| 1. |
- Aamodt, K., et al.
(författare)
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Midrapidity Antiproton-to-Proton Ratio in pp Collisons root s=0.9 and 7 TeV Measured by the ALICE Experiment
- 2010
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Ingår i: Physical Review Letters. - 1079-7114. ; 105:7
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Tidskriftsartikel (refereegranskat)abstract
- The ratio of the yields of antiprotons to protons in pp collisions has been measured by the ALICE experiment at root s = 0.9 and 7 TeV during the initial running periods of the Large Hadron Collider. The measurement covers the transverse momentum interval 0.45 < p(t) < 1.05 GeV/c and rapidity vertical bar y vertical bar < 0.5. The ratio is measured to be R-vertical bar y vertical bar<0.5 = 0.957 +/- 0.006(stat) +/- 0.0014(syst) at 0.9 Tev and R-vertical bar y vertical bar<0.5 = 0.991 +/- 0.005 +/- 0.014(syst) at 7 TeV and it is independent of both rapidity and transverse momentum. The results are consistent with the conventional model of baryon-number transport and set stringent limits on any additional contributions to baryon-number transfer over very large rapidity intervals in pp collisions.
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| 2. |
- Aamodt, K., et al.
(författare)
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Production of pions, kaons and protons in pp collisions at root s=900 GeV with ALICE at the LHC
- 2011
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Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 71:6
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Tidskriftsartikel (refereegranskat)abstract
- The production of pi(+), pi(-), K+, K-, p, and (p) over bar at mid-rapidity has been measured in proton-proton collisions at root s = 900 GeV with the ALICE detector. Particle identification is performed using the specific energy loss in the inner tracking silicon detector and the time projection chamber. In addition, time-of-flight information is used to identify hadrons at higher momenta. Finally, the distinctive kink topology of the weak decay of charged kaons is used for an alternative measurement of the kaon transverse momentum (p(t)) spectra. Since these various particle identification tools give the best separation capabilities over different momentum ranges, the results are combined to extract spectra from p(t) = 100 MeV/c to 2.5 GeV/c. The measured spectra are further compared with QCD-inspired models which yield a poor description. The total yields and the mean pt are compared with previous measurements, and the trends as a function of collision energy are discussed.
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| 3. |
- Aamodt, K., et al.
(författare)
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Transverse momentum spectra of charged particles in proton-proton collisions at root s=900 GeV with ALICE at the LHC
- 2010
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Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 693:2, s. 53-68
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Tidskriftsartikel (refereegranskat)abstract
- The inclusive charged particle transverse momentum distribution is measured in proton-proton collisions at root s = 900 GeV at the LHC using the ALICE detector. The measurement is performed in the central pseudorapidity region (vertical bar eta vertical bar < 0.8) over the transverse momentum range 0.15 < p(T) < 10 GeV/c. The correlation between transverse momentum and particle multiplicity is also studied. Results are presented for inelastic (INEL) and non-single-diffractive (NSD) events. The average transverse momentum for vertical bar eta vertical bar < 0.8 is < p(T)>(INEL) = 0.483 +/- 0.001 (stat.) +/- 0.007 (syst.) GeV/c and < p(T)>(NSD) = 0.489 +/- 0.001 (stat.) +/- 0.007 (syst.) GeV/c, respectively. The data exhibit a slightly larger < p(T)> than measurements in wider pseudorapidity intervals. The results are compared to simulations with the Monte Carlo event generators PYTHIA and PHOJET. (C) 2010 Published by Elsevier B.V.
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| 4. |
- Aamodt, K., et al.
(författare)
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Two-pion Bose-Einstein correlations in pp collisions at root s=900 GeV
- 2010
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Ingår i: Physical Review D (Particles, Fields, Gravitation and Cosmology). - 1550-2368. ; 82:5
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Tidskriftsartikel (refereegranskat)abstract
- We report on the measurement of two-pion correlation functions from pp collisions at root s = 900 GeV performed by the ALICE experiment at the Large Hadron Collider. Our analysis shows an increase of the Hanbury Brown-Twiss radius with increasing event multiplicity, in line with other measurements done in particle- and nuclear collisions. Conversely, the strong decrease of the radius with increasing transverse momentum, as observed at the Relativistic Heavy Ion Collider and at Tevatron, is not manifest in our data.
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| 5. |
- Aamodt, K., et al.
