| 1. |
- Dahlman, Joakim, 1974-, et al.
(författare)
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Effects of Motion Sickness on Encoding and Retrieval
- 2010
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Tidskriftsartikel (refereegranskat)abstract
- Objective: In this study, possible effects of motion sickness on encoding and retrieval of words were investigated. Background: The impact of motion sickness on human performance has been studied with regards to psychomotor functions and over learned skills, as well as to novel situations requiring encoding and retrieval skills through the use of short term memory. In this study, possible effects of motion sickness on encoding and retrieval of words were investigated. Method: Forty healthy participants, half of them males, performed a continuous recognition task (CRT) during exposure to a motion sickness triggering optokinetic drum. The CRT was employed as a measurement of performance and consisted of encoding and retrieval of words. The task consisted of three consecutive phases 1) encoding of familiar words; 2) encoding and retrieval of words under the influence of motion sickness; 3) retrieval of words after exposure. Results: Data analysis revealed no significant differences in the ability to encode or retrieve words during motion sickness compared with a control condition. In addition, there were no significant correlations between the level of motion sickness and performance of the CRT. Conclusion: The results indicate that encoding and retrieval of words are not affected by moderate levels of motion sickness. Application: This research has implications for operational settings where professionals experience moderate levels of motion sickness.
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| 2. |
- Sjörs, Anna, 1981-, et al.
(författare)
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Effects of motion sickness on encoding and retrieval performance and on psychophysiological responses
- 2010
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Tidskriftsartikel (refereegranskat)abstract
- Motion sickness has previously been found to deteriorate performance, e.g., regarding psychomotor functions and short term memory. Sustained ability to perform, despite motion sickness, is crucial in complex working environments. This study focuses on effects of motion sickness on encoding and retrieval of words through the use of long term memory. In addition, the temporal development of different psychophysiological responses and their relationship with perceived motion sickness were investigated. Forty healthy participants performed an encoding and retrieval task during exposure to an optokinetic drum. The results were compared with data from 20 controls that performed the task without motion sickness exposure. Measurements of heart rate, heart rate variability, skin conductance, blood volume pulse, respiration rate, and skin temperature were made throughout optokinetic drum exposure. Data analyses revealed no significant effects of moderate levels of motion sickness on the ability to encode or retrieve words. We found positive relationships between subjective motion sickness ratings and heart rate, blood volume pulse and skin temperature whereas respiration rate was negatively related to perceived motion sickness. The psychophysiological measurements did not show consistent patterns of sympathetic activation and parasympathetic withdrawal, as could be expected. Hence, they are not recommended as predictors of motion sickness.
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| 3. |
- Asplund,, Johan, et al.
(författare)
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Vem kan man lita på? : Att kommunicera risker i samband med förorenade områden
- 2007
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Samhällets kostnader för att sanera förorenad mark har ökat under senare år. Markundersökningar och saneringsprojekt kan sträcka sig över längre tidsperioder och skapa oro hos närboende och andra berörda. Effektiv och trovärdig kommunikation om riskerna är därför en viktig komponent i ett efterbehandlingsprojekt. WSP Environmental har på uppdrag av Naturvårdsverket (Hållbar sanering) gjort en litteraturgenomgång kring riskkommunikation med inriktning på förorenad mark, samt sammanställt erfarenheter från fem svenska fallstudier där kommunikationsfrågorna varit viktiga. Rapporten avslutas med råd och kommentarer till hur projektledningar och myndigheter kan hantera riskkommunikationen så att sannolikheten att det uppstår konflikter minskar. Projektet genomfördes under 2005-2006. Litteraturgenomgången visade att kommunikationskonflikter kring riskerna i ett saneringsprojekt är vanliga och kan röra fakta, tillit och värderingar. Både budbäraren och mottagaren har stor betydelse för hur situationen utvecklas och ”experterna” har inte tolkningsföreträde vad det gäller riskuppfattningen. Det gäller därför att tänka sig in i hur de olika intressenterna kan reagera och anpassa kommunikationen efter detta. Det gäller också för kommunikatören att vara flexibel och beredd på att ta hand om frågor och reaktioner som dyker upp från oväntat håll. De fem fallstudierna bekräftade att riskkommunikationen är viktig och att en väl genomförd kommunikationsinsats minskar friktionen mellan de olika aktörerna. Slentrianmässig eller dåligt samordnad kommunikation åstadkommer motsatsen. Fallstudierna visade också att massmedia kan ha en viktig roll som informatör men också påverka allmänhetens riskuppfattning. En intressant iakttagelse i några av studierna var att det var en oplanerad eller oväntad händelse som åstadkom kommunikationskonflikten. Finns det redan i början av projektet ett svagt förtroende för auktoriteterna (konsulter och myndigheter) kan en dålig kommunikationsinsats ytterligare försvaga tilliten. En utomstående expert kan bidra till ökad tillit genom att förmedla sin syn på riskerna. Följande komponenter identifierades som särskilt viktiga i samband med riskkommunikation kring förorenade områden: • Goda förberedelser, exempelvis genom att identifiera målgrupperna, planera kommunikationsinsatserna och tänka sig in i vad som kan skapa konflikter. • Att skapa en öppen och transparent process där dialogen mellan olika aktörer lyfts fram och betraktas som viktig. • Att inse att kunskap och rationalitet är olika begrepp. Enskilda personers riskuppfattning baseras på en blandning av tekniska, psykologiska, sociologiska, kulturella men även ekonomiska överväganden. • Att en genomtänkt kommunikationsplan ger bra förutsättningar för att kommunikationsfrågorna ges rätt prioritet i efterbehandlingsprojektet. När allmänheten och massmedia ringer ner telefonen är det ofta för sent för att åstadkomma en väl avvägd kommunikationsinsats.
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| 4. |
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| 5. |
- Bengtsson, Sara, 1978-, et al.
(författare)
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Chronic allopregnanolone elevation cause altered plaque production in Swe/PS1 mice
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Abstract. We have previously shown that chronic elevation of the neurosteroid allopregnanolone caused learning dysfunction and increased levels of soluble Aβ in the Swe/PS1 mouse model. The mechanism behind these findings is however unknown. We further investigated the brain tissue of these mice to identify any effects on congophilic plaque burden, Aβ42-specific plaque burden and synaptic function. We found a significant reduction in the average size of the congophilic core of neuritic plaques after chronic allopregnanolone treatment compared to vehicle. This seems to be caused by an altered plaque production, leading to more abundant, but smaller neuritic plaques. We may also have detected a decrease in the amount of synaptophysin, and thus synaptic function among the same mice. However, the long interval between the end of treatment and tissue collection possibly allowed time for recovery and only minor differences were noted. We found that the natural relationship between levels of insoluble Aβ, congophilic and Aβ42-specific plaque load was disrupted after chronically elevated allopregnanolone levels. Furthermore, the levels of syn-aptophysin and insoluble Aβ became more important in the relationship to learning and memory. The causality of these factors is still unknown and further studies are required to fully understand the effect of neurosteroids on AD development.
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| 6. |
- Bergström, Marcus, et al.
