| 1. |
- King, Michael A., et al.
(författare)
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A Monte Carlo investigation of artifacts caused by liver uptake in single-photon emission computed tomography perfusion imaging with technetium 99m-labeled agents
- 1996
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Ingår i: Journal of Nuclear Cardiology. - 1532-6551. ; 3:1, s. 18-29
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Significant hepatobiliary accumulation of technetium 99m-labeled cardiac perfusion agents has been shown to cause alterations in the apparent localization of the agents in the cardiac walls. A Monte Carlo study was conducted to investigate the hypothesis that the cardiac count changes are due to the inconsistencies in the projection data input to reconstruction, and that correction of the causes of these inconsistencies before reconstruction, or including knowledge of the physics underlying them in the reconstruction algorithm, would virtually eliminate these artifacts. METHODS AND RESULTS: The SIMIND Monte Carlo package was used to simulate 64 x 64 pixel projection images at 128 angles of the three-dimensional mathematical cardiac-torso (MCAT) phantom. Simulations were made of (1) a point source in the liver, (2) cardiac activity only, and (3) hepatic activity only. The planar projections and reconstructed point spread functions (PSFs) of the point source in the liver were investigated to study the nature of the inconsistencies introduced into the projections by imaging, and how these affect the distribution of counts in the reconstructed slices. Bull's eye polar maps of the counts at the center of the left ventricular wall of filtered back-projection (FBP) and maximum-likelihood expectation-maximization (MLEM) reconstructions of projections with solely cardiac activity, and with cardiac activity plus hepatic activity scaled to have twice the cardiac concentration, were compared to determine the magnitude and location of apparent changes in cardiac activity when hepatic activity is present. Separate simulations were made to allow the investigation of stationary spatial resolution, distance-dependent spatial resolution, attenuation, and scatter. The point source projections showed significant inconsistencies as a function of projection angle with the largest effect being caused by attenuation. When consistent projections were simulated, no significant impact of hepatic activity on cardiac counts was noted with FBP, or 100 iterations of MLEM. With inconsistent projections, reconstruction of 180 degrees resulted in greater apparent cardiac count losses than did 360 degrees reconstruction for both FBP and MLEM. The incorporation of attenuation correction in MLEM reconstruction reduced the changes in cardiac counts to that seen in simulations in which attenuation was not included, but resulted in increased apparent localization of activity in the posterior wall of the left ventricle when scatter was present in the simulated images. CONCLUSIONS: The apparent alterations in cardiac counts when significant hepatic localization is present is due to the inconsistency of the projections inherent in imaging. Prior correction of these, or accounting for them in the reconstruction algorithm, will virtually eliminate them as causes of artifactual changes in localization. Attenuation correction and scatter correction are both required to overcome the major sources of apparent count changes in the heart associated with hepatic uptake.
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| 2. |
- Lembrechts, Jonas J., et al.
(författare)
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Global maps of soil temperature
- 2022
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Ingår i: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 28:9, s. 3110-3144
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Tidskriftsartikel (refereegranskat)abstract
- Research in global change ecology relies heavily on global climatic grids derived from estimates of air temperature in open areas at around 2m above the ground. These climatic grids do not reflect conditions below vegetation canopies and near the ground surface, where critical ecosystem functions occur and most terrestrial species reside. Here, we provide global maps of soil temperature and bioclimatic variables at a 1-km2 resolution for 0–5 and 5–15cm soil depth. These maps were created by calculating the difference (i.e. offset) between in situ soil temperature measurements, based on time series from over 1200 1-km2 pixels (summarized from 8519 unique temperature sensors) across all the world's major terrestrial biomes, and coarse-grained air temperature estimates from ERA5-Land (an atmospheric reanalysis by the European Centre for Medium-Range Weather Forecasts). We show that mean annual soil temperature differs markedly from the corresponding gridded air temperature, by up to 10°C (mean=3.0±2.1°C), with substantial variation across biomes and seasons. Over the year, soils in cold and/or dry biomes are substantially warmer (+3.6±2.3°C) than gridded air temperature, whereas soils in warm and humid environments are on average slightly cooler (−0.7±2.3°C). The observed substantial and biome-specific offsets emphasize that the projected impacts of climate and climate change on near-surface biodiversity and ecosystem functioning are inaccurately assessed when air rather than soil temperature is used, especially in cold environments. The global soil-related bioclimatic variables provided here are an important step forward for any application in ecology and related disciplines. Nevertheless, we highlight the need to fill remaining geographic gaps by collecting more in situ measurements of microclimate conditions to further enhance the spatiotemporal resolution of global soil temperature products for ecological applications.
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| 3. |
- Lembrechts, Jonas J., et al.
(författare)
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SoilTemp : A global database of near-surface temperature
- 2020
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Ingår i: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 26:11, s. 6616-6629
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Tidskriftsartikel (refereegranskat)abstract
- Current analyses and predictions of spatially explicit patterns and processes in ecology most often rely on climate data interpolated from standardized weather stations. This interpolated climate data represents long-term average thermal conditions at coarse spatial resolutions only. Hence, many climate-forcing factors that operate at fine spatiotemporal resolutions are overlooked. This is particularly important in relation to effects of observation height (e.g. vegetation, snow and soil characteristics) and in habitats varying in their exposure to radiation, moisture and wind (e.g. topography, radiative forcing or cold-air pooling). Since organisms living close to the ground relate more strongly to these microclimatic conditions than to free-air temperatures, microclimatic ground and near-surface data are needed to provide realistic forecasts of the fate of such organisms under anthropogenic climate change, as well as of the functioning of the ecosystems they live in. To fill this critical gap, we highlight a call for temperature time series submissions to SoilTemp, a geospatial database initiative compiling soil and near-surface temperature data from all over the world. Currently, this database contains time series from 7,538 temperature sensors from 51 countries across all key biomes. The database will pave the way toward an improved global understanding of microclimate and bridge the gap between the available climate data and the climate at fine spatiotemporal resolutions relevant to most organisms and ecosystem processes.
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| 4. |
- Bergenfelz, Anders, et al.
(författare)
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Impact of autofluorescence for detection of parathyroid glands during thyroidectomy on postoperative parathyroid hormone levels: parallel multicentre randomized clinical trial
- 2023
-
Ingår i: The British journal of surgery. - 1365-2168 .- 0007-1323. ; 110:12, s. 1824-1833
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Techniques for autofluorescence have been introduced to visualize the parathyroid glands during surgery and to reduce hypoparathyroidism after thyroidectomy. METHODS: This parallel multicentre RCT investigated the use of Fluobeam® LX to visualize the parathyroid glands by autofluorescence during total thyroidectomy compared with no use. There was no restriction on the indication for surgery. Patients were randomized 1 : 1 and were blinded to the group allocation. The hypothesis was that autofluorescence enables identification and protection of the parathyroid glands during thyroidectomy. The primary endpoint was the rate of low parathyroid hormone (PTH) levels the day after surgery. RESULTS: Some 535 patients were randomized, and 486 patients received an intervention according to the study protocol, 246 in the Fluobeam® LX group and 240 in the control group. Some 64 patients (26.0 per cent) in the Fluobeam® LX group and 77 (32.1 per cent) in the control group had low levels of PTH after thyroidectomy (P = 0.141; relative risk (RR) 0.81, 95 per cent c.i. 0.61 to 1.07). Subanalysis of 174 patients undergoing central lymph node clearance showed that 15 of 82 (18 per cent) in the Fluobeam® LX group and 31 of 92 (33 per cent) in the control group had low levels of PTH on postoperative day 1 (P = 0.021; RR 0.54, 0.31 to 0.93). More parathyroid glands were identified during operation in patients who had surgery with Fluobeam® LX, and fewer parathyroid glands in the surgical specimen on definitive histopathology. No specific harm related to the use of Fluobeam® LX was reported. CONCLUSION: The use of autofluorescence during thyroidectomy did not reduce the rate of low PTH levels on postoperative day 1 in the whole group of patients. It did, however, reduce the rate in a subgroup of patients.
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| 5. |
- Biressi, A., et al.