(författare)
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Alignment of the ALICE Inner Tracking System with cosmic-ray tracks
- 2010
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Ingår i: Journal of Instrumentation. - 1748-0221. ; 5
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Konferensbidrag (refereegranskat)abstract
- ALICE (A Large Ion Collider Experiment) is the LHC (Large Hadron Collider) experiment devoted to investigating the strongly interacting matter created in nucleus-nucleus collisions at the LHC energies. The ALICE ITS, Inner Tracking System, consists of six cylindrical layers of silicon detectors with three different technologies; in the outward direction: two layers of pixel detectors, two layers each of drift, and strip detectors. The number of parameters to be determined in the spatial alignment of the 2198 sensor modules of the ITS is about 13,000. The target alignment precision is well below 10 mu m in some cases (pixels). The sources of alignment information include survey measurements, and the reconstructed tracks from cosmic rays and from proton-proton collisions. The main track-based alignment method uses the Millepede global approach. An iterative local method was developed and used as well. We present the results obtained for the ITS alignment using about 10(5) charged tracks from cosmic rays that have been collected during summer 2008, with the ALICE solenoidal magnet switched off.
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| 6. |
- Aamodt, K., et al.
(författare)
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Charged-particle multiplicity measurement in proton-proton collisions at root s=0.9 and 2.36 TeV with ALICE at LHC
- 2010
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Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 68:1-2, s. 89-108
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Tidskriftsartikel (refereegranskat)abstract
- Charged-particle production was studied in proton-proton collisions collected at the LHC with the ALICE detector at centre-of-mass energies 0.9 TeV and 2.36 TeV in the pseudorapidity range vertical bar eta vertical bar < 1.4. In the central region (vertical bar eta vertical bar < 0.5), at 0.9 TeV, we measure charged-particle pseudo-rapidity density dN(ch)/d eta = 3.02 +/- 0.01(stat.)(-0.05)(+0.08)(syst.) for inelastic interactions, and dN(ch)/d eta = 3.58 +/- 0.01 (stat.)(-0.12)(+0.12)(syst.) for non-single-diffractive interactions. At 2.36 TeV, we find dN(ch)/d eta = 3.77 +/- 0.01(stat.)(-0.12)(+0.25)(syst.) for inelastic, and dN(ch)/d eta = 4.43 +/- 0.01(stat.)(-0.12)(+0.17)(syst.) for non-single-diffractive collisions. The relative increase in charged-particle multiplicity from the lower to higher energy is 24.7% +/- 0.5%(stat.)(-2.8)(+5.7)%(syst.) for inelastic and 23.7% +/- 0.5%(stat.)(-1.1)(+4.6)%(syst.) for non-single-diffractive interactions. This increase is consistent with that reported by the CMS collaboration for non-single-diffractive events and larger than that found by a number of commonly used models. The multiplicity distribution was measured in different pseudorapidity intervals and studied in terms of KNO variables at both energies. The results are compared to proton-antiproton data and to model predictions.
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| 7. |
- Aamodt, K., et al.
(författare)
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Charged-particle multiplicity measurement in proton-proton collisions at root s=7 TeV with ALICE at LHC
- 2010
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Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 68:3-4, s. 345-354
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Tidskriftsartikel (refereegranskat)abstract
- The pseudorapidity density and multiplicity distribution of charged particles produced in proton-proton collisions at the LHC, at a centre-of-mass energy root s = 7 TeV, were measured in the central pseudorapidity region vertical bar eta vertical bar < 1. Comparisons are made with previous measurements at root s = 0.9 TeV and 2.36 TeV. At root s = 7 TeV, for events with at least one charged particle in |eta vertical bar| < 1, we obtain dN(ch)/d eta = 6.01 +/- 0.01(stat.)(-0.12)(+0.20) (syst.). This corresponds to an increase of 57.6%+/-0.4%(stat.)(-1.8%)(+3.6) (syst.) relative to collisions at 0.9 TeV, significantly higher than calculations from commonly used models. The multiplicity distribution at 7 TeV is described fairly well by the negative binomial distribution.
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| 8. |
- Aamodt, K., et al.
(författare)
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First proton-proton collisions at the LHC as observed with the ALICE detector: measurement of the charged-particle pseudorapidity density at root s=900 GeV
- 2010
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Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 65:1-2, s. 111-125
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Tidskriftsartikel (refereegranskat)abstract
- On 23rd November 2009, during the early commissioning of the CERN Large Hadron Collider (LHC), two counter-rotating proton bunches were circulated for the first time concurrently in the machine, at the LHC injection energy of 450 GeV per beam. Although the proton intensity was very low, with only one pilot bunch per beam, and no systematic attempt was made to optimize the collision optics, all LHC experiments reported a number of collision candidates. In the ALICE experiment, the collision region was centred very well in both the longitudinal and transverse directions and 284 events were recorded in coincidence with the two passing proton bunches. The events were immediately reconstructed and analyzed both online and offline. We have used these events to measure the pseudorapidity density of charged primary particles in the central region. In the range vertical bar eta vertical bar < 0.5, we obtain dN(ch)/d eta = 3.10 +/- 0.13(stat.) +/- 0.22(syst.) for all inelastic interactions, and dN(ch)/d eta = 3.51 +/- 0.15(stat.) +/- 0.25(syst.) for nonsingle diffractive interactions. These results are consistent with previous measurements in proton-antiproton interactions at the same centre-of-mass energy at the CERN Sp<(p)over bar>S collider. They also illustrate the excellent functioning and rapid progress of the LHC accelerator, and of both the hardware and software of the ALICE experiment, in this early start-up phase.
