| 1. |
- Johansson, LB-Å, et al.
(författare)
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Phase equilibria and formation of vesicles of dioleoylphosphatidylcholine in glycerol/water mixtures
- 1993
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Ingår i: Biochimica et Biophysica Acta - Biomembranes. - 0005-2736 .- 1879-2642. ; 1149, s. 285-291
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Tidskriftsartikel (refereegranskat)abstract
- The lipid 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) forms a lamellar liquid crystalline phase (La) in arbitrary mixtures of glycerol and water. The phase has been characterized by means of X-ray diffraction, 3IP-NMR spectroscopy and differential scanning calorimetry (DSC). In the La state, and for DOPC concentrations greater than 50% (w/w), the thickness of the lipid bilayer decreases, while the area of the polar head group increases with increasing glycerol concentration. The phase transition from gel to La state occurs in the range of 240 to 260 K. Contrary to a previous (McDaniel, R.V., McIntosh, T.J. and Simon, S.A. (1983) Biochim. Biophys. Acta 731, 97) study of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) we find that in the gel state, the thickness of the DOPC lipid bilayer is greater than that in the La state. This suggests that in the gel state, the lipid acyl chains of DOPC are in extended configuration. The lamellar phase reaches its maximum swelling at about 50% (w/w) of DOPC. At lower DOPC concentrations a two-phase system is formed where the lamellar phase exists in equilibrium with excess of solvent. Unilamellar vesicles can be prepared from a diluted suspension of the lamellar phase either by using the sonicator or extruder technique. We show this by means of 3IP-NMR, EPR and fluorescence spectroscopy. The mean radius of the vesicles, prepared by a sonicator, has been determined at different glycerol/water mixtures. It is found to decrease continously from 100 A at 100% water to a minimum of 75 Å at about 50% water in the solvent mixture. By further decreasing the water content in the solution, the radius rapidly increases, and a mean radius of 450 Å is estimated at a water content of 10%. The rotational relaxation times of a fluorescent probe and two EPR spin probes, solubilized in DOPC vesicles, have been measured at different glycerol/water mixtures. It is found that the rotational rates are always much slower in the systems containing glycerol.
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| 2. |
- Fransson, L Å, et al.
(författare)
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Effects of cycloheximide, brefeldin A, suramin, heparin and primaquine on proteoglycan and glycosaminoglycan biosynthesis in human embryonic skin fibroblasts
- 1992
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Ingår i: Biochimica et Biophysica Acta. - 0006-3002. ; 1137:3, s. 287-297
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Tidskriftsartikel (refereegranskat)abstract
- (1) We have isolated radiolabelled proteoglycans and glycosaminoglycans produced by human embryonic skin fibroblasts in the presence of (a) cycloheximide to inhibit protein synthesis or (b) brefeldin A to impede transport between the endoplasmic reticulum and the Golgi complex or (c) suramin, heparin or primaquine to interfere with internalization, recycling and degradation. Effects on glycosaminoglycan synthesis were assayed separately by using exogenous p-nitrophenyl beta-D-xylopyranoside (and [3H]galactose) or 125I-labelled p-hydroxyphenyl beta-D-xylopyranoside as initiators. (2) Inhibition of protein synthesis or blocking of transport to the Golgi complex prevented production of most of the proteoglycans with one exception: Cell-associated heparan sulphate-proteoglycan was still produced at 20% of the control level. (3) Treatment with suramin or heparin resulted in decreased deposition of proteoglycan in the pericellular matrix but increased accumulation of cell-associated proteoglycan. Primaquine blocked all proteoglycan synthesis. (4) In the presence of cycloheximide, exogenous beta-D-xyloside initiated galactosaminoglycan production. In contrast, in brefeldin A-treated cells, synthesis was completely abolished. Not even formation of the linkage-region trisaccharide could be detected. (5) These results suggest that exogenous xyloside enters the endoplasmic reticulum and is subsequently transported to the trans-Golgi complex where all further steps involved in glycosaminoglycan assembly takes place. (6) Heparan sulphate proteoglycan produced by brefeldin A-treated cells could be derived from (a) an intracellular pool of preformed core protein located to the trans-Golgi complex, or (b) resident proteoglycan that was either deglycanated/reglycanated or chain-extended. As combined treatment with suramin and brefeldin A markedly reduced cell-associated proteoglycan production, the latter possibility is favoured.
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| 3. |
- Harvey, BS, et al.
(författare)
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The green tea polyphenol (-)-epigallocatechin-3-gallate inhibits amyloid-beta evoked fibril formation and neuronal cell death in vitro
- 2011
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Ingår i: FOOD CHEMISTRY. - 0308-8146. ; 129:4, s. 1729-1736
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Tidskriftsartikel (refereegranskat)abstract
- Alzheimer’s disease is associated with amyloid-β plaques eliciting neuronal oxidative stress. Many naturally occurring compounds have antioxidant properties, but it is unclear if this alone protects against amyloid-β exposure. This study investigated the protective effects of selected bioactive compounds against amyloid-β and pro-oxidant-evoked neurotoxicity in PC12 cells. Neither resveratrol, (−)-epigallocatechin-3-gallate, cyanidin rutinoside or grape skin extract protected PC12 cells against H2O2 or tert butyl hydroperoxide toxicity. Amyloid-β resulted in a concentration-dependent reduction in PC12 cell viability that was unaffected by resveratrol or cyanidin rutinoside pre-treatment. By contrast, (−)-epigallocatechin-3-gallate and grape skin extract significantly reduced amyloid-β-evoked neurotoxicity (by 40%). Only (−)-epigallocatechin-3-gallate was directly able to inhibit amyloid-β aggregate and fibril formation. These results suggest that (−)-epigallocatechin-3-gallate protects neuronal cells by disrupting amyloid-β fibril formation; bioactive polyphenols which disrupt fibril aggregation may confer additional neuroprotection when compared against antioxidant activity alone.
