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Sökning: swepub > Umeå universitet > Högskolan Kristianstad

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  • Gillman, Anna, et al. (författare)
  • Oseltamivir-Resistant Influenza A (H1N1) Virus Strain with an H274Y Mutation in Neuraminidase Persists without Drug Pressure in Infected Mallards
  • 2015
  • Ingår i: Applied and Environmental Microbiology. - 0099-2240 .- 1098-5336. ; 81:7, s. 2378-2383
  • Tidskriftsartikel (refereegranskat)abstract
    • Influenza A virus (IAV) has its natural reservoir in wild waterfowl, and emerging human IAVs often contain gene segments from avian viruses. The active drug metabolite of oseltamivir (oseltamivir carboxylate [OC]), stockpiled as Tamiflu for influenza pandemic preparedness, is not removed by conventional sewage treatment and has been detected in river water. There, it may exert evolutionary pressure on avian IAV in waterfowl, resulting in the development of resistant viral variants. A resistant avian IAV can circulate among wild birds only if resistance does not restrict viral fitness and if the resistant virus can persist without continuous drug pressure. In this in vivo mallard (Anas platyrhynchos) study, we tested whether an OC-resistant avian IAV (H1N1) strain with an H274Y mutation in the neuraminidase (NA-H274Y) could retain resistance while drug pressure was gradually removed. Successively infected mallards were exposed to decreasing levels of OC, and fecal samples were analyzed for the neuraminidase sequence and phenotypic resistance. No reversion to wild-type virus was observed during the experiment, which included 17 days of viral transmission among 10 ducks exposed to OC concentrations below resistance induction levels. We conclude that resistance in avian IAV that is induced by exposure of the natural host to OC can persist in the absence of the drug. Thus, there is a risk that human-pathogenic IAVs that evolve from IAVs circulating among wild birds may contain resistance mutations. An oseltamivir-resistant pandemic IAV would pose a substantial public health threat. Therefore, our observations underscore the need for prudent oseltamivir use, upgraded sewage treatment, and surveillance for resistant IAVs in wild birds.
  • Järhult, Josef D., et al. (författare)
  • Environmental levels of the antiviral oseltamivir induce development of resistance mutation H274Y in influenza A/H1N1 virus in mallards
  • 2011
  • Ingår i: PLoS ONE. - 1932-6203. ; 6:9
  • Tidskriftsartikel (refereegranskat)abstract
    • Oseltamivir (Tamiflu®) is the most widely used drug against influenza infections and is extensively stockpiled worldwide as part of pandemic preparedness plans. However, resistance is a growing problem and in 2008-2009, seasonal human influenza A/H1N1 virus strains in most parts of the world carried the mutation H274Y in the neuraminidase gene which causes resistance to the drug. The active metabolite of oseltamivir, oseltamivir carboxylate (OC), is poorly degraded in sewage treatment plants and surface water and has been detected in aquatic environments where the natural influenza reservoir, dabbling ducks, can be exposed to the substance. To assess if resistance can develop under these circumstances, we infected mallards with influenza A/H1N1 virus and exposed the birds to 80 ng/L, 1 µg/L and 80 µg/L of OC through their sole water source. By sequencing the neuraminidase gene from fecal samples, we found that H274Y occurred at 1 µg/L of OC and rapidly dominated the viral population at 80 µg/L. IC₅₀ for OC was increased from 2-4 nM in wild-type viruses to 400-700 nM in H274Y mutants as measured by a neuraminidase inhibition assay. This is consistent with the decrease in sensitivity to OC that has been noted among human clinical isolates carrying H274Y. Environmental OC levels have been measured to 58-293 ng/L during seasonal outbreaks and are expected to reach µg/L-levels during pandemics. Thus, resistance could be induced in influenza viruses circulating among wild ducks. As influenza viruses can cross species barriers, oseltamivir resistance could spread to human-adapted strains with pandemic potential disabling oseltamivir, a cornerstone in pandemic preparedness planning. We propose surveillance in wild birds as a measure to understand the resistance situation in nature and to monitor it over time. Strategies to lower environmental levels of OC include improved sewage treatment and, more importantly, a prudent use of antivirals.
  • Lahermo, Päivi, et al. (författare)
  • A quality assessment survey of SNP genotyping laboratories
  • 2006
  • Ingår i: Human Mutation. - 1059-7794 .- 1098-1004. ; 27:7, s. 711-714
  • Tidskriftsartikel (övrigt vetenskapligt)abstract
    • To survey the quality of SNP genotyping, a joint Nordic quality assessment (QA) round was organized between 11 laboratories in the Nordic and Baltic countries. The QA round involved blinded genotyping of 47 DNA samples for 18 or six randomly selected SNPs. The methods used by the participating laboratories included all major platforms for small- to medium-size SNP genotyping. The laboratories used their standard procedures for SNP assay design, genotyping, and quality control. Based on the joint results from all laboratories, a consensus genotype for each DNA sample and SNP was determined by the coordinator of the survey, and the results from each laboratory were compared to this genotype. The overall genotyping accuracy achieved in the survey was excellent. Six laboratories delivered genotype data that were in full agreement with the consensus genotype. The average accuracy per SNP varied from 99.1 to 100% between the laboratories, and it was frequently 100% for the majority of the assays for which SNP genotypes were reported. Lessons from the survey are that special attention should be given to the quality of the DNA samples prior to genotyping, and that a conservative approach for calling the genotypes should be used to achieve a high accuracy.