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| 9. |
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| 10. |
- Sun, Qiang, et al.
(författare)
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Varying High Levels of Faecal Carriage of Extended-Spectrum Beta-Lactamase Producing Enterobacteriaceae in Rural Villages in Shandong, China: Implications for Global Health
- 2014
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Ingår i: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 9:11, s. e113121-
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Tidskriftsartikel (refereegranskat)abstract
- Antibiotic resistance is considered a major threat to global health and is affected by many factors, of which antibiotic use is probably one of the more important. Other factors include hygiene, crowding and travel. The rapid resistance spread in Gram-negative bacteria, in particular extended-spectrum beta-lactamase (ESBL) producing Enterobacteriaceae (ESBL-E), is a global challenge, leading to increased mortality, morbidity and health systems costs worldwide. Knowledge about resistance in commensal flora is limited, including in China. Our aim was to establish the faecal carriage rates of ESBL-E and find its association with known and suspected risk factors in rural residents of all ages in three socio-economically different counties in the Shandong Province, China. Faecal samples and risk-factor information (questionnaire) were collected in 2012. ESBL-E carriage was screened using ChromID ESBL agar. Risk factors were analysed using standard statistical methods. Data from 1000 individuals from three counties and in total 18 villages showed a high and varying level of ESBL-E carriage. Overall, 42% were ESBL-E carriers. At county level the carriage rates were 49%, 45% and 31%, respectively, and when comparing individual villages (n = 18) the rate varied from 22% to 64%. The high level of ESBL-E carriage among rural residents in China is an indication of an exploding global challenge in the years to come as resistance spreads among bacteria and travels around the world with the movement of people and freight. A high carriage rate of ESBL-E increases the risk of infection with multi-resistant bacteria, and thus the need for usage of last resort antibiotics, such as carbapenems and colistin, in the treatment of common infections.
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| 11. |
- Östholm Balkhed, Åse, et al.
(författare)
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Prevalence of extended-spectrum beta-lactamase-producing Enterobacteriaceae and trends in antibiotic consumption in a county of Sweden
- 2010
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Ingår i: Scandinavian Journal of Infectious Diseases. - : Informa Healthcare. - 0036-5548 .- 1651-1980. ; 42:11-12, s. 831-838
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Tidskriftsartikel (refereegranskat)abstract
- In the last decade extended-spectrum beta-lactamase (ESBL)-producing bacteria have become an increasing problem. Our aims were to investigate the prevalence of ESBL-producing Enterobacteriaceae and trends in antibiotic use in the county of Ostergotland, Sweden. From 2002 through 2007 there were 224 ESBL-producing Escherichia coli and 23 Klebsiella pneumoniae isolates with an ESBL-phenotype identified among all Enterobacteriaceae isolated at the clinical laboratory. Trends in antibiotic consumption expressed as defined daily doses (DDD) per 1000 inhabitants and day (DID) were studied. The prevalence of ESBL-producing isolates among Enterobacteriaceae in our region is still low (andlt; 1%). Patients with ESBL-producing E. coli increased significantly (p andlt; 0.001) from 5 in y 2002 to 47 in y 2007. CTX-M group 1 was the dominant enzyme group in both E. coli and K. pneumoniae. Antibiotic susceptibility testing of ciprofloxacin, gentamicin and trimethoprim-sulfamethoxazole revealed that 58% of E. coli and 50% of K. pneumoniae isolates were multi-resistant. Antibiotic use remained unchanged from 2001 through 2009, but there was a trend towards increased use of drugs with low ESBL selection potential, which was probably due to the increased prevalence of ESBL producers.
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| 12. |
- Östholm Balkhed, Åse, et al.