(författare)
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Autologous regulatory T cells in clinical intraportal allogenic pancreatic islet transplantation
- 2021
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Ingår i: Transplant International. - : John Wiley & Sons. - 0934-0874 .- 1432-2277. ; 34:12, s. 2816-2823
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Tidskriftsartikel (refereegranskat)abstract
- Allogeneic islet transplantation in type 1 diabetes requires lifelong immunosuppression to prevent graft rejection. This medication can cause adverse effects and increases the susceptibility for infections and malignancies. Adoptive therapies with regulatory T cells (Tregs) have shown promise in reducing the need for immunosuppression in human transplantation settings but have previously not been evaluated in islet transplantation. In this study, five patients with type 1 diabetes undergoing intraportal allogeneic islet transplantation were co-infused with polyclonal autologous Tregs under a standard immunosuppressive regimen. Patients underwent leaukapheresis from which Tregs were purified by magnetic-activated cell sorting (MACS) and cryopreserved until transplantation. Dose ranges of 0.14–1.27 × 106 T cells per kilo bodyweight were transplanted. No negative effects were seen related to the Treg infusion, regardless of cell dose. Only minor complications related to the immunosuppressive drugs were reported. This first-in-man study of autologous Treg infusion in allogenic pancreatic islet transplantation shows that the treatment is safe and feasible. Based on these results, future efficacy studies will be developed under the label of advanced therapeutic medical products (ATMP), using modified or expanded Tregs with the aim of minimizing the need for chronic immunosuppressive medication in islet transplantation.
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| 7. |
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| 8. |
- Boenink, Rianne, et al.
(författare)
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Trends in kidney transplantation rate across Europe : a study from the ERA Registry
- 2023
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Ingår i: Nephrology Dialysis Transplantation. - : Oxford University Press (OUP). - 0931-0509 .- 1460-2385. ; 38:6, s. 1528-1539
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Tidskriftsartikel (refereegranskat)abstract
- Background. The aim of this study was to identify trends in total, deceased donor (DD) and living donor (LD) kidney transplantation (KT) rates in European countries. Methods. The European Renal Association (ERA) Registry and the Global Observatory on Donation and Transplantation (GODT) databases were used to obtain the number of KTs in individual European countries between 2010 and 2018. General population counts were obtained from Eurostat or the national bureaus of statistics. The KT rate per million population (p.m.p.) and the average annual percentage change (APC) were calculated. Results. The total KT rate in the 40 participating countries increased with 1.9% annually [95% confidence interval (CI) 1.5, 2.2] from 29.6 p.m.p. in 2010 to 34.7 p.m.p. in 2018, reflecting an increase of 3.4 p.m.p. in the DD-KT rate (from 21.6 p.m.p. to 25.0 p.m.p.; APC 1.9%; 95% CI 1.3, 2.4) and of 1.5 p.m.p. in the LD-KT rate (from 8.1 p.m.p. to 9.6 p.m.p.; APC 1.6%; 95% CI 1.0, 2.3). The trends in KT rate varied widely across European countries. An East-West gradient was observed for DD-KT rate, with Western European countries performing more KTs. In addition, most countries performed fewer LD-KTs. In 2018, Spain had the highest DD-KT rate (64.6 p.m.p.) and Turkey the highest LD-KT rate (37.0 p.m.p.). Conclusions. The total KT rate increased due to a rise in the KT rate from DDs and to a lesser extent from LDs, with large differences between individual European countries.
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| 9. |
- Brandhorst, Heide, 1962-, et al.
(författare)
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The importance of tryptic-like activity in purified enzyme blends for efficient islet isolation
- 2009
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Ingår i: Transplantation. - 0041-1337 .- 1534-6080. ; 87:3, s. 370-5
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The isolation of islets from the human pancreas critically depends on an efficient enzyme blend. Previous studies have solely focused on the presence of collagenase and neutral protease/thermolysin. Despite improved characterization of these components, the lot-related variability in efficacy still persists suggesting that additional so far disregarded enzymes are required for efficient islet cleavage. METHODS: Varying activities of a tryptic-like enzyme were identified within collagenase NB1 lots, which were selected according to a matched ratio between tryptic-like and collagenase activity (TLA-ratio). Rat and human pancreata were processed with current standard procedures. RESULTS: Increasing the TLA-ratio from 1.3% to 10% reduced pancreas dissociation time in rats by 50% without affecting islet yield, viability, or posttransplant function in diabetic nude mice. Enhancing the TLA-ratio from 1.3% to 12.6% for human pancreas processing resulted in a significant reduction of recirculation time and increased incrementally human islet yield without affecting purity, in vitro function or recovery after culture. Optimized pancreas digestion correlated with a higher percentage of islet preparations fulfilling quality criteria for clinical transplantation. CONCLUSIONS: We conclude that TLA is an effective component that should be included in moderate amounts in enzyme blends for human islet isolation to optimize the efficiency and minimize the lot-related variability.
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| 10. |
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| 11. |
- Bäckström, Torbjörn, et al.
(författare)
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Isoallopregnanolone inhibits estrus cycle-dependent aggressive behavior
- 2023
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Ingår i: Biomolecules. - : MDPI. - 2218-273X. ; 13:6
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Tidskriftsartikel (refereegranskat)abstract
- Among female rats, some individuals show estrus cycle-dependent irritability/aggressive behaviors, and these individual rats may be used as a model for premenstrual dysphoric disorder (PMDD). We wanted to investigate if these behaviors are related to the estrus cycle phase containing moderately increased levels of positive GABA-A receptor-modulating steroids (steroid-PAM), especially allopregnanolone (ALLO), and if the adverse behavior can be antagonized. The electrophysiology studies in this paper show that isoallopregnanolone (ISO) is a GABA-A-modulating steroid antagonist (GAMSA), meaning that ISO can antagonize the agonistic effects of positive GABA-A receptor-modulating steroids in both α1β2γ2L and α4β3δ GABA-A receptor subtypes. In this study, we also investigated whether ISO could antagonize the estrus cycle-dependent aggressive behaviors in female Wistar rats using a resident–intruder test. Our results confirmed previous reports of estrus cycle-dependent behaviors in that 42% of the tested rats showed higher levels of irritability/aggression at diestrus compared to those at estrus. Furthermore, we found that, during the treatment with ISO, the aggressive behavior at diestrus was alleviated to a level comparable to that of estrus. We noticed an 89% reduction in the increase in aggressive behavior at diestrus compared to that at estrus. Vehicle treatment in the same animals showed a minimal effect on the diestrus-related aggressive behavior. In conclusion, we showed that ISO can antagonize Steroid-PAM both in α1β2γ2L and α4β3δ GABA-A receptor subtypes and inhibit estrus cycle-dependent aggressive behavior.
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| 12. |
- Bäckström, Torbjörn, 1948-, et al.
(författare)
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Pathogenesis in menstrual cycle-linked CNS disorders.
- 2003
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Ingår i: Annals of the New York Academy of Sciences. - : Wiley. - 0077-8923 .- 1749-6632. ; 1007, s. 42-53
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Forskningsöversikt (övrigt vetenskapligt/konstnärligt)
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| 13. |
- Caballero-Corbalán, José, et al.