(författare)
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Wound healing and arm regeneration in Ophioderma longicaudum and Amphiura filiformis (Ophiuroidea, Echinodermata): comparative morphogenesis and histogenesis
- 2010
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Ingår i: Zoomorphology. - : Springer Science and Business Media LLC. - 0720-213X .- 1432-234X. ; 129:1, s. 1-19
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Tidskriftsartikel (refereegranskat)abstract
- All species of the Ophiuroidea have exceptional regenerative capabilities; in particular, they can replace arms lost following traumatic or self-induced amputation. In order to reconstruct this complex phenomenon, we studied arm regeneration in two different ophiuroids, Ophioderma longicaudum (Retzius, 1805) and Amphiura filiformis O. F. Muller, 1776, which are quite distantly related. These species present contrasting regeneration and differentiation rates and differ in several ecological traits. The aim of this paper is to interpret the primary sequence of morphogenetic and histogenetic events leading to the complete reconstruction of a new arm, comparing the arm regenerative processes of these two ophiuroid species with those described in crinoids. Arm regeneration in ophiuroids is considered an epimorphic process in which new structures develop from a typical blastema formed from an accumulation of presumptive undifferentiated cells. Our results showed that although very different in some respects such as, for instance, the regeneration rate (0.17 mm/week for O. longicaudum and 0.99 mm/week for A. filiformis), morphogenetic and histogenetic aspects are surprisingly similar in both species. The regenerative process presents similar characteristics and follows a developmental scheme which can be subdivided into four phases: a repair phase, an early regenerative phase, an intermediate regenerative phase and an advanced regenerative phase. In terms of histogenesis, the regenerative events involve the development of new structures from migratory pluripotent cells, which proliferate actively, in addition in both cases there is a significant contribution from dedifferentiated cells, in particular dedifferentiating myocytes, although to varying extents. This evidence confirms the plasticity of the regenerative phenomenon in echinoderms, which can apparently follow different pathways in terms of growth and morphogenesis, but nevertheless involve both epimorphic and morphallactic contributions at the cellular level.
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| 6. |
- Bobbio, Emanuele, et al.
(författare)
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Association between central haemodynamics and renal function in advanced heart failure: a nationwide study from Sweden.
- 2022
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Ingår i: ESC heart failure. - : Wiley. - 2055-5822. ; 9:4, s. 2654-2663
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Tidskriftsartikel (refereegranskat)abstract
- Renal dysfunction in patients with heart failure (HF) has traditionally been attributed to declining cardiac output and renal hypoperfusion. However, other central haemodynamic aberrations may contribute to impaired kidney function. This study assessed the relationship between invasive central haemodynamic measurements from right-heart catheterizations and measured glomerular filtration rate (mGFR) in advanced HF.All patients referred for heart transplantation work-up in Sweden between 1988 and 2019 were identified through the Scandiatransplant organ-exchange organization database. Invasive haemodynamic variables and mGFR were retrieved retrospectively. A total of 1001 subjects (49±13years; 24% female) were eligible for the study. Analysis of covariance adjusted for age, sex, and centre revealed that higher right atrial pressure (RAP) displayed the strongest relationship with impaired GFR [β coefficient -0.59; 95% confidence interval (CI) -0.69 to -0.48; P<0.001], followed by lower mean arterial pressure (MAP) (β coefficient 0.29; 95% CI 0.14-0.37; P<0.001), and finally reduced cardiac index (β coefficient 3.51; 95% CI 2.14-4.84; P<0.003). A combination of high RAP and low MAP was associated with markedly worse mGFR than any other RAP/MAP profile, and high renal perfusion pressure (RPP, MAP minus RAP) was associated with superior renal function irrespective of the degree of cardiac output.In patients with advanced HF, high RAP contributed more to impaired GFR than low MAP. A higher RPP was more closely related to GFR than was high cardiac index.
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| 7. |
- Burrow, Michael, et al.
(författare)
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Track stiffness considerations for high speed railway lines
- 2009
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Ingår i: Railway Transportations: Policies, Technology and Perspectives. - Hauppauge, NY : Nova Science Publishers. - 9781606928639 - 1606928635 ; , s. 425-
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- This book provides the latest scientific research regarding the importance of infrastructure charges in establishing competitive conditions in the railway market. The current charging regimes applied throughout the EU member states are analyzed as well as the planning and scheduling that determine how and when the company's resources will be used in the case of railway organizations. Railway noise emission and its reduction are considered among the most important topics in the future development of transportation systems. This book gives an overview on the noise emitted by wheels and rails from the basic emission mechanisms up to noise attenuation by means of passive/active control. The importance of the vertical track stiffness as a means to guide railway track bed design for high speed railway lines are discussed as well. A rational approach to substructure design is described, which it is hoped will further an understanding of the process of appropriate track design and enable the adaptation of existing design procedures to provide a realistic design for the conditions at hand.
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| 8. |
- Carrick, Richard T., et al.
(författare)
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Implantable cardioverter defibrillator use in arrhythmogenic right ventricular cardiomyopathy in North America and Europe
- 2024
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Ingår i: European Heart Journal. - : OXFORD UNIV PRESS. - 0195-668X .- 1522-9645.
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Tidskriftsartikel (refereegranskat)abstract
- Background and Aims Implantable cardioverter-defibrillators (ICDs) are critical for preventing sudden cardiac death (SCD) in arrhythmogenic right ventricular cardiomyopathy (ARVC). This study aims to identify cross-continental differences in utilization of primary prevention ICDs and survival free from sustained ventricular arrhythmia (VA) in ARVC.Methods This was a retrospective analysis of ARVC patients without prior VA enrolled in clinical registries from 11 countries throughout Europe and North America. Patients were classified according to whether they received treatment in North America or Europe and were further stratified by baseline predicted VA risk into low- (<10%/5 years), intermediate- (10%-25%/5 years), and high-risk (>25%/5 years) groups. Differences in ICD implantation and survival free from sustained VA events (including appropriate ICD therapy) were assessed.Results One thousand ninety-eight patients were followed for a median of 5.1 years; 554 (50.5%) received a primary prevention ICD, and 286 (26.0%) experienced a first VA event. After adjusting for baseline risk factors, North Americans were more than three times as likely to receive ICDs {hazard ratio (HR) 3.1 [95% confidence interval (CI) 2.5, 3.8]} but had only mildly increased risk for incident sustained VA [HR 1.4 (95% CI 1.1, 1.8)]. North Americans without ICDs were at higher risk for incident sustained VA [HR 2.1 (95% CI 1.3, 3.4)] than Europeans.Conclusions North American ARVC patients were substantially more likely than Europeans to receive primary prevention ICDs across all arrhythmic risk strata. A lower rate of ICD implantation in Europe was not associated with a higher rate of VA events in those without ICDs.
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| 9. |
- Dahlberg, Anders, et al.
(författare)
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786 svampar på 2015 års rödlista
- 2015
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Ingår i: Svensk Mykologisk Tidskrift. - 1653-0357. ; 36, s. 91-97-
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- A new Swedish Red List was published April 28th 2015 by the Swedish Species Information Centre in which 786 species of fungi are listed. Compared to the previous Red List published in 2010, 11 species have been down-listed, 51 species have been added and 35 species have changed names or taxonomic rank, thus the list has increased by 41. The changes are mainly due to increased knowledge of taxonomy, ecology and distribution, not to changes in the sta-tus of the species. Here, the members of the Species Specialist Group for Fungi 2011 – 2015 summarize the results of the red listing.
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| 10. |
- Dahlberg, Anders, et al.
(författare)
-
Den nya rödlistan har 746 svampar
- 2010
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Ingår i: Svensk mykologisk tidskrift. - 1653-0357. ; 31:2, s. 37-47
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Tidskriftsartikel (refereegranskat)abstract
- The new Red List that was recently presented by the Swedish Species Information Centre (Gärdenfors 2010) includes 746 species of fungi considered to be threatened. Compared to the previous Red List published in 2005, 36 species have been down-listed whereas 150 species have been added, thus the list has increased by 114. The changes are above all due to increased knowledge of taxonomy, ecology and distribution. In the present paper members of the Species Specialist Group for Fungi 2006-2010 summarize the background and results of the red-listing process and present the habitats in which the red-listed species occur.
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| 11. |
- Dahlberg, Anders, et al.
