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1.
  • Fridén, Michael, et al. (författare)
  • Effects of a low-carbohydrate high polyunsaturated fat diet or a healthy Nordic diet versus usual care on liver fat content and cardiometabolic risk factors in people with type 2 diabetes and prediabetes: a randomized controlled trial (NAFLDiet)
  • Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
    • Background: Previous trials have shown that plant-derived polyunsaturated fatty acids (PUFA) in place of saturated fat reduces liver fat, a prerequisite for non-alcoholic fatty liver disease (NAFLD). The effect on liver fat from a novel “anti-lipogenic diet” replacing carbohydrates with PUFA or a healthy Nordic diet (HND) higher in whole-grains but lower in saturated fat has not yet been examined. Objectives: To investigate the effects on changes in liver fat (primary outcome) and other cardiometabolic risk factors after 12 months of follow-up in individuals with prediabetes or T2D from three different diet comparisons: a low carbohydrate high PUFA (LCPUFA) diet versus a HND, a LCPUFA diet versus usual care (UC) and a HND versus UC. Methods: A three-arm parallel ad libitum randomized trial was conducted. Adult men and women (n=148) were randomized to one of the three diet groups. Participants in all groups received key food items on a monthly/bimonthly basis. Liver fat and cardiometabolic risk factors were assessed at baseline and after 12 months. Dietary adherence was assessed using weighed food diaries and objective biomarkers. General linear models were employed to estimate the intention-to-treat (ITT) effect. Results: Dietary adherence was high for all diet groups. Liver fat was reduced to a similar extent in the LCPUFA and the HND group compared to UC (-1.46% (95% CI: -2.42, -0.51)) and -1.76 % (95% CI: -2.96, -0.57), respectively. No difference in liver fat between LCPUFA and HND was observed. Body weight and HbA1c decreased more in the HND compared to the other diet groups whereas no differences were observed between LCPUFA and UC. Similar reductions in LDL-cholesterol were observed for the HND and the LCPUFA group compared to UC, but only the HND reduced triglycerides and C-reactive protein (CRP) compared with UC. No differences were observed for any other secondary outcomes.Conclusions: A LCPUFA diet and a HND both reduced liver fat as compared with UC. Given the sustained weight loss after the HND compared to the other groups, together with improvements in other cardiometabolic markers, the HND in particular seems to be useful for the treatment of T2D and NAFLD.
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2.
  • Fridén, Michael, et al. (författare)
  • Hepatic Unsaturated Fatty Acids Are Linked to Lower Degree of Fibrosis in Non-alcoholic Fatty Liver Disease
  • 2022
  • Ingår i: Frontiers in Medicine. - : Frontiers Media SA. - 2296-858X. ; 8
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: The hepatic lipidome of patients with early stages of non-alcoholic fatty liver disease (NAFLD) has been fairly well-explored. However, studies on more progressive forms of NAFLD, i.e., liver fibrosis, are limited. Materials and methods: Liver fatty acids were determined in cholesteryl esters (CE), phospholipids (PL), and triacylglycerols (TAG) by gas chromatography. Cross-sectional associations between fatty acids and biopsy-proven NAFLD fibrosis (n = 60) were assessed using multivariable logistic regression models. Stages of fibrosis were dichotomized into none-mild (F0–1) or significant fibrosis (F2–4). Models were adjusted for body-mass index (BMI), age and patatin-like phospholipase domain-containing protein 3 (PNPLA3 rs738409) (I148M) genotype. A secondary analysis examined whether associations from the primary analysis could be confirmed in the corresponding plasma lipid fractions. Results: PL behenic acid (22:0) was directly associated [OR (95% CI): 1.86 (1.00, 3.45)] whereas PL docosahexaenoic acid (22:6n-3) [OR (95% CI): 0.45 (0.23, 0.89)], TAG oleic acid (18:1n-9) [OR (95% CI): 0.52 (0.28, 0.95)] and 18:1n-9 and vaccenic acid (18:1n-7) (18:1) [OR (95% CI): 0.52 (0.28, 0.96)] were inversely associated with liver fibrosis. In plasma, TAG 18:1n-9 [OR (95% CI): 0.55 (0.31, 0.99)], TAG 18:1 [OR (95% CI): 0.54 (0.30, 0.97)] and PL 22:0 [OR (95% CI): 0.46 (0.25, 0.86)] were inversely associated with liver fibrosis. Conclusion: Higher TAG 18:1n-9 levels were linked to lower fibrosis in both liver and plasma, possibly reflecting an altered fatty acid metabolism. Whether PL 22:6n-3 has a protective role, together with a potentially adverse effect of hepatic 22:0, on liver fibrosis warrants large-scale studies.
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3.
  • Glimelius, Bengt, et al. (författare)
  • U-CAN : a prospective longitudinal collection of biomaterials and clinical information from adult cancer patients in Sweden.
  • 2018
  • Ingår i: Acta Oncologica. - : Taylor & Francis. - 0284-186X .- 1651-226X. ; 57:2, s. 187-194
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Progress in cancer biomarker discovery is dependent on access to high-quality biological materials and high-resolution clinical data from the same cases. To overcome current limitations, a systematic prospective longitudinal sampling of multidisciplinary clinical data, blood and tissue from cancer patients was therefore initiated in 2010 by Uppsala and Umeå Universities and involving their corresponding University Hospitals, which are referral centers for one third of the Swedish population.Material and Methods: Patients with cancer of selected types who are treated at one of the participating hospitals are eligible for inclusion. The healthcare-integrated sampling scheme encompasses clinical data, questionnaires, blood, fresh frozen and formalin-fixed paraffin-embedded tissue specimens, diagnostic slides and radiology bioimaging data.Results: In this ongoing effort, 12,265 patients with brain tumors, breast cancers, colorectal cancers, gynecological cancers, hematological malignancies, lung cancers, neuroendocrine tumors or prostate cancers have been included until the end of 2016. From the 6914 patients included during the first five years, 98% were sampled for blood at diagnosis, 83% had paraffin-embedded and 58% had fresh frozen tissues collected. For Uppsala County, 55% of all cancer patients were included in the cohort.Conclusions: Close collaboration between participating hospitals and universities enabled prospective, longitudinal biobanking of blood and tissues and collection of multidisciplinary clinical data from cancer patients in the U-CAN cohort. Here, we summarize the first five years of operations, present U-CAN as a highly valuable cohort that will contribute to enhanced cancer research and describe the procedures to access samples and data.
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4.
  • Sennefelt Nyman, Sofi, et al. (författare)
  • Study protocol for locoregional precision treatment of hepatocellular carcinoma with transarterial chemoembolisation (TACTida), a clinical study : idarubicin dose selection, tissue response and survival
  • 2022
  • Ingår i: BMJ Open. - : BMJ Publishing Group Ltd. - 2044-6055. ; 12:11
  • Tidskriftsartikel (refereegranskat)abstract
    • INTRODUCTION: Hepatocellular carcinoma (HCC) is a common cause of cancer-related death, often detected in the intermediate stage. The standard of care for intermediate-stage HCC is transarterial chemoembolisation (TACE), where idarubicin (IDA) is a promising drug. Despite the fact that TACE has been used for several decades, treatment success is unpredictable. This clinical trial has been designed believing that further improvement might be achieved by increasing the understanding of interactions between local pharmacology, tumour targeting, HCC pathophysiology, metabolomics and molecular mechanisms of drug resistance.METHODS AND ANALYSIS: The study population of this single-centre clinical trial consists of adults with intermediate-stage HCC. Each tumour site will receive TACE with two different IDA doses, 10 and 15 mg, on separate occasions. Before and after each patient's first TACE blood samples, tissue and liquid biopsies, and positron emission tomography (PET)/MRI will be performed. Blood samples will be used for pharmacokinetics (PK) and liver function evaluation. Tissue biopsies will be used for histopathology analyses, and culturing of primary organoids of tumour and non-tumour tissue to measure cell viability, drug response, multiomics and gene expression. Multiomics analyses will also be performed on liquid biopsies. PET/MRI will be used to evaluate tumour viability and liver metabolism. The two doses of IDA will be compared regarding PK, antitumour effects and safety. Imaging, molecular biology and multiomics data will be used to identify HCC phenotypes and their relation to drug uptake and metabolism, treatment response and survival.ETHICS AND DISSEMINATION: Participants give informed consent. Personal data are deidentified. A patient will be withdrawn from the study if considered medically necessary, or if it is the wish of the patient. The study has been approved by the Swedish Ethical Review Authority (Dnr. 2021-01928) and by the Medical Product Agency, Uppsala, Sweden.TRIAL REGISTRATION NUMBER: EudraCT number: 2021-001257-31.
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5.
