| 1. |
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| 2. |
- Bonnedahl, Jonas, 1970-, et al.
(författare)
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Antibiotic susceptibility of faecal bacteria in Antarctic penguins
- 2008
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Ingår i: Polar Biology. - : Springer. - 0722-4060 .- 1432-2056. ; 31:6, s. 759-763
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Tidskriftsartikel (refereegranskat)abstract
- Faecal bacteria from 49 Gentoo penguins on the Antarctic Peninsula were identified by biochemical methods and sequencing, and tested for antibiotic susceptibility using agar dilution. Of the 42 Enterobacteriaceae isolates found, 39 belonged to the genus Edwardsiella. All isolates were susceptible to the 17 antibiotics tested. This implies that antibiotic selection pressure is a prerequisite to a high prevalence of antibiotic resistance, and in the absence of contact with human activities, antibiotic resistance in Enterobacteriaceae remains undetectable.
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| 3. |
- Bonnedahl, Jonas, et al.
(författare)
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In search of human-associated bacterial pathogens in Antarctic wildlife : report from six penguin colonies regularly visited by tourists.
- 2005
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Ingår i: Ambio: A Journal of the Human Environment. - : Springer. - 0044-7447 .- 1654-7209. ; 34:6, s. 430-2
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Tidskriftsartikel (refereegranskat)abstract
- We investigated the potential role of Antarctic tourism in the introduction of human-associated pathogens into Antarctic wildlife. We collected and analyzed 233 fecal samples from eight bird species. The samples were collected at six localities on the Antarctic Peninsula, which often is visited by tourists. Every sample was investigated for pathogens of potential human origin: Campylobacter jejuni, Salmonella spp., and Yersina spp. None of these bacteria was found. Our data suggest that the tourism industry so far has achieved its goal of not introducing pathogens into the Antarctic region. There is, however, an urgent need to further investigate the situation in areas closer to permanent Antarctic settlements.
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| 4. |
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| 5. |
- Jansson, Desirée, et al.
(författare)
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Intestinal spirochaetes (genus Brachyspira) colonise wild birds in the southern Atlantic region and Antarctica
- 2015
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Ingår i: Infection Ecology & Epidemiology. - : Informa UK Limited. - 2000-8686. ; 5
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: The genus Brachyspira contains well-known enteric pathogens of veterinary significance, suggested agents of colonic disease in humans, and one potentially zoonotic agent. There are recent studies showing that Brachyspira are more widespread in the wildlife community than previously thought. There are no records of this genus in wildlife from the southern Atlantic region and Antarctica. Our aim was therefore, to determine whether intestinal spirochaetes of genus Brachyspira colonise marine and coastal birds in this region.METHOD: Faecal samples were collected from marine and coastal birds in the southern Atlantic region, including sub-Antarctic islands and Antarctica, in 2002, 2009, and 2012, with the aim to isolate and characterise zoonotic agents. In total, 205 samples from 11 bird species were selectively cultured for intestinal spirochaetes of genus Brachyspira. To identify isolates to species level, they were subjected to phenotyping, species-specific polymerase chain reactions, sequencing of partial 16S rRNA, NADH oxidase (nox), and tlyA genes, and phylogenetic analysis. Antimicrobial susceptibility tests were performed.RESULTS: Fourteen unique strains were obtained from 10 birds of three species: four snowy sheathbills (Chionis albus), three kelp geese (Chloephaga hybrida subsp. malvinarum), and three brown skua (Stercorarius antarcticus subsp. lonnbergi) sampled on the Falkland Islands, Tierra del Fuego in Argentina, South Georgia, South Shetland Islands, and the Antarctic Peninsula. Five Brachyspira strains were closely related to potentially enteropathogenic Brachyspira sp. of chickens: B. intermedia (n=2, from snowy sheathbills), and B. alvinipulli (n=3, from a kelp goose and two snowy sheathbills). Three strains from kelp geese were most similar to the presumed non-pathogenic species 'B. pulli' and B. murdochii, whereas the remaining six strains could not be attributed to currently known species. No isolates related to human strains were found. None of the tested strains showed decreased susceptibility to tiamulin, valnemulin, doxycycline, tylvalosin, lincomycin, or tylosin.CONCLUSIONS: This is the first report of intestinal spirochaetes from this region. Despite limitations of current diagnostic methods, our results, together with earlier studies, show that Brachyspira spp., including potentially pathogenic strains, occur globally among free-living avian hosts, and that this genus encompasses a higher degree of biodiversity than previously recognised.
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| 6. |
- Ranta, Susanna, et al.
(författare)
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Extracorporeal Membrane Oxygenation Support in Children With Hematologic Malignancies in Sweden
- 2021
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Ingår i: Journal of Pediatric Hematology/Oncology. - : Wolters Kluwer. - 1077-4114 .- 1536-3678. ; 43:2, s. e272-e275
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Tidskriftsartikel (refereegranskat)abstract
- Background: Extracorporeal membrane oxygenation (ECMO) is used in severe respiratory and/or circulatory failure when conventional critical care fails. Studies on patients with hematologic malignancies on ECMO have shown contradictory results; immunosuppression and coagulopathy are relative contraindications to ECMO.Observations: This nationwide Swedish retrospective chart review identified 958 children with hematologic malignancies of whom 12 (1.3%) required ECMO support. Eight patients survived ECMO, 7 the total intensive care period, and 6 survived the underlying malignancy.Conclusions: ECMO may be considered in children with hematologic malignancy. Short-term and long-term survival, in this limited group, was similar to that of children on ECMO at large.
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| 7. |
- Ranta, Susanna, et al.
(författare)
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Icu admission in children with acute lymphoblastic leukemia in sweden: Prevalence, outcome, and risk factors
- 2021
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Ingår i: Pediatric Critical Care Medicine. - Philadelphia, PA, United States : Lippincott Williams & Wilkins. - 1529-7535 .- 1947-3893. ; 22:12, s. 1050-1060
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Forskningsöversikt (refereegranskat)abstract
- OBJECTIVES: Despite progress in the treatment of childhood acute lymphoblastic leukemia, severe complications are common, and the need of supportive care is high. We explored the cumulative prevalence, clinical risk factors, and outcomes of children with acute lymphoblastic leukemia, on first-line leukemia treatment in the ICUs in Sweden.DESIGN: A nationwide prospective register and retrospective chart review study.SETTING: Children with acute lymphoblastic leukemia were identified,and demographic and clinical data were obtained from the Swedish Childhood Cancer Registry. Data on intensive care were collected from the Swedish Intensive Care Registry. Data on patients with registered ICU admission in the Swedish Childhood Cancer Registry were supplemented through questionnaires to the pediatric oncology centers.PATIENTS: All 637 children 0-17.9 years old with acute lymphoblastic leukemia diagnosed between June 2008 and December 2016 in Sweden were included.INTERVENTIONS: None.MEASUREMENTS AND MAIN RESULTS: Twenty-eight percent of the children (178/637) were admitted to an ICU at least once. The Swedish Intensive Care Registry data were available for 96% of admissions (241/252). An ICU admission was associated with poor overall survival (hazard ratio, 3.25; 95% CI, 1.97-5.36; p ≤ 0.0001). ICU admissions occurred often during early treatment; 48% (85/178) were admitted to the ICU before the end of the first month of acute lymphoblastic leukemia treatment (induction therapy). Children with T-cell acute lymphoblastic leukemia or CNS leukemia had a higher risk of being admitted to the ICU in multivariable analyses, both for early admissions before the end of induction therapy and for all admissions during the study period.CONCLUSIONS: The need for intensive care in children with acute lymphoblastic leukemia, especially for children with T cell acute lymphoblastic leukemia and CNS leukemia, is high with most admissions occurring during early treatment.