  • Wallensten, Anders, et al. (författare)
  • Surveillance of influenza A virus in migratory waterfowl in northern Europe
  • 2007
  • Ingår i: Emerging Infectious Diseases. - 1080-6040. - 1080-6040 ; 13:3, s. 404-411
  • Tidskriftsartikel (refereegranskat)abstract
    • We conducted large-scale, systematic sampling of influenza type A virus in migratory waterfowl (mostly mallards [Anas platyrhynchos]) at Ottenby Bird Observatory, southeast Sweden. As with previous studies, we found a higher prevalence in fall than spring, and among juveniles compared with adults. However, in contrast to other studies, we found that prevalence in spring was sometimes high (mean 4.0%, highest 9.5%). This finding raises the possibility that ducks are capable of perpetuating influenza A virus of different subtypes and subtype combinations throughout the year and from 1 year to the next. Isolation of the H5 and H7 subtypes was common, which suggests risk for transmission to sensitive domestic animals such as poultry. We argue that wild bird screening can function as a sentinel system, and we give an example of how it could have been used to forecast a remote and deadly outbreak of influenza A in poultry.
  • Isehed, Catrine, et al. (författare)
  • Effectiveness of enamel matrix derivative on the clinical and microbiological outcomes following surgical regenerative treatment of peri-implantitis : a randomized controlled trial
  • 2016
  • Ingår i: Journal of Clinical Periodontology. - 0303-6979. ; 43:10, s. 863-873
  • Tidskriftsartikel (refereegranskat)abstract
    • OBJECTIVE: This randomized clinical trial aimed at comparing radiological, clinical and microbial effects of surgical treatment of peri-implantitis alone or in combination with enamel matrix derivative (EMD).METHODS: Twenty-six subjects were treated with open flap debridement and decontamination of the implant surfaces with gauze and saline preceding adjunctive EMD or no EMD. Bone level (BL) change was primary outcome and secondary outcomes were changes in pocket depth (PD), plaque, pus, bleeding and the microbiota of the peri-implant biofilm analyzed by the Human Oral Microbe Identification Microarray over a time period of 12 months.RESULTS: In multivariate modelling, increased marginal BL at implant site was significantly associated with EMD, the number of osseous walls in the peri-implant bone defect and a Gram+/aerobic microbial flora, whereas reduced BL was associated with a Gram-/anaerobic microbial flora and presence of bleeding and pus, with a cross-validated predictive capacity (Q(2) ) of 36.4%. Similar, but statistically non-significant, trends were seen for BL, PD, plaque, pus and bleeding in univariate analysis.CONCLUSION: Adjunctive EMD to surgical treatment of peri-implantitis was associated with prevalence of Gram+/aerobic bacteria during the follow-up period and increased marginal BL 12 months after treatment.
  • Sofrata, Abier H., et al. (författare)
  • Strong antibacterial effect of miswak against oral microorganisms associated with periodontitis and caries.
  • 2008
  • Ingår i: Journal of periodontology. - 0022-3492. ; 79:8, s. 1474-9
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND: The chewing stick (miswak) is used for oral hygiene in many parts of the world. In addition to the mechanical removal of plaque, an antibacterial effect has been postulated; however, tests of miswak extract from Salvadora persica (Arak) disclosed only low to moderate antibacterial effects. This may be attributable to the extraction process. Our aim was to test in vitro the antibacterial effect of miswak pieces, without extraction, on bacteria implicated in the etiology of periodontitis and caries. METHODS: Miswak pieces were standardized by size and weight (0.07 and 0.14 g) and tested against Streptococcus mutans, Lactobacillus acidophilus, Aggregatibacter actinomycetemcomitans (previously Actinobacillus actinomycetemcomitans), Porphyromonas gingivalis, and, as a reference, Haemophilus influenzae. The miswak pieces were tested in two ways: embedded in the agar plate or suspended above the agar plate. RESULTS: The inhibitory effect was most pronounced on P. gingivalis, A. actinomycetemcomitans, and H. influenzae, less on S. mutans, and least on L. acidophilus. Suspended miswak had comparable or stronger effects than miswak embedded in agar. The 0.14-g suspended miswak exhibited significantly greater inhibition on A. actinomycetemcomitans and H. influenzae than the 0.14-g miswak embedded in agar (P<0.01 and P<0.001, respectively). CONCLUSIONS: Miswak embedded in agar or suspended above the agar plate had strong antibacterial effects against all bacteria tested. The antibacterial effect of suspended miswak pieces suggests the presence of volatile active antibacterial compounds.
