| 1. |
- Andersson, Håkan S., 1967-, et al.
(författare)
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The toxicity of ribbon worms: alpha-nemertides or tetrodotoxin, or both?
- 2016
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Ingår i: Planta Medica. - : Georg Thieme Verlag KG. - 0032-0943 .- 1439-0221. ; 82:Supplement 1
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The marine ribbon worms (nemerteans) are predators which capture their prey by everting a proboscis carrying a mixture of toxins which brings on rapid paralysis [1]. Moreover, ribbon worms have a thick layer of epidermal mucus of similar constitution. Tetrodotoxin (TTX) has been identified as one of these toxins [2]. The extreme toxicity of TTX (lethal by ingestion of 0.5-2 mg) is due to its ability to block voltage-gated sodium channels. Although several bacterial species (among these Vibrio sp.) have been linked to its synthesis, the biogenic origin and biosynthesis is unclear. One hypothesis is that TTX production occurs in a symbiotic relationship with its host, in this case the ribbon worm [3]. We have made significant effort to identify TTX in a setup for production through the cultivation of Vibrio alginolyticus in nutrient broth infused with mucus from the ribbon worm Lineus longissimus. Toxicity was demonstrated by fraction injections into shore crabs, but no TTX was found, and it could be shown conclusively that toxicity was unrelated to TTX and the Vibrio culture itself, and rather a constituent of the ribbon worm mucus [4]. The following studies led us to the discovery of a new class of peptides, the alpha-nemertides, in the mucus of the ribbon worms, which could be directly linked to the toxic effects. A literature review of the available evidence for TTX in ribbon worms show that the evidence in most cases are indirect, although notable exceptions exist. This points to the necessity to further investigate the presence and roles of TTX and alpha-nemertides in ribbon worms.
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| 2. |
- Bengtsson, Sara K. S., et al.
(författare)
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Isoallopregnanolone antagonize allopregnanolone-induced effects on saccadic eye velocity and self-reported sedation in humans
- 2015
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Ingår i: Psychoneuroendocrinology. - : Elsevier BV. - 0306-4530 .- 1873-3360. ; 52, s. 22-31
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Tidskriftsartikel (refereegranskat)abstract
- Allopregnanolone (AP) is an endogenous neurosteroid. It modulates the effect of gamma-amino-butyric acid (GABA) on the GABA type A (GABA(A)) receptor, which leads to increased receptor activity. Since the GABA-system is mainly inhibitory, increased AP activity leads to modulation of neuronal activity. In vitro studies of GABA(A) receptor activity and in vivo animal studies of sedation have shown that AP-induced effects can be inhibited by another endogenous steroid, namely isoallopregnanolone (ISO). In this study we investigated if ISO can antagonize AP-induced effects in healthy female volunteers, via measurements of saccadic eye velocity (SEV) and self-rated sedation. With a single-blind cross-over design, 12 women were studied on three separate occasions; given AP alone or AP in combination with one of two ISO doses. Congruent with previous reports, AP administration decreased SEV and induced sedation and these effects were diminished by simultaneous ISO administration. Also, the ISO effect modulation was seemingly stronger for SEV than for sedation. These effects were observed already at an ISO dose exposure that was approximately half of that of AP. In conclusion, ISO antagonized AP-induced decrease in SEV and self-reported sedation, probably in a non-competitive manner.
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| 3. |
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| 4. |
- Hedström, A. K., et al.
(författare)
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Shift work influences multiple sclerosis risk
- 2015
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Ingår i: Multiple Sclerosis Journal. - : SAGE Publications. - 1352-4585 .- 1477-0970. ; 21:9, s. 1195-1199
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Tidskriftsartikel (refereegranskat)abstract
- Background:An association between working shift at a young age and subsequent risk for multiple sclerosis (MS) has been observed.Objective:To investigate whether this finding could be replicated, and to further explore the influence of age at first exposure to shift work.Methods:Using a Swedish population-based, case-control study (2337 cases and 4904 controls), the incidence of MS among subjects whom had worked shifts was compared with that of those whom had not, by calculating odds ratios (ORs) with 95% confidence intervals (CIs) by means of logistic regression.Results:The OR of developing MS was 1.5 (95% CI 1.2–1.8) among those whom started working shifts before age 20, whereas a less pronounced association was observed among those whom started working shifts at age 20 or later (OR 1.2; 95% CI 1.1–1.4). The effect of shift work was more pronounced among subjects whom had been exposed at a young age, regardless of the duration between the start of shift work and disease onset.Conclusion:Some aspects of adolescence seem to be of great importance, regarding the impact of shift work on MS risk. Circadian disruption and sleep deprivation may contribute towards explaining the association; however, the exact mechanisms behind our observations remain to be elucidated.