(författare)
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Travel-associated faecal colonization with ESBL-producing Enterobacteriaceae : incidence and risk factors
- 2013
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Ingår i: Journal of Antimicrobial Chemotherapy. - : Oxford University Press. - 0305-7453 .- 1460-2091. ; 68:9, s. 2144-2153
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Tidskriftsartikel (refereegranskat)abstract
- Objectives To study the acquisition of extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-PE) among the faecal flora during travel, with a focus on risk factors, antibiotic susceptibility and ESBL-encoding genes.Methods An observational prospective multicentre cohort study of individuals attending vaccination clinics in south-east Sweden was performed, in which the submission of faecal samples and questionnaires before and after travelling outside Scandinavia was requested. Faecal samples were screened for ESBL-PE by culturing on ChromID ESBL and an in-house method. ESBL-PE was confirmed by phenotypic and genotypic methods. Susceptibility testing was performed with the Etest. Individuals who acquired ESBL-PE during travel (travel-associated carriers) were compared with non-carriers regarding risk factors, and unadjusted and adjusted ORs after manual stepwise elimination were calculated using logistic regression.Results Of 262 enrolled individuals, 2.4% were colonized before travel. Among 226 evaluable participants, ESBL-PE was detected in the post-travel samples from 68 (30%) travellers. The most important risk factor in the final model was the geographic area visited: Indian subcontinent (OR 24.8, P < 0.001), Asia (OR 8.63, P < 0.001) and Africa north of the equator (OR 4.94, P = 0.002). Age and gastrointestinal symptoms also affected the risk significantly. Multiresistance was seen in 77 (66%) of the ESBL-PE isolates, predominantly a combination of reduced susceptibility to third-generation cephalosporins, trimethoprim/sulfamethoxazole and aminoglycosides. The most common species and ESBL-encoding gene were Escherichia coli (90%) and CTX-M (73%), respectively.Conclusion Acquisition of multiresistant ESBL-PE among the faecal flora during international travel is common. The geographical area visited has the highest impact on ESBL-PE acquisition.
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| 13. |
- Alm, Henrik, et al.
(författare)
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In Vitro Neurotoxicity of PBDE-99 : Immediate and Concentration-Dependent Effects on Protein Expression in Cerebral Cortex Cells
- 2010
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Ingår i: Journal of Proteome Research. - : American Chemical Society (ACS). - 1535-3893 .- 1535-3907. ; 9:3, s. 1226-1235
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Tidskriftsartikel (refereegranskat)abstract
- Polybrominated diphenyl ethers (PBDEs) are commonly used flame retardants in various consumer products. Pre- and postnatal exposure to congeners of PBDEs disrupts normal brain development in rodents. Two-dimensional difference gel electrophoresis (2D-DIGE) was used to analyze concentration-dependent differences in protein expression in cultured cortical cells isolated from rat fetuses (GD 21) after 24 h exposure to PBDE-99 (3, 10, or 30 muM). Changes on a post-translational level were studied using a 1 h exposure to 30 muM PBDE-99. The effects of 24 h exposure to 3 and 30 muM PBDE-99 on mRNA levels were measured using oligonucleotide microarrays. A total of 62, 46, and 443 proteins were differentially expressed compared to controls after 24 h of exposure to 3, 10, and 30 muM PDBE-99, respectively. Of these, 48, 43, and 238 proteins were successfully identified, respectively. We propose that the biological effects of low-concentration PBDE-99 exposure are fundamentally different than effects of high-concentration exposure. Low-dose PBDE-99 exposure induced marked effects on cytoskeletal proteins, which was not correlated to cytotoxicity or major morphological effects, suggesting that other more regulatory aspects of cytoskeletal functions may be affected. Interestingly, 0.3 and 3 muM, but not 10 or 30 muM increased the expression of phosphorylated (active) Gap43, perhaps reflecting effects on neurite extension processes.
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| 14. |
- Bergström, Ulf, et al.
(författare)
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Effects of adalimumab treatment on endothelial cell activation markers in the skeletal muscle of patients with rheumatoid arthritis.
- 2014
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Ingår i: Clinical and Experimental Rheumatology. - 1593-098X .- 0392-856X. ; 32:6, s. 883-890
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Tidskriftsartikel (refereegranskat)abstract
- Patients with rheumatoid arthritis (RA), particularly those with severe disease, have increased risk of cardiovascular disease (CVD). Previous studies suggest that endothelial cell activation may contribute to this co-morbidity, and that treatment with tumour necrosis factor (TNF) inhibitors could reduce the risk of CVD in these patients. The aim of this study was to investigate endothelial cell activation markers in muscle tissue of patients after adalimumab treatment.
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| 15. |
- Buttazzoni, Christian, et al.
(författare)
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Does a childhood fracture predict low bone mass in young adulthood? - A 27-year prospective controlled study.