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| 8. |
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| 9. |
- Wallensten, Anders, 1974-, et al.
(författare)
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Mounting evidence for the presence of influenza A virus in the avifauna of the Antarctic region
- 2006
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Ingår i: Antarctic Science. - New York : Cambridge University Press. - 0954-1020 .- 1365-2079. ; 18:3, s. 353-356
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Tidskriftsartikel (refereegranskat)abstract
- Penguin blood samples collected at Bird Island, sub-Antarctic South Georgia, and faecal samples taken from penguins at several localities along the Antarctic Peninsula were analysed in order to investigate if influenza A virus is present in penguin populations in the South Atlantic Antarctic region. Serology was performed on the blood samples while the faecal samples were screened by a RT-PCR method directed at the matrix protein gene for determining the presence of influenza A virus. All faecal samples were negative by PCR, but the blood samples gave serologic indications that influenza A virus is present amongst these penguin species, confirming previous studies, although the virus has still not been isolated from any bird in the Antarctic region.
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| 10. |
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| 11. |
- Bergdahl, Andreas, et al.
(författare)
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Cholesterol depletion impairs vascular reactivity to endothelin-1 by reducing store-operated Ca2+ entry dependent on TRPC1.
- 2003
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Ingår i: Circulation Research. - 0009-7330. ; 93:9, s. 839-847
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Tidskriftsartikel (refereegranskat)abstract
- The reactivity of the vascular wall to endothelin-1 (ET-1) is influenced by cholesterol, which is of possible importance for the progression of atherosclerosis. To elucidate signaling steps affected, the cholesterol acceptor methyl-ß-cyclodextrin (mßcd, 10 mmol/L) was used to manipulate membrane cholesterol and disrupt caveolae in intact rat arteries. In endothelium-denuded caudal artery, contractile responsiveness to 10 nmol/L ET-1 (mediated by the ETA receptor) was reduced by mßcd and increased by cholesterol. Neither ligand binding nor colocalization of ETA and caveolin-1 was affected by mßcd. Ca2+ inflow via store-operated channels after depletion of intracellular Ca2+ stores was reduced in mßcd-treated caudal arteries, as shown by Mn2+ quench rate and intracellular [Ca2+] response. Expression of TRPC1, 3, and 6 was detected by reverse transcriptase–polymerase chain reaction, and colocalization of TRPC1 with caveolin-1 was reduced by mßcd, as seen by immunofluorescence. Part of the contractile response to ET-1 was inhibited by Ni2+ (0.5 mmol/L) and by a TRPC1 blocking antibody. In the basilar artery, exhibiting less store-operated channel activity than the caudal artery, ET-1–induced contractions were insensitive to the TRPC1 blocking antibody and to mßcd. Increased store-operated channel activity in basilar arteries after organ culture correlated with increased sensitivity of ET-1 contraction to mßcd. These results suggest that cholesterol influences vascular reactivity to ET-1 by affecting the caveolar localization of TRPC1.
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| 12. |
- Bonaglia, Stefano, et al.
(författare)
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Activated carbon stimulates microbial diversity and PAH biodegradation under anaerobic conditions in oil-polluted sediments
- 2020
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Ingår i: Chemosphere. - : Elsevier BV. - 0045-6535 .- 1879-1298. ; 248
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Tidskriftsartikel (refereegranskat)abstract
- Biodegradation by microorganisms is a useful tool that helps alleviating hydrocarbon pollution in nature. Microbes are more efficient in degradation under aerobic than anaerobic conditions, but the majority of sediment by volume is generally anoxic. Incubation experiments were conducted to study the biodegradation potential of naphthalene-a common polycyclic aromatic hydrocarbon (PAH)-and the diversity of microbial communities in presence/absence of activated carbon (AC) under aerobic/anaerobic conditions. Radio-respirometry experiments with endogenous microorganisms indicated that degradation of naphthalene was strongly stimulated (96%) by the AC addition under anaerobic conditions. In aerobic conditions, however, AC had no effects on naphthalene biodegradation. Bioaugmentation tests with cultured microbial populations grown on naphthalene showed that AC further stimulated (92%) naphthalene degradation in anoxia. Analysis of the 16S rRNA gene sequences implied that sediment amendment with AC increased microbial community diversity and changed community structure. Moreover, the relative abundance of Geobacter, Thiobacillus, Sulfuricurvum, and methanogenic archaea increased sharply after amendment with AC under anaerobic conditions. These results may be explained by the fact that AC particles promoted direct interspecies electron transfer (DIET) between microorganisms involved in PAH degradation pathways. We suggest that important ecosystem functions mediated by microbes-such as hydrocarbon degradation-can be induced and that AC enrichment strategies can be exploited for facilitating bioremediation of anoxic oil-contaminated sediments and soils.
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| 13. |
- Bratt, Cecilia, et al.
(författare)
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Assessment of criteria development for public procurement from a strategic sustainability perspective
- 2013
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Ingår i: Journal of Cleaner Production. - : Elsevier. - 0959-6526 .- 1879-1786. ; 52, s. 309-316
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Tidskriftsartikel (refereegranskat)abstract
- Green public procurement has emerged as a policy instrument with a significant potential to steer procurers' and producers' decisions in a sustainable direction. The purpose of this study is to assess the process for development of green public procurement criteria at a Swedish governmental expert body from a strategic sustainability perspective, i.e. to identify strengths and weaknesses from such a perspective as a basis for making this process more supportive of sustainable product and service innovation. A previously published framework for strategic sustainable development is used for the assessment. The assessment shows that the criteria development process is transparent, well-documented and that it encourages a high level of participation by the members of the working groups. However, the assessment also points to several weaknesses of the process. These include, e.g., a limited impact perspective and lack of a clear definition of sustainability objectives. The development process therefore results in criteria which mainly concern a selection of current environmental impacts outside the context of long-term objectives and consequently there are no strategies to prepare for future processes. The conclusion is that the current process may result in improvements as regards some known environmental problems, but to allow for a strategic approach that could more significantly promote innovative product-service system solutions in support of sustainable development, process changes are needed. Essential process changes are proposed in this paper.
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| 14. |
- Bratt, Cecilia, et al.
(författare)
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Assessment of Eco-labelling Criteria Development from a Strategic Sustainability Perspective
- 2011
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Ingår i: Journal of Cleaner Production. - : Elsevier. - 0959-6526 .- 1879-1786. ; 19:14
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Tidskriftsartikel (refereegranskat)abstract
- To turn current patterns of consumption and production in a sustainable direction, solid and understandable market information on the socio-ecological performance of products is needed. Eco-labelling programmes have an important role in this communication. The aim of this study is to investigate what gaps there may be in the current criteria development processes in relation to a strategic sustainability perspective and develop recommendations on how such presumptive gaps could be bridged. First a previously published generic framework for strategic sustainable development is described and applied for the assessment of two eco-labelling programmes. Data for the assessment is collected from literature and in semi-structured interviews and discussions with eco-labelling experts. The assessment revealed that the programmes lack both an operational definition of sustainability, and a statement of objectives to direct and drive the criteria development processes. Consequently they also lack guidelines for how product category criteria might gradually develop in any direction. The selected criteria mainly reflect the current reality based on a selection of negative impacts in ecosystems, but how this selection, or prioritization, is made is not clearly presented. Finally, there are no guidelines to ensure that the criteria developers represent a broad enough competence to embrace all essential sustainability aspects. In conclusion the results point at deficiencies in theory, process and practice of eco-labelling, which hampers cohesiveness, transparency and comprehension. And it hampers predictability, as producers get no support in foreseeing how coming revisions of criteria will develop. This represents a lost opportunity for strategic sustainable development. It is suggested that these problems could be avoided by informing the criteria development process by a framework for strategic sustainable development, based on backcasting from basic sustainability principles.