(författare)
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No beneficial effect of two-layer storage compared with UW-storage on human islet isolation and transplantation
- 2007
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Ingår i: Transplantation. - : Ovid Technologies (Wolters Kluwer Health). - 0041-1337 .- 1534-6080. ; 84:7, s. 864-869
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Tidskriftsartikel (refereegranskat)abstract
- Background. Shipment of pancreata between distant centers is frequently associated with prolonged cold ischemia time (CIT) that leads to poorer outcomes for islet transplantation. Clinical pilot trials have indicated that oxygenation of explanted human pancreata utilizing the two-layer method (TLM) allows the use of marginal donor pancreata for islet transplantation. The present study aimed to clarify whether TLM enhances the ischemic tolerance of human pancreata. Methods. We analyzed retrospectively the outcome of 200 human islet isolations performed after TLM preservation or storage in University of Wisconsin solution (UWS). Results. Donor characteristics and digestion parameters did not vary significantly between TLM-preserved and UWS-stored pancreata. No differences were observed between experimental groups with regard to islet yield, purity, or dynamic glucose stimulation index after either short or prolonged CIT. However, CIT and stimulation index were negatively correlated in each experimental group. The isolation outcome in donors aged ≥60 years was not increased after TLM preservation when compared to UWS storage. No effect was observed regarding islet posttransplant function in recipients with established kidney grafts. Conclusions. The present study suggests that the ischemic tolerance of human pancreata cannot be extended by TLM preservation. In addition, TLM does not seem to improve the isolation outcome for pancreata from elderly donors.
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| 14. |
- Cabric, Sanja, et al.
(författare)
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Islet Surface Heparinization Prevents the Instant-Blood Mediated Inflammatory Reaction in Islet Transplantation
- 2007
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Ingår i: Diabetes. - : American Diabetes Association. - 0012-1797 .- 1939-327X. ; 56:8, s. 2008-2015
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE—In clinical islet transplantation, the instant blood-mediated inflammatory reaction (IBMIR) is a major factor contributing to the poor initial engraftment of the islets. This reaction is triggered by tissue factor and monocyte chemoattractant protein (MCP)-1, expressed by the transplanted pancreatic islets when the islets come in contact with blood in the portal vein. All currently identified systemic inhibitors of the IBMIR are associated with a significantly increased risk of bleeding or other side effects. To avoid systemic treatment, the aim of the present study was to render the islet graft blood biocompatible by applying a continuous heparin coating to the islet surface.RESEARCH DESIGN AND METHODS—A biotin/avidin technique was used to conjugate preformed heparin complexes to the surface of pancreatic islets. This endothelial-like coating was achieved by conjugating barely 40 IU heparin per full-size clinical islet transplant.RESULTS—Both in an in vitro loop model and in an allogeneic porcine model of clinical islet transplantation, this heparin coating provided protection against the IBMIR. Culturing heparinized islets for 24 h did not affect insulin release after glucose challenge, and heparin-coated islets cured diabetic mice in a manner similar to untreated islets.CONCLUSIONS—This novel pretreatment procedure prevents intraportal thrombosis and efficiently inhibits the IBMIR without increasing the bleeding risk and, unlike other pretreatment procedures (e.g., gene therapy), without inducing acute or chronic toxicity in the islets.
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| 15. |
- Daneva (Mitradjieva), Maria, et al.
(författare)
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A Sequential Linear Programming Algorithm with Multi-dimensional Search : Derivation and Convergence
- 2007
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- We present a sequential linear programming, SLP, algorithm in which the traditional line-search step is replaced by a multi-dimensional search. The algorithm is based on inner approximations of both the primal and dual spaces, which yields a method which in the primal space combines column and constraint generation. The algorithm does not use a merit function, and the linear programming subproblem of the algorithm differs from the one obtained in traditional methods of this type, in the respect that linearized constraints are taken into account only implicitly in a Lagrangiandual fashion. Convergence to a point that satisfies the Karush-Kuhn-Tucker conditions is established. We apply the new method to a selection of the Hoch-Schittkowski’s nonlinear test problems and report a preliminary computational study in a Matlab environment. Since the proposed algorithmcombines column and constraint generation, it should be advantageous with large numbers of variables and constraints.
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| 16. |
- Eich, Torsten, et al.
(författare)
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Positron emission tomography : A real-time tool to quantify early islet engraftment in a preclinical large animal model
- 2007
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Ingår i: Transplantation. - : Ovid Technologies (Wolters Kluwer Health). - 0041-1337 .- 1534-6080. ; 84:7, s. 893-898
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Tidskriftsartikel (refereegranskat)abstract
- Background. Clinical islet transplantation is currently being explored as a therapeutic option for persons with type I diabetes and hypoglycemic unawareness. Techniques to monitor graft survival are urgently needed to optimize the procedure. Therefore, the objective of the present study was to develop a technique for imaging survival of transplanted islets in the peritransplant and early posttransplant phase.Methods. Isolated porcine islets were labeled in vitro with 2-deoxy-2[18F]fluoro-D-glucose ([18F]FDG) and infused intraportally into anesthetized pigs (n=10). Dynamic examination was performed on a positron emission tomography/computed tomography hybrid system.Results. More than 95% of the radioactivity was confined to the islets at the time of transplantation. The peak percentage of infused radioactivity within the liver, quantified at the end of the islet infusion, was only 54±5.1%. The distribution of the radioactivity in the liver was found to be heterogeneous. A whole-body examination showed no accumulation in the lungs or brain; extrahepatic radioactivity was, except urinary excretion, evenly distributed in the pig body.Conclusions. Our results imply that almost 50% of the islets were damaged to the extent that the FDG contained was release within minutes after intraportal transplantation. The distribution of radioactivity without accumulation in the brain indicates that the activity is released from lysed islet cells in the form of [18F]FDG-6P rather than native [18F]FDG. The presented technique shows promise to become a powerful and quantitative tool, readily available in the clinic, to evaluate initial islet engraftment and survival.
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| 17. |
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| 18. |
- Eriksson, Olof, et al.
(författare)
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Distribution of adoptively transferred porcine T-lymphoblasts tracked by (18)F-2-fluoro-2-deoxy-D-glucose and position emission tomography
- 2011
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Ingår i: Nuclear Medicine and Biology. - : Elsevier BV. - 0969-8051 .- 1872-9614. ; 38:6, s. 827-833
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Autologous or allogeneic transfer of tumor-infiltrating T-Iymphocytes is a promising treatment for metastatic cancers, but a major concern is the difficulty in evaluating cell trafficking and distribution in adoptive cell therapy. This study presents a method of tracking transfusion of T-Iymphoblasts in a porcine model by (18)F-2-fluoro-2-deoxy-D-glucose ([(18)F]FDG) and positron emission tomography. Methods: T-Iymphoblasts were labeled with the positron-emitting tracer [(18)F]FDG through incubation. The T-Iymphoblasts were administered into the bloodstream, and the distribution was followed by positron emission tomography for 120 min. The cells were administered either intravenously into the internal jugular vein (n=5) or intraarterially into the ascending aorta (n=1). Two of the pigs given intravenous administration were pretreated with low-molecular-weight dextran sulphate. Results: The cellular kinetics and distribution were readily quantifiable for up to 120 min. High (78.6% of the administered cells) heterogeneous pulmonary uptake was found after completed intravenous transfusion. The pulmonary uptake was decreased either by preineubating and coadministrating the T-Iymphoblasts with low-molecular-weight dextran sulphate or by administrating them intraarterially. Conclusions: The present work shows the feasibility of quantitatively monitoring and evaluating cell trafficking and distribution following administration of [(18)F]FDG-labeled T-Iymphoblasts. The protocol can potentially be transferred to the clinical setting with few modifications.
