| 1. |
- Taylor, Linnéa, et al.
(författare)
-
Feet on the ground: Physical support of the inner retina is a strong determinant for cell survival and structural preservation in vitro.
- 2014
-
Ingår i: Investigative Ophthalmology & Visual Science. - : Association for Research in Vision and Ophthalmology (ARVO). - 1552-5783. ; 55:4, s. 2200-2213
-
Tidskriftsartikel (refereegranskat)abstract
- Purpose: The purpose of this study was to explore the importance of local physical tissue support for homeostasis in the isolated retina. Methods: Full-thickness retinal sheets were isolated from adult porcine eyes. Retinas were cultured for 5 or 10 days using the previously established explant protocol with photoreceptors positioned against the culture membrane (porous polycarbonate) or the Müller cell endfeet and inner limiting membrane (ILM) apposed against the membrane. The explants were analyzed morphologically using hematoxylin and eosin staining, immunohistochemistry, TUNEL labeling, and transmission electron microscopy (TEM). Results: Standard cultures displayed a progressive loss of retinal lamination and extensive cell death, with activated, hypertrophic Müller cells. In contrast, explants cultured with the ILM facing the membrane displayed a maintenance of the retinal laminar architecture, and a statistically significant attenuation of photoreceptor and ganglion cell death. TEM revealed intact synapses as well as preservation of normal cellular membrane structures. Immunohistochemistry showed no signs of Müller cell activation (GFAP), with maintained expression of important metabolic markers (GS, bFGF). Conclusion: Providing physical support to the inner but not the outer retina appears to prevent the tissue collapse resulting from perturbation of the normal biomechanical milieu in the isolated retinal sheet. Using this novel paradigm, gliotic reactions are attenuated, and metabolic processes vital for tissue health are preserved which significantly increases neuronal cell survival. This finding opens up new avenues of adult retinal tissue culture research, and increases our understanding of pathological reactions in biomechanically related conditions in vivo.
|
|
| 2. |
- Åkerström, Bo, et al.
(författare)
-
The Role of Mitochondria, Oxidative Stress, and the Radical-binding Protein A1M in Cultured Porcine Retina.
- 2017
-
Ingår i: Current Eye Research. - : Informa UK Limited. - 0271-3683 .- 1460-2202. ; 42:6, s. 948-961
-
Tidskriftsartikel (refereegranskat)abstract
- Purpose: The purpose of this study was to explore the relationship between oxidative stress, antioxidant defense, mitochondrial structure, and biomechanical tissue support in the isolated porcine retina.Methods: Full-thickness retinal sheets were isolated from adult porcine eyes. Retinas were cultured for 2 or 48 h using (1) a previously established low-support explant protocol with photoreceptors positioned against the culture membrane (porous polycarbonate) or (2) a high-support procedure developed by our group, apposing the Müller cell endfeet and inner limiting membrane against the membrane. The grafts were analyzed by quantitative polymerase chain reaction (PCR), immunohistochemistry, and transmission electron microscopy (TEM), and culture medium was assayed for the cell damage and oxidative stress markers lactate dehydrogenase and protein carbonyls.Results: In explants cultured with physical support to the inner border, cone photoreceptors were preserved and lactate dehydrogenase levels were reduced, although an initial (2 h), transient, increased oxidative stress was observed. Elevated expression of the antioxidants α1-microglobulin and heme oxygenase-1 was seen in the mitochondria-rich inner segments after 48 h compared to low-support counterparts. Housekeeping gene expression suggested a higher degree of structural integrity of mitochondria in high-support explants, and TEM of inner segments confirmed preservation of a normal mitochondrial morphology.Conclusion: Providing retinal explants with inner retinal support leads to mobilization of antioxidant proteins, preservation of mitochondrial function, and increased cell viability. Consequently, the failure of low-support retinal cultures to mobilize an adequate response to the oxidative environment may play a key role in their rapid demise. These findings shed new light on pathological reactions in biomechanically related conditions in vivo.
|
|
| 3. |
- Ademuyiwa, Adesoji O., et al.
