| 1. |
- Langefors, Åsa, et al.
(författare)
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Association between major histocompatibility complex class IIB alleles and resistance to Aeromonas salmonicida in Atlantic salmon
- 2001
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Ingår i: Royal Society of London. Proceedings B. Biological Sciences. - : The Royal Society. - 1471-2954 .- 0962-8452. ; 268:1466, s. 479-485
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Tidskriftsartikel (refereegranskat)abstract
- We have tested the importance of genetic variation in the major histocompatibility complex (MHC) class IIB in Atlantic salmon (Salmo salar) for survival after challenge with a highly virulent bacterial pathogen. Forty juvenile full siblings from each of 120 families were infected with the bacterium Aeromonas salmonicida, which causes high mortality in salmon due to furunculosis. Fishes from high-resistance (HR, < 35% mortality) and low-resistance (LR, > 80% mortality) families were screened for their MHC class IIB genotypes using the denaturing gradient gel electrophoresis (DGGE) technique. The exon 2 sequences, encoding the major part of the peptide-binding region, were established far each DGGE fragment. One allele, e, containing a missense single base substitution was significantly more prevalent in HR families than in LR families. An odds-ratio test showed that broods carrying this allele had a 12-fold higher chance of being HR than broods without the e allele. A second allele, i, showed significantly higher frequencies in uninfected and surviving individuals than in infected dead individuals. A third allele, j, tended to be more prevalent both in LR families and in individuals that had died of the infection. There was no correlation between MHC heterozygosity and resistance to A. salmonicida. Our results support the hypothesis that MHC polymorphism is maintained through pathogen-driven selection acting by means of frequency-dependent selection rather than heterozygous advantage.
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| 2. |
- Lohm, Jakob, et al.
(författare)
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Experimental evidence for major histocompatibility complex-allele-specific resistance to a bacterial infection
- 2002
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Ingår i: Proceedings of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 269:1504, s. 2029-2033
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Tidskriftsartikel (refereegranskat)abstract
- The extreme polymorphism found at some major histocompatibility complex (MHC) loci is believed to be maintained by balancing selection caused by infectious pathogens. Experimental support for this is inconclusive. We have studied the interaction between certain MHC alleles and the bacterium Aeromonas salmonicida, which causes the severe disease furunculosis, in Atlantic salmon (Salmo salar L.). We designed full-sibling broods consisting of combinations of homozygote and heterozygote genotypes with respect to resistance or susceptibility alleles. The juveniles were experimentally infected with A. salmonicida and their individual survival was monitored. By comparing full siblings carrying different MHC genotypes the effects on survival due to other segregating genes were minimized. We show that a pathogen has the potential to cause very intense selection pressure on particular MHC alleles; the relative fitness difference between individuals carrying different MHC alleles was as high as 0.5. A co-dominant pattern of disease resistance/susceptibility was found, indicative of qualitative difference in the immune response between individuals carrying the high- and low-resistance alleles. Rather unexpectedly, survival was not higher among heterozygous individuals as compared with homozygous ones.
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| 3. |
- Andersen, Øivind, et al.