(författare)
-
Den nya Rödlistan har 746 svampar
- 2010
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Ingår i: Svensk mykologisk tidskrift. - 0280-5057. ; 31, s. 37-47
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- Den 28 april i år presenterade ArtDatabanken en ny rödlista och med den en reviderad och upp-daterad lista över hotade svampar i Sverige (Gärdenfors 2010). Det är den femte rödlistan för svampar som tagits fram sedan 1990, eller den sjätte om man räknar med listan över hotade svampar i skog från 1984 (tab. 1). Nu är 746 svamparter rödlistade. Antalet rödlistade arter har gradvis ökat sedan de första listorna. I jämförelse med den senaste från 2005 (632 arter) har 36 arter avförts och 150 arter tillkommit (fig. 1). Förändringarna är framförallt en följd av förbättrat kunskapsläge om arternas taxonomi, ekologi, förekomst och utbredning i landet och beror alltså inte på förändringar av det verkliga tillståndet för arterna. Inte minst har alla observationer och ekologiska uppgifter som SMF:s medlemmar under årens lopp bidragit med varit ytterst värdefulla. Vi sammanfattar här resultatet och presenterar i vilka miljöer de rödlistade arterna finns, lite om vilka åtgärder som behövs för att förbättra deras situation samt vad rödlistning innebär och hur arbetet att ta fram rödlistan har gått till.
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| 12. |
- Dahlberg, Anders, et al.
(författare)
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Svampar – Fungi
- 2010
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Ingår i: Rödlistade arter i Sverige 2010 – The 2010 Red List of Swedish Species. - 9789188506351 ; , s. 231-246
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 13. |
- Dahlberg, Anders, et al.
(författare)
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Svampar Fungi
- 2020
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Ingår i: Rödlistade arter i Sverige 2020. - 9789187853548 ; , s. 67-88
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 14. |
- Dahlberg, Anders, et al.
(författare)
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Svampar Fungi
- 2015
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Ingår i: Rödlistade arter i Sverige 2015. - 9789187853104 ; , s. 53-71
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 15. |
- Dahlberg, Carina, 1980-
(författare)
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Drugs and polymers in dissolving solid dispersions : NMR imaging and spectroscopy
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The number of poorly water-soluble drug substances in the pharmaceutical pipeline is increasing, and thereby also the need to design effective drug delivery systems providing high bioavailability. One favourable formulation approach is preparation of solid dispersions, where dispersing a poorly water-soluble drug in a water-soluble polymer matrix improves the dissolution behaviour and the bioavailability of the drug. However, in order to take full advantage of such formulations the impact of material properties on their performance needs to be investigated. An experimental toolbox has been designed, and applied, for analysing the processes which govern the behaviour of solid pharmaceutical formulations in general, and that of solid dispersions in particular. For the purpose of monitoring multifaceted phenomena in situ during tablet dissolution, nuclear magnetic resonance (NMR) spectroscopy and NMR imaging are superior to many other techniques, both on macroscopic and molecular levels. The versatility of NMR with its isotope and chemical selectivity allows one to follow the influence of the original tablet properties on polymer mobilisation, drug migration and water penetration selectively. Mapping these processes on relevant time scales in dissolving tablets highlighted the gel layer inhomogeneity below the originally dry tablet surface as a key factor for drug release kinetics. Furthermore, NMR relaxometry has been shown to provide novel information about the particle size of the drug and its recrystallisation behaviour within swelling solid dispersions. The NMR experiments have been complemented and supported by investigation of the crystalline state, the powder morphology and the surface composition of the dry solid dispersions. These experiments have been performed by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), powder X-ray diffraction (pXRD), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR) and dynamic contact angle (DAT) measurements. The methods presented in this thesis provide a new avenue towards better understanding of the behaviour of solid dispersions, which in turn may result in more effective distribution of promising drug candidates despite their low water-solubility.
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| 16. |
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| 17. |
- Dahlberg, Carl F. O., et al.
(författare)
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Size Scaling of Plastic Deformation in Simple Shear : Fractional Strain-Gradient Plasticity and Boundary Effects in Conventional Strain-Gradient Plasticity
- 2020
-
Ingår i: Journal of applied mechanics. - : ASME. - 0021-8936 .- 1528-9036. ; 87:3
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Tidskriftsartikel (refereegranskat)abstract
- A recently developed model based on fractional derivatives of plastic strain is compared with conventional strain-gradient plasticity (SGP) models. Specifically, the experimental data and observed model discrepancies in the study by Mu et al. (2016, "Dependence of Confined Plastic Flow of Polycrystalline Cu Thin Films on Microstructure," MRS Com. Res. Let. 20, pp. 1-6) are considered by solving the constrained simple shear problem. Solutions are presented both for a conventional SGP model and a model extension introducing an energetic interface. The interface allows us to relax the Dirichlet boundary condition usually assumed to prevail when solving this problem with the SGP model. We show that the particular form of a relaxed boundary condition does not change the underlying size scaling of the yield stress and consequently does not resolve the scaling issue. Furthermore, we show that the fractional strain-gradient plasticity model predicts a yield stress with a scaling exponent that is equal to the fractional order of differentiation.
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| 18. |
- Dahlberg, Carina, et al.
(författare)
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Polymer Swelling, Drug Mobilization and Drug Recrystallization in Hydrating Solid Dispersion Tablets Studied by Multinuclear NMR Microimaging and Spectroscopy
- 2011
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Ingår i: Molecular Pharmaceutics. - : American Chemical Society (ACS). - 1543-8384 .- 1543-8392. ; 8:4, s. 1247-1256
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Tidskriftsartikel (refereegranskat)abstract
- Despite the advantages offered by solid dispersions, the marketed products based on this technology are few. The most frequent concern is the stability of the amorphous drug. The state of the drug in solid dispersions is, in general, poorly characterized as the number of characterization techniques available to monitor nanometer-sized drug particles embedded in a matrix are limited. Here we present a combination of localized NMR spectroscopic and NMR imaging techniques which allow in situ monitoring of the state of the drug during tablet disintegration and dissolution. (19)F NMR relaxation is shown to be sensitive to both the crystalline/amorphous state and the size of the model nanoparticles made of the drug substance flutamide. The time course of drug mobilization and recrystallization is detected with spatial resolution within swelling solid dispersion tablets. Comparing results from spatially resolved (19)F, (2)H and (1)H NMR experiments, recrystallization is related to its enabling factors such as local hydration level and local mobility of the polymer matrix. The initially amorphous drug may recrystallize either by nanoparticle coalescence or by ripening of crystalline grains.
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| 19. |
- Dahlberg, Carina, et al.
(författare)
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Polymer–drug interactions and wetting of solid dispersions
- 2009
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Ingår i: European Journal of Pharmaceutical Sciences. - : Elsevier BV. - 0928-0987 .- 1879-0720. ; 39:1-3, s. 125-133
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate the ability of drugs to influence the wetting of solid dispersion tablets in unexpected ways. Five model drugs of different water solubility and ability to interact with the involved polymers were incorporated in hydrophilic polymer matrices, made of either hydroxypropyl methylcellulose (HPMC) or polyvinyl pyrrolidone (PVP). The physical mixtures of all combinations of drug and polymer presented surface hydrophobicities, as measured by the equilibrium advancing contact angle of water, which are expected for materials that do not influence the interactions of each other with water. However, the solid dispersions containing HPMC deviated from this regular behaviour and displayed contact angles below those of the pure compounds involved, either drug or polymer. This behaviour is explained by changed surface exposure of HPMC side groups, as a result of changes in intermolecular hydrogen bonds. In addition to water contact angle measurements, we employed NMR imaging to monitor the time course of water ingress and swelling.
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| 20. |
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| 21. |
- Dahlberg, C., et al.