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| 5. |
- Mattiasson, B., et al.
(författare)
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Nanoenvironmental Effects Dramatically Influence the Sensitivity of Immunoassays
- 2017
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Ingår i: Trends in Biotechnology. - : Elsevier BV. - 0167-7799. ; 35:11, s. 1021-1024
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Tidskriftsartikel (refereegranskat)abstract
- It is possible to improve the sensitivity of immunoassays by several orders of magnitude by exploiting nanoenvironmental effects. This approach can detect trace amounts of compounds and will better illuminate the presence of signal substances in biological systems. Here we describe a method for ultrasensitive immunoassays using 'normal' antibodies (Abs).
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| 6. |
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| 7. |
- Ramanujam, Ryan, et al.
(författare)
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Effect of smoking cessation on multiple sclerosis prognosis
- 2015
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Ingår i: JAMA Neurology. - : American Medical Association. - 2168-6149 .- 2168-6157. ; 21, s. 164-164
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Tidskriftsartikel (refereegranskat)abstract
- IMPORTANCE: Smoking tobacco is a well-established risk factor for multiple sclerosis (MS), a chronic inflammatory disorder of the central nervous system usually characterized by bouts and remissions and typically followed by a secondary progressive (SP) course. However, it is not clear whether smoking after diagnosis is detrimental. OBJECTIVE: To determine whether smoking after MS diagnosis is associated with a change in time to SP disease. DESIGN, SETTING, AND PARTICIPANTS: Cross-sectional study of patients with prevalent MS who smoked at diagnosis (n = 728) taken from the Genes and Environment in Multiple Sclerosis Study, which consists of patients from the Swedish National MS Registry. The study entrance date was at time of first-year smoking. The study was conducted between November 2008 and December 2011, with patient environmental data collected from November 2009 to March 2011 via questionnaire. Study participants were from all counties in Sweden diagnosed as havingMS at the time of the Genes and Environment in Multiple Sclerosis Study and registered in the Swedish National MS Registry. Patients with MS with relapsing-remitting disease course or SP were included. These patients' conditions were diagnosed according to the McDonald criteria and the patients responded to recruitment letters with detailed questionnaires. EXPOSURE: Smoking, considered yearly after diagnosis and combined into a time-invariant covariate before diagnosis. MAINOUTCOMES ANDMEASURES: Time to SPMS, measured using an accelerated failure time model, with smoking as a time-varying covariate. Other covariates included sex, age at diagnosis, snuff use, and smoking before diagnosis. RESULTS: The optimized model illustrated that each additional year of smoking after diagnosis accelerated the time to conversion to SPMS by 4.7% (acceleration factor, 1.047; 95% CI, 1.023-1.072; P <.001). Kaplan-Meier plots demonstrated that those who continued to smoke continuously each year after diagnosis converted to SPMS faster than those who quit smoking, reaching SP disease at 48 and 56 years of age, respectively. CONCLUSIONS AND RELEVANCE: This study provides evidence that continued smoking is associated with an acceleration in time to SPMS and that those who quit fare better. Therefore, wepropose that patients withMS should be advised to stop smoking once a diagnosis has been made, not only to lessen risks for comorbidities, but also to avoid aggravating MS-related disability.
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| 8. |
- Ryd, Daniel, et al.