- 2013
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Ingår i: Journal of Bone and Mineral Research. - : Wiley. - 1523-4681 .- 0884-0431. ; 28:2, s. 351-359
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: A fracture in childhood is associated with low bone mineral density (BMD), but it is debated whether a fracture at growth also predicts low BMD in young adulthood. PURPOSE: To gender-specifically evaluate whether children with a fracture are at increased risk of low BMD in young adulthood. METHODS: Distal forearm BMD (g/cm(2) ) was measured with single photon absorptiometry (SPA) in 47 boys and 26 girls (mean age 10 years, range 3-16) with an index fracture and in 41 boys and 43 girls (mean age 10 years, range 4-16) with no fracture. BMD was re-measured mean 27 years later with the same SPA apparatus and with dual energy absorptiometry (DXA), quantitative ultrasound (QUS) and peripheral computed tomography (pQCT). Individual Z-scores were calculated using the control cohort as reference population. Data are presented as means with 95% confidence intervals (95% CI) within brackets and correlation with Pearson's correlation coefficient RESULTS: Boys with an index fracture had at fracture event a distal forearm BMD Z-score of -0.4 (-0.7, -0.1) and at follow-up -0.4 (-0.7, -0.1). Corresponding values in girls were -0.2 (-0.5, 0.1) and -0.3 (-0.7, 0.1). The deficit in absolute bone mass was driven by men with index fractures in childhood due to low rather than moderate or high energy. There were no changes in BMD Z-score during the follow-up period. The BMD deficit at follow-up was in boys with an index fracture verified with all advocated techniques CONCLUSIONS: A childhood fracture in men was associated with low BMD and smaller bone size in young adulthood while the deficit in women did not reach statistical significance. © 2012 American Society for Bone and Mineral Research.
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| 16. |
- Hanberger, Håkan, et al.
(författare)
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Rational use of aminoglycosides-Review and recommendations by the Swedish Reference Group for Antibiotics (SRGA)
- 2013
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Ingår i: Scandinavian journal of infectious diseases. - : Informa UK Limited. - 1651-1980 .- 0036-5548. ; 45:3, s. 161-175
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Forskningsöversikt (refereegranskat)abstract
- The Swedish Reference Group for Antibiotics (SRGA) has carried out a risk-benefit analysis of aminoglycoside treatment based on clinical efficacy, antibacterial spectrum, and synergistic effect with beta-lactam antibiotics, endotoxin release, toxicity, and side effects. In addition, SRGA has considered optimal dosage schedules and advice on serum concentration monitoring, with respect to variability in volume of drug distribution and renal clearance. SRGA recommends that aminoglycoside therapy should be considered in the following situations: (1) progressive severe sepsis and septic shock, in combination with broad-spectrum beta-lactam antibiotics, (2) sepsis without shock, in combination with broad-spectrum beta-lactam antibiotics if the infection is suspected to be caused by multi-resistant Gram-negative pathogens, (3) pyelonephritis, in combination with a beta-lactam or quinolone until culture and susceptibility results are obtained, or as monotherapy if a serious allergy to beta-lactam or quinolone antibiotics exists, (4) serious infections caused by multi-resistant Gram-negative bacteria when other alternatives are lacking, and (5) endocarditis caused by difficult-to-treat pathogens when monotherapy with beta-lactam antibiotics is not sufficient. Amikacin is generally more active against extended-spectrum beta-lactamase (ESBL)-producing and quinolone-resistant Escherichia coli than other aminoglycosides, making it a better option in cases of suspected infection caused by multidrug-resistant Enterobacteriaceae. Based on their resistance data, local drug committees should decide on the choice of first-line aminoglycoside. Unfortunately, aminoglycoside use is rarely followed up with audiometry, and in Sweden we currently have no systematic surveillance of adverse events after aminoglycoside treatment. We recommend routine assessment of adverse effects, including hearing loss and impairment of renal function, if possible at the start and after treatment with aminoglycosides, and that these data should be included in hospital patient safety surveillance and national quality registries.
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| 17. |
- Lindqvist, Maria, 1983-
(författare)
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Epidemiological and molecular biological studies of multi-resistant methicillin-susceptible Staphylococcus aureus
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Antibiotic resistance is increasingly recognised as a major problem and threat. During the last decades Gram-positive bacteria in general, and methicillin-resistant Staphylococcus aureus (MRSA) in particular, have been in focus both concerning matters of antibiotic resistance and as pathogens causing health care-associated (nosocomial) infections. In contrast to MRSA, studies on clonal distribution of methicillin-susceptible S. aureus (MSSA) are scarce. However, interest in MSSA has increased since it was shown that MRSA emerges from susceptible backgrounds by acquisition of a staphylococcal cassette chromosome element, carrying the mecA gene encoding methicillin-resistance (SCCmec).In an outbreak investigation of MRSA in Östergötland County, Sweden, in 2005, a high incidence of MSSA isolates with concomitant resistance to erythromycin, clindamycin and tobramycin (ECT-R) was detected. Analysis showed that 91 % of the investigated isolates were genetically related (clonal). The ECT-R clone was divided into four different but closely related patterns with pulsed-field gel electrophoresis (PFGE), and was designated spa type t002. Whole genome sequencing revealed that the ECT-R clone carried a pseudo-SCC element estimated to be 12 kb in size, showing a resemblance of more than 99 % with the SCCmec type II element of MRSA strain N315 (New York/Japan clone). This suggested a probable derivation from a highly successful MRSA strain, which had partially excised its SCCmec. The clonal outbreak was concentrated in eight hospital departments and two primary care centres, all located in the city of Linköping. Despite a high exchange of patients with the hospitals in the neighbouring counties in southeast Sweden (Jönköping- and Kalmar County), the ECT-R clone seemed to be limited to Östergötland County. However, a tobramycin-resistant clone predominated by isolates of spa type t084 was found in all three counties in southeast Sweden, and in particular among newborns, suggesting inter-hospital transmission.The ECT-R clone has survived as an abundant MSSA clone for a decade in Östergötland County, which indicates an insufficiency in the maintenance of basic hygiene guidelines, and that the clone probably possesses mechanisms of virulence and transmission that are yet to be discovered.