(författare)
-
Determinants of morbidity and mortality following emergency abdominal surgery in children in low-income and middle-income countries
- 2016
-
Ingår i: BMJ Global Health. - : BMJ Publishing Group Ltd. - 2059-7908. ; 1:4
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Child health is a key priority on the global health agenda, yet the provision of essential and emergency surgery in children is patchy in resource-poor regions. This study was aimed to determine the mortality risk for emergency abdominal paediatric surgery in low-income countries globally.Methods: Multicentre, international, prospective, cohort study. Self-selected surgical units performing emergency abdominal surgery submitted prespecified data for consecutive children aged <16 years during a 2-week period between July and December 2014. The United Nation's Human Development Index (HDI) was used to stratify countries. The main outcome measure was 30-day postoperative mortality, analysed by multilevel logistic regression.Results: This study included 1409 patients from 253 centres in 43 countries; 282 children were under 2 years of age. Among them, 265 (18.8%) were from low-HDI, 450 (31.9%) from middle-HDI and 694 (49.3%) from high-HDI countries. The most common operations performed were appendectomy, small bowel resection, pyloromyotomy and correction of intussusception. After adjustment for patient and hospital risk factors, child mortality at 30 days was significantly higher in low-HDI (adjusted OR 7.14 (95% CI 2.52 to 20.23), p<0.001) and middle-HDI (4.42 (1.44 to 13.56), p=0.009) countries compared with high-HDI countries, translating to 40 excess deaths per 1000 procedures performed.Conclusions: Adjusted mortality in children following emergency abdominal surgery may be as high as 7 times greater in low-HDI and middle-HDI countries compared with high-HDI countries. Effective provision of emergency essential surgery should be a key priority for global child health agendas.
|
|
| 4. |
- Bodén, Linnea, 1981-, et al.
(författare)
-
Relational Materialism
- 2020
-
Ingår i: The Oxford encyclopedia of qualitative research methods in education. - : Oxford University Press. - 9780190643768 - 9780190643751
-
Bokkapitel (refereegranskat)abstract
- Relational materialism was first articulated and framed within Actor Network Theory. In educational research, the concept has emerged with the growing influence of Agential Realism and New Material Feminism, and in the engagements in the “turn to materiality” and/or “turn to ontology.” A relational materialist approach to educational studies can be narrowed down to three key principles: the principle of general symmetry; the principle of material semiotics; and the principle of method. The enactment of relational materialism depends on how these principles come to work in the engagement with central educational problems, such as subjectivity, performativity and practice. Relational materialism takes the starting-point in the problems and concerns of human and material actors or agents, for whom the research can make a difference. While doing so, it acknowledges the methodological difficulties and possibilities when carefully attending simultaneously to discourse, materialities and their relations. Striving towards a methodological sensibility, the enactment of relational materialism in education research entails the emergence and creation of more and multiple methods to know the multiple realities of education. This also makes it possible for relational materialist research to become productive of new and additional educational realities that can, perhaps, make an affirmative difference to the actors or agents concerned.
|
|
| 5. |
- Falck-Ytter, Terje, et al.
(författare)
-
The Babytwins Study Sweden (BATSS): A Multi-Method Infant Twin Study of Genetic and Environmental Factors Influencing Infant Brain and Behavioral Development
- 2021
-
Ingår i: Twin Research and Human Genetics. - : Cambridge University Press (CUP). - 1832-4274 .- 1839-2628. ; 24:4, s. 217-227
-
Tidskriftsartikel (refereegranskat)abstract
- Twin studies can help us understand the relative contributions of genes and environment to phenotypic trait variation, including attentional and brain activation measures. In terms of applying methodologies such as electroencephalography (EEG) and eye tracking, which are key methods in developmental neuroscience, infant twin studies are almost nonexistent. Here, we describe the Babytwins Study Sweden (BATSS), a multi-method longitudinal twin study of 177 MZ and 134 DZ twin pairs (i.e., 622 individual infants) covering the 5-36 month time period. The study includes EEG, eye tracking and genetics, together with more traditional measures based on in-person testing, direct observation and questionnaires. The results show that interest in participation in research among twin parents is high, despite the comprehensive protocol. DNA analysis from saliva samples was possible in virtually all participants, allowing for both zygosity confirmation and polygenic score analyses. Combining a longitudinal twin design with advanced technologies in developmental cognitive neuroscience and genomics, BATSS represents a new approach in infancy research, which we hope to have impact across multiple disciplines in the coming years.