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| 19. |
- Eriksson, Olof, et al.
(författare)
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Positron emission tomography in clinical islet transplantation
- 2009
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Ingår i: American Journal of Transplantation. - : Elsevier BV. - 1600-6135 .- 1600-6143. ; 9:12, s. 2816-2824
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Tidskriftsartikel (refereegranskat)abstract
- The fate of islets in clinical transplantation is unclear. To elude on this positron emission tomography combined with computed tomography (PET/CT) was performed for 60 min during islet transplantation in five patients receiving six transplants. A fraction of the islets (23%) were labeled with 18F-fluorodeoxyglucose ([(18)F]FDG) and carefully mixed with unlabeled islets just prior to intraportal transplantation. The peak radioactivity concentration in the liver was found at 19 min after start of islet infusion and corresponded to only 75% of what was expected, indicating that islets are lost during the transplantation procedure. No accumulation of radioactivity was found in the lungs. A nonphysiological peak of C-peptide was found in plasma during and immediately after transplantation in all subjects. Distribution in the liver was heterogeneous with wide variations in location and concentration. Islets found in areas with concentrations of >400 IEQ/cc liver tissue varied between 1% and 32% of the graft in different subjects. No side effects attributed to the PET/CT procedure were found. Clinical outcome in all patients was comparable to that previously observed indicating that the [(18)F]FDG labeling procedure did not harm the islets. The technique has potential to be used to assess approaches to enhance islet survival and engraftment in clinical transplantation.
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| 20. |
- Erlandsson, Helen, et al.
(författare)
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Scoring of medial arterial calcification predicts cardiovascular events and mortality after kidney transplantation
- 2022
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Ingår i: Journal of Internal Medicine. - : Wiley. - 0954-6820 .- 1365-2796. ; 291:6, s. 813-823
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Tidskriftsartikel (refereegranskat)abstract
- Background Progression of vascular calcification causes cardiovascular disease, which is the most common cause of death in chronic kidney failure and after kidney transplantation (KT). The prognostic impact of the extent of medial vascular calcification at KT is unknown. Methods In this prospective cohort study, we investigated the impact of medial calcification compared to a mix of intimal and medial calcification represented by coronary artery calcification (CAC score) and aortic valve calcification in 342 patients starting on kidney failure replacement therapy. The primary outcomes were cardiovascular events (CVE) and death. The median follow-up time was 6.4 years (interquartile range 3.7-9.6 years). Exposure was CAC score and arteria epigastrica medial calcification scored as none, mild, moderate, or severe by a pathologist at time of KT (n = 200). We divided the patients according to kidney failure replacement therapy during follow-up, that is, living donor KT, deceased donor KT, or dialysis. Results Moderate to severe medial calcification in the arteria epigastrica was associated with higher mortality (p = 0.001), and the hazard ratio for CVE was 3.1 (95% confidence interval [CI] 1.12-9.02, p < 0.05) compared to no or mild medial calcification. The hazard ratio for 10-year mortality in the dialysis group was 33.6 (95% CI, 10.0-113.0, p < 0.001) compared to living donor recipients, independent of Framingham risk score and prevalent CAC. Conclusion Scoring of medial calcification in the arteria epigastrica identified living donor recipients as having 3.1 times higher risk of CVE, independent of traditional risk factors. The medial calcification score could be a reliable method to identify patients with high and low risk of CVE and mortality following KT.
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| 21. |
- Friberg, Andrew S, et al.
(författare)
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Transplantable functional islet mass – predictive biomarkers of graft function in islet after kidney transplanted patients
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The ability to predict clinical function of a specific islet batch released for clinical transplantation using standardized variables remains an elusive goal. Analysis of donor, islet isolation, quality control and recipient variables was undertaken in 110 islet after kidney (IAK) transplants and correlated to the pre- to 28-day posttransplant change in C-peptide to glucose and creatinine ratio (ΔCP/GCr). Using backward multiple regression the variables positively associated to ΔCP/GCr were islet volume transplanted (p<0.001) and glucose stimulated insulin secretion (SI) (p=0.009). Factors negatively associated to ΔCP/GCr were cold ischemia time (CIT) (p=0.002) and total tissue volume (p=0.009). Donor age, donor body mass index, number of retrieved organs from the donor, preservation solution, islet insulin content, body weight of the recipient of the islets had no influence on transplant function. The transplantable functional islet mass (TFIM), accounting for islet volume transplanted, SI, CIT, and total tissue volume explained 39% of the variance of the clinical outcome in the IAK data set. Therefore, the TFIM provides a straightforward and potent tool to guide the decision to utilize a specific islet preparation for clinical transplantation.
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| 22. |
- Friberg, Andrew S., et al.
(författare)
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Transplanted functional islet mass : donor islet preparation, and recipitent factors influence early graft function in islet-after-kidney patients
- 2012
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Ingår i: Transplantation. - 0041-1337 .- 1534-6080. ; 93:6, s. 632-638
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Tidskriftsartikel (refereegranskat)abstract
- Background.The ability to predict clinical function of a specific islet batch released for clinical transplantation using standardized variables remains an elusive goal.Methods. Analysis of 10 donor, 7 islet isolation, 3 quality control, and 6 recipient variables was undertaken in 110 islet-after-kidney transplants and correlated to the pre- to 28-day posttransplant change in C-peptide to glucose and creatinine ratio ([DELTA]CP/GCr).Results.Univariate analysis yielded islet volume transplanted (Spearman r=0.360, P<0.001) and increment of insulin secretion (r=0.377, P<0.001) as variables positively associated to [DELTA]CP/GCr. A negative association to [DELTA]CP/GCr was cold ischemia time (r=-0.330, P<0.001). A linear, backward-selection multiple regression was used to obtain a model for the transplanted functional islet mass (TFIM). The TFIM model, composed of islet volume transplanted, increment of insulin secretion, cold ischemia time, and exocrine tissue volume transplanted, accounted for 43% of the variance of the clinical outcome in the islet-after-kidney data set.Conclusion.The TFIM provides a straightforward and potent tool to guide the decision to use a specific islet preparation for clinical transplantation.
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| 23. |
- Fröberg, Klara, et al.
