| 1. |
- Aberg, Fredrik, et al.
(författare)
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A Dynamic Aspartate-to-Alanine Aminotransferase Ratio Provides Valid Predictions of Incident Severe Liver Disease
- 2021
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Ingår i: HEPATOLOGY COMMUNICATIONS. - : John Wiley & Sons. - 2471-254X. ; 5:6, s. 1021-1035
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Tidskriftsartikel (refereegranskat)abstract
- The aspartate-to-alanine aminotransferase ratio (AAR) is associated with liver fibrosis, but its predictive performance is suboptimal. We hypothesized that the association between AAR and liver disease depends on absolute transaminase levels and developed and validated a model to predict liver-related outcomes in the general population. A Cox regression model based on age, AAR, and alanine aminotransferase (ALT) level (dynamic AAR [dAAR]) using restricted cubic splines was developed in Finnish population-based health-examination surveys (FINRISK, 2002-2012; n = 18,067) with linked registry data for incident liver-related hospitalizations, hepatocellular carcinoma, or liver death. The model was externally validated for liver-related outcomes in a Swedish population cohort (Swedish Apolipoprotein Mortality Risk [AMORIS] subcohort; n = 126,941) and for predicting outcomes and/or prevalent fibrosis/cirrhosis in biopsied patients with nonalcoholic fatty liver disease (NAFLD), chronic hepatitis C, or alcohol-related liver disease (ALD). The dynamic AAR model predicted liver-related outcomes both overall (optimism-corrected C-statistic, 0.81) and in subgroup analyses of the FINRISK cohort and identified persons with >10% risk for liver-related outcomes within 10 years. In independent cohorts, the C-statistic for predicting liver-related outcomes up to a 10-year follow-up was 0.72 in the AMORIS cohort, 0.81 in NAFLD, and 0.75 in ALD. Area-under-the-curve (AUC) for detecting prevalent cirrhosis was 0.80-0.83 in NAFLD, 0.80 in hepatitis C, but only 0.71 in ALD. In ALD, model performance improved when using aspartate aminotransferase instead of ALT in the model (C-statistic, 0.84 for outcome; AUC, 0.82 for prevalent cirrhosis). Conclusion: A dAAR score provides prospective predictions for the risk of incident severe liver outcomes in the general population and helps detect advanced liver fibrosis/cirrhosis. The dAAR score could potentially be used for screening the unselected general population and as a trigger for further liver evaluations.
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| 2. |
- Aberg, Fredrik, et al.
(författare)
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Differences in long-term mortality among liver transplant recipients and the general population: A population-based Nordic study.
- 2015
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Ingår i: Hepatology (Baltimore, Md.). - : Ovid Technologies (Wolters Kluwer Health). - 1527-3350 .- 0270-9139. ; 61:2, s. 668-677
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Tidskriftsartikel (refereegranskat)abstract
- Dramatic improvement in first-year outcomes post-liver transplantation (LT) has shifted attention to long-term survival, where efforts are now needed to achieve improvement. Understanding the causes for premature death is a prerequisite for improving long-term outcome. Overall and cause-specific mortality of 3299 Nordic LT patients (1985-2009) having survived 1 year post-LT were divided by expected rates in the general population, adjusted for age, sex, calendar time, and country to yield standardized mortality ratios (SMRs). Data came from the Nordic Liver-Transplant Registry and WHO mortality-indicator database. Stagnant patient survival rates >1 year post-LT were 21% lower at 10 years than expected survival for the general population. Overall SMR for death before age 75 (premature mortality) was 5.8 (95%CI 5.4-6.3), with improvement from 1985-1999 to 2000-2010 in hepatitis C (HCV) (SMR change 23.1-9.2), hepatocellular carcinoma (HCC) (SMR 38.4-18.8), and primary sclerosing cholangitis (SMR 11.0-4.2), and deterioration in alcoholic liver disease (8.3-24.0) and acute liver failure (ALF) (5.9-7.6). SMRs for cancer and liver disease (recurrent or transplant-unrelated disease) were elevated in all indications except primary biliary cirrhosis (PBC). Absolute mortality rates underestimated the elevated premature mortality from infections (SMR 22-693) and kidney disease (SMR 13-45) across all indications, and from suicide in HCV and ALF. SMR for cardiovascular disease was significant only in PBC and alcoholic liver disease, owing to high mortality in the general population. Transplant-specific events caused 16% of deaths. Conclusion: standardized premature mortality provided an improved picture of long-term post-LT outcome, showing improvement over time in some indications, not revealed by overall absolute mortality rates. Causes with high premature mortality (infections, cancer, kidney and liver disease, and suicide) merit increased attention in clinical patient follow-up and future research. (Hepatology 2014;).