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| 18. |
- Nilsson, Lennart E, et al.
(författare)
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Comparative activity of tigecycline and tetracycline on Gram-negative and Gram-positive bacteria revealed by a multicentre study in four North European countries
- 2011
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Ingår i: Scandinavian Journal of Infectious Diseases. - : Informa Healthcare. - 0036-5548 .- 1651-1980. ; 43:9, s. 707-713
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Tidskriftsartikel (refereegranskat)abstract
- Background: This study involves a multicentre surveillance of tigecycline and tetracycline activity against Gram-negative and Gram-positive bacteria from primary care centres (PCCs), general hospital wards (GHWs) and intensive care units (ICUs) in Denmark (n = 9), Finland (n = 10), Norway (n = 7) and Sweden (n = 19). Methods: The hospitals were each asked to test 30 consecutive Gram-positive and 30 Gram-negative clinical isolates. Supportive information accompanying each isolate included the study centre, ward level (PCC, GHW, or ICU), patient identification and source of the isolate. Minimum inhibitory concentrations (MICs) for tetracycline and tigecycline were determined with the Etest. Results: The isolates collected comprised 1610 Gram-negative and 1767 Gram-positive clinical isolates. The study showed low rates of non-susceptibility (intermediate (I) and resistant (R)) to tigecycline: andlt; 1% in Escherichia coli, though other Enterobacteriaceae showed higher rates (Enterobacter cloacae (7%), Klebsiella pneumoniae (9%) and Serratia spp. (23%)). The overall non-susceptibility rate for tigecycline in Enterobacteriaceae with species-related breakpoints for tigecycline was 6% (4% excluding Serratia spp.). The activity of tigecycline against Haemophilus influenzae and Acinetobacter spp. was high with a MIC(50) of 0.25 mg/l and MIC(90) of 1 mg/l. The prevalence of non-susceptibility to tigecycline among Gram-positive bacteria was andlt; 1%. The corresponding figure for tetracycline was 14%. The activity of tigecycline against Streptococcus pneumoniae was high with MIC(50) and MIC(90) of 0.125 mg/l. Conclusion: Tigecycline showed good overall in vitro activity against Gram-positive and Gram-negative isolates, including both tetracycline-susceptible and resistant isolates. Most non-susceptibility to tigecycline among Enterobacteriaceae other than E. coli was I (6%), rather than R (andlt; 1%). This indicates a problem setting interpretive species-related tigecycline breakpoints for Enterobacteriaceae other than E. coli.
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| 19. |
- Samuelsson, Annika, 1964-, et al.
(författare)
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Changes in the aerobic faecal flora of patients treated with antibiotics for acute intra-abdominal infection
- 2012
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Ingår i: Scandinavian Journal of Infectious Diseases. - : Informa UK Limited. - 0036-5548 .- 1651-1980. ; 44:11, s. 820-827
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Tidskriftsartikel (refereegranskat)abstract
- Background: An open observational study was performed to investigate changes in the rectal flora and antibiotic susceptibility among faecal bacteria in patients treated with antibiotics for acute intra-abdominal infection. Methods: One hundred and forty patients with acute intra-abdominal infection requiring antibiotic treatment and hospitalization were included. Eight surgical units from the southern part of Sweden participated, between January 2006 and November 2007. Antibiotic treatments were according to local guidelines. Rectal swabs were obtained on admission (sample 1) and 214 days after the end of antibiotic treatment (sample 2). Aerobic bacteria and yeasts were analysed. The material was divided into 2 groups: 1 group with Enterobacteriaceae and 1 group with non-fermentative Gram-negative bacteria. The susceptibility to antibiotics in each group was compared between samples 1 and 2. Results: The main finding of this study on patients with severe intra-abdominal infections was a shift in the aerobic faecal flora following antibiotic treatment, from Escherichia coli to other more resistant Enterobacteriaceae, Enterococcus faecium, and yeasts. The susceptibility to cephalosporins and piperacillintazobactam decreased in Enterobacteriaceae. Conclusions: Following antibiotic treatment, a shift in the aerobic rectal flora to species with intrinsic antibiotic resistance was observed. This indicates that the emergence of resistance is not due to new mutations, but rather to selection of more resistant species. This should be taken into account when designing treatments for secondary intra-abdominal infections.