(författare)
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Refining the model system of central nervous system regeneration in Ciona intestinalis
- 2009
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Ingår i: PLoS One. ; 4:2
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Tidskriftsartikel (refereegranskat)abstract
- Background New, practical models of central nervous system regeneration are required and should provide molecular tools and resources. We focus here on the tunicate Ciona intestinalis, which has the capacity to regenerate nerves and a complete adult central nervous system, a capacity unusual in the chordate phylum. We investigated the timing and sequence of events during nervous system regeneration in this organism. Methodology/Principal Findings We developed techniques for reproducible ablations and for imaging live cellular events in tissue explants. Based on live observations of more than 100 regenerating animals, we subdivided the regeneration process into four stages. Regeneration was functional, as shown by the sequential recovery of reflexes that established new criteria for defining regeneration rates. We used transgenic animals and labeled nucleotide analogs to describe in detail the early cellular events at the tip of the regenerating nerves and the first appearance of the new adult ganglion anlage. Conclusions/Significance The rate of regeneration was found to be negatively correlated with adult size. New neural structures were derived from the anterior and posterior nerve endings. A blastemal structure was implicated in the formation of new neural cells. This work demonstrates that Ciona intestinalis is as a useful system for studies on regeneration of the brain, brain-associated organs and nerves.
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| 22. |
- Dahlberg, Carina, et al.
(författare)
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Relationships between solid dispersion preparation process, particle size and drug release : an NMR and NMR microimaging study
- 2010
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Ingår i: European journal of pharmaceutics and biopharmaceutics. - : Elsevier BV. - 0939-6411 .- 1873-3441. ; 76:2, s. 311-319
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Tidskriftsartikel (refereegranskat)abstract
- Solid dispersion tablets prepared by either spray drying or rotoevaporation and exhibiting different grain and pore sizes were investigated under the process of hydration-swelling-gelation. H-2 and H-1 NMR microimaging experiments were used to selectively follow water penetration and polymer mobilization kinetics, respectively, while the drug release kinetics was followed by H-1 NMR spectroscopy. The obtained data, in combination with morphological information by scanning electron microscopy (SEM), reveal a complex process that ultimately leads to release of the drug into the aqueous phase. We find that the rate of water ingress has no direct influence on release kinetics, which also renders air in the tablets a secondary factor. On the other hand, drug release is directly correlated with the polymer mobilization kinetics. Water diffusion into the originally dry polymer grains determines the rate of grain swelling and the hydration within the grains varies strongly with grain size. We propose that this sets the stage for creating homogeneous gels for small grain sizes and heterogeneous gels for large grain sizes. Fast diffusion through water-rich sections of the inhomogeneous gels that exhibit a large mesh size is the factor which yields a faster drug release from tablets prepared by rotoevaporation.
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| 23. |
- Dahlberg, Carina, et al.
(författare)
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Surface composition and contact angle relationships for differently prepared solid dispersions
- 2008
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Ingår i: European journal of pharmaceutics and biopharmaceutics. - : Elsevier BV. - 0939-6411 .- 1873-3441. ; 70, s. 478-485
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Tidskriftsartikel (refereegranskat)abstract
- Solid dispersions are promising drug delivery forms which offer the possibility to disperse a hydrophobic drug in a hydrophilic matrix and thereby improve the dissolution behavior and the bioavailability of the drug. One important aspect and a prerequisite in understanding the drug dissolution mechanism from solid dispersions is a better analytical monitoring of the solid dispersion surface properties, such as powder surface composition and water adsorption properties. In this paper, we have considered chemical and structural surface analysis data for solid dispersions processed by spray drying or roto-evaporation and compared these data with information obtained by contact angle measurements. Firstly, we establish the usefulness and suitability of X-ray photoelectron spectroscopy (XPS) for determination of surface chemical composition and scanning electron microscopy (SEM) for determining the structure of solid dispersions composed of different types of carriers, drugs and drug concentrations. Secondly, we measure contact angles of solid dispersions to describe wettability, to finally establish a link between the surface chemical composition, the powder structure and the wetting behavior. These experimental methods offer a rapid screening tool for the selection of carrier, drug concentration and/or process in early development. In addition, they provide a useful tool for investigating structural aspects of solid dispersions which have intrinsic relevance for drug dissolution and stability.
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| 24. |
- Dahlberg-Grundberg, Michael, 1983-
(författare)
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Digital media and the transnationalization of protests
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Recent developments in communications technology have transformed how social movements might mobilize, and how they can organize their activities. This thesis explores some of the geographical consequences of the use of digital media for political activism. It does this by focusing on the transnationalization of protests. The aim is to analyse how movements with different organizational structures and political scopes are affected by their use of digital media. This is done with a specific focus on how digital media use influences or enables transnational modes of organization and activism. The thesis comprises four different case studies where each study examines a social movement with a specific organizational structure. There are, however, also important similarities between the movements. In each study, somewhat different perspectives and methodological approaches are used. Some of the methods used are semi-structured interviews, content analysis of written data (retrieved from Facebook as well as Twitter), and social network analysis.The analysis indicates that digital media do have a role in the transnationalization of protest. This role, however, differs depending on what type of social movement one studies. The organizational structure of social movements, together with their specific forms of digital media use, influences how the transnationalization of protests and movements is articulated and formed. In cases where a social movement has a hierarchical organizational structure, there is less transnationalization, whereas in social movements with a more non-hierarchical organizational structure one sees more transnationalization. The thesis concludes that the transnationalization of protests is affected by social movements’ organizational structure. The more decentralized the social movement, the more vibrant the transnational public. In order to explain how transnational social movements, using digital media, can emerge in cases where geographical distances might make such coalitions unlikely, the thesis introduces the notion of affectual proximity. This concept helps us understand how transnational social movements, connecting actors from all over the world, can emerge through digital media.
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| 25. |
- Dahlberg-Grundberg, Michael, 1983-, et al.
(författare)
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Extending the local : activist types and forms of social media use in the case of an anti-mining struggle
- 2017
-
Ingår i: Social Movement Studies. - : Informa UK Limited. - 1474-2837 .- 1474-2829. ; 16:3, s. 309-322
-
Tidskriftsartikel (refereegranskat)abstract
- As political activists increasingly use social media in local protests, scholars must redirect attention from large-scale campaigns to scrutinize the ways in which geographically confined actors use social media to engage in protests. This paper analyses how a 2013 anti-mining campaign in Kallak, Sweden, combined on-site resistance with social media strategies via Facebook-pages. The study examines which activist roles and forms of social media use that emerged and aims to explore what larger practical and theoretical implications one can derive from this specific case of place-based struggles. Results show that three typologically distinct activist roles emerged during the protests: local activists, digital movement intellectuals and digital distributors. These different types of actors were involved in four different forms of social media use: mobilization, construction of the physical space, extension of the local and augmentation of local and translocal bonds. Based on our findings, we argue that the coming together of these different activist roles and the different uses of social media added a translocal dimension to the peripheral and physically remote political conflict in Kallak. Media users were able to extend a locally and physically situated protest by linking it to a global contentious issue such as the mining boom and its consequences for indigenous populations.
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| 26. |
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| 27. |
- Dahlberg-Grundberg, Michael, 1983-, et al.
(författare)
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Social Media and the Transnationalization of Mass Activism : Twitter and the labour movement
- 2016
-
Ingår i: First Monday. - : University of Illinois Libraries. - 1396-0466. ; 21:8
-
Tidskriftsartikel (refereegranskat)abstract
- This paper explores the labour movement organization LabourStart, a digital initiative that, by various means such as e-mail campaigns and social media use, seeks to promote workers’ rights and to strengthen the labour movement on a global scale. The main aim of this study is to analyse a) how LabourStart employs Twitter for communication and organisation and b) how the Twitter-sphere that LabourStart constitutes — and is constituted by — is geographically structured. Our dataset consisted of all tweets containing the word “labourstart” and all tweets coming from or addressing any LabourStart–related account during the period 2008–2015. As theoretical points of departure, the notions of transnationalization/translocalism were used, in part together with the concept of connective action, to conceptualise the research. In terms of methodology, network analysis was the main approach employed to obtain and visualise the findings. Our results indicate that LabourStart’s Twitter use does not seem to have had any effects in terms of creating a decentralised transnational movement with translocal traits, thus suggesting that LabourStart has failed to fully make use of the connective features of Twitter and to establish a decentralized, transnational union movement. This, we suggest, is to some extent caused by LabourStart’s centralized organizational — and thus communicational — structure. In the concluding section, we interpret our findings in broader terms relating to the context and history of labour movements, and we discuss LabourStart’s work in relation to local and global worker issues.