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| 15. |
- Braun, Matthias, et al.
(författare)
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Regulated Exocytosis of GABA-containing Synaptic-like Microvesicles in Pancreatic {beta}-cells.
- 2004
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Ingår i: Journal of General Physiology. - : Rockefeller University Press. - 0022-1295 .- 1540-7748. ; 123:3, s. 191-204
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Tidskriftsartikel (refereegranskat)abstract
- We have explored whether {gamma}-aminobutyric acid (GABA) is released by regulated exocytosis of GABA-containing synaptic-like microvesicles (SLMVs) in insulin-releasing rat pancreatic ß-cells. To this end, ß-cells were engineered to express GABAA-receptor Cl--channels at high density using adenoviral infection. Electron microscopy indicated that the average diameter of the SLMVs is 90 nm, that every ß-cell contains ~3,500 such vesicles, and that insulin-containing large dense core vesicles exclude GABA. Quantal release of GABA, seen as rapidly activating and deactivating Cl--currents, was observed during membrane depolarizations from -70 mV to voltages beyond -40 mV or when Ca2+ was dialysed into the cell interior. Depolarization-evoked GABA release was suppressed when Ca2+ entry was inhibited using Cd2+. Analysis of the kinetics of GABA release revealed that GABA-containing vesicles can be divided into a readily releasable pool and a reserve pool. Simultaneous measurements of GABA release and cell capacitance indicated that exocytosis of SLMVs contributes ~1% of the capacitance signal. Mathematical analysis of the release events suggests that every SLMV contains 0.36 amol of GABA. We conclude that there are two parallel pathways of exocytosis in pancreatic ß-cells and that release of GABA may accordingly be temporally and spatially separated from insulin secretion. This provides a basis for paracrine GABAergic signaling within the islet.
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| 16. |
- Broman, Emanuel, et al.
(författare)
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Efficient capacity allocation on deregulated railway markets
- 2022
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Ingår i: Journal of Rail Transport Planning & Management. - : Elsevier B.V.. - 2210-9706 .- 2210-9714. ; 21
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Tidskriftsartikel (refereegranskat)abstract
- As railway markets are increasingly deregulated, coordinating and prioritising between capacity requests becomes more complex and more important. This paper describes the advantages and challenges of different allocation methods in vertically separated open-access railway markets, with several railway operators and heterogeneous traffic, and where a public infrastructure manager must resolve operators’ conflicting path requests. Three broad groups of allocation methods are described: administrative methods, allocation by social cost-benefit analysis and willingness-to-pay based allocation. We describe pros and cons of these allocation principles for three different market segments: commercial traffic with long planning horizons, (subsidized) traffic controlled by public transport agencies, and traffic with short planning horizons. We then outline an allocation process that meets the requirements of a deregulated market better than conventional methods. It is a mixed method, which uses an auction-like mechanism to allocate pre-defined paths to commercial operators on specified, capacity-constrained lines. The net social benefits of capacity reserved for traffic controlled by public transport agencies is assessed through social cost-benefit analysis of timetables. The benefits decrease when timetables are adjusted to make room for additional commercial train paths; the size of this loss determines the reservation price of the auction-like mechanism. Dynamic pricing is used for short-term allocation on congested line segments. © 2021
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| 17. |
- Broman, Elias, 1985-, et al.
(författare)
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Long-Term Pollution Does Not Inhibit Denitrification and DNRA by Adapted Benthic Microbial Communities
- 2023
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Ingår i: Microbial Ecology. - : Elsevier. - 0095-3628 .- 1432-184X. ; 86, s. 2357-2372
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Tidskriftsartikel (refereegranskat)abstract
- Denitrification in sediments is a key microbial process that removes excess fixed nitrogen, while dissimilatory nitrate reduction to ammonium (DNRA) converts nitrate to ammonium. Although microorganisms are responsible for essential nitrogen (N) cycling, it is not yet fully understood how these microbially mediated processes respond to toxic hydrophobic organic compounds (HOCs) and metals. In this study, we sampled long-term polluted sediment from the outer harbor of Oskarshamn (Baltic Sea), measured denitrification and DNRA rates, and analyzed taxonomic structure and N-cycling genes of microbial communities using metagenomics. Results showed that denitrification and DNRA rates were within the range of a national reference site and other unpolluted sites in the Baltic Sea, indicating that long-term pollution did not significantly affect these processes. Furthermore, our results indicate an adaptation to metal pollution by the N-cycling microbial community. These findings suggest that denitrification and DNRA rates are affected more by eutrophication and organic enrichment than by historic pollution of metals and organic contaminants.
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| 18. |
- Broman, Emanuel, et al.
(författare)
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Market dynamics in on-rail competition
- 2017
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Ingår i: 19th EURO Working Group on Transportation Meeting, EWGT2016. - : Elsevier. ; , s. 232-244
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Konferensbidrag (refereegranskat)abstract
- On-rail competition is perhaps the most far-reaching form of deregulation of the railways, giving travellers several options on a single line. It aims to lower fairs and raise quality of service, thereby boosting demand and social welfare. Concerns have been raised, however, regarding if effective competition is possible on such a market, allowing two or more operators to be profitable and eliminating through incentives or regulation the purchase by one operator of the others' access rights, thus restoring monopoly. In addition, the effect of competition on total welfare is unclear. The issue of how to regulate the market and conduct capacity allocation in order to maximise welfare is also as yet unanswered. Addressing these issues, the present paper studies a duopoly market through simulations. It builds on the hypothesis that competition occurs between trains with close departure times. Results indicate that total welfare increases significantly when going from profit-maximising monopoly to competition, as consumers make large gains while operators' profits fall. The way the regulator allocates departure slots has significant importance for market outcomes, including prices, frequencies and total welfare. In particular, it is possible to improve welfare by regulating the succession of departures. If trading in access rights is allowed, a would-be monopolist has incentives to buy its competitors' slots for a price they would accept. A monopolist that uses high frequency of departures as a deterrence strategy against competition increases frequency a lot compared to the profit-maximising level.
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| 19. |
- Broman, Elias, et al.
(författare)
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Salinity drives meiofaunal community structure dynamics across the Baltic ecosystem
- 2019
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Ingår i: Molecular Ecology. - : Blackwell Publishing. - 0962-1083 .- 1365-294X. ; 28:16, s. 3813-3829
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Tidskriftsartikel (refereegranskat)abstract
- Coastal benthic biodiversity is under increased pressure from climate change, eutrophication, hypoxia, and changes in salinity due to increase in river runoff. The Baltic Sea is a large brackish system characterized by steep environmental gradients that experiences all of the mentioned stressors. As such it provides an ideal model system for studying the impact of on-going and future climate change on biodiversity and function of benthic ecosystems. Meiofauna (animals < 1 mm) are abundant in sediment and are still largely unexplored even though they are known to regulate organic matter degradation and nutrient cycling. In this study, benthic meiofaunal community structure was analysed along a salinity gradient in the Baltic Sea proper using high-throughput sequencing. Our results demonstrate that areas with higher salinity have a higher biodiversity, and salinity is likely the main driver influencing meiofauna diversity and community composition. Furthermore, in the more diverse and saline environments a larger amount of nematode genera classified as predators prevailed, and meiofauna-macrofauna associations were more prominent. These findings show that in the Baltic Sea, a decrease in salinity resulting from accelerated climate change will likely lead to decreased benthic biodiversity, and cause profound changes in benthic communities, with potential consequences for ecosystem stability, functions and services.