(författare)
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Outcome after total pancreatectomy with islet autotransplantation : a European single-center study
- 2024
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Ingår i: Scandinavian Journal of Surgery. - : Sage Publications. - 1457-4969 .- 1799-7267. ; 113:2, s. 80-87
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Tidskriftsartikel (refereegranskat)abstract
- Background and aims: Chronic pancreatitis may cause intractable abdominal pain, with total pancreatectomy sometimes being the last resort. To mitigate the subsequent diabetes, total pancreatectomy can be followed by islet autotransplantation (TP-IAT). The primary aim of this study was to assess the outcomes in patients undergoing TP-IAT at Karolinska University Hospital with respect to safety, postoperative complications, and islet graft function. A secondary aim was to compare liver to skeletal muscle as autotransplantation sites.Methods: Single-center observational cohort study on patients undergoing TP-IAT. Islets were transplanted either into the liver or skeletal muscle. Data on baseline characteristics and pretransplantory conditions were collected. Outcome measures included mortality and major postoperative complications as well as the glycemic measures: insulin use, fasting C-peptide, and HbA1c.Results: Between 2004 and 2020, 24 patients underwent TP-IAT. Islets were transplanted into the liver in 9 patients and into skeletal muscle in 15 patients. There was no 90-day mortality, and major complications (Clavien–Dindo ⩾IIIa) occurred in 26.7%, all related to the procedure of total pancreatectomy. Fasting C-peptide could be detected postoperatively, with higher levels in patients receiving islet autotransplantation into the liver (p = 0.006). Insulin independence was not achieved, although insulin doses at last follow-up were significantly lower in patients receiving islet autotransplantation into the liver compared to skeletal muscle (p = 0.036).Conclusion: TP-IAT is safe and associated with tolerable risk, the component of islet autotransplantation being seemingly harmless. Although islet grafts maintain some endocrine function, insulin independence should not be expected. Regarding islet autotransplantation sites, the liver seems superior to skeletal muscle. Clinical trial registration: Not applicable.
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| 24. |
- Hansson, Josef, 1991, et al.
(författare)
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Bipolar electrochemical capacitors using double-sided carbon nanotubes on graphite electrodes
- 2020
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Ingår i: Journal of Power Sources. - : Elsevier BV. - 0378-7753. ; 451
-
Tidskriftsartikel (refereegranskat)abstract
- The electrochemical capacitor (EC) is a key enabler for the miniaturized self-powered systems expected to become ubiquitous with the advent of the internet-of-things (IoT). Vertically aligned carbon nanotubes (VACNTs) on graphite holds promise as electrodes for compact and low-loss ECs. However, as with all ECs, the operating voltage is low, and miniaturization of higher voltage devices necessitates a bipolar design. In this paper, we demonstrate a bipolar EC using graphite/VACNTs electrodes fabricated using a joule heating chemical vapor deposition (CVD) setup. The constructed EC contains one layer of double-sided VACNTs on graphite as bipolar electrode. Compared to a series connection of two individual devices, the bipolar EC has 22% boost in volumetric energy density. More significant boost is envisaged for stacking more bipolar electrode layers. The energy enhancement is achieved without aggravating self-discharge (71.2% retention after 1 h), and at no sacrifice of cycling stability (96.7% over 50000 cycles) owing to uniform growth of VACNTs and thus eliminating cell imbalance problems.
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| 25. |
- Henriksson, Andreas, 1979, et al.
(författare)
-
RIFEL - Ripple and Electromagnetic Fields in Electric Vehicles
- 2018
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The electrical system in an electrified vehicle consists of high voltage (HV) components interacting in a complex way. The switching interaction in the power electronics results in ripple causing electromagnetic fields, disturbing other electronics and degradation of components. An overview of this can first be obtained when a physical system is built which could lead to unintentional over- or under dimensioning of HV components. This lack of information within the electrical system can lead to late verifications in the project causing substantial cost if changes are needed. This project aims at improving early evaluation of new concepts, create tools and build the necessary competence for a virtual system model that includes the key HV components: battery, electrical motor and power electronics, a simple load along with cable and connectors. This virtual model shall be able to simulate voltage and current ripple generated by the power electronics, initially in a frequency range up to 100 kHz. Results from the simulations shall be presented both in time and frequency domain as well as be expressed in RMS values for easier comparison to measured results. Some of the more important findings are briefly summarised below; For the high voltage battery, the electrical characteristics up to a frequency of roughly 1000 Hz was well determined using an impedance spectroscopy instrument at cell level and then multiplied by the numbers of cells. However for finding the impedance behaviour for frequencies above 1000 Hz, the determination must be done on the battery pack level since bus bars and other component in the complete battery pack will be dominating in this frequency range. From measurements of differential mode impedance in high voltage cables it is found that it is important that the mutual inductance between the centre conductor and shield is included in the model to describe cable impedance below 10 kHz properly. The control of the inverter is very important for the overall behaviour and in this project SVM was used which has been shown to give the lowest current and voltage ripple of the traditional switching schemes. And for the machine model, the temperature variations must be taken into account since the machine parameters has been found to vary with ~20 % over the specified temperature range. The system model is found to agree well with rig measurements well up to 1 MHz with regards to both currents and voltages at the DC and AC sides. Furthermore, measurements in a real car match those in the rig. For time domain simulations, it was decided to use Ansys Simplorer since it can handle the inverter and the electrical machine simulations very well and for frequency domain simulations, it was decided to use LTspice since it is freeware, has support for AC-sweeps, improved switching compared to other SPICE-simulators, and is easy to use. Magnetic field simulations have been calculated and compared to measurements in the driveline rig at Chalmers. It was a good match across the investigated frequency range 10 Hz to 100 kHz. In this project, only internally developed component models were considered. To expand the functionality of the system modelling tool, international interface standards such as the Functional Mockup Interface (FMI) need to be investigated. Consequently, it would be a good idea to include additional automotive OEMs as well as suppliers and software vendors in future research collaborations.
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| 26. |
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| 27. |
- Johansson, Helena, et al.
(författare)
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Tissue factor produced by the endocrine cells of the islets of Langerhans is associated with a negative outcome of clinical islet transplantation
- 2005
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Ingår i: Diabetes. - : American Diabetes Association. - 0012-1797 .- 1939-327X. ; 54:6, s. 1755-62
-
Tidskriftsartikel (refereegranskat)abstract
- There are strong indications that only a small fraction of grafts successfully engraft in clinical islet transplantation. One explanation may be the instant blood-mediated inflammatory reaction (IBMIR) elicited by tissue factor, which is produced by the endocrine cells. In the present study, we show that islets intended for islet transplantation produce tissue factor in both the transmembrane and the alternatively spliced form and that the membrane-bound form is released as microparticles often associated with both insulin and glucagon granules. A low-molecular mass factor VIIa (FVIIa) inhibitor that indirectly blocks both forms of tissue factor was shown in vitro to be a promising drug to eliminate the IBMIR. Thrombin-antithrombin complex (TAT) and FVIIa-antithrombin complex (FVIIa-AT) were measured in nine patients who together received 20 infusions of isolated human islets. Both the TAT and FVIIa-AT complexes increased rapidly within 15-60 min after infusion. When the initial TAT and FVIIa-AT levels were plotted against the increase in C-peptide concentration after 7 days, patients with an initially strong IBMIR showed no significant increase in insulin synthesis after 7 days. In conclusion, tissue factor present in both the islets and the culture medium and elicits IBMIR, which affects the function of the transplanted islets.
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| 28. |
- Jordan, Stanley C, et al.
(författare)
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IgG Endopeptidase in Highly Sensitized Patients Undergoing Transplantation.