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| 28. |
- Dahlberg-Grundberg, Michael, 1983-
(författare)
-
Technology as movement : on hybrid organizational types and the mutual constitution of movement identity and technological infrastructure in digital activism
- 2016
-
Ingår i: Convergence. The International Journal of Research into New Media Technologies. - : SAGE Publications. - 1354-8565 .- 1748-7382. ; 22:5, s. 524-542
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Tidskriftsartikel (refereegranskat)abstract
- New communication technologies bring about new ways for political groups and movements to mobilize and organize. A consequence of this might be that established interpretations of and attitudes towards social movements may have to be revisited, for example, when it comes to their internal constitution and their modes of working. This interview case study looks at the digital activist cluster Telecomix and its interventions during the Arab Spring. The study addresses how the network used technological and communicational infrastructures and platforms and how it was organizationally affected by these. By using concepts such as ‘one media bias’, ‘media ecology’, ‘hybridity’ and ‘cognitive praxis’, the article aims to conceptualize how the identity of a movement and its technological infrastructure mutually constitute each other.
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| 29. |
- Dahlberg-Grundberg, Michael, 1983-, et al.
(författare)
-
Translocal Frame Extensions in a Networked Protest : Situating the #IdleNoMore hashtag
- 2014
-
Ingår i: IC. - 1696-2508 .- 2173-1071. ; 11, s. 49-77
-
Tidskriftsartikel (refereegranskat)abstract
- The aim of the present study was to examine how locally situated social movements can use social media to deploy translocally networked forms of protests. The study looks at the Canadian Idle No More movement, an indigenous and environmental grassroots initiative that emerged around the end of 2012 and the beginning of 2013 as a reaction to previous neglect of indigenous groups and to the omnibus bill proposal C-45 (which threatened both the partial sovereignty of indigenous territories and the Canadian environment). Focusing on the -decentralized and heterogeneous- movement’s Twitter use in general, and the employment of the hashtag #idlenomore in particular, the study examines to which extent and how Twitter may be a means for establishing bonds between geographically dispersed social movements.
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| 30. |
- Dahlberg, Johan, 1988-
(författare)
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Genetic Cartography at Massively Parallel Scale
- 2018
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Massively parallel sequencing (MPS) is revolutionizing genomics. In this work we use, refine, and develop new tools for the discipline.MPS has led to the discovery of multiple novel subtypes in Acute Lymphoblastic Leukemia (ALL). In Study I we screen for fusion genes in 134 pediatric ALL patients, including patients without an assigned subtype. In approximately 80% of these patients we detect novel or known fusion gene families, most of which display distinct methylation and expression patterns. This shows the potential for improvements in the clinical stratification of ALL. Large sample sizes are important to detect recurrent somatic variation. In Study II we investigate if a non-index overlapping pooling schema can be used to increase sample size and detect somatic variation. We designed a schema for 172 ALL samples and show that it is possible to use this method to call somatic variants.Around the globe there are many ongoing and completed genome projects. In Study III we sequenced the genome of 1000 Swedes to create a reference data set for the Swedish population. We identified more than 10 million variants that were not present in publicly available databases, highlighting the need for population-specific resources. Data, and the tools developed during this study, have been made publicly available as a resource for genomics in Sweden and abroad.The increased amount of sequencing data has created a greater need for automation. In Study IV we present Arteria, a computational automation system for sequencing core facilities. This system has been adopted by multiple facilities and has been used to analyze thousands of samples. In Study V we developed CheckQC, a program that provides automated quality control of Illumina sequencing runs. These tools make scaling up MPS less labour intensive, a key to unlocking the full future potential of genomics.The tools, and data presented here are a valuable contribution to the scientific community. Collectively they showcase the power of MPS and genomics to bring about new knowledge of human health and disease.
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| 31. |
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| 32. |
- Dahlberg, Michael
(författare)
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Rectal cancer : Aspects of surgery and radiotherapy
- 1999
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In rectal cancer, local failure is one of the principle causes of morbidity and mortality. The use of radiotherapy as an adjuvant treatment in resectable rectal cancer is extensively studied in order to lower unacceptably high local failure rates. Data from the literature clearly indicate that preoperative radiotherapy is superior to postoperative irradiation in reducing failure rates. Provided the dose is sufficiently high, a relative reduction in the local recurrence rate of 60% in combination with "standard" surgery is to be expected. In addition, this reduction seems to increase survival. An important and unanswered question is the role of adjuvant radiotherapy with "optimised" surgery as total mesorectal excision. Our data show that the results of treatment can be improved by concentration of surgery to a colorectal team. Changed primary treatment with a combination of optimised surgery and preoperative radiotherapy will further improve treatment outcome with lowered local recurrence rates and increased survival. With proper radiation technique, the acute-subacute toxicity can be kept acceptably low and besides bowel dysfunction, no evidence of substantial late adverse effects have been found.The cost-effectiveness of preoperative radiotherapy is in accordance with other well-accepted medical interventions.
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| 33. |
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| 34. |
- Einarsson, Emma, et al.
(författare)
-
The role of cartilage glycosaminoglycan structure in gagCEST
- 2020
-
Ingår i: NMR in Biomedicine. - : Wiley. - 0952-3480 .- 1099-1492. ; 33:5
-
Tidskriftsartikel (refereegranskat)abstract
- Glycosaminoglycan (GAG) chemical exchange saturation transfer (gagCEST) is a potential method for cartilage quality assessment. The aim of this study was to investigate how the gagCEST effect depends on the types and molecular organization of GAG typically found in articular cartilage. gagCEST was performed on different concentrations of GAG in various forms: free chains of chondroitin sulfate (CS) of different types (-A and -C) and GAG bound to protein in aggregated and nonaggregated aggrecan extracted from calf articular cartilage. The measured magnetization transfer ratio asymmetry (MTRasym ) was compared with known GAG concentrations or GAG concentrations determined through biochemical analysis. The gagCEST effect was assessed through the linear regression coefficient with 95% confidence interval of MTRasym per GAG concentration. We observed a lower gagCEST effect in phantoms containing a mixture of CS-A and CS-C compared with phantoms containing mainly CS-A. The difference in response corresponds well to the difference in CS-A concentration. GAG bound in aggrecan from calf articular cartilage, where CS-A is assumed to be the major type of GAG, produed a similar gagCEST effect as that observed for free CS-A. The effect was also similar for aggregated (ie, bound to hyaluronic acid) and nonaggregated aggrecan. In conclusion, our results indicate that the aggrecan structure in itself does not impact the gagCEST effect, but that the effect is strongly dependent on GAG type. In phantoms, the current implementation of gagCEST is sensitive to CS-A while for CS-C, the main GAG component in mature human articular cartilage, the sensitivity is limited. This difference in gagCEST sensitivity between GAG types detected in phantoms is a strong motivation to also explore the possibility of a similar effect in vivo.
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| 35. |
- Gardell, Mattias, 1959-, et al.
(författare)
-
Den ensamme terroristen? : Om lone wolves, näthat och brinnande flyktingförläggningar
- 2017
-
Bok (refereegranskat)abstract
- Hotet från ensamagerande terrorister ökar. Även i Sverige. Vad drev Rakhmat Akilov, Anton Lundin Pettersson, Peter Mangs och Taimour Abdulwahab att döda för att nå politiska mål? Vad får en människa att attackera ett flyktingboende, en moské, en synagoga eller en romsk boplats?Heléne Lööw, Mattias Gardell och Michael Dahlberg-Grundberg har, på uppdrag av den Nationella samordnaren mot våldsbejakande extremism, kartlagt attackerna mot asylboenden, bedömt hotet från ”ensamvargar” och undersökt sociala medier som politiskt verktyg för våldspredikanter i Sverige. Det övergripande syftet har varit att belysa symbiosen mellan organiserad och oorganiserad politisk våldsbrottslighet.Den ensamme terroristen? är en skakande och grundligt underbyggd redogörelse för den våg av dödligt politiskt våld som skruvat upp oron i landet. Hur ska vi förstå utvecklingen? Och är den ensamme terroristen verkligen ensam?
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| 36. |
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| 37. |
- Kressner, Marit, et al.
(författare)
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The impact of hospital volume on surgical outcome in patients with rectal cancer.