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| 20. |
- Broman, Emanuel, et al.
(författare)
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Tåglägestilldelning genom auktion : ett experiment
- 2024
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Ingår i: Sammanställning av referat från Transportforum 2024. - Linköping : Statens väg- och transportforskningsinstitut. ; , s. 162-162
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Current track allocation methods are poor proxies for welfare optimality and the traffic allowed by the resulting timetables therefore generate less welfare than would be possible under a better system. Willingness-to-pay based allocation such as auctions would lead to a more efficient use of the infrastructure in many cases, since it reveals operators’ own valuation of track access and incentivises frugality in capacity usage. It would also increase transparency, thus fostering competition in the market. But introducing a system that is so different from current practice is risky, since any unforeseen problem could potentially mean that no feasible timetable is ready for use in time. Alas, the implications of introducing track capacity allocation by auction must be studied on beforehand.Addressing this, a number of serious games of a track slot auction were set up. We tested feasibility issues, which is not easily done by other means. Auctions can potentially be very complex, with each bid being a function of departure time, travel time and connections. Are operators able to place bid in their own self-interest? Are they able to adapt their strategy to account for different competitive circumstances and the unique characteristics of their own firm?There is also the risk of systemic failure. The auction might result in an inefficient or infeasible timetable. Perhaps the auction can be ‘gamed’ so that one operator wins but the overall result is inefficient. The auction might not be properly concluded in a reasonable number of rounds, so it must either be terminated prematurely or continue when the timetable should already have been done.The participants were selected for their industry knowledge. They were all employees of the Swedish infrastructure manager Trafikverket and had roles including key account manager and capacity analytic for railways. Several had previous experience of working at train operators as timetable coordinators and in other roles. The participants therefore understood the tasks before them, while being ‘neutral’ in terms of the competitive situation between operators. In the games, the participants took the role of train operator and bid for departure slots.
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| 21. |
- Broman, Emanuel, et al.
(författare)
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Welfare effects of open access competition on railway markets
- 2019
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Ingår i: Transportation Research Part A. - : Elsevier. - 0965-8564 .- 1879-2375. ; 129, s. 72-91
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Tidskriftsartikel (refereegranskat)abstract
- In recent years, several countries have deregulated passenger railway markets to allow open access. The aim is for competition to lower fares and increase quality of service, thereby increasing demand, economic efficiency and overall social welfare. We use a stylised simulation model to study how open access competition affects fares, demand, supply, consumer surplus and operator profits compared to a profit maximising monopoly and to a welfare maximising benchmark situation. We conclude that aggregate social welfare increases substantially when going from profit maximising monopoly to duopoly competition, as consumers make large gains while operators’ profits fall. It matters how the infrastructure manager sets the timetable based on operators’ capacity requests: the infrastructure manager should strive to increase competition by mixing competing operators’ departures as much as possible. According to simulations, there generally exists a stable competitive Nash equilibrium with two or more profitable operators. Although operators are identical in the model setup, the Nash equilibrium outcome is asymmetric: one operator has more departures and higher average fares than the other does. If operators are allowed to cooperate, however, for example by trading or selling departure slots, the equilibrium situation tends to revert to monopoly. The regulatory framework must therefore prevent collusion and facilitate market entry. Even the potential for competitive entry tends to increase social welfare, as the monopolist has incentives to increase supply as an entry deterrence strategy.
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| 22. |
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| 23. |
- Broman, Karolina, Universitetslektor, 1969-, et al.
(författare)
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Spatial Ability in Organic Chemistry : Can Virtual and Augmented Reality be Valuable?
- 2019
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Ingår i: 7:e Utvecklingskonferensen för Sveriges ingenjörsutbildningar. - : Luleå tekniska universitet.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In this paper, the roles of digital technologies as Virtual Reality (VR), and Augmented Reality (AR), are discussed to explore how biotechnology engineering students develop their spatial ability in organic chemistry. We have, through stereochemistry workshops, followed how students, in specific, visualise and rotate molecular representations and how the use of digital tools influences the students’ interest.
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| 24. |
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| 25. |
- Broman, T., et al.
(författare)
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Campylobacter jejuni in black-headed gulls (Larus ridibundus) : prevalence, genotypes, and influence on C. jejuni epidemiology
- 2002
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Ingår i: Journal of Clinical Microbiology. - 0095-1137 .- 1098-660X. ; 40:12, s. 4594-4602
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Tidskriftsartikel (refereegranskat)abstract
- Campylobacteriosis is a zoonotic disease in which birds have been suggested to play an important role as a reservoir. We investigated the prevalence of Campylobacter jejuni subsp. jejuni in black-headed gulls (Larus ridibundus) in southern Sweden with the aim of examining the nature of C. jejuni infection in this bird species. Birds were sampled in four sampling series each year during 1999 (n = 419) and 2000 (n = 365). Longitudinally sampled C. jejuni isolates from individual gulls were subjected to macrorestriction profiling (MRP) by pulsed-field gel electrophoresis to investigate the genotypical stability during the natural course of infection. Furthermore, a subset (n = 76) of black-headed gull isolates was compared to isolates from broiler chickens (n = 38) and humans (n = 56) originating from the same geographic area. We found a pronounced seasonal variation in C. jejuni carriage, with the highest rates found in late autumn. MRP similarities were higher between isolates of human and broiler chicken origin, than between those of wild bird origin and either of the other two hosts. However, identical MRPs were found in two gull isolates and one human isolate after digestion with two restriction enzymes, strongly indicating that they may have been colonized by the same clone of C. jejuni. The MRPs most prevalent in gull isolates did not occur among isolates from humans and broiler chickens, suggesting the existence of a subpopulation of C. jejuni adapted to species-specific colonization or environmental survival.
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| 26. |
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| 27. |
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| 28. |
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| 29. |
- Christensson, Maria, et al.
(författare)
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Time course of cerebellar morphological development in postnatal ferrets: Ontogenetic and comparative perspectives.
- 2007
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Ingår i: Journal of Comparative Neurology. - : Wiley. - 1096-9861 .- 0021-9967. ; 501:6, s. 916-930
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Tidskriftsartikel (refereegranskat)abstract
- We provide the first systematic description of the morphological ontogenesis of the ferret cerebellum and compare its relative time-course to that of the rat cerebellum. Overall cerebellar size, foliation, and thickness of cortical layers were quantified and Purkinje cell morphology was characterized at 24 timepoints in ferrets from postnatal day (P)1 to P63. The ferret cerebellum was substantially larger than that of the rat and had a much longer developmental period. In ferrets, Purkinje cells were dispersed into a monolayer by P9, the formation of folia declined abruptly around P20, and the external granular layer peaked in thickness around P22 and disappeared by P56. Timepoints of corresponding relative developmental maturity of the quantified architectural features of rat and ferret cerebella were determined and their relationship was analyzed by linear regression. The time-conversion equation derived, describing the relationship between cerebellar morphogenesis in the two species, had a determination coefficient (r2) of 0.95. Conspicuously, the equation predicted with high accuracy the timing of structural changes in individual Purkinje cells in the ferret cerebellum. The conversion equation should be useful for precise quantitative translation of data between studies of ferret and rat cerebellum and for comparisons between development of motor and sensory structures and functions in ferrets. The degree of similarity in the time-courses of cerebellar development in two distantly related mammals makes explicit in quantitative terms how remarkably conserved the cerebellum is in phylogenesis. Therefore, the methodology should be applicable to precise quantitative conversions of cerebellar developmental time-courses also between other species.