- 2017
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Ingår i: New England Journal of Medicine. - : Massachusetts Medical Society. - 0028-4793 .- 1533-4406. ; 377:5, s. 442-453
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Donor-specific antibodies create an immunologic barrier to transplantation. Current therapies to modify donor-specific antibodies are limited and ineffective in the most highly HLA-sensitized patients. The IgG-degrading enzyme derived from Streptococcus pyogenes (IdeS), an endopeptidase, cleaves human IgG into F(ab')2 and Fc fragments inhibiting complement-dependent cytotoxicity and antibody-dependent cellular cytotoxicity, which suggests that IdeS might be useful for desensitization. We report on the combined experience of two independently performed open-label, phase 1-2 trials (conducted in Sweden and the United States) that assessed the efficacy of IdeS with regard to desensitization and transplantation of a kidney from an HLA-incompatible donor.METHODS: We administered IdeS to 25 highly HLA-sensitized patients (11 patients in Uppsala or Stockholm, Sweden, and 14 in Los Angeles) before the transplantation of a kidney from an HLA-incompatible donor. Frequent monitoring for adverse events, outcomes, donor-specific antibodies, and renal function was performed, as were renal biopsies. Immunosuppression after transplantation consisted of tacrolimus, mycophenolate mofetil, and glucocorticoids. Patients in the U.S. study also received intravenous immune globulin and rituximab after transplantation to prevent antibody rebound.RESULTS: Recipients in the U.S. study had a significantly longer cold ischemia time (the time elapsed between procurement of the organ and transplantation), a significantly higher rate of delayed graft function, and significantly higher levels of class I donor-specific antibodies than those in the Swedish study. A total of 38 serious adverse events occurred in 15 patients (5 events were adjudicated as being possibly related to IdeS). At transplantation, total IgG and HLA antibodies were eliminated. A total of 24 of 25 patients had perfusion of allografts after transplantation. Antibody-mediated rejection occurred in 10 patients (7 patients in the U.S. study and 3 in the Swedish study) at 2 weeks to 5 months after transplantation; all these patients had a response to treatment. One graft loss, mediated by non-HLA IgM and IgA antibodies, occurred.CONCLUSIONS: IdeS reduced or eliminated donor-specific antibodies and permitted HLA-incompatible transplantation in 24 of 25 patients. (Funded by Hansa Medical; ClinicalTrials.gov numbers, NCT02224820 , NCT02426684 , and NCT02475551 .).
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| 29. |
- Jörnsten, Kurt O., et al.
(författare)
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An entropy model with variable target
- 1990
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Ingår i: Environment and planning A. - : SAGE Publications. - 0308-518X .- 1472-3409. ; 22:4, s. 493-506
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Tidskriftsartikel (refereegranskat)abstract
- In this paper an entropy model with variable target is presented, in which target values are assumed to belong to a specified convex set, so that multiple base-year information and forecasts of future trends can be handled without prior aggregation of such information into one fixed target.Three solution methods for such a model are presented -- one cutting-plane and two search methods -- all of which utilize the fact that entropy models with fixed targets can be solved efficiently. Some comments on potential applications and reasonable target-set specifications are made and numerical examples are presented
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| 30. |
- Kask, Kristiina, et al.
(författare)
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Allopregnanolone has no effect on startle response and prepulse inhibition of startle response in patients with premenstrual dysphoric disorder or healthy controls
- 2009
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Ingår i: Pharmacology, Biochemistry and Behavior. - : Elsevier BV. - 0091-3057 .- 1873-5177. ; 92:4, s. 608-613
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Tidskriftsartikel (refereegranskat)abstract
- Background: Allopregnanolone is an endogenous neuroactive steroid which, through the binding to the GABA(A) receptor. enhances inhibitory neurotransmission and exerts anxiolytic, sedative and antiepileptic effects. Following acute administration, allopregnanolone reliably acts as an anxiolytic compound. The primary aim of this study was to investigate if allopregnanolone, administered to healthy women and women with premenstrual dysphoric disorder (PMDD), would have an anxiolytic effect, expressed as a decreased startle response. Materials and methods: Sixteen PMDD patients and twelve healthy controls completed the study. The participants were scheduled for the startle tests twice in the luteal phase. During the test sessions an intravenous allopregnanolone and placebo bolus injection was administered in double-blinded, randomized order at intervals of 48 h. Following the allopregnanolone/placebo injections startle response and prepulse inhibition of startle response (PPI) were assessed by electromyography. Results: Following the intravenous allopregnanolone administration the serum concentrations of allopregnanolone increased to 50-70 nmol/l. corresponding to levels that are seen during pregnancy. The obtained serum concentrations of allopregnanolone were significantly lower in PMDD patients than among the healthy controls, p<0.05. The allopregnanolone injection resulted in significant increases of self-rated sedation in both groups, p<0.01. Allopregnanolone did not induce any changes in startle response or prepulse inhibition of startle response in comparison to placebo. No differences in allopregnanolone-induced changes in startle response or PPI could be detected between PMDD patients and controls subjects. Conclusion: Startle response and PPI were unaffected by acute intravenous administration of allopregnanolone in PMDD patients and healthy controls.
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| 31. |
- Kjellman, Christian, et al.
(författare)
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Outcomes at 3 years posttransplant in imlifidase-desensitized kidney transplant patients
- 2021
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Ingår i: American Journal of Transplantation. - : Elsevier. - 1600-6135 .- 1600-6143. ; 21:12, s. 3907-3918
-
Tidskriftsartikel (refereegranskat)abstract
- Imlifidase is a cysteine proteinase which specifically cleaves IgG, inhibiting Fc-mediated effector function within hours of administration. Imlifidase converts a positive crossmatch to a potential donor (T cell, B cell, or both), to negative, enabling transplantation to occur between previously HLA incompatible donor-recipient pairs. To date, 39 crossmatch positive patients received imlifidase prior to a kidney transplant in four single-arm, open-label, phase 2 studies. At 3 years, for patients who were AMR+ compared to AMR-, death-censored allograft survival was 93% vs 77%, patient survival was 85% vs 94%, and mean eGFR was 49 ml/min/1.73 m2 vs 61 ml/min/1.73 m2 , respectively. The incidence of AMR was 38% with most episodes occurring within the first month post-transplantation. Sub-analysis of patients deemed highly sensitized with cPRA ≥ 99.9%, and unlikely to be transplanted who received crossmatch-positive, deceased donor transplants had similar rates of patient survival, graft survival, and eGFR but a higher rate of AMR. These data demonstrate that outcomes and safety up to 3 years in recipients of imlifidase-enabled allografts is comparable to outcomes in other highly sensitized patients undergoing HLA-incompatible transplantation. Thus, imlifidase is a potent option to facilitate transplantation among patients who have a significant immunologic barrier to successful kidney transplantation.
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| 32. |
- Korsgren, Olle, et al.
(författare)
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Optimising islet engraftment is critical for successful clinical islet transplantation
- 2008
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Ingår i: Diabetologia. - : Springer Science and Business Media LLC. - 0012-186X .- 1432-0428. ; 51:2, s. 227-32
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Tidskriftsartikel (refereegranskat)abstract
- Clinical islet transplantation is currently being explored as a treatment for persons with type 1 diabetes and hypoglycaemia unawareness. Although 'proof-of-principle' has been established in recent clinical studies, the procedure suffers from low efficacy. At the time of transplantation, the isolated islets are allowed to embolise the liver after injection in the portal vein, a procedure that is unique in the area of transplantation. A novel view on the engraftment of intraportally transplanted islets is presented that could explain the low efficacy of the procedure.