  • Benzein, Eva, et al. (författare)
  • Families' importance in nursing care : nurses' attitudes - an instrument development
  • 2008
  • Ingår i: Journal of Family Nursing. - 1074-8407. ; 14:1, s. 97-117
  • Tidskriftsartikel (refereegranskat)abstract
    • This article describes the development and testing of a research instrument, Families' Importance in Nursing Care-Nurses' Attitudes (FINC-NA), designed to measure nurses' attitudes about the importance of involving families in nursing care. The instrument was inductively developed from a literature review and tested with a sample of Swedish nurses. An item-total correlation and a first principal component analysis were used to validate the final instrument, including a second principal component analysis to analyze dimensionality, and Cronbach's alpha was used to estimate internal consistency. The instrument consists of 26 items and reveals four factors: families as a resource in nursing care, family as a conversational partner, family as a burden, and family as its own resource. Cronbach's alpha was 0.88 for the total instrument and 0.69 to 0.80 for the subscales. The instrument requires further testing with other nurse populations.
  • Deutschmann, Mats, et al. (författare)
  • “Let’s Keep it Informal, Guys” a Study of the Effects of Teacher Communicative Strategies on Student Activity and Collaborative Learning in Internet-based English Courses
  • 2008
  • Ingår i: Tidskrift för lärarutbildning och forskning. - Umeå : The faculty board for teacher education. - ISSN 1404-7659. ; 15:2, s. 36-58
  • Tidskriftsartikel (refereegranskat)abstract
    • The paper explores the quantity and quality of communication produced by teachers in Internet courses of academic English, particularly during the initial stages of course activity. The courses are entirely conducted in virtual learning environments without physical meetings, and are part of the Bachelor programme (A–C level) of English at Mid Sweden University. The pedagogic design of the courses is based on collaborative learning, which presupposes a communicative environment with positive interdependence and interaction, where knowledge is shared by students questioning and challenging each other. Consequently, the teacher’s role in setting communicative norms which encourage an environment of high acceptance, where students feel that they can express their opinions freely, is of utmost importance. The results suggest that there are two important factors that affect student activity in the initial stages of an online course: how much the teacher communicates with the class and the manner in which he or she does so.
  • Lundström, Jan O., et al. (författare)
  • The geographic distribution of mosquito species in Sweden
  • 2013
  • Ingår i: Journal of the European Mosquito Control Association. - 1460-6127. ; 31, s. 21-35
  • Tidskriftsartikel (refereegranskat)abstract
    • Surveillance of the actual distribution of mosquito species in Northern Europe is fundamental for evaluating risk for emerging pathogens, and for research on potential vectors. The Swedish mosquito fauna composition and geographic distribution, originally described by Professor Christine Dahl in the 1970´s, included 43 species. We have compiled the information published from 1978 to 2012, and our own surveillance data from 2001 to 2013, and compared this with the species list and geographic distribution provided in “Taxonomy and geographic distribution of Swedish Culicidae” by Dahl (1977). New species detected during these 36 years were Culiseta (Culicella) ochroptera (Peus, 1935) published 1984, Aedes (Aedes) rossicus Dolbeskin, Goritzkaja & Mitrofanova, 1930 published 1986, Anopheles (Anopheles) beklemishevi published 1986, Aedes (Ochlerotatus) euedes (Howard, Dyar & Knab, 1912) published 2001, Aedes (Ochlerotatus) nigrinus (Eckstein, 1918) first recorded in 2012, and Anopheles (Anopheles) algeriensis Theobald, 1903, first recorded in 2013. We provide maps with the distribution by province for each species, including historic information up until 1977, and new records from 1978 to 2013, showing the similarities and differences between the old and the new records. Important findings in recent years include the wide distribution of the Sindbis virus enzootic vector Culex (Culex) torrentium Martinii, 1925, and the more limited distribution of the potential West Nile virus vector Culex (Culex) pipiens Linnaeus, 1758. The updated list of mosquito species in Sweden now includes 49 species.
  • Wallensten, A., et al. (författare)
  • Multiple gene segment reassortment between Eurasian and American lineages of influenza A virus (H6N2) in Guillemot (Uria aalge)
  • 2005
  • Ingår i: Archives of Virology. - 0304-8608. - 0304-8608 ; 150:8, s. 1685-1692
  • Tidskriftsartikel (refereegranskat)abstract
    • Guillemots banded in the northern Baltic Sea were screened for influenza A virus (IAV). Three out of 26 sampled birds tested positive by RT-PCR. Two of these were characterized as subtype H6N2. Phylogenetic analyses showed that five gene segments belonged to the American avian lineage of IAVs, whereas three gene segments belonged to the Eurasian lineage. Our findings indicate that avian IAVs may have a taxonomically wider reservoir spectrum than previously known and we present the first report of a chimeric avian IAV with genes of American and Eurasian origin in Europe.
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