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| 30. |
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| 31. |
-
Från storslagna visioner till professionell bedömning : Om barndom, utbildning och styrning
- 2010
-
Samlingsverk (redaktörskap) (övrigt vetenskapligt/konstnärligt)abstract
- I denna antologi presenteras ett axplock av pågående forskning vid enheten Barn-Unga-Samhälle (BUS) inom Lärarutbildningen vid Malmö högskola. Antologin belyser en utbildningshistorisk förskjutning från visionärt arbete och tilltro om en bättre framtid via uppfostran och utbildning, till en ökad oro för framtiden i en global konkurrens. Styrning och kontroll av barndom och utbildning, via exempelvis dokumentation, bedömning och utvärdering, blir allt mer framträdande, både nationellt och internationellt. Antologin vänder sig till alla som är intresserade av frågor om barndom och utbildning ur ett samhällsperspektiv.
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| 32. |
- Havton, LA, et al.
(författare)
-
Systemic administration of cholera toxin B subunit conjugated to horseradish peroxidase in the adult rat labels preganglionic autonomic neurons, motoneurons, and select primary afferents for light and electron microscopic studies
- 2005
-
Ingår i: Journal of Neuroscience Methods. - : Elsevier BV. - 1872-678X .- 0165-0270. ; 149:2, s. 101-109
-
Tidskriftsartikel (refereegranskat)abstract
- Retrograde and transganglionic labeling techniques are commonly used to visualize subsets of neurons and sensory afferent projections in the nervous system. These methods commonly require anesthesia and surgical methods. However, some tracers can also be administered systemically in awake animals, thus reducing risks associated with anesthesia and surgery and allowing for labeling of neuronal populations that are difficult to label with local tracer injections. Here, we demonstrate in the adult rat that intraperitoneal administration of cholera toxin subunit B conjugated to horseradish peroxidase labels preganglionic autonomic neurons, motoneurons, and the terminal projections of select primary afferents for both light and electron microscopic studies. We demonstrate also that this method can be combined with post-embedding immunogold labeling to detect amino acid transmitters in synaptic boutons.
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| 33. |
- Ichiyama, Ronaldo M., et al.
(författare)
-
Ultrastructural synaptic features differ between alpha- and gamma-motoneurons innervating the tibialis anterior muscle in the rat
- 2006
-
Ingår i: Journal of Comparative Neurology. - : Wiley. - 1096-9861 .- 0021-9967. ; 499:2, s. 306-315
-
Tidskriftsartikel (refereegranskat)abstract
- We investigated the synaptology of retrogradely labeled spinal motoneurons after injection of horseradish peroxidase into the tibialis anterior (TA) muscle of adult rat. In total, 32 TA motoneurons were investigated in the electron microscope and demonstrated a bimodal size distribution with cell diameter peaks at 40 mu m and 20 mu m, likely representing alpha- and gamma-motoneurons, respectively. Both alpha- and gamma-motoneurons were apposed by S- and F-type synaptic boutons, whereas only alpha-motoneurons demonstrated inputs by the large M- and C-type boutons. The proportion of cell body membrane covered by synaptic inputs was surprisingly indistinguishable between alpha-motoneurons (72.2%) and gamma-motoneurons (63.5%). The ratio between the number of F- and S-type boutons in apposition with the motoneuron cell body (F/S ratio) and the ratio between the soma membrane coverage provided by F- and S-type boutons were both significantly higher in alpha- than in gamma-motoneurons. When comparing our data with previous findings in other species, we conclude that rat TA alpha-motoneurons are similar to cat and primate alpha-motoneurons with regard to synaptic terminal morphology, frequency, and distribution. However, rat gamma-motoneurons show a markedly higher total synaptic coverage and frequency than cat gamma-motoneurons, although both species exhibit appositions made by the same synaptic types and similar ratios between inhibitory and excitatory inputs.
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| 34. |
- Jönsson, Daniel, et al.
(författare)
-
Demonstration of mitochondrial oestrogen receptor beta and oestrogen-induced attenuation of cytochrome c oxidase subunit I expression in human periodontal ligament cells.
- 2007
-
Ingår i: Archives of Oral Biology. - : Elsevier BV. - 1879-1506 .- 0003-9969. ; 52:7, s. 669-676
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Periodontal ligament (PDL) cells express oestrogen receptor beta (ERbeta) protein, but cellular functions regulated by ERbeta in these cells have not been identified. In this study we determine if ERbeta is localised to mitochondria and if oestrogen regulates mitochondrial function in human PDL cells obtained from teeth extracted for orthodontic reasons. DESIGN: Subcellular distribution of ERbeta was determined by confocal microscopy of cells co-stained with ERbeta antibody and the mitochondrion-selective probe MitoTracker and by immunogold electron microscopy. Expression of the mitochondrial enzyme cytochrome c oxidase subunit I, involved in oxidative phosphorylation, was determined by Western blotting in cells treated with or without physiological concentrations of the endogenous oestrogen 17beta-oestradiol. RESULTS: ERbeta immunoreactivity was observed both in the nuclei and the cytoplasm. MitoTracker-labelling was observed in the cytoplasm, especially in the perinuclear region, but not in the nuclei. Co-localisation of ERbeta and MitoTracker was observed in cells derived from both male and female subjects. Mitochondrial localisation of ERbeta was confirmed by immunogold electron microscopy. Cells treated with or without 17beta-oestradiol (100 nM) displayed an identical pattern of staining for mitochondria. Treatment with 100 nM 17beta-oestradiol attenuated cytochrome c oxidase subunit I expression by about 30%, while combined treatment with 17beta-oestradiol and the ER blocker ICI 182780 (10 microM) had no effect. CONCLUSION: This study demonstrates mitochondrial localisation of ERbeta and oestrogen-induced decrease in the expression of cytochrome c oxidase subunit I in human PDL cells, suggesting that oestrogen probably via ERbeta influences mitochondrial function and PDL cell energy
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| 35. |
- Kechagias, Stergios, et al.
(författare)
-
Compartmentation of glutamate and glutamine in the lateral cervical nucleus : Further evidence for glutamate as a spinocervical tract neurotransmitter
- 1994
-
Ingår i: Journal of Comparative Neurology. - : Wiley-Blackwell. - 0021-9967 .- 1096-9861. ; 340:4, s. 531-540
-
Tidskriftsartikel (refereegranskat)abstract
- Previous observations indicate that spinocervical tract terminals contain relatively high levels of glutamate. To examine whether these high glutamate levels are likely to represent a neurotransmitter pool or an elevated metabolic pool, the distributions of glutamate- and glutamine-like immunoreactivities were examined in adjacent immunogold-labeled sections of the lateral cervical nucleus. Spinocervical tract terminals were identified by anterograde transport of horseradish peroxidase and wheat germ agglutinin-horseradish peroxidase conjugate from the spinal cord. Spinocervical tract terminals were found to contain significantly higher levels of glutamate-like immunoreactivity than other examined tissue compartments (large neuronal cell bodies, terminals with pleomorphic vesicles, astrocytes, and average tissue level). In contrast, the highest levels of glutamine-like immunoreactivity were detected in astrocytes. The different analyzed tissue elements formed three groups with respect to glutamate: glutamine ratios: one high ratio group including spinocervical tract terminals, a second group with intermediate ratios consisting of neuronal cell bodies and terminals containing pleomorphic synaptic vesicles, and a third low ratio group including astrocytes. Our findings indicate the presence of a compartmentation of glutamate and glutamine in the lateral cervical nucleus, similar to that postulated in biochemical studies of the central nervous system. The results also show that spinocervical tract terminals have high glutamate: glutamine ratios, similar to those previously observed in putative glutamatergic terminals in the cerebellar cortex. Thus, spinocervical tract terminals display biochemical characteristics that would be expected of glutamatergic terminals and the present findings therefore provide further evidence for glutamate as a spinocervical tract neurotransmitter.