(författare)
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The conserved Phe GH5 of importance for hemoglobin intersubunit contact is mutated in gadoid fish
- 2014
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Ingår i: BMC Evolutionary Biology. - 1471-2148. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- Abstract Background Functionality of the tetrameric hemoglobin molecule seems to be determined by a few amino acids located in key positions. Oxygen binding encompasses structural changes at the interfaces between the α1β2 and α2β1 dimers, but also subunit interactions are important for the oxygen binding affinity and stability. The latter packing contacts include the conserved Arg B12 interacting with Phe GH5, which is replaced by Leu and Tyr in the α A and α D chains, respectively, of birds and reptiles. Results Searching all known hemoglobins from a variety of gnathostome species (jawed vertebrates) revealed the almost invariant Arg B12 coded by the AGG triplet positioned at an exon-intron boundary. Rare substitutions of Arg B12 in the gnathostome β globins were found in pig, tree shrew and scaled reptiles. Phe GH5 is also highly conserved in the β globins, except for the Leu replacement in the β1 globin of five marine gadoid species, gilthead seabream and the Comoran coelacanth, while Cys and Ile were found in burbot and yellow croaker, respectively. Atlantic cod β1 globin showed a Leu/Met polymorphism at position GH5 dominated by the Met variant in northwest-Atlantic populations that was rarely found in northeast-Atlantic cod. Site-specific analyses identified six consensus codons under positive selection, including 122β(GH5), indicating that the amino acid changes identified at this position may offer an adaptive advantage. In fact, computational mutation analysis showed that the replacement of Phe GH5 with Leu or Cys decreased the number of van der Waals contacts essentially in the deoxy form that probably causes a slight increase in the oxygen binding affinity. Conclusions The almost invariant Arg B12 and the AGG codon seem to be important for the packing contacts and pre-mRNA processing, respectively, but the rare mutations identified might be beneficial. The Leu122β1(GH5)Met and Met55β1(D6)Val polymorphisms in Atlantic cod hemoglobin modify the intradimer contacts B12-GH5 and H2-D6, while amino acid replacements at these positions in avian hemoglobin seem to be evolutionary adaptive in air-breathing vertebrates. The results support the theory that adaptive changes in hemoglobin functions are caused by a few substitutions at key positions.
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| 4. |
- Blomqvist, Jerker, et al.
(författare)
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Grekiska skeptiker och grekisk bildning
- 1999
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Ingår i: Dannelse — humanitas — paideia. - 8291224234 ; , s. 169-180
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 5. |
- Dangmann, C., et al.
(författare)
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Resilience in Syrian refugee youth
- 2022
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Ingår i: European Journal of Public Health. - : Oxford University Press. - 1101-1262 .- 1464-360X. ; 32:Suppl. 3
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Tidskriftsartikel (refereegranskat)abstract
- Background: The importance of resilience factors in the positive adaptation of refugee youth is widely recognised. However, their actual mechanism of impact remains under-researched. The aim of this study was therefore to explore protective and promotive resilience mechanisms on both negative and positive mental health outcomes. Promotive resilience is seen as a direct main effect and protective resilience as a moderating effect.Methods: Cross-sectional study with 160 Syrian youth aged 13-24 years, who recently resettled in Norway. A multi-dimensional measure for resilience was used to explore the potential impact of resilience factors on pathways between potentially traumatic events from war and flight (PTE), post-migration stress, mental distress and health-related quality of life (HRQoL). Analyses included regression, moderation and moderated mediation using the PROCESS macro for SPSS.Results: A direct main effect of resilience factors (promotive resilience mechanism) was found for HRQoL and general mental distress, but not for post-traumatic stress disorder (PTSD). No moderating effects of resilience factors (protective resilience mechanism) were found. Post-migration stressors mediated the effects of PTE, and this indirect effect was present at all levels of resilience. Relational and environmental level resilience factors and combined amounts had more impact than individual level factors.Conclusions: Despite high risk exposure and mental distress, resilience was also high. The direct main effect of resilience factors and less impact on PTSD, suggests universal resilience building interventions may be beneficial, compared to exclusively targeting groups with high symptom levels. These interventions should target relational and environmental resilience factors as well as individual coping techniques. Additionally, reducing current stress and symptoms could increase the efficacy of resilience factors already present.
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| 6. |
- Dangmann, Cecilie, et al.
