of the hydrophilic anti-epilepsy drug ethosuximide
- 2012
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Ingår i: Journal of Controlled Release. - : Elsevier BV. - 0168-3659 .- 1873-4995. ; 161:3, s. 942-948
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Tidskriftsartikel (refereegranskat)abstract
- Thermo-gelling injectable nanogels, with no burst release of loaded drug, were prepared by a simple route by combining self assembled nanocapsules of amphiphilically modified chitosan with glycerophosphate di-sodium salt and glycerol. The potential as a depot drug delivery system was demonstrated in vivo through the therapeutic effect of ethosuximide (ESM) loaded nanogels, suppressing spike wave discharges (SWDs) in Long Evan rat model. Simultaneously clearance of gels from the site of administration was monitored non-invasively using MRI. The gel structure was characterized using TEM and SEM, confirming the gels to be an assembly of nanocapsules and using two-photon microscopy to visualize the network structure. In vitro drug release studies using ESM revealed that the nanogels exhibited extended, mostly Fickian release. Finally, all investigated formulations displayed excellent cytotoxicity data determined by MTT assay using human retinal pigmented epithelium cells. All presented properties are highly desirable for injectable depot gels for drug delivery.
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| 8. |
- Larsson, Kjell, et al.
(författare)
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Effects of an extensive Prymnesium polylepis bloom on breeding eiders in the Baltic Sea
- 2014
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Ingår i: Journal of Sea Research. - : Elsevier. - 1385-1101 .- 1873-1414. ; 88, s. 21-28
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Tidskriftsartikel (refereegranskat)abstract
- The effects of an extensive bloom of the potentially toxic Prymnesium polylepis (Haptophyta) on breeding eiders (Somateria mollissima) in the Baltic Sea were analysed. Increasing abundances of the alternate stage P. polylepis was detected by a marine monitoring programme in the autumn 2007. The bloom peaked between March and May 2008 in the southern, central and northwestern Baltic Proper and abundances of up to 5 x 106 cells l- 1 were recorded. At several sites P. polylepis constituted between 30 and 90% of the total phytoplankton biovolume. The flagellate was only recorded in low numbers in the northeastern Baltic Proper and Gulf of Finland. The abundances were low in 2007, 2009 and 2010. In 28 eider colonies situated in the southern and central Baltic Proper, sharp and synchronous declines in the number of nesting eiders were observed from 2007 to 2008. In colonies on Gotland in the central Baltic Proper, a 76% decrease, from 6650 nests to 1620 nests, was followed by increases in 2009 and 2010, although not up to numbers observed in 2007. At Utklippan and Ertholmene in the southern Baltic Proper, the observed decreases of 55%, from 144 to 65 nests, and 36%, from 1660 to 1060 nests, respectively, between 2007 and 2008, were followed by increases in 2009 and 2010 up to the level observed in 2007. By contrast, no general decline of the number of nesting eiders was observed from 2007 to 2008 in 75 colonies in the northeastern Baltic Proper and Gulf of Finland. Hence, the spatial distribution of the P. polylepis bloom in 2008 closely matched the observed distribution of extensive non-breeding of female eiders. We suggest that the intensive spring bloom of P. polylepis, either through a toxic or non-toxic pathway, affected the main benthic food of eiders, i.e. blue mussels (Mytilus trossulus x Mytilus edulis), at pre-breeding foraging sites close to the breeding sites, and, subsequently, the body condition of adult female eiders and their breeding propensity.
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| 9. |
- Larsson, Mikael, 1982, et al.
(författare)
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Determination of the glass transition of powder samples using Dynamic Mechanic Analysis on compacts
- 2010
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Ingår i: Annual Transactions - The Nordic Rheology Society. - 1601-4057. ; 18, s. 59-64
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Dynamic Mechanic Analysis, DMA, is asensitive method to determine the glasstransition temperature (Tg) of materials.Several different sample geometries such asthree point bending, stretched films orcompressed cylinders, are commonly used.The Tg of a powder is related to its “stickypoint”, i.e. the temperature when the powderparticles interact instead of flowing freely.The determination of powder Tg is notstraightforward using DMA due to thelimiting geometry. Here it is demonstratedthat the Tg of powder samples canbe effectively and correctly determinedby DMA on compacts in compression mode,using a standard wedge shaped probe usuallyutilized in three point bend analysis. Theanalysis of compacts holds the benefits ofanalysing powder samples as received frommanufacturers, being relatively robust withregard to deformation as the materialbecomes rubbery, and enabling easy samplepreparation and handling.
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| 10. |
- Larsson, Mikael, 1982, et al.
(författare)
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Different types of microfibrillated cellulose as filler materials in polysodium acrylate superabsorbents
- 2011
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Ingår i: Chinese Journal of Polymer Science (English Edition). - : Springer Science and Business Media LLC. - 1439-6203 .- 0256-7679. ; 29:4, s. 407-413
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Tidskriftsartikel (refereegranskat)abstract
- Three types of microfibrillated cellulose (MFC) with differences in structure and surface charge were used at low concentration as filler materials in polysodium acrylate superabsorbents (SAPs). The swelling of the composite hydrogels was determined in 0.9% NaCl solution as well as in deionized water. The shear modulus of the samples was determined through uniaxial compression analysis after synthesis and after swelling in 0.9% NaCl solution. Furthermore, the ability to retain filler effects after washing was investigated. The results showed that all of the investigated MFCs had a strong reinforcing effect on the shear modulus after synthesis. The filler effect on swelling and on the associated shear modulus of swollen samples showed a more complicated dependence on structure and surface charge. Finally, it was found that the filler effects were reasonably retained after washing and subsequent drying. The results confirm that MFC holds great potential as a filler material in superabsorbent applications. Furthermore, the results provide some insight on how the structural properties and surface charge of MFC will affect gel properties depending on swelling conditions. This information should be useful in evaluating the use of different types of MFC in future applications.
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