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| 4. |
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| 5. |
- Lund, Jo-Å, et al.
(författare)
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Late radiation effects to the rectum and anus after treatment for prostate cancer; validity of the LENT/SOMA score
- 2013
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Ingår i: Acta Oncologica. - : Taylor & Francis. - 0284-186X .- 1651-226X. ; 52:4, s. 727-735
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Tidskriftsartikel (refereegranskat)abstract
- Background. The Late Effects Normal Tissue/Subjective Objective Management Analytic (LENT/SOMA) system for grading of side effects after radiotherapy was proposed several years ago. Only a few studies have previously been performed on the validity of the LENT/SOMA. The aim of the present study was to validate the LENT/SOMA scoring system for recto-anal side effects after treatment for prostate cancer in a randomized trial.Material and methods. A total of 875 patients with locally advanced prostate cancer were randomized to either hormonal treatment alone or hormonal treatment plus radiotherapy in the Scandinavian Prostate Cancer Group 7 (SPCG-7) study. At least three years after treatment was started, the 178 patients that were randomized at St. Olavs Hospital were approached. One hundred and three patients of these accepted inclusion. The side effects according to LENT/SOMA were graded by oncologist and nurse. In addition, side effects were graded according to the European Organisation for Research and Treatment of Cancer and the Radiation Therapy Oncology Group (EORTC/RTOG) toxicity scale and patient-reported health-related quality of life (HRQOL) questionnaires. Content/face validity, sensitivity and inter-rater reliability of the LENT/SOMA tables for rectum were analyzed.Results. Content/face analysis of LENT/SOMA revealed serious problems. Significant correlations (Spearman's rho > 0.4) were found between three of 15 LENT/SOMA items and similar HRQOL items. LENT/SOMA score made it possible to detect significant differences between the two groups of patients (p < 0.001), EORTC/RTOG toxicity score did not (p = 0.138). Inter-rater reliability was acceptable.Conclusions. LENT/SOMA scoring system for recto-anal side effects after radiotherapy for prostate cancer displays serious difficulties in the present study. Replacement of LENT/SOMA tables for rectum by a combination of patient-reported HRQOL questionnaires, clinical examination and objective physiological measurements might be called for.
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| 6. |
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| 7. |
- Nilsonne, Gustav, et al.
(författare)
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A multimodal brain imaging dataset on sleep deprivation in young and old humans
- 2017
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The Stockholm Sleepy Brain Study I is a functional brain imaging study of 48 younger (20-30 years) and 36 older (65-75 years) healthy participants, with magnetic resonance imaging after normal sleep and partial sleep deprivation in a crossover design. We performed experiments investigating emotional mimicry, empathy for pain, and cognitive reappraisal, as well as resting state functional magnetic resonance imaging (fMRI). We also acquired T1- and T2-weighted structural images and diffusion tensor images (DTI). On the night before imaging, participants were monitored with ambulatory polysomnography and were instructed to sleep either as usual or only three hours. Participants came to the scanner the following evening. Besides MRI scanning, participants underwent behavioral tests and contributed blood samples, which have been stored in a biobank and used for DNA analyses. Participants also completed a variety of self-report measures. The resulting multimodal dataset may be useful for hypothesis generation or independent validation of effects of sleep deprivation and aging, as well as investigation of cross-sectional associations between the different outcomes. V. 2 of this manuscript published 2017-10-12. Changes: new co-author (Claus Lamm), changed affiliations for Kristoffer Månsson, minor changes in the abstract, and revisions of the main text and figures.
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| 8. |
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| 9. |
- Persson, P-A, et al.
(författare)
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Physical properties of pressure polymerized C60
- 1995
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Ingår i: High Pressure Science and Technology. - Singapore : World Scientific and Engineering Academy and Society. - 9810225474 ; , s. 716-718
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Konferensbidrag (refereegranskat)
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| 10. |
- Segalini, Antonio, et al.
(författare)
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Gust structure and generation in canopy flows
- 2011
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Ingår i: European Wind Energy Conference and Exhibition 2011. - 9781618399915 ; , s. 217-221
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Konferensbidrag (refereegranskat)abstract
- Due to an increased demand to place wind turbines in forest areas it is of importance to know the details of the wind flow field over forest canopies. In this study we compare the flow characteristics of an atmospheric boundary layer over a forest canopy and a wind tunnel canopy model. Both the mean velocity distribution and the turbulence intensities were measured for both cases and the friction velocity was determined from the Reynolds shear stress above the edge of the canopy. The comparison between the two data sets is reasonably good, especially close to the canopy edge. The analysis of the time series of both measurement sets has highlighted that the turbulent canopy flow (in both wind tunnel and atmospheric data sets) is composed, beside the high frequency turbulence, by some flow structures detectable only through phase averages approaches.
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