(författare)
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Syrian Refugee Youth Resettled in Norway : Mechanisms of Resilience Influencing Health-Related Quality of Life and Mental Distress
- 2021
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Ingår i: Frontiers In Public Health. - : Frontiers Media S.A.. - 2296-2565. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Background: The importance of resilience factors in the positive adaptation of refugee youth is widely recognised. However, their actual mechanism of impact remains under-researched. The aim of this study was therefore to explore protective and promotive resilience mechanisms to inform future interventions and policy. Promotive resilience is seen as a direct main effect and protective resilience as a moderating effect. Methods: This was a cross-sectional study of Syrian youth recently resettled in Norway, aged 13-24 years. Regression and moderation analyses were used to explore different interactions, including moderated mediation using the PROCESS macro for SPSS.Result: A direct main effect of promotive resilience was found for health-related quality of life (HRQoL) and general mental distress, but not for post-traumatic stress disorder (PTSD). No moderating effects of protective resilience were found. Post-migration stressors mediated the effects of potentially traumatic events (PTE) from war and flight, and this indirect effect was present at all levels of resilience. Conclusion: Despite high risk exposure and mental distress, resilience was also high. Broad resilience interventions targeting multiple factors would likely benefit the group, but these should include both individual assets and building supportive environments. Additionally, reducing current stress and providing treatment for those in need could enable recovery and increase the efficacy of resilience factors already present.
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| 7. |
- Heggheim, Siri Elise, et al.
(författare)
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AIS ANALYSIS OF IDLE TIME IN DIFFERENT SCANDINAVIAN OIL REFINERY PORT AREA
- 2018
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- A ship’s productivity is measured by the number of loaded days at sea. Time in ballast, time off hire and port time are the three main factors that influence productivity. Since the tanker segment has limited possibilities for backhauls, it is common that time in ballast accounts for about 50% of their annual voyages. Time off hire depend on the time spent on essentials as repair and surveys, and of course conditions in the freight market. The overall shipping industry suffers from a continuous imbalance of supply and demand (Stopford, 2009). The last couple of years has been challenging, as new external factors makes demand less predictable (Bellemare, 2017). For the tanker industry, 2015 was probably the best year since the market crisis in 2008 (UNCTAD, 2016, p. 57). However, in 2016, the fortune faded (BIMCO, 2017). Time use at port is the last factor to influence productivity. As an element that is to some extent controllable, port time is a central and widely discussed topic. The functions of a port are crucial for a ship’s productivity. Especially since port charges are a major part of a ship’s voyage cost (Stopford, 2009). As a part of the Interreg project - NØKS II (Nærskipsfart i Øresund / Kattegat/Skagerrak), this research addresses the topic of port time. NØKS II focuses on facilitation and development of sea transportation in a specified area. The aim is to evolve an attractive, environmental, safe and sustainable freight flow between Norway, Sweden and Denmark (Vestfold Fylkeskommune, 2015). This study has been conducted based upon analysis of AIS-data from the year 2016. The total amount of time the vessel that arrived or departed from the selected ports are measured and classified as active or idle time. The majority of the idle time is when the vessel is entering the anchorage area which means that the idle time occurs under an “inward voyage”. The fact is that more than two vessels are often calling to a refinery at the same time, thus the build-up starts. Every ship owner or charter want as many sailing days pr. ship since this when they are making their money, not when the ship is at anchor, also known as idle time. The paper presents the extent of idle time in oil ports by the use of AIS data. The study is performed on two ports, one in Sweden and one I Norway. The paper presents a comperative study between ports in Norway and Sweden. In Sweden the choice of port landed on Brofjorden, an oil port owned by the largest fuel company in Sweden, Preem AB (Preem AB, 2017). In Norway Slagentangen refinery owned by Norwegian Esso was selected.
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| 8. |
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| 9. |
- Nissen, Alexander, et al.