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| 33. |
- Ladd, Brian, et al.
(författare)
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Proof-of-Concept of Continuous Transfection for Adeno-Associated Virus Production in Microcarrier-Based Culture
- 2022
-
Ingår i: Processes. - : MDPI AG. - 2227-9717. ; 10:3
-
Tidskriftsartikel (refereegranskat)abstract
- Adeno-associated virus vectors (AAV) are reported to have a great potential for gene therapy, however, a major bottleneck for this kind of therapy is the limitation of production capacity. Higher specific AAV vector yield is often reported for adherent cell systems compared to cells in suspension, and a microcarrier-based culture is well established for the culture of anchored cells on a larger scale. The purpose of the present study was to explore how microcarrier cultures could provide a solution for the production of AAV vectors based on the triple plasmid transfection of HEK293T cells in a stirred tank bioreactor. In the present study, cells were grown and expanded in suspension, offering the ease of this type of operation, and were then anchored on microcarriers in order to proceed with transfection of the plasmids for transient AAV vector production. This process was developed in view of a bioreactor application in a 200 mL stirred-tank vessel where shear stress aspects were studied. Furthermore, amenability to a continuous process was studied. The present investigation provided a proof-of-concept of a continuous process based on microcarriers in a stirred-tank bioreactor.
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| 34. |
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| 35. |
- Larsson, Torbjörn, et al.
(författare)
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Allocation of Link Flow Detectors for Origin-Destination Matrix Estimation-A Comparative Study
- 2010
-
Ingår i: COMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING. - : Wiley. - 1093-9687 .- 1467-8667. ; 25:2, s. 116-131
-
Tidskriftsartikel (refereegranskat)abstract
- Origin-destination (OD) matrices are essential for various analyses in the field of traffic planning, and they are often estimated from link flow observations. We compare methods for allocating link flow detectors to a traffic network with respect to the quality of the estimated OD-matrix. First, an overview of allocation methods proposed in the literature is presented. Second, we construct a controlled experimental environment where any allocation method can be evaluated, and compared to others, in terms of the quality of the estimated OD-matrix. Third, this environment is used to evaluate and compare three fundamental allocation methods. Studies are made on the Sioux Falls network and on a network modeling the city of Linkoping. Our conclusion is, that the most commonly studied approach for detector allocation, maximizing the coverage of OD-pairs, seems to be unfavorable for the quality of the estimated OD-matrix.
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| 36. |
- Lilja, Josefine, et al.
(författare)
-
Five Facets Mindfulness Questionnaire-Reliability and Factor Structure : A Swedish Version
- 2011
-
Ingår i: Cognitive Behaviour Therapy. - Abingdon : Routledge. - 1650-6073 .- 1651-2316. ; 40:4, s. 291-303
-
Tidskriftsartikel (refereegranskat)abstract
- Two studies were conducted to assess the Swedish version of the Five Facets Mindfulness Questionnaire (FFMQ), which was originally created by Baer et al. (2006). The aim of Study 1 was to examine the psychometric properties of the FFMQ using data from 495 individuals. Quantitative and qualitative analyses resulted in a reduction of the scale by 10 items. Psychometric properties, including internal consistency of the revised instrument, were examined. The Swedish FFMQ provides results comparable to those obtained by Baer. Cronbach’s alphas were high for all the facets. The Swedish FFMQ appears to be a potentially useful tool in measuring mindfulness among Swedish participants. The aim of Study 2 was to test the suggested hierarchical five-factor solution and construct validity, using a confirmatory factor analysis (CFA). Similar to findings for the English version of the FFMQ, the CFA showed that the Observing facet was not a significant part of an overall self-reported mindfulness structure in a Swedish population with little meditation experience. © 2011 Copyright Swedish Association for Behaviour Therapy.
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| 37. |
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| 38. |
- Lundgren, Magdalena, et al.
(författare)
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Sex- and depot-specific lipolysis regulation in human adipocytes : interplay between adrenergic stimulation and glucocorticoids
- 2008
-
Ingår i: Hormone and Metabolic Research. - Stuttgart, New York : Georg Thieme Verlag KG. - 0018-5043 .- 1439-4286. ; 40, s. 854-860
-
Tidskriftsartikel (refereegranskat)abstract
- The purpose of this investigation was to explore interactions between adrenergic stimulation, glucocorticoids, and insulin on the lipolytic rate in isolated human adipocytes from subcutaneous and omental fat depots, and to address possible sex diff erences. Fat biopsies were obtained from 48 nondiabetic subjects undergoing elective abdominal surgery. Lipolysis rate was measured as glycerol release from isolated cells and proteins involved in lipolysis regulation were assessed by immunoblots. Fasting blood samples were obtained and metabolic and infl ammatory variables were analyzed. In women, the rate of 8-bromo-cAMP- and isoprenaline-stimulated lipolysis was ~ 2- and 1.5-fold higher, respectively, in subcutaneous compared to omental adipocytes, whereas there was no diff erence between the two depots in men. Dexamethasone treatment increased the ability of 8-bromo-cAMP to stimulate lipolysis in the subcutaneous depot in women, but had no consistent eff ects in fat cells from men. Protein kinase A, Perilipin A, and hormone sensitive lipase content in adipocytes was not aff ected by adipose depot, sex, or glucocorticoid treatment. In conclusion, catecholamine and glucocorticoid regulation of lipolysis in isolatedhuman adipocytes diff ers between adipose tissue depots and also between sexes. These findings may be of relevance for the interaction between endogenous stress hormones and adipose tissue function in visceral adiposity and the metabolic syndrome.
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| 39. |
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| 40. |
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| 41. |
- Lundgren, Torbjörn
(författare)
-
Evaluation of strategies to predict and improve early graft survival in clinical islet transplantation
- 2010
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Transplantation of the islets of Langerhans as a treatment for type 1 diabetes (T1DM) is a procedure still under development. For the last decade it has been possible to obtain insulin independence by repeated infusions of islets. However, most patients must resume insulin therapy in 2-3 years. The side effects associated with today s immunosuppressive medication limit the procedure to patients with severe and frequent episodes of hypoglycemia or to T1DM patients who need immunosuppressive medication for other reasons, e.g. due to previous kidney transplantation. The efficacy and long term results of islet transplantation need to be improved for the treatment to be considered for also other categories of patients. In this thesis a new technique, the two-layer method (TLM), to avoid hypoxic damage to the pancreas during the period of cold storage between donor operation and islet isolation was evaluated. PET/CT was introduced in a preclinical large animal model of islet transplantation and thereafter used to study the early post-transplantation phase of clinical islet transplantation. Finally, a new ratio, delta CP/GCr, was used to evaluate short term outcomes of repeated clinical islet transplantations. No significant differences could be seen in islet isolation yield or islet transplantation outcomes using TLM compared to conventional cold storage. When utilizing PET/CT to monitor the transplantation of [18F]-FDG labeled islets, these were heterogeneously spread in the liver, with fractions of the graft found in hot spots . At least 25 % of the radioactivity contained within the islets was lost during the transplantation indicating significant early damage to the graft, possibly due to the instant blood mediated inflammatory reaction (IBMIR). Evaluating the clinical outcome of 110 transplantations, we showed that a large islet graft, a high stimulation index and short cold ischemia time (CIT) were factors that significantly improved clinical outcome. No correlation was found between initial renal graft function and the outcome of islet transplantation from the same donor. This thesis has investigated areas where improvements must be made for islet transplantation to reach higher efficacy and become a treatment modality for more patients. The need for repeated islet infusions has made it difficult to study the effect of each islet preparation. Tools have here been introduced to facilitate this individual evaluation. Factors that predict the clinical outcome have been identified. Findings include the importance of CIT. New methods to preserve the pancreas before isolation are needed to improve outcome of both isolation and transplantation. A large fraction of islets implanted is lost during transplantation. The presented PET/CT technique may be used to further characterize early post-transplantation events and can become an important instrument in evaluation of new methods to enhance initial islet survival.