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| 20. |
- Scholz, Birger, et al.
(författare)
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Neuropeptidomic analysis of the embryonic Japanese quail diencephalon
- 2010
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Ingår i: BMC Developmental Biology. - 1471-213X. ; 10, s. 30-
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Tidskriftsartikel (refereegranskat)abstract
- Background: Endogenous peptides such as neuropeptides are involved in numerous biological processes in the fully developed brain but very little is known about their role in brain development. Japanese quail is a commonly used bird model for studying sexual dimorphic brain development, especially adult male copulatory behavior in relation to manipulations of the embryonic endocrine system. This study uses a label-free liquid chromatography mass spectrometry approach to analyze the influence of age (embryonic days 12 vs 17), sex and embryonic day 3 ethinylestradiol exposure on the expression of multiple endogenous peptides in the developing diencephalon.Results: We identified a total of 65 peptides whereof 38 were sufficiently present in all groups for statistical analysis. Age was the most defining variable in the data and sex had the least impact. Most identified peptides were more highly expressed in embryonic day 17. The top candidates for EE2 exposure and sex effects were neuropeptide K (downregulated by EE2 in males and females), gastrin-releasing peptide (more highly expressed in control and EE2 exposed males) and gonadotropin-inhibiting hormone related protein 2 (more highly expressed in control males and displaying interaction effects between age and sex). We also report a new potential secretogranin-2 derived neuropeptide and previously unknown phosphorylations in the C-terminal flanking protachykinin 1 neuropeptide.Conclusions: This study is the first larger study on endogenous peptides in the developing brain and implies a previously unknown role for a number of neuropeptides in middle to late avian embryogenesis. It demonstrates the power of label-free liquid chromatography mass spectrometry to analyze the expression of multiple endogenous peptides and the potential to detect new putative peptide candidates in a developmental model.
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| 21. |
- Tärnberg, Maria, et al.
(författare)
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In vitro activity of beta-lactam antibiotics against CTX-M-producing Escherichia coli
- 2011
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Ingår i: European Journal of Clinical Microbiology and Infectious Diseases. - : Springer Science Business Media. - 0934-9723 .- 1435-4373. ; 30:8, s. 981-987
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Tidskriftsartikel (refereegranskat)abstract
- Beta-lactam antibiotics have been discussed as options for the treatment of infections caused by multiresistant extended-spectrum beta-lactamase (ESBL)-producing bacteria if the minimum inhibitory concentration (MIC) is low. The objective of this study was to investigate the in vitro activity of different beta-lactam antibiotics against CTX-M-producing Escherichia coli. A total of 198 isolates of E. coli with the ESBL phenotype were studied. Polymerase chain reaction (PCR) amplification of CTX-M genes and amplicon sequencing were performed. The MICs for amoxicillin-clavulanic acid, aztreonam, cefepime, cefotaxime, ceftazidime, ceftibuten, ertapenem, imipenem, mecillinam, meropenem, piperacillin-tazobactam, and temocillin were determined with the Etest. Susceptibility was defined according to the breakpoints of the European Committee on Antimicrobial Susceptibility Testing (EUCAST). MIC(50) and MIC(90) values were calculated. Isolates from CTX-M group 9 showed higher susceptibility to the beta-lactam antibiotics tested than isolates belonging to CTX-M group 1. More than 90% of the isolates belonging to CTX-M group 9 were susceptible to amoxicillin-clavulanic acid, ceftazidime, ceftibuten, piperacillin-tazobactam, and temocillin. The susceptibility was high to mecillinam, being 91%, regardless of the CTX-M group. All isolates were susceptible to imipenem and meropenem, and 99% to ertapenem. This study shows significant differences in susceptibility to different beta-lactam antibiotics among the CTX-M-producing E. coli isolates and a significant difference for many antibiotics tested between the CTX-M-producing groups 1 and 9. The good in vitro activity of other beta-lactam antibiotics compared to carbapenems indicate that clinical studies are warranted in order to examine the potential role of these beta-lactam antibiotics in the treatment of infections caused by multiresistant ESBL-producing E. coli.
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| 22. |
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| 23. |
- Woksepp, Hanna, et al.