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| 36. |
- Larsson, Max, et al.
(författare)
-
Different basal levels of CaMKII phosphorylated at Thr at nociceptive and low-threshold primary afferent synapses.
- 2005
-
Ingår i: European Journal of Neuroscience. - : Wiley. - 1460-9568 .- 0953-816X. ; 21:9, s. 2445-2458
-
Tidskriftsartikel (refereegranskat)abstract
- Postsynaptic autophosphorylation of Ca2+/calmodulin-dependent protein kinase II (CaMKII) at Thr286/287 is crucial for the induction of long-term potentiation at many glutamatergic synapses, and has also been implicated in the persistence of synaptic potentiation. However, the availability of CaMKII phosphorylated at Thr286/287 at individual glutamatergic synapses in vivo is unclear. We used post-embedding immunogold labelling to quantitatively analyse the ultrastructural localization of CaMKII phosphorylated at Thr286/287 (pCaMKII) at synapses formed by presumed nociceptive and low-threshold mechanosensitive primary afferent nerve endings in laminae I-IV of rat spinal cord. Immunogold labelling was enriched in the postsynaptic densities of such synapses, consistent with observations in pre-embedding immunoperoxidase-stained dorsal horn. Presynaptic axoplasm also exhibited sparse immunogold labelling, in peptidergic terminals partly associated with dense core vesicles. Analysis of single or serial pCaMKII-immunolabelled sections indicated that the large majority of synapses formed either by presumed peptidergic or non-peptidergic nociceptive primary afferent terminals in laminae I-II of the spinal cord, or by presumed low-threshold mechanosensitive primary afferent terminals in laminae IIi-IV, contained pCaMKII in their postsynaptic density. However, the postsynaptic levels of pCaMKII immunolabelling at low-threshold primary afferent synapses were only approximately 50% of those at nociceptive synapses. These results suggest that constitutively autophosphorylated CaMKII in the postsynaptic density is a common characteristic of glutamatergic synapses, thus potentially contributing to maintenance of synaptic efficacy. Furthermore, pCaMKII appears to be differentially regulated between high- and low-threshold primary afferent synapses, possibly reflecting different susceptibility to synaptic plasticity between these afferent pathways.
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| 37. |
- Larsson, Max, et al.
(författare)
-
Different basal levels of CaMKII phosphorylated at Thr286/287 at nociceptive and low-threshold primary afferent synapses.
- 2005
-
Ingår i: European Journal of Neuroscience. - : Wiley-Blackwell Publishing Inc.. - 0953-816X .- 1460-9568. ; 21:9, s. 2445-2458
-
Tidskriftsartikel (refereegranskat)abstract
- Postsynaptic autophosphorylation of Ca2+/calmodulin-dependent protein kinase II (CaMKII) at Thr286/287 is crucial for the induction of long-term potentiation at many glutamatergic synapses, and has also been implicated in the persistence of synaptic potentiation. However, the availability of CaMKII phosphorylated at Thr286/287 at individual glutamatergic synapses in vivo is unclear. We used post-embedding immunogold labelling to quantitatively analyse the ultrastructural localization of CaMKII phosphorylated at Thr286/287 (pCaMKII) at synapses formed by presumed nociceptive and low-threshold mechanosensitive primary afferent nerve endings in laminae I-IV of rat spinal cord. Immunogold labelling was enriched in the postsynaptic densities of such synapses, consistent with observations in pre-embedding immunoperoxidase-stained dorsal horn. Presynaptic axoplasm also exhibited sparse immunogold labelling, in peptidergic terminals partly associated with dense core vesicles. Analysis of single or serial pCaMKII-immunolabelled sections indicated that the large majority of synapses formed either by presumed peptidergic or non-peptidergic nociceptive primary afferent terminals in laminae I-II of the spinal cord, or by presumed low-threshold mechanosensitive primary afferent terminals in laminae IIi-IV, contained pCaMKII in their postsynaptic density. However, the postsynaptic levels of pCaMKII immunolabelling at low-threshold primary afferent synapses were only approximately 50% of those at nociceptive synapses. These results suggest that constitutively autophosphorylated CaMKII in the postsynaptic density is a common characteristic of glutamatergic synapses, thus potentially contributing to maintenance of synaptic efficacy. Furthermore, pCaMKII appears to be differentially regulated between high- and low-threshold primary afferent synapses, possibly reflecting different susceptibility to synaptic plasticity between these afferent pathways.
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| 38. |
- Larsson, Max, et al.
(författare)
-
Pathway-specific bidirectional regulation of Ca2+/calmodulin-dependent protein kinase II at spinal nociceptive synapses after acute noxious stimulation.
- 2006
-
Ingår i: JNeurosci. - : Society for Neuroscience. - 1529-2401 .- 0270-6474. ; 26:16, s. 4198-4205
-
Tidskriftsartikel (refereegranskat)abstract
- An intensely painful stimulus may lead to hyperalgesia, the enhanced sensation of subsequent painful stimuli. This is commonly believed to involve facilitated transmission of sensory signals in the spinal cord, possibly by a long-term potentiation-like mechanism. However, plasticity of identified synapses in intact hyperalgesic animals has not been reported. Here, we show, using neuronal tracing and postembedding immunogold labeling, that after acute noxious stimulation (hindpaw capsaicin injections), immunolabeling of Ca2+/calmodulin-dependent protein kinase II (CaMKII) and of CaMKII phosphorylated at Thr(286/287) (pCaMKII) are upregulated postsynaptically at synapses established by peptidergic primary afferent fibers in the superficial dorsal horn of intact rats. In contrast, postsynaptic pCaMKII immunoreactivity was instead downregulated at synapses of nonpeptidergic primary afferent C-fibers; this loss of pCaMKII immunolabel occurred selectively at distances greater than approximately 20 nm from the postsynaptic membrane and was accompanied by a smaller reduction in total CaMKII contents of these synapses. Both pCaMKII and CaMKII immunogold labeling were unaffected at synapses formed by presumed low-threshold mechanosensitive afferent fibers. Thus, distinct molecular modifications, likely indicative of plasticity of synaptic strength, are induced at different populations of presumed nociceptive primary afferent synapse by intense noxious stimulation, suggesting a complex modulation of parallel nociceptive pathways in inflammatory hyperalgesia. Furthermore, the activity-induced loss of certain postsynaptic pools of autophosphorylated CaMKII at previously unmanipulated synapses supports a role for the kinase in basal postsynaptic function.
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| 39. |
- Larsson, Max, et al.
(författare)
-
Quantitative analysis of immunogold labeling indicates low levels and non-vesicular localization of L-aspartate in rat primary afferent terminals.
- 2001
-
Ingår i: Journal of Comparative Neurology. - : John Wiley & Sons. - 0021-9967 .- 1096-9861. ; 430:2, s. 147-159
-
Tidskriftsartikel (refereegranskat)abstract
- The role of L-aspartate as an excitatory neurotransmitter in primary afferent synapses in the spinal cord dorsal horn is disputed. To further investigate this issue, we examined the presence of aspartate-like immunoreactivity in primary afferent nerve terminals and other tissue components of the dorsal horn. We also examined the relationship between aspartate and glutamate immunogold labeling density and the density of synaptic vesicles in primary afferent terminals and presumed inhibitory terminals forming symmetric synapses. Weak aspartate immunosignals, similar to or lower than those displayed by presumed inhibitory terminals, were detected in both C-fiber primary afferent terminals in lamina II (dense sinusoid axon terminals, identified by morphological criteria) and in A-fiber primary afferent terminals in laminae III-IV (identified with anterograde transport of choleragenoid-horseradish peroxidase conjugate). The aspartate immunogold signal in primary afferent terminals was only about one-fourth of that in deep dorsal horn neuronal cell bodies. Further, whereas significant positive correlations were evident between synaptic vesicle density and glutamate immunogold labeling density in both A- and C-fiber primary afferent terminals, none of the examined terminal populations displayed a significant correlation between synaptic vesicle density and aspartate immunogold labeling density. Thus, our results indicate relatively low levels and a non-vesicular localization of aspartate in primary afferent terminals. It is therefore suggested that aspartate, rather than being a primary afferent neurotransmitter, serves a role in the intermediary metabolism in primary afferent terminals.