  • Abrahamsson, Ingemar, et al. (författare)
  • Kvalitet och kalkbehov inom kalkningsverksamheten : En granskning av de regionala åtgärdsplanerna
  • 2013
  • Rapport (övrigt vetenskapligt/konstnärligt)abstract
    • År 2010 upprättade länsstyrelserna regionala åtgärdsplaner för kalkning av sjöar och vattendrag på uppdrag av Naturvårdsverket. Den 1 juli 2011 övertog Havs- och vattenmyndigheten det nationella ansvaret för kalkningsverksamheten och vintern 2012 påbörjade myndigheten en granskning av åtgärdsplanerna. Syftet var att utvärdera kvaliteten i kalkningsverksamheten och erhålla ett underlag vid fördelning av statsbidragsmedel. Denna rapport utgör en sammanställning av de resultat som framkom vid granskningen.   Åtgärdsplanerna innehåller detaljerade redovisningar av den pågående verksamheten i form av försurningsstatus, motiv, mål, målområden, kalkningsinsatser, uppföljningsprogram och uppnådda resultat. Dessutom redovisas planerade förändringar och kalkmängder för åren 2011-2015.   För varje åtgärdsområde bedömdes kvaliteten utifrån nio olika aspekter, bland annat angivna pH-mål, vattenkemisk effektuppföljning, vattenkemisk måluppfyllelse och kalkningsstrategi. Dessutom uppskattades kalkbehovet baserat på förutsättningen att de vattenkemiska målen ska kunna uppnås i samtliga målområden. Bedömningarna gjordes med utgångspunkt från de råd, riktlinjer och riktvärden som anges i Handboken för kalkning av sjöar och vattendrag.  Granskningen visade att kvaliteten i den svenska kalkningsverksamheten har förbättrats avsevärt under den senaste tioårsperioden. Idag framstår verksamheten överlag som välmotiverad och effektiv. Samtidigt är de regionala skillnaderna omotiverat stora. I några län kvarstår ett betydande behov av ytterligare kvalitetsförbättringar.  Försurningsbedömningar av kalkade vatten behöver förbättras. Den pågående målvattendragsundersökningen kommer att bidra med ett utökat underlagsmaterial. Samtidigt är det uppenbart att mycket arbete kvarstår. Bedömningsverktyget måste förenklas och utbildningsinsatserna behöver öka.  De vattenkemiska målen behöver ses över så att tillämpningen blir likartad. I flera län förekommer ett överutnyttjande av pH-mål 6,0. I andra län används pH-mål 5,6 utan att risken för skadligt höga halter av oorganiskt aluminium har beaktats.  Den vattenkemiska uppföljningen i vattendragen behöver förbättras. Detta gäller i olika grad för nästan alla län. En väl fungerande högflödesprovtagning är grundläggande för att bedöma måluppfyllelse och optimera kalkningsinsatsen.   Den vattenkemiska måluppfyllelsen behöver förbättras i vattendragen. Förmågan att uppnå pH-målen varierar avsevärt från ett län till ett annat. För att öka måluppfyllelsen och höja effekten behöver kalkningsstrategierna optimeras i en fjärdedel av åtgärdsområdena. Kalkdoserarnas tekniska status behöver uppgraderas i några län och organisationen för tillsyn, larm och felavhjälpning behöver generellt stärkas. Omotiverad överdosering och kalkning av målområden som saknar kalkbehov bör, i olika omfattning, åtgärdas i samtliga län.  Det totala årliga kalkbehovet beräknades till 105 000-121 000 ton inom befintliga åtgärdsområden, vilket kan jämföras med länsstyrelsernas planerade på 122 000 ton. Beräkningen visar att de vattenkemiska målen kan uppnås utan att det erfordrar en ökad kalkförbrukning i ett nationellt perspektiv. I vissa åtgärdsområden behövs utökad kalkning, men detta kompenseras av minskade behov i andra. Det finns en betydande besparingspotential i flera län. Endast i ett län behöver kalkanvändningen öka på länsnivå.   Till följd av ökade omkostnader för kvalitetshöjande åtgärder och förväntade prishöjningar kommer behovet av statliga bidragsmedel sannolikt att öka. Besparingspotentialen liksom behovet av kvalitetshöjande insatser varierar mellan länen, vilket antyder att det också finns behov av en regional omfördelning.   Länsstyrelser och huvudmän är ansvariga för att åtgärda brister i verksamheten. Förbättring av effektuppföljningen bör genomföras direkt. Försurningsbedömningar och pH-mål bör ses över i takt med att nya data inkommer. Justering av kalkdoser och avslutande av onödig kalkning bör ske inför nästkommande spridningstillfälle. Förändringar av kalkningsstrategin är i regel mera tidskrävande och bör prioriteras till åtgärdsområden där den kemiska målsättningen inte uppnås eller där kalkförbrukningen är omotiverat hög.  Den regionala verksamheten behöver fortsatt stöd och styrning från Havs- och vattenmyndigheten. En betydande del av de förbättringar som uppnåtts under de senaste tio åren har åstadkommits via medelsfördelning och bidragsvillkor. Samtidigt finns det fortfarande uppenbara brister i verksamheten varför ytterligare och andra typer av styrmedel behövs. HaV behöver också bidra med utbildningsinsatser och rådgivning samt att bedömningsverktyg och vägledningar utvecklas i takt med att ny kunskap tillkommer.
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6.
  • Ahlström, Christer, 1977-, et al. (författare)
  • Noninvasive investigation of blood pressure changes using the pulse wave transit time : A novel approach in the monitoring of hemodialysis patients
  • 2005
  • Ingår i: Journal of Artificial Organs. - : Springer Science and Business Media LLC. - 1434-7229 .- 1619-0904. ; 8:3, s. 192-197
  • Tidskriftsartikel (refereegranskat)abstract
    • Severe blood pressure changes are well known in hemodialysis. Detection and prediction of these are important for the well-being of the patient and for optimizing treatment. New noninvasive methods for this purpose are required. The pulse wave transit time technique is an indirect estimation of blood pressure, and our intention is to investigate whether this technique is applicable for hemodialysis treatment. A measurement setup utilizing lower body negative pressure and isometric contraction was used to simulate dialysis-related blood pressure changes in normal test subjects. Systolic blood pressure levels were compared to different pulse wave transit times, including and excluding the cardiac preejection period. Based on the results of these investigations, a pulse wave transit time technique adapted for dialysis treatment was developed and tried out on patients. To determine systolic blood pressure in the normal group, the total pulse wave transit time was found most suitable (including the cardiac preejection period). Correlation coefficients were r = 0.80 ± 0.06 (mean ± SD) overall and r = 0.81 ± 0.16 and r = 0.09 ± 0.62 for the hypotension and hypertension phases, respectively. When applying the adapted technique in dialysis patients, large blood pressure variations could easily be detected when present. Pulse wave transit time is correlated to systolic blood pressure within the acceptable range for a trend-indicating system. The method's applicability for dialysis treatment requires further studies. The results indicate that large sudden pressure drops, like those seen in sudden hypovolemia, can be detected. © The Japanese Society for Artificial Organs 2005.
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7.
  • Ahlström, Fredrik, et al. (författare)
  • Does gender matter at triage?
  • 2007
  • Ingår i: Australasian emergency nursing journal. - : Elsevier Ltd. - 1574-6267. ; 10:4, s. 202-203
  • Tidskriftsartikel (refereegranskat)
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8.
  • Ahlström, Johan, et al. (författare)
  • Arbetsfördelning och resursanvändning inom kalkningsverksamheten
  • 2015
  • Rapport (övrigt vetenskapligt/konstnärligt)abstract
    • Under det första decenniet av 2000-talet genomförde Naturvårdsverket en rad åtgärder med syfte att skapa gemensamma strukturer och förbättra kvaliteten i den svenska kalkningsverksamheten. Efter att ha granskat länsstyrelsernas regionala åtgärdsplaner för 2010-2015  konstaterade Havs- och vattenmyndigheten att kvaliteten förbättrats avsevärt, men att de regionala skillnaderna fortfarande var omotiverat stora. I syfte att kartlägga den regionala arbetsfördelningen och resursanvändningen samt behovet av fortbildning och stödsystem inhämtade Havs- och vattenmyndigheten under 2014 information från kalkningens regionala och lokala aktörer.  Uppgifterna insamlades via enkäter till länsstyrelser och huvudmän samt genom inhämtande av underlag i form av tidsredovisning och nyckeltal från länsstyrelserna. I föreliggande rapport presenteras resultaten av kartläggningen samt förslag på förändringar som kan leda till att resurser frigörs för kvalitetshöjande åtgärder.   Kalkningsverksamheten finansieras huvudsakligen med statsbidrag som fördelas till huvudmän via länsstyrelsen. I nuläget finns drygt 150 huvudmän som huvudsakligen utgörs av kommuner. I enkätsvaren uppgav drygt 80 procent av huvudmännen att systemet med statsbidrag är bra. Utifrån denna synvinkel finns således ingen anledning att förändra nuvarande system.   Till stor del finansieras kalkningsverksamheten via anslaget 1:12 ”åtgärder för havs- och vattenmiljö”. Inför 2013 genomfördes en förändring som innebar att länsstyrelsernas anslag till kalkning inte specificerades i förhållande till övriga verksamheter inom 1:12. Det nya förfaringssättet tycks inte generellt ha påverkat kalkningsverksamhetens finansiella utrymme under 2013. Det finns emellertid indikationer på att den biologiska uppföljningen minskade i några län.   Länsstyrelsernas prioritering av verksamheten via ramanslagen varierade avsevärt. I förhållande till den förstärkning som länsstyrelserna erhöll på ramanslaget 2002 redovisade några län betydligt lägre lönekostnader 2013. Det förekom också att anslaget 1:12 belastats med lönekostnader som inte omfattas av villkoren i bidragsbeslutet och därmed borde belasta ramanslaget.    Enkätsvaren samt länsstyrelsernas tidsredovisning visade att det föreligger stora skillnader mellan länen avseende såväl arbetsfördelning som tidsåtgång för de olika arbetsmomenten. Detta gäller även till vad och i vilken omfattning som konsulter anlitas. Skillnaderna mellan länen är delvis beroende på verksamhetens omfattning och karaktär. Till stor del framstår emellertid skillnaderna som en konsekvens av att länsverksamheten med tiden kommit att utformas på olika sätt.   Tidsåtgången för länsstyrelsernas bidragsadministration kunde bara i liten utsträckning förklaras med verksamhetens omfattning och antalet huvudmän. På flera län finns utrymme för effektivisering av rutiner och arbetsmoment. I Havs- och vattenmyndighetens rapport 2015:3  10 förhållande till den enkla redovisning som länsstyrelserna efterfrågar framstår många huvudmäns tidsåtgång för bidragsadministration inte heller som rimlig. Länsstyrelserna behöver kommunicera med huvudmännen i syfte att tydliggöra behovet av underlag och därmed reducera tidsåtgången.  Upphandling av kalk och kalkspridning bör i större utsträckning samordnas mellan flera huvudmän och även mellan flera län. Små uppdrag innebär höga kostnader för kalk och kalkspridning. Genom att samordna upphandlingar och välja fleråriga avtal när detta är relevant och möjligt kan arbetstiden sannolikt mer än halveras.  Försurningsbedömningen av kalkade vatten upplevs både som krånglig och osäker. Oklarheter kring beräkningsverktyg och bedömningsgrunder behöver redas ut. Dessutom behöver länsstyrelser och huvudmän ytterligare utbildning och vägledning.  Översyn och justering av kalkdoseringen bör ske årligen. För all kalkning i landet kan detta teoretiskt genomföras på ungefär 50 arbetsdagar.  Enligt enkätsvaren arbetade länsstyrelser och huvudmän närmare 800 arbetsdagar med spridningsplanering under 2013. Endera är uppgifterna i enkätsvaren rejält överskattade eller så präglas arbetet av stor ineffektivitet.   I princip behövs en lika omfattande organisation för att sköta en kalkdoserare som 20 eller 30. Detta talar för att doserardriften bör samordnas för att uppnå stordriftsvinster. Endera mellan flera huvudmän eller med liknande kommunala verksamheter. Ansvaret för att sköta kalkdoserarna åligger huvudmannen. Länsstyrelsen ska se till att driftorganisationen uppfyller nödvändiga krav och behöver därför vara insatt i teknik och skötselbehov. Mot denna bakgrund är det oroväckande att huvudmännen i flera län bedömer länsstyrelsens kompetens som mindre bra avseende doserare.  Kalkningens effektuppföljning omsätter årligen närmare 25 miljoner kronor. Uppföljningens kvalitet och omfattning uppvisade omotiverat stora skillnader mellan länen. Det behövs system som säkerställer att vattenprover tas när kalkeffekten kan befaras vara otillräcklig, vilket i praktiken innebär vid höga flöden. För den biologiska uppföljningen behövs system som reglerar verksamhetens omfattning i förhållande till erhållna medel.  Spridningskontrollens kostnader varierade avsevärt mellan länen. Till viss del torde detta vara en följd av olika ambitionsnivå. Till stor del beror emellertid skillnaderna på att olika schabloner tillämpas för att beräkna huvudmannens kostnader samt ett varierande nyttjande av konsulter. Detta talar för att det finns utrymme att minska kostnaderna för spridningskontrollen inom ett antal län.  Baserat på det underlag som legat till grund för denna resurskartläggning bedöms den samlade arbetstid som länsstyrelser och huvudmän lägger på kalkningsverksamheten vara tillräckligt omfattande för att säkerställa en bra kvalitet. De brister i kvalitet som framkommit vid tidigare granskningar antyder därför att verksamheten inte på ett effektivt sätt förmår att omsätta tillgängliga resurser till effektiv arbetstid. En viktig orsak torde vara splittringen på många aktörer där flera huvudmän och ett antal länsstyrelser hanterar mycket små kalkmängder. Ineffektiva rutiner för hantering av exempelvis kalkdata, kemidata och bidragsutbetalningar utgör också ett problem. Likaså dubbelarbete och arbete som utförs av personal med otillräcklig erfarenhet och kompetens.   Fördelningen av ekonomiska resurser mellan länen för bland annat administration, upphandling, spridningsplanering, spridningskontroll, försurningsbedömning och effektuppföljning har sedan 1990-talet skett via schabloner. Syftet med att använda schabloner är främst att skapa rättvisa förutsättningar mellan länen. Ursprungligen baserades schablonerna enbart på totalmängden spridd kalk. Varefter nya underlag funnits tillgängliga har justering gjorts för såväl spridningsmetoder som målområden. Det finns inget som pekar på att schablonerna i nämnvärd omfattning skapat orättvisa förutsättningar mellan länen.