|
|
| 6. |
- Ghosh, Fredrik, et al.
(författare)
-
Acute tissue reactions, inner segment pathology, and effects of the antioxidant α1-microglobulin in an in vitro model of retinal detachment
- 2018
-
Ingår i: Experimental Eye Research. - : Elsevier BV. - 0014-4835. ; 173, s. 13-23
-
Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to explore acute tissue reactions, ultrastructural photoreceptor morphology with emphasis on inner segments, and the effect of antioxidant treatment in an in vitro model of rhegmatogenous retinal detachment (RRD). A previously described method of RRD simulation was used with adult retinal porcine explants kept free-floating in culture medium with or without treatment with the radical scavenger α1-microglobulin (A1M). Explants were examined at 5 time points from 1 to 24 h using transmission electron microscopy as well as quantitative real-time PCR (RT-PCR) to quantify gene expression of the cell stress marker heat shock protein 70 (Hsp70) and oxidative stress marker heme oxygenase (HO-1). The culture medium level of the cell damage marker lactate dehydrogenase (LDH) and oxidative stress DNA damage marker 8-Oxo-2'-deoxyguanosine (8-OHdG) was also assessed at each time point. We found that the levels of Hsp70 and LDH rapidly increased in both groups, and at 3 and 6 h, Hsp70 was significantly higher in A1M treated retinas. At 24 h, Hsp70 and LDH, as well as 8-OHdG were significantly lower compared with controls, whereas the tissue level of HO-1 was significantly higher. Progressive ultrastructural photoreceptor changes were seen in untreated control explants from 1 h and onwards including outer segment shortening and loss, disruption of organelles within the inner segments and loss of perikarya in the outer nuclear layer. Inner segment pathology was more rapid and extensive in rods compared with in cones. In A1M treated counterparts, damage to rod inner segment mitochondria was significantly higher after 1 h of culture, but after this time, no statistical difference was found. At 24 h, cone inner segment mitochondrial disruption was significantly higher in control retinas and the number of surviving perikarya lower. From our results, we conclude that retinal explants elicit acute cell stress reactions when placed in culture without physical support simulating a detached retina floating in the vitreous space. Photoreceptors rapidly display degenerative changes including extensive damage to inner segment mitochondria indicating loss of energy transduction as an early key event. A1M increases initial mitochondrial stress in the rods, however, subsequent pathology is attenuated by the treatment, highlighting the dynamics of protective as well as disruptive oxidative stress reactions in the detached retina.
|
|
| 7. |
- Ghosh, Fredrik, et al.
(författare)
-
Exogenous Glutamate Modulates Porcine Retinal Development in vitro.
- 2012
-
Ingår i: Developmental Neuroscience. - : S. Karger AG. - 1421-9859 .- 0378-5866.