- 2009
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Ingår i: Diseases of the colon and rectum. - 1530-0358 .- 0012-3706. ; 52:9, s. 1542-9
-
Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: This study was designed to investigate, in a population-based setting, the surgical outcome in patients with rectal cancer according to the hospital volume. METHODS: Since 1995 all patients with rectal cancer have been registered in the Swedish Rectal Cancer Registry. Hospitals were classified, according to number treated per year, as low-volume, intermediate-volume, or high-volume hospitals (<11, 11-25, or >25 procedures per year). Postoperative mortality, reoperation rate within 30 days, local recurrence rate, and overall five-year survival were studied. For postoperative morbidity and mortality the whole cohort from 1995 to 2003 (n = 10,425) was used. For cancer-related outcome only, those with five-year follow-ups, from 1995 to 1998, were used (n = 4,355). RESULTS: In this registry setting the postoperative mortality rate was 3.6% in low-volume hospitals, and 2.2% in intermediate-volume and high-volume hospitals (P = 0.002). The reoperation rate was 10%, with no differences according to volume. The overall local recurrence rates were 9.4%, 9.3%, and 7.5%, respectively (P = 0.06). Significant difference was found among the nonirradiated patients (P = 0.004), but not among the irradiated patients (P = 0.45). No differences were found according to volume in the absolute five-year survival. CONCLUSION: Postoperative mortality and local recurrence in nonirradiated patients were lower in high-volume hospitals. No difference was seen between volumes in reoperation rates, overall local recurrence, or absolute five-year survival.
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| 38. |
- Lilford, Robert D., et al.
(författare)
-
Increased Incidence and Mortality of Civilian Penetrating Traumatic Brain Injury in Sweden : A Single-Center Registry-Based Study
- 2024
-
Ingår i: World Neurosurgery. - : Elsevier. - 1878-8750 .- 1878-8769. ; 182, s. e493-e505
-
Tidskriftsartikel (refereegranskat)abstract
- BackgroundPenetrating trauma to the head and neck has increased during the past decade in Sweden. The aim of this study was to characterize these injuries and evaluate the outcomes for patients treated at a tertiary trauma center.MethodsSwedish trauma registry data were extracted on patients with head and neck injuries admitted to Karolinska University Hospital (Stockholm, Sweden) between 2011 and 2019. Outcome information was extracted from hospital records, with the primary endpoints focusing on the physiological outcome measures and the secondary endpoints on the surgical and radiological outcomes.ResultsOf 1436 patients with penetrating trauma, 329 with penetrating head and neck injuries were identified. Of the 329 patients, 66 (20%) had suffered a gunshot wound (GSW), 240 (73%) a stab wound (SW), and 23 (7%) an injury from other trauma mechanisms (OTMs). The median age for the corresponding 3 groups of patients was 25, 33, and 21 years, respectively. Assault was the primary intent, with 54 patients experiencing GSWs (81.8%) and 158 SWs (65.8%). Patients with GSWs had more severe injuries, worse admission Glasgow coma scale, motor, scores, and a higher intubation rate at the injury site. Most GSW patients underwent major surgery (59.1%) as the initial procedure and were more likely to have intracranial hemorrhage (21.2%). The 30-day mortality was 45.5% (n = 30) for GSWs, 5.4% (n = 13) for SWs, and 0% (n = 0) for OTMs. There was an annual increase in the incidence and mortality for GSWs and SWs.ConclusionsBetween 2011 and 2019, an increasing annual trend was found in the incidence and mortality from penetrating head and neck trauma in Stockholm, Sweden. GSW patients experienced more severe injuries and intracranial hemorrhage and underwent more surgical interventions compared with patients with SWs and OTMs.
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| 39. |
- Lindgren, Simon, 1974-, et al.
(författare)
-
Hybrid media culture : an introduction
- 2013
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Ingår i: Hybrid media culture. - London : Routledge. - 9780415824071 ; , s. 1-15
-
Bokkapitel (refereegranskat)
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| 40. |
- Ljungman, Charlotta, 1977, et al.
(författare)
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Differences in phenotypes, symptoms, and survival in patients with cardiomyopathy-a prospective observational study from the Sahlgrenska CardioMyoPathy Centre.
- 2023
-
Ingår i: Frontiers in cardiovascular medicine. - 2297-055X. ; 10
-
Tidskriftsartikel (refereegranskat)abstract
- Cardiomyopathy is the fourth most common cause of heart failure. The spectrum of cardiomyopathies may be impacted by changes in environmental factors and the prognosis may be influenced by modern treatment. The aim of this study is to create a prospective clinical cohort, the Sahlgrenska CardioMyoPathy Centre (SCMPC) study, and compare patients with cardiomyopathies in terms of phenotype, symptoms, and survival.The SCMPC study was founded in 2018 by including patients with all types of suspected cardiomyopathies. This study included data on patient characteristics, background, family history, symptoms, diagnostic examinations, and treatment including heart transplantation and mechanical circulatory support (MCS). Patients were categorized by the type of cardiomyopathy on the basis of the diagnostic criteria laid down by the European Society of Cardiology (ESC) working group on myocardial and pericardial diseases. The primary outcomes were death, heart transplantation, or MCS, analyzed by Kaplan-Meier and Cox proportional regression, adjusted for age, gender, LVEF and QRS width on ECG in milliseconds.In all, 461 patients and 73.1% men with a mean age of 53.6±16 years were included in the study. The most common diagnosis was dilated cardiomyopathy (DCM), followed by cardiac sarcoidosis and myocarditis. Dyspnea was the most common initial symptom in patients with DCM and amyloidosis, while patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) presented with ventricular arrythmias. Patients with ARVC, left-ventricular non-compaction cardiomyopathy (LVNC), hypertrophic cardiomyopathy (HCM), and DCM had the longest time from the debut of symptoms until inclusion in the study. Overall, 86% of the patients survived without heart transplantation or MCS after 2.5 years. The primary outcome differed among the cardiomyopathies, where the worst prognosis was reported for ARVC, LVNC, and cardiac amyloidosis. In a Cox regression analysis, it was found that ARVC and LVNC were independently associated with an increased risk of death, heart transplantation, or MCS compared with DCM. Further, female gender, a lower LVEF, and a wider QRS width were associated with an increased risk of the primary outcome.The SCMPC database offers a unique opportunity to explore the spectrum of cardiomyopathies over time. There is a large difference in characteristics and symptoms at debut and a remarkable difference in outcome, where the worst prognosis was reported for ARVC, LVNC, and cardiac amyloidosis.
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| 41. |
- Lohmander, L. Stefan, et al.
(författare)
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Cartilage matrix metabolism in osteoarthritis : markers in synovial fluid, serum, and urine
- 1992
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Ingår i: Clinical Biochemistry. - 0009-9120. ; 25:3, s. 167-174
-
Tidskriftsartikel (refereegranskat)abstract
- Osteoarthritis is a major cause of disability and early retirement. Yet we lack the means to diagnose the disease in its early stages or to monitor the effects of treatment on the target tissue, the joint cartilage. Neither can we identify the disease mechanisms at the tissue or cell level. Current research focuses on the use of markers of cartilage matrix metabolism in body fluids as a means to diagnose and monitor osteoarthritis. Cartilage proteoglycan, collagen and glycoprotein fragments, as well as proteinases and their inhibitors, are being suggested for this purpose. Structural information on matrix molecule fragments released into body fluids may also help to identify the enzymes active in the destruction of the cartilage, a central issue in osteoarthritis.
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| 42. |
- Lohmander, L. S., et al.