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9.
  • Ahlström, Petter, 1970-, et al. (författare)
  • Affärsstrategier och seniorbostadsmarknaden
  • 2005
  • Ingår i: Fastighetsnytt. - 1104-8913. ; 12 nr 5, s. 36-37
  • Tidskriftsartikel (populärvet., debatt m.m.)abstract
    •   Artikeln beskriver några av resultaten från licentiatavhandlingen "Affärsstrategier för seniorbostadsmarknaden" av Petter Ahlström.      
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10.
  • Ahlström, Petter, 1970-, et al. (författare)
  • Att mobilisera och vårda samverkan i forskning
  • 2007
  • Ingår i: Högskolor och samhälle i samverkan 2007 HSS07,2007.
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • Kunskapsutveckling är en långsiktig process där kontaktskapande och kontaktvård ofta har stor omfattning jämfört med den konkreta forskningsinsatsen. Utmaningen är att mobilisera och vårda en allians där forskare och praktiker samverkar. Ibland kan även finansiärer ha en aktiv roll. Intresse för forskningsinsatsen är en viktig utgångspunkt för samverkan men inte sällan finns det ytterligare orsaker till att ett samarbete kommer till stånd och består. Teoretisk inspiration för att diskutera detta kan hämtas från studier av s.k. imaginära och virtuella organisationer. I uppsatsen diskuteras detta mot bakgrund av erfarenheter från faktiska forskningsprojekt.     
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11.
  • Ahlström, Petter, 1970-, et al. (författare)
  • Att mobilisera och vårda samverkan i forskning
  • 2008. - 1
  • Ingår i: Gemensamt kunskapande - den interaktiva forskningens praktik. - Växjö : Växjö University Press. - 9789176366219 ; , s. 115-132
  • Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
    • I en tid då universitetens kunskapsmonopol är på väg att brytas får en nära samverkan mellan forskare, finansiär och studieobjekt en allt större betydelse (Nowotny et al., 2002, "Re-thinking Science"). Denna typ av samverkan är en central utgångspunkt i interaktiv forskning där ett vanligt syfte är att bedriva praktiknära studier med stor utomvetenskaplig relevans. I denna uppsats diskuteras hur samverkan mobiliseras och vårdas. Frågor som behandlas är hur forskarnas och praktikernas intressen ska förenas samt vad forskarna kan göra för att skapa rimliga förväntningar hos praktikerna och sprida sina resultat. Diskussionen baseras på egna erfarenheter där ett antal minifall får illustrera vad vi uppfattar vara typiska utmaningar i den här typen av samarbeten.   
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12.
  • Ahlström, Petter, 1970-, et al. (författare)
  • Boende för äldre - utmaningar och möjligheter
  • 2007
  • Rapport (övrigt vetenskapligt/konstnärligt)abstract
    • Det projekt som här avrapporteras är initierat och finansierat av Sveriges Kommuner och Landstings FoU-fond för fastighetsfrågor. I rapporten diskuteras och analyseras ett antal faktorer som kan antas påverka kommunernas kostnader, i vid bemärkelse, för service, vård och omsorg. Analysen inriktas på hur utformningen av dagens och framtidens boende för äldre kan antas påverka kostnadsläget. Rapporten omfattar 88 sidor.        
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13.
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14.
  • Ahlström, Petter, 1970-, et al. (författare)
  • Mobilising and nurturing collaboration in research - the value of a focused imagination
  • 2007
  • Ingår i: International Journal of Action Research. - 1861-1303 .- 1861-9916. ; 3:No 3, s. 297-327
  • Tidskriftsartikel (refereegranskat)abstract
    •    Establishing and nurturing contacts are important and time-consuming elements of interactive research. It is usually the researcher who has to establish and nurture collaboration with practitioners, a task that is not normally part of traditional research. A mutual interest in the subject of the research is a prerequisite for collaboration, but there are quite often other factors that explain why collaboration begins and endures. On the basis of the experience gained in a number of interactive research projects, we address the conditions required for an effective and lasting interplay between collaborating partners. Theoretical inspiration has been provided by studies of so-called imaginary organisations.        
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15.
  • Ahlström, Petter, 1970- (författare)
  • Strategier och styrsystem för seniorboendemarknaden
  • 2008
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Den demografiska utvecklingen i Sverige går mot en befolkningssammansättning med allt högre medelålder. Prognosen tyder på att nästan var fjärde svensk år 2025 kommer vara 65 år eller äldre. Många av dessa individer har en aktiv, frisk och relativt lång ålderdom framför sig. Studier har visat att morgondagens seniorer är en relativt välbeställd grupp med höga krav och stora förväntningar på ålderdomen och det framtida boendet. Allt detta innebär en utmaning för samhället där nödvändiga prioriteringar kan leda till att individen måste ta ett större ansvar och eget initiativ för boende och omvårdnadstjänster gentemot tidigare. I avhandlingen (”studien”) har seniorboendekonceptet med integrerade service-, vård- och omsorgstjänster studerats särskilt. Seniorboenden är ett marknadssegment med kraftig tillväxt under 2000-talet. Antalet seniorbostäder i Sverige har ökat från ca 10 000 år 2000 till ca 28 000 år 2007. Det som karaktäriserar konceptet är att boendet och de anslutande tjänsterna har anpassats och särskilt utformats för ett liv i åldrande.Studien rapporteras i form av en monografi bestående av två olika delstudier. Forskningsfrågan som varit vägledande för den första delstudien är ”Vad skapar en stark marknadsposition för en aktör på seniorbostadsmarknaden med integrerad service, vård och omsorg?”. Forskningsfrågan i den andra delstudien är ”Vilka produktionsstrategier och styrsystem går att identifiera hos några av de mest framgångsrika konceptbyggarna?”. Den andra delstudien utgår från den första delstudiens resultat. Forskningen, som har bedrivits som en explorativ fältstudie, har pågått under perioden 2002-2008. Mätinstrumentet har bestått av fasta intervjufrågor med öppna svarsalternativ. De underliggande intervjuerna har tillsammans med sekundärdata presenterats i ett antal fallbeskrivningar. I studien har ett antal framgångsrika, såväl svenska som nordamerikanska, aktörer medverkat. Den första delstudien har analyserats utifrån en föreställningsram som byggts upp kring begreppen omgivning, strategi, resurs, tjänstekoncept och konkurrenskraft. Resultaten har formulerats i ett antal strategiska vägval vilka sammanfattats i begreppen differentiering, fokus, integration, samverkan, kontroll, verksamhetsutveckling, kärnkompetens och resurser. Det har kunnat påvisas att framgångsrika aktörer följer den differentieringsstrategi om Porter (1980) definierat. Vidare har en affärsstrategisk typologi över aktörer på seniorboendemarknaden formulerats. Den första delstudiens slutsatser har formulerats i fyra strategiska idealtyper: förvaltare, konceptbyggare, entreprenörer och idealister.Utgångspunkten i den andra delstudien, som bl.a. hämtats i Nilssons och Rapps (2005) teoretiska ramverk, har varit idealtypen konceptbyggare. Med vissa kompletteringar har detta ramverk nyttjats och utvecklats för att beskriva och analysera orsakssambanden kring strategisk kongruens och integrerad styrning. Kompletteringar och justeringar har skett för att även omfatta strategier och styrsystem för bygg- och tjänsteproduktion. Föreställningsramen har, utifrån den erfarenhet som erhållits vid analysen av insamlad data, justerats. Justeringen har bestått i klassificeringsdimensionerna IT, organisationskultur och värdegrund. I studien, som bl.a. består av fallbeskrivning och analys av konceptbyggare, har framkommit att de konceptbyggare som nått framgång också har lyckats uppnå strategisk kongruens och integrerad styrning. Studien har bl.a. kunnat påvisa vad betydelsen av boendets fysiska planering innebär för möjligheten att bedriva tjänsteproduktion. Studien har bl.a. visat att nordamerikanska konceptbyggare har en hög grad av samstämmighet mellan strategi och styrsystem. Samstämmigheten kan sammanfattas i marknadskännedom, tydlig verksamhetsidé, branscherfarenhet, insikt om skalfördelar via klustring, organisatorisk småskalighet, känsla för värdeskapande, målinriktning, långtgående befogenheter och delegerat ansvar, värdestyrd verksamhet och en väl utvecklad organisationskultur. De nordamerikanska konceptbyggarna har definierat sina verksamheter som hotellverksamhet för seniorer vilket innebär att de boende blivit kunder och de äldre i allmänhet betraktas som en tillgång.
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16.