(författare)
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Quantification of blood flow in the fetus with cardiovascular magnetic resonance imaging using Doppler ultrasound gating : validation against metric optimized gating
- 2019
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Ingår i: Journal of cardiovascular magnetic resonance : official journal of the Society for Cardiovascular Magnetic Resonance. - : Springer Science and Business Media LLC. - 1097-6647. ; 21
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: Fetal cardiovascular magnetic resonance (CMR) imaging is used clinically and for research, but has been previously limited due to lack of direct gating methods. A CMR-compatible Doppler ultrasound (DUS) gating device has resolved this. However, the DUS-gating method is not validated against the current reference method for fetal phase-contrast blood flow measurements, metric optimized gating (MOG). Further, we investigated how different methods for vessel delineation affect flow volumes and observer variability in fetal flow acquisitions.AIMS: To 1) validate DUS gating versus MOG for quantifying fetal blood flow; 2) assess repeatability of DUS gating; 3) assess impact of region of interest (ROI) size on flow volume; and 4) compare time-resolved and static delineations for flow volume and observer variability.METHODS: Phase-contrast CMR was acquired in the fetal descending aorta (DAo) and umbilical vein by DUS gating and MOG in 22 women with singleton pregnancy in gestational week 360 (265-400) with repeated scans in six fetuses. Impact of ROI size on measured flow was assessed for ROI:s 50-150% of the vessel diameter. Four observers from two centers provided time-resolved and static delineations. Bland-Altman analysis was used to determine agreement between both observers and methods.RESULTS: DAo flow was 726 (348-1130) ml/min and umbilical vein flow 366 (150-782) ml/min by DUS gating. Bias±SD for DUS-gating versus MOG were - 45 ± 122 ml/min (-6 ± 15%) for DAo and 19 ± 136 ml/min (2 ± 24%) for umbilical vein flow. Repeated flow measurements in the same fetus showed similar volumes (median CoV = 11% (DAo) and 23% (umbilical vein)). Region of interest 50-150% of vessel diameter yielded flow 35-120%. Bias±SD for time-resolved versus static DUS-gated flow was 33 ± 39 ml/min (4 ± 6%) for DAo and 11 ± 84 ml/min (2 ± 15%) for umbilical vein flow.CONCLUSIONS: Quantification of blood flow in the fetal DAo and umbilical vein using DUS-gated phase-contrast CMR is feasible and agrees with the current reference method. Repeatability was generally high for CMR fetal blood flow assessment. An ROI similar to the vessel area or slightly larger is recommended. A static ROI is sufficient for fetal flow quantification using currently available CMR sequences.
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| 9. |
- Sandberg, Camilla, et al.
(författare)
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Home-based interval training increases endurance capacity in adults with complex congenital heart disease
- 2018
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Ingår i: Congenital Heart Disease. - : Computers, Materials and Continua (Tech Science Press). - 1747-079X .- 1747-0803. ; 13:2, s. 254-262
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Tidskriftsartikel (refereegranskat)abstract
- ObjectiveThe beneficial effects of exercise training in acquired heart failure and coronary artery disease are well known and have been implemented in current treatment guidelines. Knowledge on appropriate exercise training regimes for adults with congenital heart disease is limited, thus further studies are needed. The aim of this study was to examine the effect of home-based interval exercise training on maximal endurance capacity and peak exercise capacity. MethodsTwenty-six adults with complex congenital heart disease were recruited from specialized units for adult congenital heart disease. Patients were randomized to either an intervention group12 weeks of home-based interval exercise training on a cycle ergometer (n=16), or a control group (n=10). The latter was instructed to maintain their habitual physical activities. An incremental cardiopulmonary exercise test and a constant work rate cardiopulmonary exercise test at 75% of peak workload were performed preintervention and postintervention. ResultsTwenty-three patients completed the protocol and were followed (intervention n=13, control n=10). Postintervention exercise time at constant work rate cardiopulmonary exercise test increased in the intervention group compared to controls (median[range] 12[-4 to 52]min vs 0[-4 to 5]min, P=.001). At incremental cardiopulmonary exercise test, peak VO2 increased 15% within the intervention group (P=.019) compared to 2% within the control group (P=.8). However, in comparison between the groups no difference was found (285[-200 to 535] ml/min vs 17[-380 to 306] ml/min, P=.10). In addition, peak workload at incremental cardiopulmonary exercise test increased in the intervention group compared to controls (20[-10 to 70]W vs 0[-20 to 15]W, P=.003). ConclusionHome-based interval exercise training increased endurance capacity and peak exercise capacity in adults with complex congenital heart disease. Aerobic endurance might be more relevant than peak oxygen uptake with regard to daily activities, and therefore a more clinically relevant measure to evaluate.
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| 11. |
- Spaiser, Viktoria, et al.
(författare)
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Identifying Complex Dynamics in Social Systems : A New Methodological Approach Applied to Study School Segregation
- 2018
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Ingår i: Sociological Methods & Research. - : SAGE PUBLICATIONS INC. - 0049-1241 .- 1552-8294. ; 47:2, s. 103-135
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Tidskriftsartikel (refereegranskat)abstract
- It is widely recognized that segregation processes are often the result of complex nonlinear dynamics. Empirical analyses of complex dynamics are however rare, because there is a lack of appropriate empirical modeling techniques that are capable of capturing complex patterns and nonlinearities. At the same time, we know that many social phenomena display nonlinearities. In this article, we introduce a new modeling tool in order to partly fill this void in the literature. Using data of all secondary schools in Stockholm county during the years 1990 to 2002, we demonstrate how the methodology can be applied to identify complex dynamic patterns like tipping points and multiple phase transitions with respect to segregation. We establish critical thresholds in schools' ethnic compositions, in general, and in relation to various factors such as school quality and parents' income, at which the schools are likely to tip and become increasingly segregated.
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