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| 3. |
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| 4. |
- Hallén, Anders., et al.
(författare)
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Ion implantation of silicon carbide
- 2002
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Ingår i: Nuclear Instruments and Methods in Physics Research Section B. - 0168-583X .- 1872-9584. ; 186, s. 186-194
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Tidskriftsartikel (refereegranskat)abstract
- Ion implantation is an important technique for a successful implementation of commercial SiC devices. Much effort has also been devoted to optimising implantation and annealing parameters to improve the electrical device characteristics. However, there is a severe lack of understanding of the fundamental implantation process and the generation and annealing kinetics of point defects and defect complexes. Only very few of the most elementary intrinsic point defects have been unambiguously identified so far. To reach a deeper understanding of the basic mechanisms SiC samples have been implanted with a broad range of ions, energies, doses, etc., and the resulting defects and damage produced in the lattice have been studied with a multitude of characterisation techniques. In this contribution we will review some of the results generated recently and also try to indicate where more research is needed. In particular, deep level transient spectroscopy (DLTS) has been used to investigate point defects at very low doses and transmission electron microscopy (TEM) and Rutherford backscattering spectrometry (RBS) are used for studying the damage build-up at high doses.
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| 5. |
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| 6. |
- Liedberg, Fredrik, et al.
(författare)
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Local recurrence and progression of non-muscle-invasive bladder cancer in Sweden : a population-based follow-up study
- 2015
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Ingår i: Scandinavian journal of urology. - : Medical Journals Sweden AB. - 2168-1805 .- 2168-1813. ; 49:4, s. 290-295
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Tidskriftsartikel (refereegranskat)abstract
- Objective. The aim of this study was to investigate recurrence and progression of non-muscle-invasive bladder cancer (NMIBC) in a large population-based setting. Materials and methods. Patients with bladder cancer (stage Ta, T1 or carcinoma in situ) diagnosed in 2004-2007 (n = 5839) in Sweden were investigated 5 years after diagnosis using a questionnaire. Differences in time to recurrence and progression were analysed in relation to age, gender, tumour stage and grade, intravesical treatment, healthcare region, and hospital volume of NMIBC patients (stratified in three equally large groups). Results. Local bladder recurrence and progression occurred in 50 and 9% of the patients, respectively. The rate of local recurrence was 56% in the southern healthcare region compared to 37% in the northern region. A multivariate Cox proportional hazards model, adjusting for age, gender, tumour stage and grade, intravesical treatment, healthcare region and hospital volume, showed that recurrence was associated with TaG2 and T1 disease, no intravesical treatment and treatment in the southern healthcare region, but indicated a lower risk of recurrence in the northern healthcare region. Adjusting for the same factors in a multivariate analysis suggested that increased relative risk of progression correlated with older age, higher tumour stage and grade, and diagnosis in the Uppsala/Orebro healthcare region, whereas such risk was decreased by intravesical treatment (relative risk 0.72, 95% confidence interval 0.55-0.93, p = 0.012). Conclusions. The incidence of NMIBC recurrence and progression was found to be high in Sweden, and important disparities in outcome related to care patterns appear to exist between different healthcare regions.
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| 7. |
- Liljeros, Fredrik, et al.
(författare)
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The web of human sexual contacts.
- 2001
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Ingår i: Nature. - 0028-0836. ; 411:6840, s. 907-8
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 8. |
- Storasta, Liutauras, et al.