  • Ahlström, Petter, et al. (författare)
  • Why space is not enough : Service innovation and service delivery in senior housing
  • 2022. - 1
  • Ingår i: Management and Information Technology after Digital Transformation. - Abingdon and New York : Routledge. - 9780367612764 - 9780367628789 - 9781003111245 ; , s. 72-80
  • Bokkapitel (refereegranskat)abstract
    • This chapter discusses senior housing to support the well-being of older individuals through the provision of physical and social resources. The authors show how digital services contribute to these developments by increasing the resources available and the capacity of older people to integrate resources and take advantage of the value-creating opportunities offered by senior housing solutions. They point out that senior users play a crucial role as active co-creators of their own well-being and contributors to both service innovation and service delivery. As digital services become essential for how older people manage their daily lives, they need to be more integrated in the physical spaces where the actions and memories that shape the lives of seniors take place. Digital services have the potential to both create and deliver new services that will enhance these experiences, which makes their integration with the physical space an important and inseparable component of service innovation and delivery in the context of senior housing.
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17.
  • Alsaqal, Salem, et al. (författare)
  • The Combination of MR Elastography and Proton Density Fat Fraction Improves Diagnosis of Nonalcoholic Steatohepatitis.
  • 2022
  • Ingår i: Journal of Magnetic Resonance Imaging. - : John Wiley & Sons. - 1053-1807 .- 1522-2586. ; 56:2, s. -379
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND: Nonalcoholic fatty liver disease (NAFLD) is rapidly increasing worldwide. It is subdivided into nonalcoholic fatty liver (NAFL) and the more aggressive form, nonalcoholic steatohepatitis (NASH), which carries a higher risk of developing fibrosis and cirrhosis. There is currently no reliable non-invasive method for differentiating NASH from NAFL.PURPOSE: To investigate the ability of magnetic resonance imaging (MRI)-based imaging biomarkers to diagnose NASH and moderate fibrosis as well as assess their repeatability.STUDY TYPE: Prospective.SUBJECTS: Sixty-eight participants (41% women) with biopsy-proven NAFLD (53 NASH and 15 NAFL). Thirty participants underwent a second MRI in order to assess repeatability.FIELD STRENGTH/SEQUENCE: 3.0 T; MR elastography (MRE) (a spin-echo echo-planar imaging [SE-EPI] sequence with motion-encoding gradients), MR proton density fat fraction (PDFF) and R2* mapping (a multi-echo three-dimensional gradient-echo sequence), T1 mapping (a single-point saturation-recovery technique), and diffusion-weighted imaging (SE-EPI sequence).ASSESSMENT: Quantitative MRI measurements were obtained and assessed alone and in combination with biochemical markers (cytokeratin-18 [CK18] M30, alanine transaminase [ALT], and aspartate transaminase [AST]) using logistic regression models. Models that could differentiate between NASH and NAFL and between moderate to advanced fibrosis (F2-4) and no or mild fibrosis (F0-1), based on the histopathological results, were identified.STATISTICAL TESTS: Independent samples t-test, Pearson's chi-squared test, area under the receiver operating characteristic curve (AUROC), Spearman's correlation, intra-individual coefficient of variation, and intraclass correlation coefficient (ICC). Statistical significance was set at P < 0.05.RESULTS: There was a significant difference between the NASH and NAFL groups with liver stiffness assessed with MRE, CK18 M30, and ALT, with an AUROC of 0.74, 0.76, and 0.70, respectively. Both MRE and PDFF contributed significantly to a bivariate model for diagnosing NASH (AUROC = 0.84). MRE could significantly differentiate between F2-4 and F0-1 (AUROC = 0.74). A model combining MRE with AST improved the diagnosis of F2-4 (AUROC = 0.83). The ICC for repeatability was 0.94 and 0.99 for MRE and PDFF, respectively.DATA CONCLUSION: MRE can potentially diagnose NASH and differentiate between fibrosis stages. Combining MRE with PDFF improves the diagnosis of NASH.LEVEL OF EVIDENCE: 2 TECHNICAL EFFICACY: Stage 2.
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18.
  • Andersson, Robin, 1986, et al. (författare)
  • Numerical investigation of crack initiation in rails and wheels affected by martensite spots
  • 2018
  • Ingår i: International Journal of Fatigue. - : Elsevier BV. - 0142-1123. ; 114, s. 238-251
  • Tidskriftsartikel (refereegranskat)abstract
    • White etching layers (WELs) in the form of thermally induced martensite spots are often associated to so-called stud defects on rail surfaces and so-called rolling contact fatigue clusters on wheel treads. These defects might promote further material deterioration of rails and wheels and it is thus of importance to deepen the knowledge regarding their initiation mechanisms. The aim of this study is to gain insight into the problem by making qualitative assessments of different operational scenarios, involving various axle loads and amount of friction. To this end, this paper considers crack initiation, quantified through the Jiang–Sehitoglu low cycle fatigue criterion, in the vicinity of pre-existing WELs (in the form of martensite spots) subjected to varying contact load conditions. Three-dimensional finite element analyses are conducted to model phase transformations as well as the resulting residual stresses. It is seen that the contact pressure magnitude and WEL thickness affect the results only moderately, while the traction coefficient has a significant detrimental influence. It is furthermore seen that occasional wheel passages that are off-set in the lateral direction with respect to the WEL spot’s centre might be responsible for crack initiation on the gauge corner side of the rail surface.
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19.
  • Bergström, Göran, 1964, et al. (författare)
  • Prevalence of Subclinical Coronary Artery Atherosclerosis in the General Population
  • 2021
  • Ingår i: Circulation. - Philadelphia : American Heart Association. - 0009-7322 .- 1524-4539. ; 144:12, s. 916-929
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Early detection of coronary atherosclerosis using coronary computed tomography angiography (CCTA), in addition to coronary artery calcification (CAC) scoring, may help inform prevention strategies. We used CCTA to determine the prevalence, severity, and characteristics of coronary atherosclerosis and its association with CAC scores in a general population.Methods: We recruited 30 154 randomly invited individuals age 50 to 64 years to SCAPIS (the Swedish Cardiopulmonary Bioimage Study). The study includes individuals without known coronary heart disease (ie, no previous myocardial infarctions or cardiac procedures) and with high-quality results from CCTA and CAC imaging performed using dedicated dual-source CT scanners. Noncontrast images were scored for CAC. CCTA images were visually read and scored for coronary atherosclerosis per segment (defined as no atherosclerosis, 1% to 49% stenosis, or ≥50% stenosis). External validity of prevalence estimates was evaluated using inverse probability for participation weighting and Swedish register data.Results: In total, 25 182 individuals without known coronary heart disease were included (50.6% women). Any CCTA-detected atherosclerosis was found in 42.1%; any significant stenosis (≥50%) in 5.2%; left main, proximal left anterior descending artery, or 3-vessel disease in 1.9%; and any noncalcified plaques in 8.3% of this population. Onset of atherosclerosis was delayed on average by 10 years in women. Atherosclerosis was more prevalent in older individuals and predominantly found in the proximal left anterior descending artery. Prevalence of CCTA-detected atherosclerosis increased with increasing CAC scores. Among those with a CAC score >400, all had atherosclerosis and 45.7% had significant stenosis. In those with 0 CAC, 5.5% had atherosclerosis and 0.4% had significant stenosis. In participants with 0 CAC and intermediate 10-year risk of atherosclerotic cardiovascular disease according to the pooled cohort equation, 9.2% had CCTA-verified atherosclerosis. Prevalence estimates had excellent external validity and changed marginally when adjusted to the age-matched Swedish background population.Conclusions: Using CCTA in a large, random sample of the general population without established disease, we showed that silent coronary atherosclerosis is common in this population. High CAC scores convey a significant probability of substantial stenosis, and 0 CAC does not exclude atherosclerosis, particularly in those at higher baseline risk.
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20.
  • Bergström, Göran, et al. (författare)
  • Prevalence of Subclinical Coronary Artery Atherosclerosis in the General Population
  • 2021
  • Ingår i: Circulation. - : Wolters Kluwer. - 0009-7322 .- 1524-4539. ; 144:12, s. 916-929
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Early detection of coronary atherosclerosis using coronary computed tomography angiography (CCTA), in addition to coronary artery calcification (CAC) scoring, may help inform prevention strategies. We used CCTA to determine the prevalence, severity, and characteristics of coronary atherosclerosis and its association with CAC scores in a general population.Methods: We recruited 30 154 randomly invited individuals age 50 to 64 years to SCAPIS (the Swedish Cardiopulmonary Bioimage Study). The study includes individuals without known coronary heart disease (ie, no previous myocardial infarctions or cardiac procedures) and with high-quality results from CCTA and CAC imaging performed using dedicated dual-source CT scanners. Noncontrast images were scored for CAC. CCTA images were visually read and scored for coronary atherosclerosis per segment (defined as no atherosclerosis, 1% to 49% stenosis, or ≥50% stenosis). External validity of prevalence estimates was evaluated using inverse probability for participation weighting and Swedish register data.Results: In total, 25 182 individuals without known coronary heart disease were included (50.6% women). Any CCTA-detected atherosclerosis was found in 42.1%; any significant stenosis (≥50%) in 5.2%; left main, proximal left anterior descending artery, or 3-vessel disease in 1.9%; and any noncalcified plaques in 8.3% of this population. Onset of atherosclerosis was delayed on average by 10 years in women. Atherosclerosis was more prevalent in older individuals and predominantly found in the proximal left anterior descending artery. Prevalence of CCTA-detected atherosclerosis increased with increasing CAC scores. Among those with a CAC score >400, all had atherosclerosis and 45.7% had significant stenosis. In those with 0 CAC, 5.5% had atherosclerosis and 0.4% had significant stenosis. In participants with 0 CAC and intermediate 10-year risk of atherosclerotic cardiovascular disease according to the pooled cohort equation, 9.2% had CCTA-verified atherosclerosis. Prevalence estimates had excellent external validity and changed marginally when adjusted to the age-matched Swedish background population.Conclusions: Using CCTA in a large, random sample of the general population without established disease, we showed that silent coronary atherosclerosis is common in this population. High CAC scores convey a significant probability of substantial stenosis, and 0 CAC does not exclude atherosclerosis, particularly in those at higher baseline risk.
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21.
  • Elmsjö, Albert, et al. (författare)
  • NMR-based metabolic profiling in healthy individuals overfed different types of fat : links to changes in liver fat accumulation and lean tissue mass.