-
Tidskriftsartikel (refereegranskat)abstract
- Embryogenesis of the retina is a complex event orchestrated by a multitude of physical and biochemical signals. To study the impact of intrinsic developmental cues, the retinal tissue can be isolated in culture which also enables modulation of normal development for other purposes, i.e. transplantation of specific neuronal cell types. In the present experiment, cell type development of immature porcine retinal tissue kept in culture was explored using specific immunohistochemical markers. Retinal explants were either kept under standard culture conditions or supplemented with glutamate and their morphology was compared with in vivo controls of corresponding age. After 15 days in vitro (DIV), E45 retinal explants displayed several signs of atypical development when compared with E60 in vivo controls. First, an accelerated photoreceptor differentiation was evident, seen in sections labeled with antibodies directed against recoverin, rhodopsin and synaptophysin. Second, apoptotic cells in the inner retina were more prevalent in the cultured retinas (TUNEL). Rod photoreceptor differentiation as well as inner retinal apoptosis was even more pronounced in glutamate-supplemented specimens in which they occurred already at 8 DIV. Müller cell, vimentin and GFAP expression was not affected in any of the cultured retinas. These results suggest that normal retinal embryogenesis is more dependent on tissue extrinsic factors than what has been deduced from previous small animal experiments. Glutamate, which has been identified as an important regulator of cell cycle exit, may also be important for photoreceptor differentiation and induction of developmental apoptosis. Insights into retinal cell type differentiation under in vitro conditions is of interest from a biological standpoint, and the possibility of modulation of this process is valuable for research directed towards cell replacement in retinal degenerative disease.
|
|
| 8. |
- Ghosh, Fredrik, et al.
(författare)
-
In vitro biomechanical modulation-retinal detachment in a box.
- 2016
-
Ingår i: Graefe's Archive for Clinical and Experimental Ophthalmology. - : Springer Science and Business Media LLC. - 1435-702X .- 0721-832X. ; 254:3, s. 475-487
-
Tidskriftsartikel (refereegranskat)abstract
- To illustrate the importance of biomechanical impact on tissue health within the central nervous system (CNS), we herein describe an in vitro model of rhegmatogenous retinal detachment (RRD) in which disruption and restoration of physical tissue support can be studied in isolation.
|
|
| 9. |
- Ghosh, Fredrik, et al.
(författare)
-
Retinal neuroinflammatory induced neuronal degeneration - Role of toll-like receptor-4 and relationship with gliosis
- 2018
-
Ingår i: Experimental Eye Research. - : Elsevier BV. - 0014-4835. ; 169, s. 99-110
-
Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to explore retina-intrinsic neuroinflammatory reactions, effects on neuronal survival, relationship with classic gliosis, and possible role of the toll-like receptor 4 (TLR4). To isolate the adult retina from the systemic immune system, a previously described large animal explant culture model was used in which full-thickness porcine retinal sheets can be kept in vitro for extended time periods. Explants were kept for 5 days in vitro (DIV) and were treated with either; lipopolysaccharide (LPS), a Toll-like receptor-4 (TLR4) inhibitor (CLI-095), LPS + CLI-095, or solvent vehicle throughout the culture period after which retinal sections were examined with hematoxylin and eosin staining and extensive immunohistochemistry. In addition, the culture medium of all explants was assayed for a panel of cytokines at 2 and 5DIV. Compared with in vivo controls, vehicle controls (CT) as well as CLI-095 explants displayed moderate reduction of total thickness and number of retinal neurons with upregulation of glial fibrillary acidic protein (GFAP) throughout the Müller cells. In contrast, LPS and LPS + CLI-095 treated counterparts showed extensive overall thinning with widespread neuronal degeneration but only minimal signs of classical Müller cell gliosis (limited upregulation of GFAP and no downregulation of glutamine synthetase (GS). These specimens also displayed a significantly increased expression of galectin-3 and TGF-beta activated kinase 1 (TAK1). Multiplex proteomic analysis of culture medium at 2DIV revealed elevated levels of IL-1β, IL-6, IL-4 and IL-12 in LPS-treated explants compared to CLI-095 and CT counterparts. LPS stimulation of the isolated adult retina results in substantial neuronal cell death despite only minimal signs of gliosis indicating a retina-intrinsic neuroinflammatory response directly related to the degenerative process. This response is characterized by early upregulation of several inflammatory related cytokines with subsequent upregulation of Galectin-3, TLR4 and TAK1. Pharmacological block of TLR4 does not attenuate neuronal loss indicating that LPS induced retinal degeneration is mediated by TLR4 independent neuroinflammatory pathways.
|
|
| 10. |
|
|