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| 40. |
- Larsson, Max, 1975-, et al.
(författare)
-
Synaptic Organization of VGLUT3 Expressing Low-Threshold Mechanosensitive C Fiber Terminals in the Rodent Spinal Cord
- 2019
-
Ingår i: eNeuro. - : Society for Neuroscience. - 2373-2822. ; 6:1
-
Tidskriftsartikel (refereegranskat)abstract
- Low-threshold mechanosensitive C fibers (C-LTMRs) that express the vesicular glutamate transporter VGLUT3 are thought to signal affective touch, and may also play a role in mechanical allodynia. However, the nature of the central termination of C-LTMRs in the dorsal horn remains largely unexplored. Here, we used light and electron microscopy in combination with VGLUT3 immunolabeling as a marker of C-LTMR terminations to investigate this issue. VGLUT3+ C-LTMRs formed central terminals of Type II glomeruli in the inner part of lamina II of the dorsal horn, often establishing multiple asymmetric synapses with postsynaptic dendrites but also participating in synaptic configurations with presynaptic axons and dendrites. Unexpectedly, essentially all VGLUT3+ C-LTMR terminals showed substantial VGLUT1 expression in the rat, whereas such terminals in mice lacked VGLUT1. Most VGLUT3+ C-LTMR terminals exhibited weak-to-moderate VGLUT2 expression. Further, C-LTMR terminals formed numerous synapses with excitatory protein kinase C? (PKC?) interneurons and inhibitory parvalbumin neurons, whereas synapses with calretinin neurons were scarce. C-LTMR terminals rarely if ever established synapses with neurokinin 1 receptor (NK1R)-possessing dendrites traversing lamina II. Thus, VGLUT3+ C-LTMR terminals appear to largely correspond to neurofilament-lacking central terminals of Type II glomeruli in inner lamina II and can thus be identified at the ultrastructural level by morphological criteria. The participation of C-LTMR terminals in Type II glomeruli involving diverse populations of interneuron indicates highly complex modes of integration of C-LTMR mediated signaling in the dorsal horn. Furthermore, differences in VGLUT1 expression indicate distinct species differences in synaptic physiology of C-LTMR terminals.
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| 41. |
- Larsson, Max, et al.
(författare)
-
Synaptic Plasticity and Pain : Role of Ionotropic Glutamate Receptors
- 2011
-
Ingår i: The Neuroscientist. - : Sage Publications. - 1073-8584 .- 1089-4098. ; 17:3
-
Tidskriftsartikel (refereegranskat)abstract
- Pain hypersensitivity that develops after tissue or nerve injury is dependent both on peripheral processes in the affected tissue and on enhanced neuronal responses in the central nervous system, including the dorsal horn of the spinal cord. It has become increasingly clear that strengthening of glutamatergic sensory synapses, such as those established in the dorsal horn by nociceptive thin-caliber primary afferent fibers, is a major contributor to sensitization of neuronal responses that leads to pain hypersensitivity. Here, the authors review recent findings on the roles of ionotropic glutamate receptors in synaptic plasticity in the dorsal horn in relation to acute and persistent pain.
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| 42. |
- Larsson, Max, et al.
(författare)
-
Translocation of GluR1-containing AMPA receptors to a spinal nociceptive synapse during acute noxious stimulation.
- 2008
-
Ingår i: Journal of Neuroscience. - Washington, DC, United States : Society for Neuroscience. - 0270-6474 .- 1529-2401. ; 28:28, s. 7084-7090
-
Tidskriftsartikel (refereegranskat)abstract
- Potentiation of spinal nociceptive transmission by synaptic delivery of AMPA receptors, via an NMDA receptor- and Ca(2+)/calmodulin-dependent protein kinase II (CaMKII)-dependent pathway, has been proposed to underlie certain forms of hyperalgesia, the enhanced pain sensitivity that may accompany inflammation or tissue injury. However, the specific synaptic populations that may be subject to such plasticity have not been identified. Using neuronal tracing and postembedding immunogold labeling, we show that a model of acute inflammatory hyperalgesia is associated with an elevated density of GluR1-containing AMPA receptors, as well as an increased synaptic ratio of GluR1 to GluR2/3 subunits, at synapses established by C-fibers that lack the neuropeptide substance P. A more subtle increase in GluR1 immunolabeling was noted at synapses formed by substance P-containing nociceptors. No changes in either GluR1 or GluR2/3 contents were observed at synapses formed by low-threshold mechanosensitive primary afferent fibers. These results contrast with our previous observations in the same pain model of increased and decreased levels of activated CaMKII at synapses formed by peptidergic and nonpeptidergic nociceptive fibers, respectively, suggesting that the observed redistribution of AMPA receptor subunits does not depend on postsynaptic CaMKII activity. The present ultrastructural evidence of topographically specific, activity-dependent insertion of GluR1-containing AMPA receptors at a central synapse suggests that potentiation of nonpeptidergic C-fiber synapses by this mechanism contributes to inflammatory pain.
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| 43. |
- Levinsson, Anders, et al.
(författare)
-
Spinal sensorimotor transformation: Relation between cutaneous somatotopy and a reflex network
- 2002
-
Ingår i: The Journal of Neuroscience. - 1529-2401. ; 22:18, s. 8170-8182
-
Tidskriftsartikel (refereegranskat)abstract
- The projection of primary afferents onto spinal interneurons constitutes the first step in sensorimotor transformations performed by spinal reflex systems. Despite extensive studies on spinal somatotopy, uncertainties remain concerning the extent and significance of representational overlap and relation to spinal reflex circuits. To address these issues, the cutaneous projection from the hindpaw and its relation to the topography of lamina V neurons encoding withdrawal reflex strength ("reflex encoders") was studied in rats. Thin and coarse primary afferent terminations in laminas II and III-IV, respectively, were mapped by wheat germ agglutinin-horseradish peroxidase and choleragenoid tracing. The functional weights of these projections were characterized by mapping nociceptive and tactile field potentials and compared with the topography of reflex encoders. Both anatomical and physiological data indicate that thin and coarse skin afferent input is spatially congruent in the horizontal plane. The representation of the hindpaw in the spinal cord was found to be intricate, with a high degree of convergence between the projections from different skin sites. "Somatotopic disruptions" such as the representation of central pads medial to that of the digits were common. The weight distribution of the cutaneous convergence patterns in laminas III-IV was similar to that of lamina V reflex encoders. This suggests that the cutaneous convergence and features such as somatotopic disruptions have specific relations to the sensorimotor transformations performed by reflex interneurons in the deep dorsal horn. Hence, the spinal somatotopic map may be better understood in light of the topography of such reflex systems.
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| 44. |
- Lindström, Sarah, et al.