  • 2015
  • Ingår i: Nutrition & Diabetes. - : Springer Science and Business Media LLC. - 2044-4052. ; 5:19, s. e182-
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND: Overeating different dietary fatty acids influence the amount of liver fat stored during weight gain, however, the mechanisms responsible are unclear. We aimed to identify non-lipid metabolites that may differentiate between saturated (SFA) and polyunsaturated fatty acid (PUFA) overfeeding using a non-targeted metabolomic approach. We also investigated the possible relationships between plasma metabolites and body fat accumulation.METHODS: In a randomized study (LIPOGAIN study), n=39 healthy individuals were overfed with muffins containing SFA or PUFA. Plasma samples were precipitated with cold acetonitrile and analyzed by nuclear magnetic resonance (NMR) spectroscopy. Pattern recognition techniques were used to overview the data, identify variables contributing to group classification and to correlate metabolites with fat accumulation.RESULTS: We previously reported that SFA causes a greater accumulation of liver fat, visceral fat and total body fat, whereas lean tissue levels increases less compared with PUFA, despite comparable weight gain. In this study, lactate and acetate were identified as important contributors to group classification between SFA and PUFA (P<0.05). Furthermore, the fat depots (total body fat, visceral adipose tissue and liver fat) and lean tissue correlated (P(corr)>0.5) all with two or more metabolites (for example, branched amino acids, alanine, acetate and lactate). The metabolite composition differed in a manner that may indicate higher insulin sensitivity after a diet with PUFA compared with SFA, but this needs to be confirmed in future studies.CONCLUSION: A non-lipid metabolic profiling approach only identified a few metabolites that differentiated between SFA and PUFA overfeeding. Whether these metabolite changes are involved in depot-specific fat storage and increased lean tissue mass during overeating needs further investigation.
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22.
  • Fors, Carina, et al. (författare)
  • Camera-based sleepiness detection : final report of the project SleepEYE
  • 2011
  • Rapport (övrigt vetenskapligt/konstnärligt)abstract
    • Two literature reviews were conducted in order to identify indicators of driver sleepiness and distraction. Three sleepiness indicators – blink duration, blink frequency and Perclos – were implemented in the camera system.The aims of the study were firstly to develop and evaluate a low cost 1-camera unit for detection of driver impairment, and secondly to identify indicators of driver sleepiness and to create a sleepiness classifier for driving simulators.The project included two experiments. The first was a field test where 18 participants conducted one alert and one sleepy driving session on a motorway. 16 of the 18 participants also participated in the second experiment which was a simulator study similar to the field test.The field test data was used for evaluation of the 1-camera system, with respect to the sleepiness indicators. Blink parameters from the 1-camera system was compared to blink parameters obtained from a reference 3-camera system and from the EOG. It was found that the 1-camera system missed many blinks and that the blink duration was not in agreement with the blink duration obtained from the EOG and from the reference 3-camera system. However, the results also indicated that it should be possible to improve the blink detection algorithm since the raw data looked well in many cases where the algorithm failed to identify blinks.The sleepiness classifier was created using data from the simulator experiment. In the first step, the indicators identified in the literature review were implemented and evaluated. The indicators also included driving and context related parameters in addition to the blink related ones. The most promising indicators were then used as inputs to the classifier.
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23.
  • Fridén, Michael, et al. (författare)
  • Associations between fatty acid composition in serum cholesteryl esters and liver fat, basal fat oxidation, and resting energy expenditure : a population-based study
  • 2021
  • Ingår i: American Journal of Clinical Nutrition. - : Oxford University Press. - 0002-9165 .- 1938-3207. ; 114:5, s. 1743-1751
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND: We have repeatedly shown in short-term feeding trials that a high intake of dietary n-6 PUFAs, i.e. linoleic acid, prevents liver fat accumulation compared with saturated fat. However, population-based data is lacking and the mechanisms behind such effects are unclear.OBJECTIVE: To investigate associations between serum cholesteryl ester (CE) fatty acids and liver fat, basal fat oxidation [respiratory quotient (RQ)], and resting energy expenditure (REE). We hypothesized that PUFA in particular is inversely associated with liver fat and that such a relation is partly explained by a PUFA-induced increase in basal fat oxidation or REE.METHODS: Cross-sectional analyses using linear regression models in a population-based cohort with data on serum CE fatty acid composition and liver fat (n = 308).RESULTS: Linoleic acid (18:2n-6) (β = -0.03, 95% CI: -0.06, -0.001) and Δ5 desaturase index were inversely associated, whereas, γ-linolenic acid (18:3n-6) (β = 0.59, 95% CI: 0.28, 0.90), dihomo-γ-linolenic acid (20:3n-6) (β = 1.20, 95% CI: 0.65, 1.75), arachidonic acid (20:4n-6) (β = 0.08, 95% CI: 0.002, 0.16), palmitoleic acid (16:1n-7) (β = 0.37, 95% CI: 0.04, 0.70), Δ6 desaturase, and stearoyl CoA desaturase-1 (SCD-1) index were directly associated with liver fat after adjustment for confounders. Several serum CE fatty acids were correlated with both liver fat and REE, but only the association between DHA (22:6n-3) and liver fat was clearly attenuated after adjustment for REE (from β = -0.63 95% CI: -1.24, -0.02 to β = -0.34, 95% CI: -0.95, 0.27). Palmitoleic acid and SCD-1 were weakly inversely correlated with RQ but could not explain a lower liver fat content.CONCLUSIONS: Several serum CE fatty acids are associated with liver fat, among them linoleic acid. Although we identified novel associations between individual fatty acids and RQ and REE, our findings imply that PUFAs might prevent liver fat accumulation through mechanisms other than enhanced whole-body energy metabolism.
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24.
  • Fridén, Michael, et al. (författare)
  • Intake of Ultra-Processed Food and Ectopic-, Visceral- and Other Fat Depots : A Cross-Sectional Study.
  • 2022
  • Ingår i: Frontiers in nutrition. - : Frontiers Media S.A.. - 2296-861X. ; 9
  • Tidskriftsartikel (refereegranskat)abstract
    • Introduction: The purpose of this study was to investigate associations between intake of ultra-processed food (UPF) and liver fat, pancreas fat and visceral adipose tissue (VAT) but also subcutaneous adipose tissue (SAT), VAT/SAT ratio and total fat mass.Materials and Methods: Cross-sectional analysis of n = 286 50-year old men and women. Energy percentage (%E) from UPF was calculated from a semi-quantitative food frequency questionnaire. Food items were categorized according to the NOVA-classification system and fat depots were assessed using magnetic resonance imaging (MRI) and bioelectrical impedance analysis (BIA). Associations were analyzed using linear regression, adjusted for sex, education, physical activity, smoking, dietary factors and BMI.Results: Mean intake of UPF was 37.8 ± 10.2 %E and the three largest contributors to this were crisp- and wholegrain breads and spreads, indicating overall healthy food choices. Consumption of UPF was associated with higher intake of energy, carbohydrates and fiber and lower intake of protein and polyunsaturated fat but no differences were observed for total fat, saturated fat (SFA), monounsaturated fat, sugar or alcohol between tertiles of UPF. Intake of UPF was positively associated with liver- and pancreas fat, VAT, VAT/SAT and inversely associated with total fat mass in crude models. The association for VAT remained after full adjustment (β = 0.01 (95% CI: 0.002, 0.02), P = 0.02) and was driven by women.Conclusion: Energy intake from UPF is not associated with ectopic fat, SAT or total fat after adjustment for multiple confounders in this population having overall healthy food habits. However, a positive association between UPF and VAT was observed which was driven by women.
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25.
  • Giandomenico, Valeria, et al. (författare)
  • Improving the Diagnosis and Management of Neuroendocrine Tumors : Utilizing New Advances in Biomarker and Molecular Imaging Science
  • 2013
  • Ingår i: Neuroendocrinology. - : S. Karger AG. - 0028-3835 .- 1423-0194. ; 98:1, s. 16-30
  • Tidskriftsartikel (refereegranskat)abstract
    • Neuroendocrine tumors (NET) are malignant solid tumors that arise in hormone-secreting tissue of the diffuse neuroendocrine system or endocrine glands. Although traditionally understood to be a rare disease, the incidence and prevalence of NET have increased greatly in the past 3 decades. However, during this time, progress in diagnosis and outcome of NET has generally been modest. In order to achieve improved outcome in NET, a better understanding of NET biology combined with more reliable serum markers and better techniques to identify tumor localization and small lesions are needed. Although some NET biomarkers exist, sensitive and specific markers that predict tumor growth and behavior are generally lacking. In addition, the integration of new molecular imaging technologies in patient diagnosis and follow-up has the potential to enhance care. To discuss developments and issues required to improve diagnostics and management of NET patients, with specific focus on the latest advances in molecular imaging and biomarker science, 17 global leaders in the fields of NET, molecular imaging and biomarker technology gathered to participate in a 2-day meeting hosted by Prof. Kjell Oberg at the University of Uppsala in Sweden. During this time, findings were presented regarding methods with potential prognostic and treatment applications in NET or other types of cancers. This paper describes the symposium presentations and resulting discussions.
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26.
  • Johansson, Hans-Erik, 1960-, et al. (författare)
  • Energy restriction in obese women suggest linear reduction of hepatic fat content and time-dependent metabolic improvements
  • 2019
  • Ingår i: Nutrition & Diabetes. - : Springer Science and Business Media LLC. - 2044-4052. ; 9:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Energy restriction reduces liver fat, improves hepatic insulin resistance and lipid metabolism. However, temporal data in which these metabolic improvements occur and their interplay is incomplete. By performing repeated MRI scans and blood analysis at day 0, 3, 7, 14 and 28 the temporal changes in liver fat and related metabolic factors were assessed at five times during a low-calorie diet (LCD, 800-1100 kcal/day) in ten obese non-diabetic women (BMI 41.7 ± 2.6 kg/m2) whereof 6 had NAFLD. Mean weight loss was 7.4 ± 1.2 kg (0.7 kg/day) and liver fat decreased by 51 ± 16%, resulting in only three subjects having NAFLD at day 28. Marked alteration of insulin, NEFA, ALT and 3-hydroxybuturate was evident 3 days after commencing LCD, whereas liver fat showed a moderate but a linear reduction across the 28 days. Other circulating-liver fat markers (e.g. triglycerides, adiponectin, stearoyl-CoA desaturase-1 index, fibroblast growth factor 21) demonstrated modest and variable changes. Marked elevations of NEFA, 3-hydroxybuturate and ALT concentrations occurred until day 14, likely reflecting increased tissue lipolysis, fat oxidation and upregulated hepatic fatty acid oxidation. In summary, these results suggest linear reduction in liver fat, time-specific changes in metabolic markers and insulin resistance in response to energy restriction.
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27.