(författare)
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Cohort profile : Resettlement in Uprooted Groups Explored (REFUGE)-a longitudinal study of mental health and integration in adult refugees from Syria resettled in Norway between 2015 and 2017
- 2020
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Ingår i: BMJ Open. - : BMJ Publishing Group Ltd. - 2044-6055. ; 10:7
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: In the field of forced migration and mental health research, longitudinal studies with large sample sizes and rigorous methodology are lacking. Therefore, the Resettlement in Uprooted Groups Explored (REFUGE)-study was initiated in order to enhance current knowledge on mental health, quality of life and integration among adult refugees from Syria resettled in Norway. The main aims of the study are to investigate risk and protective factors for mental ill health in a longitudinal perspective; to trace mental health trajectories and investigate important modifiers of these trajectories and to explore the association between mental health and integration in the years following resettlement. The aims will be pursued by combining data from a longitudinal, three-wave questionnaire survey with data from population-based registries on education; work participation and sick-leave; healthcare utilisation and drug prescription. The goal is to incorporate the data in an internationally shared database, the REFUGE-database, where collaborating researchers may access and use data from the study as well as deposit data from similar studies.PARTICIPANTS: Adult (≥18 years), Syrian citizens who arrived in Norway as quota refugees, asylum seekers or through Norway's family reunion programme between 1 January 2015 and 31 December 2017. Of the initial 9990 sampled individuals for the first wave of the study (REFUGE-I), 8752 were reached by post or telephone and 902 responded (response rate=10.3%).FINDINGS TO DATE: None published.FUTURE PLANS: The REFUGE-cohort study will conduct two additional data collections (2020 and 2021). Furthermore, questionnaire data will be linked to population-based registries after all three waves of data collection have been completed. Registry data will be obtained for time-periods both prior to and after the survey data collection points. Finally, pending ethics approval, we will begin the process of merging the Norwegian REFUGE-cohort with existing datasets in Sweden, establishing the extended REFUGE-database.TRIAL REGISTRATION NUMBER: ClincalTrials.gov Registry (NCT03742128).
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| 10. |
- Nissen, Alexander, et al.
(författare)
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Mental health in adult refugees from Syria resettled in Norway between 2015 and 2017 : a nationwide, questionnaire-based, cross-sectional prevalence study
- 2021
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Ingår i: European Journal of Psychotraumatology. - : Taylor & Francis. - 2000-8198 .- 2000-8066. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- Background The number of forcibly displaced people globally has never been higher, with refugees from Syria constituting the largest displaced population worldwide. Many studies have documented elevated levels of mental health problems in refugee populations, though prevalence estimates of common mental disorders vary considerably between studies, explained both by methodological and contextual factors.Objective Using questionnaire-based screening checklists to approximate the prevalence of and investigate risk factors for post-traumatic stress disorder (PTSD), anxiety and depression among adult refugees from Syria resettled in Norway and to compare estimates with a sister-study in Sweden.Method Cross-sectional survey of a randomly selected sample from the National Population Register in Norway of adult refugees from Syria who were granted residency rights in Norway between 2015 and 2017 (N (sample) = 9,990; n (respondents) = 902). Above-threshold scores on the Harvard Trauma Questionnaire (HTQ) and Hopkins Symptoms Checklist (HSCL-25) defined caseness for PTSD (HTQ>2.06); anxiety (HSCLanxitey>1.75); and depression (HSCLdepression>1.80).Results Weighted, checklist-positive prevalence estimates for PTSD, anxiety and depression were 29.7% (25.4%-34.4%), 30.1% (25.7%-34.9%), and 45.2% (40.6%-49.8%), respectively. Cumulative exposure to potentially traumatic experiences before or during flight was a clear risk factor for all outcomes, and female gender was a risk factor for anxiety and depression, though only in adjusted analyses. The choice of HTQ cut-off to define PTSD caseness (2.5 vs. 2.06) had a notable effect on prevalence estimates. Conclusion In line with prior evidence, the present study suggests adult refugees from Syria resettled in Norway have higher rates of anxiety and depression and markedly higher rates of PTSD compared to general, non-refugee populations, and that this is clearly linked to past traumatic experiences. Prevalence estimates were highly consistent with estimates from the sister-study in Sweden, which used almost identical methodology. Findings underline the importance of screening for and intervening on mental health problems in newly arrived refugees.
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