(författare)
-
VGluT1 Deficiency Impairs Visual Attention and Reduces the Dynamic Range of Short-Term Plasticity at Corticothalamic Synapses
- 2020
-
Ingår i: Cerebral Cortex. - : OXFORD UNIV PRESS INC. - 1047-3211 .- 1460-2199. ; 30:3, s. 1813-1829
-
Tidskriftsartikel (refereegranskat)abstract
- The most common excitatory neurotransmitter in the central nervous system, glutamate, is loaded into synaptic vesicles by vesicular glutamate transporters (VGluTs). The primary isoforms, VGluT1 and 2, are expressed in complementary patterns throughout the brain and correlate with short-term synaptic plasticity. VGluT1 deficiency is observed in certain neurological disorders, and hemizygous (VGluT1(+/-)) mice display increased anxiety and depression, altered sensorimotor gating, and impairments in learning and memory. The synaptic mechanisms underlying these behavioral deficits are unknown. Here, we show that VGluT1(+/-) mice had decreased visual processing speeds during a sustained visual-spatial attention task. Furthermore, in vitro recordings of corticothalamic (CT) synapses revealed dramatic reductions in short-term facilitation, increased initial release probability, and earlier synaptic depression in VGluT1+/- mice. Our electron microscopy results show that VGluT1 concentration is reduced at CT synapses of hemizygous mice, but other features (such as vesicle number and active zone size) are unchanged. We conclude that VGluT1-haploinsuficiency decreases the dynamic range of gain modulation provided by CT feedback to the thalamus, and this deficiency contributes to the observed attentional processing deficit. We further hypothesize that VGluT1 concentration regulates release probability by applying a "brake" to an unidentified presynaptic protein that typically acts as a positive regulator of release.
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| 45. |
- Liu, Y, et al.
(författare)
-
Brainstem and thalamic projections from a craniovascular sensory nervous centre in the rostral cervical spinal dorsal horn of rats.
- 2009
-
Ingår i: Cephalalgia. - : SAGE Publications. - 0333-1024 .- 1468-2982. ; 29, s. 935-948
-
Tidskriftsartikel (refereegranskat)abstract
- To examine the ascending projections from the headache-related trigeminocervical complex in rats, biotinylated dextran amine (BDA) was injected into the ventrolateral dorsal horn of segments C1 and C2, a region previously demonstrated to receive input from sensory nerves in cranial blood vessels. Following injections into laminae I-II, BDA-labelled terminations were found bilaterally in several nuclei in the pons and the midbrain, including the pontine reticular nucleus, the parabrachial nuclei, the cuneiform nucleus and the periaqueductal grey. In the diencephalon, terminations were confined to the contralateral side and evident foremost in the posterior nuclear group, especially its triangular part, and in the ventral posteromedial nucleus. Following injections extending through laminae I-IV, anterograde labelling was more extensive. Some of the above regions are likely to be involved in the central processing of noxious signals of craniovascular origin and therefore putatively involved in mechanisms associated with primary headaches.
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| 46. |
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| 47. |
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| 48. |
- Liu, Yi, et al.
(författare)
-
Central projections of the sensory innervation of the rat middle meningeal artery.
- 2008
-
Ingår i: Brain Research. - : Elsevier BV. - 1872-6240 .- 0006-8993. ; 1208, s. 103-110
-
Tidskriftsartikel (refereegranskat)abstract
- Headaches, especially migraine, involve not only pain but also aspects such as vasodilation of cranial vessels and sensitization of nerve endings, processes dependent on and connected to the central nervous system. To understand pathogenic mechanisms of headache, it is important to elucidate the central projections of sensory nerves that innervate cranial vessels, of which the middle meningeal artery (MMA) is the largest artery supplying the dura mater. In this study, cholera toxin subunit b (CTb) or wheat germ agglutinin-horseradish peroxidase conjugate (WGA-HRP) was applied on the adventitia of MMA. After perfusion fixation, the brainstem, the C1-C4 spinal segments and the trigeminal and C2 dorsal root ganglia were removed and sections from these tissues were processed to visualize transported tracers. Labeled cell bodies were seen ipsilaterally in the trigeminal and C2 dorsal root ganglia. Labeled nerve terminations were found ipsilaterally in the lateral part of the spinal dorsal horn of segments C1-C3 and in the caudal and interpolar parts of the spinal trigeminal nucleus. WGA-HRP labeled terminations were mainly located in laminae I and II, whereas CTb labeled terminations located in laminae III-V. These results indicate that sensory information from the MMA is transmitted through both trigeminal and cervical spinal nerve branches to a region in the central nervous system extending rostrally from the C3 dorsal horn to the interpolar part of the spinal trigeminal nucleus. Our data further substantiates that the sensory innervation of the MMA, in addition to putative nociceptive afferents, include a population of large caliber afferents with an as yet unclear but presumably non-nociceptive role.
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| 49. |
- Lobo, Leonor Q., et al.
(författare)
-
Salinity and resource availability as drivers of Baltic benthic fungal diversity
- 2024
-
Ingår i: Environmental DNA. - : John Wiley & Sons. - 2637-4943. ; 6:1
-
Tidskriftsartikel (refereegranskat)abstract
- Marine biodiversity consists of a complex network of organisms responsible for keeping the ecosystem's balance. Fungi are an understudied group of organisms despite their recognized importance for ecosystem processes and diversity. How fungi respond to environmental change remains poorly understood, especially in marine benthic habitats. The Baltic Sea is a brackish coastal ecosystem with steep environmental gradients in a relatively limited geographical area and is therefore a particularly good system to investigate the impact of different abiotic factors on benthic fungal diversity. This study used environmental DNA (eDNA) metabarcoding to analyze the spatial dynamics of benthic fungal diversity in the Baltic Sea and quantify the environmental drivers that shape these dynamics. Based on 59 stations spreading over 1145 km the results showed that benthic fungal communities were dominated by the phylum Chytridiomycota, and the fungal species Alphamyces chaetifer and Operculomyces laminatus from this phylum were the main drivers of the community structure dissimilarities observed between regions. Water depth and salinity were the main predictors of the benthic fungal community composition. The impact of nutrient availability was also significant, possibly related to the known role of Chytridiomycota species such as A. chaetifer and O. laminatus in nutrient cycling. Our results indicate that the benthic fungal diversity of the Baltic Sea is shaped by salinity gradients and nutrient availability and highlights that the current fungal biodiversity is at risk of species shift or decline with predicted changes in salinity due to climate change and intensified eutrophication.
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| 50. |
- Mouton, LJ, et al.
(författare)
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Lateral cervical nucleus projections to periaqueductal gray matter in cat
- 2004
-
Ingår i: Journal of Comparative Neurology. - : Wiley. - 1096-9861 .- 0021-9967. ; 471:4, s. 434-445
-
Tidskriftsartikel (refereegranskat)abstract
- The midbrain periaqueductal gray matter (PAG) integrates the basic responses necessary for survival of individuals and species. Examples are defense behaviors such as fight, flight, and freezing, but also sexual behavior, vocalization, and micturition. To control these behaviors the PAG depends on strong input from more rostrally located limbic structures, as well as from afferent input from the lower brainstem and spinal cord. Mouton and Holstege (2000, J Comp Neurol 428:389-410) showed that there exist at least five different groups of spino-PAG neurons, each of which is thought to subserve a specific function. The lateral cervical nucleus (LCN) in the upper cervical cord is not among these five groups. The LCN relays information from hair receptors and noxious information and projects strongly to the contralateral ventroposterior and posterior regions of thalamus and to intermediate and deep tectal layers. The question is whether the LCN also projects to the PAG. The present study in cat, using retrograde and anterograde tracing techniques, showed that neurons located in the lateral two-thirds of the LCN send fibers to the lateral part of the PAG, predominantly at rostrocaudal levels A0.6-P0.2. This part of the PAG is known to be involved in flight behavior. A concept is put forward according to which the LCN-PAG pathway alerts the animal about the presence of cutaneous stimuli that might represent danger, necessitating flight. (C) 2004 Wiley-Liss, Inc.
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