  • Jonsson, Ove, 1966-, et al. (författare)
  • Minimal Safe Arterial Blood Flow During Selective Antegrade Cerebral Perfusion at 20° Centigrade
  • 2011
  • Ingår i: Annals of Thoracic Surgery. - : Elsevier BV. - 0003-4975 .- 1552-6259. ; 91:4, s. 1198-1205
  • Tidskriftsartikel (refereegranskat)abstract
    • BackgroundSelective antegrade cerebral perfusion (SACP) enables surgery on the aortic arch, where cerebral ischemia may cause neurologic sequels. This study aims to identify the minimum arterial flow level to maintain adequate cerebral perfusion during SACP in deep hypothermia in the pig.MethodsTwo groups of pigs were subjected to SACP at 20°C α-stat. In group 1 (n = 6), flow was stepwise adjusted from 8-6-4-2-8 mL · kg−1 · min−1 and in group 2 (n = 5), flow was kept constant at 6 mL · kg−1 · min−1. Magnetic resonance imaging and spectroscopy were performed at each flow level together with hemodynamic monitoring and blood gas analysis. The biochemical marker of cerebral damage protein S100β was measured in peripheral blood.ResultsDecreased mixed venous oxygen saturation and increased lactate in magnetic resonance spectroscopy was seen as a sign of anaerobic metabolism below 6 mL · kg−1 · min−1. No ischemic damage was seen on diffusion-weighted imaging, but the concentrations of S100β were significantly elevated in group 1 compared with group 2 at the end of the experiment (p < 0.05). Perfusion-weighted imaging showed coherence between flow setting and cerebral perfusion, increase of blood volume across time, and regional differences in perfusion during SACP.ConclusionsThe findings suggest an ischemic threshold close to 6 mL · kg−1 · min−1 in the present model. Regional differences in perfusion during SACP may be of pathogenic importance to focal cerebral ischemia.
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28.
  • Juhl, Carsten B., et al. (författare)
  • TNF-alpha inhibitors for juvenile idiopathic arthritis
  • 2020
  • Ingår i: Cochrane Database of Systematic Reviews. - 1361-6137. ; 2020:8
  • Forskningsöversikt (refereegranskat)abstract
    • Objectives: This is a protocol for a Cochrane Review (intervention). The objectives are as follows:. To assess the benefits and harms of TNFi in patients with JIA.
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29.
  • Kechagias, Stergios, et al. (författare)
  • Effects of moderate red wine consumption on liver fat and blood lipids : a prospective randomized study
  • 2011
  • Ingår i: Annals of Medicine. - : Informa Healthcare. - 0785-3890 .- 1365-2060. ; 43:7, s. 545-554
  • Tidskriftsartikel (refereegranskat)abstract
    • Background : There have been no human prospective randomized studies of the amount of alcohol that can induce hepatic steatosis. less thanbrgreater than less thanbrgreater thanMethods : Thirty-two healthy women and twelve healthy men (34 +/- 9 years of age) were randomized to consume 150 ml of red wine/day for women (16 g ethanol/day) or double that amount for men (33 g ethanol/day), or to alcohol abstention for 90 days. Participants underwent proton-nuclear magnetic-resonance spectroscopy for measurement of hepatic triglyceride content (HTGC). Blood samples for assessment of cardiovascular risk were drawn before and after the intervention. less thanbrgreater than less thanbrgreater thanResults: After exclusion of three subjects with steatosis at baseline a trend towards increased HTGC was apparent for red wine (before median: 1.1%, range 0.2-3.9%, after median: 1.1%, range 0.5-5.2%, P = 0.059) a difference that was statistically significant compared with abstainers (p = 0.02). However, no subject developed hepatic steatosis. Low-density lipoprotein (LDL)-cholesterol was lowered by red wine (-0.3 mmol/l, SE-0.1, 95% CI-0.6 to -0.04). less thanbrgreater than less thanbrgreater thanConclusions: Moderate consumption of red wine during three months increased HTGC in subjects without steatosis at baseline. However, since not a single participant developed steatosis we suggest that the threshold of alcohol consumption to define nonalcoholic fatty liver disease should not be lower than the amount in our study.
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30.
  • Langner, Taro, et al. (författare)
  • Uncertainty-Aware Body Composition Analysis with Deep Regression Ensembles on UK Biobank MRI
  • 2021
  • Ingår i: Computerized Medical Imaging and Graphics. - : Elsevier BV. - 0895-6111 .- 1879-0771. ; 93
  • Tidskriftsartikel (refereegranskat)abstract
    • Along with rich health-related metadata, an ongoing imaging study has acquired MRI of over 40,000 male and female UK Biobank participants aged 44-82 since 2014. Phenotypes derived from these images, such as measurements of body composition, can reveal new links between genetics, cardiovascular disease, and metabolic conditions. In this retrospective study, six measurements of body composition were automatically estimated by ResNet50 neural networks for image-based regression from neck-to-knee body MRI. Despite the potential for high speed and accuracy, these networks produce no output segmentations that could indicate the reliability of individual measurements. The presented experiments therefore examine mean-variance regression and ensembling for predictive uncertainty estimation, which can quantify individual measurement errors and thereby help to identify potential outliers, anomalies, and other failure cases automatically. In 10-fold cross-validation on data of about 8,500 subjects, mean-variance regression and ensembling showed complementary benefits, reducing the mean absolute error across all predictions by 12%. Both improved the calibration of uncertainties and their ability to identify high prediction errors. With intra-class correlation coefficients (ICC) above 0.97, all targets except the liver fat content yielded relative measurement errors below 5%. Testing on another 1,000 subjects showed consistent performance, and the method was finally deployed for inference to 30,000 subjects with missing reference values. The results indicate that deep regression ensembles could ultimately provide automated, uncertainty-aware measurements of body composition for more than 120,000 UK Biobank neck-to-knee body MRI that are to be acquired within the coming years. 
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31.
  • Lennmyr, Fredrik, et al. (författare)
  • Increased brain injury and vascular leakage after pretreatment with p38-inhibitor SB203580 in transient ischemia
  • 2003
  • Ingår i: Acta Neurologica Scandinavica. - : Hindawi Limited. - 0001-6314 .- 1600-0404. ; 108:5, s. 339-45
  • Tidskriftsartikel (refereegranskat)abstract
    • OBJECTIVES: Focal cerebral ischemia activates intracellular signaling pathways including the mitogen-activated protein kinase p38, which may be involved in the process of ischemic brain injury. In this study, the effect of pretreatment with the p38-inhibitor SB203580 on infarct size and blood-brain barrier (BBB) breakdown was investigated with magnetic resonance imaging (MRI). MATERIALS AND METHODS: Rats were given SB203580 (n = 6) or vehicle (n = 6) in the right lateral ventricle prior to transient (90 min) middle cerebral artery occlusion (MCAO) on the left side. The rats were examined with serial MRI during MCAO, at reperfusion and after 1 and 4 days. RESULTS: The mean infarct size on T2-weighted images after 1 day was significantly higher in the SB203580-treated group than in controls (300 +/- 95 mm3 vs 126 +/- 75 mm3; P < 0.01). Vascular gadolinium leakage, indicating BBB breakdown, was significantly larger in the SB203580-treated group than in controls after 1 day (median leakage score 18.5; range 15-21 vs 6.5; 4-17; P < 0.05) and 4 days (11; 6-15 vs 3.5; 1-9; P < 0.05), although no significant difference was seen initially. CONCLUSION: Pretreatment with SB203580 may aggravate ischemic brain injury and cerebral vascular leakage in the present model of transient ischemia.
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32.
  • Lennmyr, Fredrik, et al. (författare)
  • Src family kinase-inhibitor PP2 reduces focal ischemic brain injury
  • 2004
  • Ingår i: Acta Neurologica Scandinavica. - : Hindawi Limited. - 0001-6314 .- 1600-0404. ; 110:3, s. 175-9
  • Tidskriftsartikel (refereegranskat)abstract
    • OBJECTIVES: To investigate the neuroprotective potential of the Src family kinase (SFK) inhibitor 4-amino-5-(4-chlorophenyl)-7-(t-butyl) pyrazolo(3,4-d)pyrimidine (PP2) in transient focal cerebral ischemia in the rat. MATERIAL AND METHODS: Sprague-Dawley rats were exposed to transient (90 min) middle cerebral artery occlusion (MCAO) and evaluated after 1 day of survival. PP2 (1.5 mg/kg i.p.) or vehicle was given 30 min after MCAO. The lesions were examined with magnetic resonance imaging (MRI), tri-phenyl tetrazolium chloride (TTC) staining and the functional outcome was determined using neurological scoring according to Bederson et al. RESULTS: PP2-treated rats showed approximately 50% reduction of infarct size on T2-weighted MRI and in TTC staining compared with controls (P < 0.05). Moreover, the neurological score was better in the PP2 group than controls (P < 0.05). CONCLUSION: PP2 is a potential neuroprotective agent in cerebral ischemia-reperfusion. The interference of PP2 with SFKs and/or other pathways remains to be elucidated.
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33.
  • Lind, Lars, et al. (författare)
  • Obesity is associated with coronary artery stenosis independently of metabolic risk factors : the population-based SCAPIS study
  • 2022
  • Ingår i: Atherosclerosis. - : Elsevier. - 0021-9150 .- 1879-1484. ; 362, s. 1-10
  • Tidskriftsartikel (refereegranskat)abstract
    • Background and aims: Previous studies reported divergent results on whether metabolically healthy obesity is associated with increased coronary artery calcium and carotid plaques. We investigated this in a cross-sectional fashion in a large, well-defined, middle-aged population using coronary CT angiography (CCTA) and carotid ultrasound. Methods: In the SCAPIS study (50–65 years, 51% female), CCTA and carotid artery ultrasound were performed in 23,674 individuals without clinical atherosclerotic disease. These subjects were divided into six groups according to BMI (normal weight, overweight, obese) and the presence of metabolic syndrome (MetS) according to the NCEP consensus criteria. Results: The severity of coronary artery stenosis was increased in individuals with obesity without MetS compared to normal-weight individuals without MetS (OR 1.47, 95%CI 1.34–1.62; p < 0.0001), even after adjusting for non-HDL-cholesterol and several lifestyle factors. Such difference was not observed for the presence of carotid artery plaques (OR 0.94, 95%CI 0.87–1.02; p = 0.11). Obese or overweight individuals without any MetS criteria (except the waist criterion) showed significantly more pronounced stenosis in the coronary arteries as compared to the normal-weight individuals, while one criterion was needed to show increased plaque prevalence in the carotid arteries. High blood pressure was the most important single criterion for increased atherosclerosis in this respect. Conclusions: Individuals with obesity without MetS showed increased severity of coronary artery stenosis, but no increased occurrence of carotid artery plaques compared to normal-weight individuals without MetS, further emphasizing that obesity is not a benign condition even in the absence of MetS.
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34.
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35.