(författare)
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Temporal patterns of stromelysin-1, tissue inhibitor, and proteoglycan fragments in human knee joint fluid after injury to the cruciate ligament or meniscus
- 1994
-
Ingår i: Journal of Orthopaedic Research. - 0736-0266. ; 12:1, s. 21-28
-
Tidskriftsartikel (refereegranskat)abstract
- Stromelysin-1, tissue inhibitor of metalloproteinases-1 (TIMP-1), and proteoglycan fragments were quantified in knee synovial fluid samples in a cross-sectional study of patients who had injury to the anterior cruciate ligament or the meniscus. The average concentrations of stromelysin-1 and TIMP-1 increased 25-fold and 10-fold within the first day after the trauma, respectively, and the concentration of proteoglycan fragments increased 4- fold. From approximately 1-6 months after injury, the levels of these markers were higher after injury to the cruciate ligament than after injury to the meniscus. From 6 months to 18 years after trauma, however, the levels of stromelysin-1 and TIMP-1 in patients who had an injury to the ligament were the same as the levels in patients who had a meniscal lesion, but the levels were increased compared with those for a reference group of healthy volunteers. The molar balance of stromelysin-1 to TIMP-1 in synovial fluid in both groups of injured joints changed from a balance representing an excess of free inhibitor in the normal joint to one representing an excess of free enzyme in the injured joint. The increased release of these markers to joint fluid both early and late after trauma may be caused by a change in the loading patterns in the knee with an injured ligament or meniscus or by synovitis induced by bleeding. The increased release may be associated with the frequent development of posttraumatic osteoarthritis in patients with these injuries.
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| 43. |
- Lundqvist, Heléne, 1982-
(författare)
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Empirical Essays in Political and Public Economics
- 2011
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis consists of four self-contained essays. Essay 1: Despite the key role played by political payoffs in theory, very little is known empirically about the types of payoffs that motivate politicians. The purpose of this paper is to bring light onto this. I estimate causal effects of being elected in a local election on monetary returns. The claim for causality, I argue, can be made thanks to a research design where the income of some candidate who just barely won a seat is compared to that of some other candidate who was close to winning a seat for the same party, but ultimately did not. This research design is made possible thanks to a comprehensive, detailed data set covering all Swedish politicians who have run for office in the period 1991—2006. I establish that monetary returns are absent both in the short and long run. In stead, politicians seem to be motivated by non-monetary payoffs that can be realized with a successful political career. Essay 2 (with Matz Dahlberg and Karin Edmark): In recent decades, the immigration of workers and refugees toEurope has increased substantially, and the composition of the population in many countries has consequently become much more heterogeneous in terms of ethnic background. If people exhibit in-group bias in the sense of being more altruistic to one's own kind, such increased heterogeneity will lead to reduced support for redistribution among natives. This paper exploits a nationwide program placing refugees in municipalities throughoutSweden during the period 1985—94 to isolate exogenous variation in immigrant shares. We match data on refugee placement to panel survey data on inhabitants of the receiving municipalities to estimate the causal effects of increased immigrant shares on preferences for redistribution. The results show that a larger immigrant population leads to less support for redistribution in the form of preferred social benefit levels. This reduction in support is especially pronounced for respondents with high income and wealth. We also establish that OLS estimators that do not properly deal with endogeneity problems – as in earlier studies – are likely to yield positively biased (i.e., less negative) effects of ethnic heterogeneity on preferences for redistribution. Essay 3: While the literature on how intergovernmental grants affect the budget of receiving jurisdictions is numerous, the very few studies that explicitly deal with likely endogeneity problems focus on grants targeted towards specific sectors or specific type of recipients. The results from these studies are mixed and make it clear that the knowledge about grants effects is to this date still insufficient. This paper contributes to this literature by estimating causal effects on local expenditures and income tax rates of general, non-targeted grants. This is done in a difference-in-difference model utilizing policy-induced increases in grants to a group of remotely populated municipalities inFinland. The robust finding is that increased grants have a negligible effect on local income tax rates, but that there is a substantial positive immediate response in local expenditures. Furthermore, there is no evidence of dynamic crowding-out – i.e., that the immediate response in expenditures is reversed in later years. The flypaper behavior displayed by the treatment group can potentially be explained by “separate mental accounting” – i.e., voters treating the government budget constraint separately from their own. Essay 4 (with Matz Dahlberg and Eva Mörk): Public employment plays an important role in most countries, as it is closely linked to both the quality of publicly provided welfare services and total employment. Large parts of those employed by the public sector are typically employed by lower-level governments, and one potential instrument with which central decision-makers can affect public employment is thus grants to lower-level governments. This paper investigates the effects of general grants on local public employment. Applying the regression kink design to the Swedish grant system, we are able to estimate causal effects of intergovernmental grants on personnel in different local government sectors. Our robust conclusion is that there was a substantial increase in personnel in the central administration after a marginal increase in grants, but that such an effect was lacking both for total personnel and personnel in child care, schools, elderly care, social welfare and technical services. We suggest several potential reasons for these results, such as heterogeneous treatment effects and bureaucratic influence in the local decision-making process.
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| 44. |
- Löwenmark, Thyra, 1995-
(författare)
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Gut microbiota in colorectal cancer : The importance of Parvimonas micra
- 2024
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Colorectal cancer (CRC) is a heterogenous disease consisting of multiple molecular subtypes, each of which has diverse treatment responses and prognoses. The importance of the gut microbiota in CRC development and progression has undergone increasing recognition in recent years, with a structural segregation in terms of microbial composition between CRC patients and healthy controls. However, many questions remain before a full understanding of the impact of the gut microbiota on CRC is reached. The overall aim of this thesis was to explore the role of gut microbes in CRC, including their potential as CRC biomarkers and associations with clinicopathological, immunological, and molecular traits of CRC. A particular focus was the CRC-associated oral pathogen Parvimonas micra.To investigate faecal microbiota as a potential biomarker for CRC, we studied the presence of specific bacteria in faeces from CRC patients and controls using qPCR. We found higher levels of P. micra in faecal samples from CRC patients than from control patients. A test for high levels of P. micra was able to identify CRC with a specificity of 87.3% and a sensitivity of 60.5%. Adding the oral pathogen Fusobacterium nucleatum, colibactin-producing bacteria, and faecal haemoglobin to the test enhanced its sensitivity.We further aimed to explore the associations of P. micra and F. nucleatum with molecular subtypes of CRC and the tumour immune response. The levels of P. micra and F. nucleatum, as analysed by qPCR in both faeces and tumour tissue from CRC patients, were found to be positively correlated. High levels of intratumoural P. micra and F. nucleatum were associated with tumours of the microsatellite instable subtype and BRAF-mutated tumours. For F. nucleatum, an additional association with right-sided tumours was found. Moreover, both P. micra and F. nucleatum in tumour tissue were associated with the immune-activated consensus molecular subtype (CMS) 1 subtype of CRC. In line with this finding, we found novel associations between intratumoural P. micra and specific immune traits, which were evaluated by flow cytometry, indicating an active immune response in CRC. These results were further confirmed using transcriptomics. However, no associations with specific immune traits were found for F. nucleatum.We also investigated associations between faecal and intratumoural levels of P. micra and F. nucleatum and survival in CRC patients. CRC patients with high levels of intratumoural P. micra and F. nucleatum showed reduced five-year cancer-specific survival. This association remained significant for P. micra in multivariable analysis. No associations with cancer-specific survival were found for levels of P. micra and F. nucleatum in faeces.To investigate the faecal microbial landscape of CRC patients on a larger scale, we used 16S rRNA sequencing. Network analysis revealed a cluster of associated bacteria, including P. micra and F. nucleatum, as well as other CRC-related pathogens such as Bacteroides fragilis, Peptostreptococcus stomatitis, and Porphyromonas spp. Furthermore, beta-diversity analysis indicated a significantly different gut microbial composition depending on tumour location and microsatellite instability status. Interestingly, three of the six annotated species most strongly associated with microsatellite instable tumours were also present in the cluster: P. micra, F. nucleatum, and P. stomatis.In conclusion, our results suggest P. micra as a putative candidate for a future non-invasive microbial test panel for detection of CRC. Moreover, our results indicate that intratumoural P. micra and F. nucleatum are associated with immune-active subtypes of CRC, including microsatellite instable tumours and tumours of the CMS1 subtype, as well as decreased patient survival. Furthermore, P. micra and F. nucleatum were found to be associated with a cluster of other CRC-related oral pathogens. An improved understanding of the role of the gut microbiota in tumour progression may lead to the identification of important biomarkers for CRC disease and outcome, as well as potential targets for future therapy.
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| 45. |
- Löwenmark, Thyra, et al.