(författare)
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Proton irradiation induced defects in 4H-SiC
- 2001
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Ingår i: Materials Science Forum, Vols. 353-356. ; , s. 431-434
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Konferensbidrag (refereegranskat)abstract
- Defects created by proton irradiation of n-type 4H-SiC epilayers with different fluences and six annealing steps were investigated by Deep Level Transient Spectroscopy (DLTS) and Minority Carrier Transient Spectroscopy (MCTS). Three previously unreported hole traps with energy levels of E-V + 0.35 eV, E-V + 0.44 eV, E-V + 0.80 eV and several electron traps were found. Annealing properties and dependence upon irradiation dose of majority and minority carrier traps is presented. High temperature stability of a E-V + 0.35 eV trap has been demonstrated.
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| 9. |
- Svensson, BG, et al.
(författare)
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Doping of silicon carbide by ion implantation
- 2001
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Ingår i: Materials Science Forum, Vols. 353-356. - : Trans Tech Publications Inc.. - 9780878498734 - 0878498737 ; , s. 549-554, s. 549-554
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Konferensbidrag (refereegranskat)abstract
- A brief survey is given of some recent results on doping of 4H- and 6H-SiC by ion implantation. The doses and energies used are between 10(9) and 10(15) cm(-2) and 100 keV and 5 MeV, respectively, and B and Al ions (p-type dopants) are predominantly studied. After low dose implantation (less than or equal to 10(10) cm(-2)) a strong compensation is observed in n-type samples and this holds irrespective of implantation temperature up to 600 degreesC. However, at higher doses (10(14)-10(15) Al/cm(2)) the rate of defect recombination (annihilation) increases substantially during hot implants (greater than or equal to 200 degreesC) and in these samples one type of structural defect dominates after past-implant annealing at 1700-2000 degreesC. The defect is identified as a dislocation loop composed of clustered interstitial atoms inserted on the basal plane in the hexagonal crystal structure. Finally, transient enhanced diffusion (TED) of ion-implanted boron in 4H-samples is discussed.
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| 10. |
- Åberg, N David, 1970, et al.
(författare)
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Insulin-like growth factor-I increases astrocyte intercellular gap junctional communication and connexin43 expression in vitro.
- 2003
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Ingår i: Journal of neuroscience research. - : Wiley. - 0360-4012. ; 74:1, s. 12-22
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Tidskriftsartikel (refereegranskat)abstract
- Connexin43 (cx43) forms gap junctions in astrocytes, and these gap junctions mediate intercellular communication by providing transport of low-molecular-weight metabolites and ions. We have recently shown that systemic growth hormone increases cx43 in the brain. One possibility was that local brain insulin-like growth factor-I (IGF-I) could mediate the effect by acting directly on astrocytes. In the present study, we examined the effects of direct application of recombinant human IGF-I (rhIGF-I) on astrocytes in primary culture concerning cx43 protein expression and gap junctional communication (GJC). After 24 hr of stimulation with rhIGF-I under serum-free conditions, the GJC and cx43 protein were analyzed. Administration of 30 ng/ml rhIGF-I increased the GJC and the abundance of cx43 protein. Cell proliferation of the astrocytes was not significantly increased by rhIGF-I at this concentration. However, a higher concentration of rhIGF-I (150 ng/ml) had no effect on GJC/cx43 but increased cell proliferation. Because of the important modulatory role of IGF binding proteins (IGFBPs) on IGF-I action, we analyzed IGFBPs in conditioned media. In cultures with a low abundance of IGFBPs (especially IGFBP-2), the GJC response to 30 ng/ml rhIGF-I was 81%, compared with the average of 25%. Finally, as a control, insulin was given in equimolar concentrations. However, GJC was not affected, which suggests that rhIGF-I acted via IGF-I receptors. In summary, the data show that rhIGF-I may increase GJC/cx43, whereas a higher concentration of rhIGF-I--at which stimulation of proliferation occurred--did not affect GJC/cx43. Furthermore, IGFBP-2 appeared to modulate the action of rhIGF-I on GJC in astrocytes by a paracrine mechanism.
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