(författare)
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Evaluation of High-Resolution Melting Curve Analysis of Ligation-Mediated Real-Time PCR, a Rapid Method for Epidemiological Typing of ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter Species) Pathogens
- 2014
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Ingår i: Journal of Clinical Microbiology. - : American Society for Microbiology. - 0095-1137 .- 1098-660X. ; 52:12, s. 4339-4342
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Tidskriftsartikel (refereegranskat)abstract
- A single-tube method, ligation-mediated real-time PCR high-resolution melt analysis (LMqPCR HRMA), was modified for the rapid typing of Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp. (ESKAPE) pathogens. A 97% agreement (60/62 isolates) was achieved in comparison to pulsed-field gel electrophoresis (PFGE) results, which indicates that LMqPCR HRMA is a rapid and accurate screening tool for monitoring nosocomial outbreaks.
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| 24. |
- Woksepp, Hanna, et al.
(författare)
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High-Resolution Melting-Curve Analysis of Ligation-Mediated Real-Time PCR for Rapid Evaluation of an Epidemiological Outbreak of Extended-Spectrum-Beta-Lactamase-Producing Escherichia coli
- 2011
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Ingår i: Journal of Clinical Microbiology. - : American Society for Microbiology. - 0095-1137 .- 1098-660X. ; 49:12, s. 4032-4039
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Tidskriftsartikel (refereegranskat)abstract
- Methods for the confirmation of nosocomial outbreaks of bacterial pathogens are complex, expensive, and time-consuming. Recently, a method based on ligation-mediated PCR (LM/PCR) using a low denaturation temperature which produces specific melting-profile patterns of DNA products has been described. Our objective was to further develop this method for real-time PCR and high-resolution melting analysis (HRM) in a single-tube system optimized in order to achieve results within 1 day. Following the optimization of LM/PCR for real-time PCR and HRM (LM/HRM), the method was applied for a nosocomial outbreak of extended-spectrum-beta-lactamase (ESBL)-producing and ST131-associated Escherichia coli isolates (n = 15) and control isolates (n = 29), including four previous clusters. The results from LM/HRM were compared to results from pulsed-field gel electrophoresis (PFGE), which served as the gold standard. All isolates from the nosocomial outbreak clustered by LM/HRM, which was confirmed by gel electrophoresis of the LM/PCR products and PFGE. Control isolates that clustered by LM/PCR (n = 4) but not by PFGE were resolved by confirmatory gel electrophoresis. We conclude that LM/HRM is a rapid method for the detection of nosocomial outbreaks of bacterial infections caused by ESBL-producing E. coli strains. It allows the analysis of isolates in a single-tube system within a day, and the discriminatory power is comparable to that of PFGE.
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| 25. |
- Östholm Balkhed, Åse, et al.
(författare)
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High frequency of co-resistance in CTX-M-producing Escherichia coli to non-beta-lactam antibiotics, with the exception of amikacin, nitrofurantoin, colistin, tigecycline, and fosfomycin, in a county of Sweden
- 2013
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Ingår i: Scandinavian Journal of Infectious Diseases. - : Informa UK Limited. - 0036-5548 .- 1651-1980. ; 45:4, s. 271-278
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Tidskriftsartikel (refereegranskat)abstract
- Background: The objective of this study was to investigate the in vitro activity of different antibiotics against CTX-M-producing Escherichia coli in a county of Sweden, and to determine the occurrence of multi-resistance and plasmid- mediated quinolone resistance among these isolates. Methods: A total of 198 isolates of E. coli with extended-spectrum beta-lactamase (ESBL) phenotype and mainly CTX-M genotype were studied. The minimum inhibitory concentrations (MICs) for amikacin, chloramphenicol, ciprofloxacin, colistin, fosfomycin, gentamicin, nalidixic acid, nitrofurantoin, tigecycline, tobramycin, trimethoprim, and trimethoprim-sulfamethoxazole were determined with the Etest. Susceptibility was defined according to the breakpoints of the European Committee on Antimicrobial Susceptibility Testing (EUCAST). MIC(50) and MIC(90) values were calculated. Results: Ninety-five percent or more of the isolates were susceptible to amikacin, nitrofurantoin, colistin, tigecycline, and fosfomycin. CTX-M group 9 was more susceptible than CTX-M group 1 to ciprofloxacin, gentamicin, and tobramycin. Sixty-eight percent of the isolates were multi-resistant, and the most common multi-resistance pattern was ESBL phenotype with decreased susceptibility to trimethoprim, trimethoprim-sulfamethoxazole, ciprofloxacin, gentamicin, and tobramycin. Only 1 isolate carried a qnrS1 gene, but 37% carried aac(6')-Ib-cr. Conclusions: A high frequency of co-resistance between ESBL-producing E. coli and non-beta-lactam antibiotics was seen. On the other hand, very high susceptibility was seen for amikacin, nitrofurantoin, colistin, tigecycline, and fosfomycin. These data support the replacement of gentamicin and tobramycin, normally used in Sweden, with amikacin, for severe infections.
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