  • Lång, Lars-Ove, et al. (författare)
  • Digital insamling av vattentäktsdata till databas DGV– exempel på metodik för miljömålsuppföljning
  • 2007
  • Rapport (övrigt vetenskapligt/konstnärligt)abstract
    • SGU har under några år arbetat med att bygga upp ett system för överföring av vattentäktsdatafrån landets kommuner till en nationell databas för grundvattenförekomster och vattentäkter(DGV). Arbetet har främst varit inriktat mot landets allmänna vattentäkter, men även övrigavattentäkter som försörjer > 50 personer eller har ett uttag > 10m3/dygn ingår. Ett av huvudskälentill uppbyggnaden av databasen är behovet inom miljömålsarbetet av data avseende vattenförsörjningen.Användningen ligger framförallt inom miljömålet ”Grundvatten av god kvalitet”,men uppgifter i DGV har även tillämpning inom andra miljömål. Detta projekt är en del iarbetet med att utveckla DGV samt beskriva användbarheten utifrån miljömålssynpunkt.Arbetet med insamling av vattentäktsuppgifter direkt från kommunerna inleddes i slutet av2002. Under 2006 har för första gången en förfrågan om uppdatering av inlagrade uppgifterskett. I januari 2007 var 215 kommuner färdiga med inregistreringen av allmänna vattentäkter.Inlämningen av uppgifter från kommunerna är frivillig. Därför har inför efterfrågan av dataavstämning skett mot ett antal utvalda kontaktkommuner så att uppgiftslämnandet innebär enrimlig arbetsinsats. Det har också eftersträvats från SGUs sida att ha en effektiv teknisk supportoch kommunens egna data är alltid tillgängliga via webben. För att underlätta för kommunernainsamlas vattenanalysresultat direkt från anlitade laboratorier efter att avtal undertecknats avkommunerna eller vattentäktsinnehavare.I denna rapport ingår en sammanfattning av hur insamlingen av vattentäktsdata till DGV gårtill samt kortfattade beskrivningar av uppbyggnaden av databas och webbapplikation. För meruppgifter om den tekniska utformningen kan kontakt tas med SGU.En sammanfattning ingår också i rapporten avseende användningen av DGV-data imiljömålsarbetet på nationell, regional och lokal nivå. Uppgifter från DGV används vid framtagandeav indikatorer samt vid uppföljningen av dessa. DGV-data är ett av de viktigasteunderlagen i det nu pågående arbetet med den andra Fördjupade utvärderingen av miljömålet”Grundvatten av god kvalitet”.Arbetet med DGV är omfattande vad gäller kontakter och systemuppbyggnad. Ett stort antalpersoner har medverkat vid inmatningen av uppgifter hos kommunerna. Deras intresse ochengagemang har inneburit att de flesta av landets allmänna vattentäkter nu har registrerats iDGV. Arbetet med DGV innebär ett stort erfarenhetsutbyte mellan SGU, kommunerna ochandra berörda myndigheter. Förhoppningen är att verksamheten inom DGV ökar förståelsen församverkan mellan kommunerna och statliga myndigheter inom miljömålsarbetet. Denerfarenhet av webbaserad insamling av data som DGV-arbetet innebär bör kunna användas isamband med annat miljömålsarbete.
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36.
  • Morell, Arvid, et al. (författare)
  • Influence of blood/tissue differences in contrast agent relaxivity on tracer based MR perfusion measurements
  • 2015
  • Ingår i: Magnetic Resonance Materials in Physics, Biology and Medicine. - : Springer Science and Business Media LLC. - 0968-5243 .- 1352-8661. ; 28:2, s. 135-147
  • Tidskriftsartikel (refereegranskat)abstract
    • PURPOSE:Perfusion assessment by monitoring the transport of a tracer bolus depends critically on conversion of signal intensity into tracer concentration. Two main assumptions are generally applied for this conversion; (1) contrast agent relaxivity is identical in blood and tissue, (2) change in signal intensity depends only on the primary relaxation effect. The purpose of the study was to assess the validity and influence of these assumptions.MATERIALS AND METHODS:Blood and cerebral tissue relaxivities r1, r2, and r2* for gadodiamide were measured in four pigs at 1.5 T. Gadolinium concentration was determined by inductively coupled plasma atomic emission spectroscopy. Influence of the relaxivities, secondary relaxation effects and choice of singular value decomposition (SVD) regularization threshold was studied by simulations.RESULTS:In vivo relaxivities relative to blood concentration [in s-1 mM-1 for blood, gray matter (GM), white matter (WM)] were for r1 (2.614 ± 1.061, 0.010 ± 0.001, 0.004 ± 0.002), r2 (5.088 ± 0.952, 0.091 ± 0.008, 0.059 ± 0.014), and r2* (13.292 ± 3.928, 1.696 ± 0.157, 0.910 ± 0.139). Although substantial, by a nonparametric test for paired samples, the differences were not statistically significant. The GM to WM blood volume ratio was estimated to 2.6 ± 0.9 by r1, 1.6 ± 0.3 by r2, and 1.9 ± 0.2 by r2*. Secondary relaxation was found to reduce the tissue blood flow, as did the SVD regularization threshold.CONCLUSION:Contrast agent relaxivity is not identical in blood and tissue leading to substantial errors. Further errors are introduced by secondary relaxation effects and the SVD regularization.
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37.
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38.
  • Nilsson, Daniel, 1982- (författare)
  • A ΔJ approach for nonlinear fatigue crack propagation : Experimental and numerical investigation of a ductile superalloy
  • 2024
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • This dissertation is a product of an academic-industrial collaboration between the Division of Solid Mechanics at Linköping University and Siemens Energy AB. The focus is on enhancing the design optimisation procedures for high-temperature components in industrial gas turbines (IGT). The research is centred around the behaviour of the nickelbased high-temperature superalloy Haynes 230 under service-like conditions with predominant thermal loads. The aim is to improve fatigue crack propagation life predictions for nonlinear conditions.The research findings validate the thermal ageing fatigue effects on Haynes 230 as seen in existing literature, especially on constitutive properties and crack initiation. Additionally, it was observed that thermal ageing has a minor effect on the crack growth rate up to 600 °C, which can be managed by updating the crack driving force with thermally aged properties.The project mainly focused on nonlinear crack propagation at isothermal and thermomechanical fatigue conditions. A new method for crack length description, using a modified compliance method, is introduced. This method simplifies and enhances the accuracy of crack length measurements and has become an established method for evaluating the single edge notch specimen used in the project under thermo-mechanical fatigue conditions.The nonlinear fatigue parameter ΔJ was incorporated into both Finite element method (FEM) computations and test evaluations, revealing linear trends with crack growth rates in loglog. The research highlights the crucial role of crack opening in establishing a correlation between ΔJ and crack growth rate. It was also concluded that the linear fatigue fracture parameter ΔK tends to underestimate the crack growth behaviour, resulting in non-conservative outcomes if the elasto-plastic stresses from the tests are considered.Lastly, a constitutive description of Haynes 230, based on the Ohno-Wang theory, under negligible viscoplastic effects, and an extension of the cycle jumping procedure that takes into account the significant hardening between the initial and midlife stages of the material, is presented. By this the notched geometry in 3D could be simulated with satisfying accuracy.
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39.
  • Omran, Meis, et al. (författare)
  • Whole-Body MRI Surveillance : Baseline Findings in the Swedish Multicentre Hereditary TP53-Related Cancer Syndrome Study (SWEP53)
  • 2022
  • Ingår i: Cancers. - : MDPI. - 2072-6694. ; 14:2
  • Tidskriftsartikel (refereegranskat)abstract
    • A surveillance strategy of the heritable TP53-related cancer syndrome (hTP53rc), commonly referred to as the Li–Fraumeni syndrome (LFS), is studied in a prospective observational nationwide multi-centre study in Sweden (SWEP53). The aim of this sub-study is to evaluate whole-body MRI (WB-MRI) regarding the rate of malignant, indeterminate, and benign imaging findings and the associated further workup generated by the baseline examination. Individuals with hTP53rc were enrolled in a surveillance program including annual whole-body MRI (WB-MRI), brain-MRI, and in female carriers, dedicated breast MRI. A total of 68 adults ≥18 years old have been enrolled to date. Of these, 61 fulfilled the inclusion criteria for the baseline MRI scan. In total, 42 showed a normal scan, while 19 (31%) needed further workup, of whom three individuals (3/19 = 16%) were diagnosed with asymptomatic malignant tumours (thyroid cancer, disseminated upper GI cancer, and liver metastasis from a previous breast cancer). Forty-three participants were women, of whom 21 had performed risk-reducing mastectomy prior to inclusion. The remaining were monitored with breast MRI, and no breast tumours were detected on baseline MRI. WB-MRI has the potential to identify asymptomatic tumours in individuals with hTP53rc syndrome. The challenge is to adequately and efficiently investigate all indeterminate findings. Thus, a multidisciplinary team should be considered in surveillance programs for individuals with hTP53rc syndrome.
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40.
  • Rosqvist, Fredrik, 1985-, et al. (författare)
  • Abdominal Fat and Metabolic Health Markers but Not PNPLA3 Genotype Predicts Liver Fat Accumulation in Response to Excess Intake of Energy and Saturated Fat in Healthy Individuals
  • 2020
  • Ingår i: Frontiers in Nutrition. - : Frontiers Media SA. - 2296-861X. ; 7
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Saturated fat (SFA) has consistently been shown to increase liver fat, but the response appears variable at the individual level. Phenotypic and genotypic characteristics have been demonstrated to modify the hypercholesterolemic effect of SFA but it is unclear which characteristics that predict liver fat accumulation in response to a hypercaloric diet high in SFA.Objective: To identify predictors of liver fat accumulation in response to an increased intake of SFA.Design: We pooled our two previously conducted double-blind randomized trials (LIPOGAIN and LIPOGAIN-2, clinicaltrials.gov NCT01427140 and NCT02211612) and used data from the n = 49 metabolically healthy men (n = 32) and women (n = 17) randomized to a hypercaloric diet through addition of SFA-rich muffins for 7-8 weeks. Associations between clinical and metabolic variables at baseline and changes in liver fat during the intervention were analyzed using Spearman rank correlation. Linear regression was used to generate a prediction model.Results: Liver fat increased by 33% (IQR 5.4-82.7%; P < 0.0001) in response to excess energy intake and this was not associated (r = 0.17, P = 0.23) with the increase in body weight (1.9 kg; IQR 1.1-2.9 kg). Liver fat accumulation was similar (P = 0.28) in carriers (33%, IQR 14-79%) and non-carriers (33%, IQR -11 to +87%) of the PNPLA3-I148M variant. Baseline visceral and liver fat content, as well as levels of the liver enzyme gamma-glutamyl transferase (GT), were the strongest positive predictors of liver fat accumulation-in contrast, adiponectin and the fatty acid 17:0 in adipose tissue were the only negative predictors in univariate analyses. A regression model based on eight clinical and metabolic variables could explain 81% of the variation in liver fat accumulation.Conclusion: Our results suggest there exists a highly inter-individual variation in the accumulation of liver fat in metabolically healthy men and women, in response to an increased energy intake from SFA and carbohydrates that occurs over circa 2 months. This marked variability in liver fat accumulation could largely be predicted by a set of clinical (e.g., GT and BMI) and metabolic (e.g., fatty acids, HOMA-IR, and adiponectin) variables assessed at baseline.