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| 42. |
- Löfgren, Magnus, 1979-, et al.
(författare)
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Progesterone withdrawal effects in the open field test can be predicted by elevated plus maze performance
- 2006
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Ingår i: Hormones and Behavior. - : Elsevier BV. - 0018-506X .- 1095-6867. ; 50:2, s. 208-215
-
Tidskriftsartikel (refereegranskat)abstract
- Allopregnanolone (3alpha-hydroxy-5alpha-pregnane-20-one) is a ring-A-reduced metabolite of progesterone, which is naturally produced during the luteal phase of the menstrual cycle, during pregnancy and by stressful events. The steroid hormone inhibits neural functions through increased chloride ion flux through the GABAA receptor. The effects and subsequent withdrawal symptoms are similar to those caused by alcohol, benzodiazepines and barbiturates. This study examined the withdrawal effects of progesterone with regards to the influence of individual baseline exploration and risk taking. Rats were tested on the elevated plus maze (EPM) before hormonal treatment, in order to evaluate differences in risk taking and exploration of open and elevated areas. Treatment consisted of ten consecutive once a day progesterone or vehicle s.c. injections. On the last day of treatment, estradiol was injected in addition to progesterone, followed by a 24-h withdrawal before testing in the open field test (OF). Progesterone-treated rats showed a withdrawal effect of open area avoidance in the OF. The vehicle-treated control rats showed strong correlations between the EPM and OF parameters. This relationship was not found for the progesterone group at withdrawal. Rats with greater numbers of open arm entrance in the EPM pretest showed an increased sensitivity to progesterone withdrawal (PWD) compared to rats with low exploration and risk taking. The results indicate that the effects of PWD relate to individual exploration and risk taking. Furthermore, the possible analogy of PWD and PMS/PMDD in relation to individual traits is discussed.
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| 43. |
- Mitradjieva-Daneva, Maria, 1974-
(författare)
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Feasible Direction Methods for Constrained Nonlinear Optimization : Suggestions for Improvements
- 2007
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis concerns the development of novel feasible direction type algorithms for constrained nonlinear optimization. The new algorithms are based upon enhancements of the search direction determination and the line search steps.The Frank-Wolfe method is popular for solving certain structured linearly constrained nonlinear problems, although its rate of convergence is often poor. We develop improved Frank--Wolfe type algorithms based on conjugate directions. In the conjugate direction Frank-Wolfe method a line search is performed along a direction which is conjugate to the previous one with respect to the Hessian matrix of the objective. A further refinement of this method is derived by applying conjugation with respect to the last two directions, instead of only the last one.The new methods are applied to the single-class user traffic equilibrium problem, the multi-class user traffic equilibrium problem under social marginal cost pricing, and the stochastic transportation problem. In a limited set of computational tests the algorithms turn out to be quite efficient. Additionally, a feasible direction method with multi-dimensional search for the stochastic transportation problem is developed.We also derive a novel sequential linear programming algorithm for general constrained nonlinear optimization problems, with the intention of being able to attack problems with large numbers of variables and constraints. The algorithm is based on inner approximations of both the primal and the dual spaces, which yields a method combining column and constraint generation in the primal space.
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| 44. |
- Nilsson, Louise, 1973-
(författare)
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Färger, former, ljus : Svensk reklam och reklampsykologi, 1900-1930
- 2010
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This dissertation examines the rise of an advertisement business in Sweden and the breakthrough of advertising psychology as a field of knowledge. The aim of the investigation is to show first, how the advertising landscape changed in Sweden and, second, how technologies were used in designing the different forms of advertisement that became integrated into media and public environments, during the period 1900-1930. The study raises questions such as: Who were the entrepreneurs behind the outbreak of psychological advertising in Sweden during the early 20th century? How did advertisement become integrated into media and urban landscapes as part of everyday life in Swedish society? How did handbooks in advertising psychology describe the effects of external visual stimuli, such as light, colors and shapes on the viewers’ consciousness and the role of such stimuli in transforming viewers to consumers? The dissertation is written within the interdisciplinary field of visual culture studies. Here the theoretical point of departure combines perspectives from media, film and art studies. Drawing on Crary’s works, the intention of my study is to highlight how such changes resulted in strategies and tools that were used in commercial business and not necessarily in the sciences. The ability to capture human attention and influence her through visual stimuli was also of great interest to trade and industry. Within commercial business the human sense of sight was perceived as an object that could be stimulated for creating consumers. I examine the development of techniques and strategies in commercial business for influencing individuals by external stimuli.
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| 45. |
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| 46. |
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| 47. |
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| 48. |
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| 49. |
- Peterson, Anders, 1976-
(författare)
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The Origin-Destination Matrix Estimation Problem : Analysis and Computations
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- For most kind of analyses in the field of traffic planning, there is a need for origin--destination (OD) matrices, which specify the travel demands between the origin and destination nodes in the network. This thesis concerns the OD-matrix estimation problem, that is, the calculation of OD-matrices using observed link flows. Both time-independent and time-dependent models are considered, and we also study the placement of link flow detectors.Many methods have been suggested for OD-matrix estimation in time-independent models, which describe an average traffic situation. We assume a user equilibrium to hold for the link flows in the network and recognize a bilevel structure of the estimation problem. A descent heuristic is proposed, in which special attention is given to the issue of calculating the change of a link flow with respect to a change of the travel demand in a certain pair of origin and destination nodes.When a time-dimension is considered, the estimation problem becomes more complex. Besides the problem of distributing the travel demand onto routes, the flow propagation in time and space must also be handled. The time-dependent OD-matrix estimation problem is the subject for two studies. The first is a case study, where the conventional estimation technique is improved through introducing pre-adjustment schemes, which exploit the structure of the information contained in the OD-matrix and the link flow observations. In the second study, an algorithm for time-independent estimation is extended to the time-dependent case and tested for a network from Stockholm, Sweden.Finally, we study the underlying problem of finding those links where traffic flow observations are to be performed, in order to ensure the best possible quality of the estimated OD-matrix. There are different ways of quantifying a common goal to cover as much traffic as possible, and we create an experimental framework in which they can be evaluated. Presupposing that consistent flow observations from all the links in the network yields the best estimate of the OD-matrix, the lack of observations from some links results in a relaxation of the estimation problem, and a poorer estimate. We formulate the problem to place link flow detectors as to achieve the least relaxation with a limited number of detectors.
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| 50. |
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