(författare)
-
Parvimonas micra as a putative non-invasive faecal biomarker for colorectal cancer
- 2020
-
Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 10:1
-
Tidskriftsartikel (refereegranskat)abstract
- The use of faecal microbial markers as non-invasive biomarkers for colorectal cancer (CRC) has been suggested, but not fully elucidated. Here, we have evaluated the importance of Parvimonas micra as a potential non-invasive faecal biomarker in CRC and its relation to other microbial biomarkers. The levels of P. micra, F. nucleatum and clbA+bacteria were quantified using qPCR in faecal samples from a population-based cohort of patients undergoing colonoscopy due to symptoms from the large bowel. The study included 38 CRC patients, 128 patients with dysplasia and 63 controls. The results were validated in a second consecutive CRC cohort including faecal samples from 238 CRC patients and 94 controls. We found significantly higher levels of P. micra in faecal samples from CRC patients compared to controls. A test for P. micra could detect CRC with a specificity of 87.3% and a sensitivity of 60.5%. In addition, we found that combining P. micra with other microbial markers, could further enhance test sensitivity. Our findings support the potential use of P. micra as a non-invasive biomarker for CRC. Together with other microbial faecal markers, P. micra may identify patients with "high risk" microbial patterns, indicating increased risk and incidence of cancer.
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| 46. |
- Löwenmark, Thyra, et al.
(författare)
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Tumour colonisation of Parvimonas micra is associated with decreased survival in colorectal cancer patients
- 2022
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Ingår i: Cancers. - : MDPI AG. - 2072-6694. ; 14:23
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Tidskriftsartikel (refereegranskat)abstract
- Increasing evidence suggests that the gut microbiota may impact colorectal cancer (CRC) development and progression. In this study, the tumour colonisation of two CRC-associated bacteria, Parvimonas micra and Fusobacterium nucleatum, was studied in relation to patient survival in a cohort of 257 CRC patients. Colonisation of P. micra and F. nucleatum was analysed in fresh frozen tumour tissue (n = 112) and in faeces (n = 250) by qPCR. When analysing tumour tissues, both P. micra and F. nucleatum were found to be associated with decreased five-year cancer-specific survival, an association that remained significant in multivariable analysis for P. micra. Furthermore, we found significant associations of high levels of P. micra and F. nucleatum with tumour molecular characteristics, i.e., tumours mutated in BRAFV600E, and tumours of the MSI subtype. The analysis of faecal samples showed weaker associations with prognosis and tumour molecular characteristics. In conclusion, our findings support a novel association of tumour colonisation of P. micra with decreased patient survival. A better understanding of the role of the gut microbiota in CRC might contribute to the advancement of prognostic tools and new targets for therapy.
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| 47. |
- Näsvall, Pia, 1967-
(författare)
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Parastomal hernia : investigation and treatment
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- BackgroundParastomal hernia is a common stoma complication causing the patient considerable inconvenience. The patient becomes aware of a bulge around the stoma, but a bulge is not always a parastomal hernia and diagnostics must be performed to enable differential treatment. It is difficult to distinguish between a bulge and a hernia. Results based on clinical examination and computerised tomography (CT) in the supine position, have not been convincing. Three-dimensional intrastomal ultrasonography (3D US) is a novel technique shown to be promising in the assessment of stoma complaints. Two studies were performed to determine inter- and intra-observer reliability as well as the validity of 3D US as an alternative to CT when assessing stoma complaints.There are numerous options for the treatment of parastomal hernia, but none has been shown superior. In the recent decades the use of mesh in the repair of incisional and inguinal hernia has become routine. New materials must be evaluated as there are potential morbidity and even mortality risks with mesh repair. As recurrence of a parastomal hernia is an even greater challenge, the method of choice should have a low risk for recurrence. A prospective multicenter study was performed to evaluate safety and recurrence rate when using Parastomal Hernia Patch BARDTM (PHP), a mesh specially designed for parastomal hernia repair.A stoma has a profound impact on the patient´s daily life, both physical and psychological. A parastomal hernia with its associated risk for leakage and incarceration worsens the situation. Patient driven assessment of healthcare outcome is important if we are to improve medical care. A quality of life (QoL) survey was performed to assess the impact of parastomal bulging and hernia on the patient´s daily life.MethodsForty patients were investigated and the 3D US images were twice evaluated by two or three physicians to assess inter- and intra-observer reliability. Totally 20 patients with stoma complaints requiring surgery were examined with CT and 3D US prior to surgery. The findings were compared with the intraoperative findings – regarded as the true outcome.Fifty patients with parastomal hernia requiring surgery were enrolled from three hospitals. Patients were followed up one month and one year after repair using PHP.Patients still alive in 2008 who had been operated between1996 and 2004 for rectal cancer in Uppsala/Örebro-, Stockholm/Gotland-, and Northern Regions (986 patients) and registered in the Swedish Rectal Cancer Registry (SRCR) were invited to fill in four QoL questionnaires.ResultsInter-observer agreement using 3D US reached 80% for the last 10 patients examined, with a kappa value of 0.70. Intra-observer agreement for two examiners was 80% and 95%. The learning curve levelled out at 30 patients. Both CT and 3D US showed high sensitivity and specificity when compared with intraoperative findings.After surgery for parastomal hernia with a PHP, the complication rate at one month was 30% and recurrence rate at one year was 22%. Twelve patients were reoperated within one year.In the QoL study, 31.5% of the patients with a stoma reported a bulging or a hernia. 11.7% had been operated for parastomal hernia. A hernia or a bulge gave rise to significantly more pain and impaired stoma function. Overall QoL was inferior in patients with a permanent stoma compared to a group without a stoma.
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| 48. |
- Näsvall, Pia, 1967-, et al.
(författare)
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Parastomal hernia repair with intraperitoneal mesh
- 2017
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Ingår i: Surgery Research and Practice. - : Hindawi Publishing Corporation. - 2356-7759 .- 2356-6124. - 9789176012413 ; 2017
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Tidskriftsartikel (refereegranskat)abstract
- Purpose. Parastomal hernia is a common complication following a stoma and may cause leakage or incarceration. No optimal treatment has been established, and existing methods using mesh repair are associated with high recurrence rates and a considerable risk for short- and long-term complications including death. A double-layer intraperitoneal on-lay mesh (IPOM), the Parastomal Hernia Patch (BARD™), consisting of ePTFE and polypropylene, has been developed and tailored to avoid recurrence. To evaluate the safety of and recurrence rate using this mesh, a nonrandomised prospective multicentre study was performed. Method. Fifty patients requiring surgery for parastomal hernia were enrolled. Clinical examination and CT scan prior to surgery were performed. All patients were operated on using the Parastomal Hernia Patch (BARD). Postoperative follow-up at one month and one year was scheduled to detect complications and hernia recurrence. Results. The postoperative complication rate at one month was 15/50 (30%). The parastomal hernia recurrence rate at one year was 11/50 (22%). The reoperation rate at one month was 7/50 (14%), and further 5/50 (10%) patients were reoperated on during the following eleven months.
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| 49. |
- Odensten, Christoffer, et al.
(författare)
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Parastomal hernia repair; seldom performed and seldom reported : Results from a nationwide survey
- 2020
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Ingår i: Scandinavian Journal of Surgery. - : Sage Publications. - 1457-4969 .- 1799-7267. ; 109:2, s. 96-101
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Parastomal hernia is common, but there are few population-based studies showing the frequency and outcome of parastomal hernia repair in routine surgical practice. The aim of this study was to identify patients undergoing surgery for parastomal hernia in Sweden and to define risk factors for complication and recurrence.METHODS: A broad search of the Swedish National Patient Register 1998-2007 for all possible parastomal hernia repairs using surgical procedure codes. Records of all patients identified were reviewed and those with a definite parastomal hernia procedure were included and analyzed.RESULTS: A total of 71 patients were identified after review of the records. The most common reason for surgery was cosmetic and the most frequent method was relocation of the stoma. Parastomal hernia recurrence rate was 18% during follow-up of a minimum 2 years. Overall, a surgical complication occurred in 32%. Possible risk factors were analyzed including emergency surgery versus planned, gender, age, indication for surgery, and method of surgery; none of which was significant.CONCLUSION: The frequency of parastomal hernia procedures was much lower than suggested by previous studies. The number of procedures per surgeon was even lower than expected. No specific risk factor could be identified. Parastomal hernia auditing in the form of a nationwide quality register should be mandatory. Centralization should be considered.
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| 50. |
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