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41.
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42.
  • Rosqvist, Fredrik, 1985-, et al. (författare)
  • Fatty acid composition in serum cholesterol esters and phospholipids is linked to visceral and subcutaneous adipose tissue content in elderly individuals : a cross-sectional study
  • 2017
  • Ingår i: Lipids in Health and Disease. - : Springer Science and Business Media LLC. - 1476-511X. ; 16, s. 1-10
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Visceral adipose tissue (VAT) and truncal fat predict cardiometabolic disease. Intervention trials suggest that saturated fatty acids (SFA), e. g. palmitic acid, promote abdominal and liver fat storage whereas polyunsaturated fatty acids (PUFA), e. g. linoleic acid, prevent fat accumulation. Such findings require investigation in population-based studies of older individuals. We aimed to investigate the relationships of serum biomarkers of PUFA intake as well as serum levels of palmitic acid, with abdominal and total adipose tissue content.Methods: In a population-based sample of 287 elderly subjects in the PIVUS cohort, we assessed fatty acid composition in serum cholesterol esters (CE) and phospholipids (PL) by gas chromatography and the amount of VAT and abdominal subcutaneous (SAT) adipose tissue by magnetic resonance imaging (MRI), liver fat by MR spectroscopy (MRS), and total body fat, trunk fat and leg fat by dual-energy X-ray absorptiometry (DXA). Insulin resistance was estimated by HOMA-IR.Results: VAT and trunk fat showed the strongest correlation with insulin resistance (r = 0.49, P < 0.001). Linoleic acid in both CE and PL was inversely related to all body fat depots (r = -0.24 to -0.33, P < 0.001) including liver fat measured in a sub-group (r = -0.26, P < 0.05, n = 73), whereas n-3 PUFA showed weak inverse (18: 3n-3) or positive (20: 5n-3) associations. Palmitic acid in CE, but not in PL, was directly correlated with VAT (r = 0.19, P < 0.001) and trunk fat (r = 0.18, P = 0.003). Overall, the significant associations remained after adjusting for energy intake, height, alcohol, sex, smoking, education and physical activity. The inverse correlation between linoleic acid and VAT remained significant after further adjustment for total body fat.Conclusions: Serum linoleic acid is inversely related to body fat storage including VAT and trunk fat whereas palmitic acid was less consistently but directly associated, in line with recent feeding studies. Considering the close link between VAT and insulin resistance, a potential preventive role of plant-based PUFA in VAT accumulation warrants further study.
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43.
  • Rosqvist, Fredrik, 1985-, et al. (författare)
  • Overeating saturated fat promotes fatty liver and ceramides compared to polyunsaturated fat : a randomized trial
  • 2019
  • Ingår i: Journal of Clinical Endocrinology and Metabolism. - : Oxford University Press. - 0021-972X .- 1945-7197. ; 104:12, s. 6207-6219
  • Tidskriftsartikel (refereegranskat)abstract
    • CONTEXT: Saturated fat (SFA) versus polyunsaturated fat (PUFA) may promote non-alcoholic fatty liver disease (NAFLD) by yet unclear mechanisms.OBJECTIVE: To investigate if overeating SFA- and PUFA-enriched diets lead to differential liver fat accumulation in overweight and obese humans.DESIGN: Double-blind randomized trial (LIPOGAIN-2). Overfeeding SFA vs PUFA for 8 weeks, followed by 4 weeks of caloric restriction.SETTING: General community.Participants: n=61 overweight or obese men and women.INTERVENTION: Muffins high in either palm (SFA)- or sunflower oil (PUFA) were added to the habitual diet.MAIN OUTCOME MEASURE: Lean tissue mass (not reported here). Secondary and exploratory outcomes included liver and ectopic fat depots.RESULTS: By design, body weight gain was similar in SFA (2.31±1.38 kg) and PUFA (2.01±1.90 kg) groups, P=0.50. SFA markedly induced liver fat content (50% relative increase) along with liver enzymes and atherogenic serum lipids. In contrast, despite similar weight gain, PUFA did not increase liver fat or liver enzymes or cause any adverse effects on blood lipids. SFA had no differential effect on the accumulation of visceral fat, pancreas fat or total body fat compared with PUFA. SFA consistently increased, while PUFA reduced circulating ceramides; changes that were moderately associated with liver fat changes and proposed markers of hepatic lipogenesis. The adverse metabolic effects of SFA were reversed by calorie restriction.CONCLUSIONS: Saturated fat markedly induces liver fat and serum ceramides whereas dietary polyunsaturated fat prevent liver fat accumulation, reduce ceramides and hyperlipidemia during excess energy intake and weight gain in overweight individuals.
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44.
  • Rosqvist, Fredrik, et al. (författare)
  • Overfeeding Polyunsaturated and Saturated Fat Causes Distinct Effects on Liver and Visceral Fat Accumulation in Humans
  • 2014
  • Ingår i: Diabetes. - : American Diabetes Association. - 0012-1797 .- 1939-327X. ; 63:7, s. 2356-2368
  • Tidskriftsartikel (refereegranskat)abstract
    • Excess ectopic fat storage is linked to type 2 diabetes. The importance of dietary fat composition for ectopic fat storage in humans is unknown. We investigated liver fat accumulation and body composition during overfeeding saturated (SFA) or polyunsaturated (PUFA) fat. LIPOGAIN was a double-blind, parallel-group, randomized trial. Thirty-nine young and normal-weight individuals were overfed muffins high in SFA (palm oil) or n-6 PUFA (sunflower oil) for 7 weeks. Liver fat, visceral (VAT), subcutaneous abdominal (SAT), and total adipose tissue (TAT), pancreatic fat, and lean tissue was assessed by MRI. Transcriptomics were performed in SAT. Both groups gained similar weight. SFA however markedly increased liver fat compared with PUFA and caused 2-fold larger increase in VAT than PUFA. Conversely, PUFA caused a nearly 3-fold larger increase in lean tissue than SFA. Increase in liver fat directly correlated with changes in plasma SFA and inversely with PUFA. Genes involved in regulating energy dissipation, insulin resistance, body composition and fat cell differentiation in SAT were differentially regulated between diets, and associated with increased PUFA in SAT. In conclusion, overeating SFA promotes hepatic and visceral fat storage whereas excess energy from PUFA may instead promote lean tissue in healthy humans.
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45.
  • Rosqvist, Fredrik, et al. (författare)
  • Overfeeding polyunsaturated fat compared to saturated fat does not differentially influence lean tissue accumulation in overweight individuals : a randomized controlled trial.
  • 2024
  • Ingår i: American Journal of Clinical Nutrition. - 0002-9165 .- 1938-3207.
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND: Fatty acids may influence lean tissue volume and skeletal muscle function. We previously reported in young lean participants that overfeeding polyunsaturated fat (PUFA) compared with saturated fat (SFA) induced greater lean tissue accumulation despite similar weight gain.OBJECTIVE: In a double-blind randomized controlled trial (RCT), we aimed to investigate if the differential effects of overfeeding SFA and PUFA on lean tissue accumulation could be replicated in individuals with overweight, and identify potential determinants. Further, using substitution models, we investigated associations between SFA and PUFA levels with lean tissue volume, in a large population-based sample (UK Biobank).METHODS: Sixty-one males and females with overweight (BMI 27.3 (interquartile range 25.4 to 29.3), age 43 (interquartile range 36 to 48)) were overfed SFA (palm oil) or n-6 PUFA (sunflower oil) for 8 weeks. Lean tissue was assessed by magnetic resonance imaging (MRI). We had access to n=13849 participants with data on diet, covariates and MRI measurements of lean tissue, as well as 9119 participants with data on circulating fatty acids, in the UK Biobank.RESULTS: Body weight gain (mean±SD) was similar in PUFA (2.01±1.90 kg) and SFA (2.31±1.38 kg) groups. Lean tissue increased to a similar extent (0.54±0.93 L and 0.67±1.21 L for PUFA and SFA group, respectively, with a difference between groups of 0.07 (-0,21, 0,35)). We observed no differential effects on circulating amino acids, myostatin or interleukin-15 and no clear determinants of lean tissue accumulation. Similar non-significant results for SFA and PUFA were observed in UK Biobank, but circulating fatty acids demonstrated ambiguous and sex-dependent associations.CONCLUSION: Overfeeding SFA or PUFA does not differentially affect lean tissue accumulation during 8 weeks in individuals with overweight. A lack of dietary fat type-specific effects on lean tissue is supported by specified substitution models in a large population-based cohort consuming their habitual diet.TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02211612.
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46.
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47.
  • Straniero, S., et al. (författare)
  • Acute caloric restriction counteracts hepatic bile acid and cholesterol deficiency in morbid obesity
  • 2017
  • Ingår i: Journal of Internal Medicine. - : Wiley. - 0954-6820 .- 1365-2796. ; 281:5, s. 507-517
  • Tidskriftsartikel (refereegranskat)abstract
    • BackgroundBile acid (BA) synthesis is regulated by BA signalling in the liver and by fibroblast growth factor 19 (FGF19), synthesized and released from the intestine. In morbid obesity, faecal excretion and hepatic synthesis of BAs and cholesterol are strongly induced and caloric restriction reduces their faecal excretion considerably. We hypothesized that the high intestinal food mass in morbidly obese subjects promotes faecal excretion of BAs and cholesterol, thereby creating a shortage of both BAs and cholesterol in the liver.MethodsTen morbidly obese women (BMI 42 ± 2.6 kg m−2) were monitored on days 0, 3, 7, 14 and 28 after beginning a low‐calorie diet (800–1100 kcal day−1). Serum was collected and liver size and fat content determined. Synthesis of BAs and cholesterol was evaluated from serum markers, and the serum levels of lipoproteins, BAs, proprotein convertase subtilisin/kexin type 9 (PCSK9), insulin, glucose and FGF19 were monitored. Fifty‐four nonobese women (BMI <25 kg m−2) served as controls.ResultsAt baseline, synthesis of both BAs and cholesterol and serum levels of BAs and PCSK9 were elevated in the obese group compared to controls. Already after 3 days on a low‐calorie diet, BA and cholesterol synthesis and serum BA and PCSK9 levels normalized, whereas LDL cholesterol increased. FGF19 and triglyceride levels were unchanged, and liver volume was reduced by 10%.ConclusionsThe results suggest that hepatic BAs and cholesterol are deficient in morbid obesity. Caloric restriction rapidly counteracts these deficiencies, normalizing BA and cholesterol synthesis and circulating PCSK9 levels, indicating that overproduction of cholesterol in enlarged peripheral tissues cannot explain this phenotype. We propose that excessive food intake promotes faecal loss of BAs and cholesterol contributing to their hepatic deficiencies.
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