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- Blixt Wojciechowski, Anita, et al.
(författare)
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Long-term survival and glial differentiation of the brain-derived precursor cell line RN33B after subretinal transplantation to adult normal rats
- 2002
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Ingår i: Stem Cells. - : Oxford University Press (OUP). - 1549-4918 .- 1066-5099. ; 20:2, s. 163-173
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Tidskriftsartikel (refereegranskat)abstract
- The potential use of in vitro-expanded precursor cells or cell lines in repair includes transplantation of such cells for cell replacement purposes and the activation of host cells to provide "self-repair." Recently, we have reported that cells from the brain-derived cell line RN33B (derived from the embryonic rat medullary raphe and immortalized through retroviral transduction of the temperature-sensitive mutant of the simian virus 40 ([SV40] large T-antigen) survive for at least 4 weeks, integrate, and differentiate after subretinal grafting to normal adult rats. Here, we demonstrate that grafts of these cells survive for at least 4 months after subretinal transplantation to adult, normal immunosuppressed rats. Implanted cells integrate into the retinal pigment epithelium and the inner retinal layers, and the anterior part of the optic nerve. In addition, the RN33B cells migrate within the retina, occupying the whole retina from one eccentricity to the other. A large fraction of the grafted cells differentiate into glial cells, as shown by double labeling of the reporter genes LacZ or green fluorescent protein, and several glial markers, including oligodendrocytes. However, the cells did not differentiate into retinal neurons, judging from their lack of expression of retinal neuronal phenotypic markers. A significant number of the implanted cells in the host retina were in a proliferative stage, judging from proliferative cell nuclear antigen and SV40 large T-antigen immunohistochemistry. To conclude, the cells survived, integrated, and migrated over long distances within the host. Therefore, our results may be advantageous for future design of therapeutic strategies, since such cells may have the potential of being a source of, for example, growth factor delivery in experimental models of retinal degeneration.
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- Blixt Wojciechowski, Anita, et al.
(författare)
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Migratory capacity of the cell line RN33B and the host glial cell response after subretinal transplantation to normal adult rats
- 2004
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Ingår i: Glia. - : John Wiley & Sons. - 0894-1491 .- 1098-1136. ; 47:1, s. 58-67
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Tidskriftsartikel (refereegranskat)abstract
- As previously reported, the brain-derived precursor cell line RN33B has a great capacity to migrate when transplanted to adult brain or retina. This cell line is immortalized with the SV40 large T-antigen and carries the reporter gene LacZ and the green fluorescent protein GFP. In the present study, the precursor cells were transplanted to the subretinal space of adult rats and investigated early after grafting. The purpose was to demonstrate the migration of the grafted cells from the subretinal space into the retina and the glial cell response of the host retina. Detachment caused by the transplantation method was persistent up to 4 days after transplantation, and then reattachment occurred. The grafted cells were shown to migrate in between the photoreceptor cells before entering into the plexiform layers. Molecules involved in migration of immature neuronal cells as the polysialylated neural cell adhesion molecule (PSA-NCAM) and the collapsing response-mediated protein 4 (TUC-4) was found in the plexiform layers of the host retina, but not in the grafted cells. The expression of the intermediate filaments GFAP, vimentin, and nestin was intensely upregulated immediately after transplantation. A less pronounced upregulation was observed on sham-operated animals. In summary, the RN33B cell line migrated promptly posttransplantation and settled preferably into the plexiform layers of the retina, the same layers where the migration cues PSA-NCAM and TUC-4 were established. In addition, both the transplantation method per se and the implanted cells caused an intense glial cell response by the host retina.
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- Blixt Wojciechowski, Anita, et al.
(författare)
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Subretinal Transplantation of Brain-derived Precursor Cells to Young RCS Rats Promotes Photoreceptor Cell Survival☆
- 2002
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Ingår i: Experimental Eye Research. - : Elsevier. - 0014-4835 .- 1096-0007. ; 75:1, s. 23-37
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Tidskriftsartikel (refereegranskat)abstract
- The potential use of in vitro-expanded precursor cells or cell lines in brain repair includes transplantation of such cells for cell replacement purposes and the activation of host cells to provide 'self-repair'. Recently, it has been reported that the immortalized brain-derived cell line RN33B (derived from the embryonic rat medullary raphe) survive, integrate and differentiate after subretinal grafting to normal adult rats. Here, it is demonstrated that grafts of these cells survive for at least 6 weeks after implantation into postnatal days 21 and 35 retinas of normal and Royal College of Surgeons rats, a model of retinal degeneration. Implanted cells integrate into the retinal pigment epithelium and the inner retinal layers, and the anterior part of the optic nerve of both normal and Royal College of Surgeons rats. The RN33B cells migrate within the retina, occupying the whole retina from one eccentricity to the other. A significant number of the grafted cells differentiate into glial cells, as shown by the double labelling of the reporter genes LacZ or green fluorescent protein, with several glial markers, including oligodendrocytic markers. Many implanted cells in the host retina were in a proliferative stage judging from proliferative cell nuclear antigen and SV40 large T-antigen immunohistochemistry. Interestingly, there was a promotion of photoreceptor survival, extending over more than 2/3 of the superior hemisphere, in Royal College of Surgeons rats transplanted at postnatal day 21, but not at postnatal day 35. In addition, grafted cells were found in the surviving photoreceptor layer in these rats.
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- Blixt Wojciechowski, Anita, et al.
(författare)
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Survival and long distance migration of brain-derived precursor cells transplanted to adult rat retina
- 2004
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Ingår i: Stem Cells. - : AlphaMed Press. - 1549-4918 .- 1066-5099. ; 22:1, s. 27-38
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Tidskriftsartikel (refereegranskat)abstract
- Neural precursor cells transplanted to adult retina can integrate into the host. This is especially true when the neural precursor rat cell line RN33B is used. This cell line carries the reporter genes LacZ and green fluorescent protein (GFP). In grafted rat eyes, RN33B cells are localized from one eccentricity to the other of the host retina. In the present study, whole-mounted retinas were analyzed to obtain a more appropriate evaluation of the amount of transgene-expressing cells and the migratory capacity of these cells 3 and 8 weeks post-transplantation. Quantification was made of the number of beta-galactosidase- and GFP-expressing cells with a semiautomatized stereological cell counting system. With the same system, delineation of the distribution area of the grafted cells was also performed. At 3 weeks, 68% of the grafted eyes contained marker-expressing cells, whereas at 8 weeks only 35% of the eyes contained such cells. Counting of marker-expressing cells demonstrated a lower number of transgene-expressing cells at 3 weeks compared with 8 weeks post-transplantation. The distribution pattern of marker gene-expressing cells revealed cells occupying up to 21% at 3 weeks and up to 68% at 8 weeks of the entire host retina post-grafting. The precursor cells survived well in the adult retina although the most striking feature of the RN33B cell line was its extraordinary migratory capacity. This capability could be useful if precursor cells are used to deliver necessary genes or gene products that need to be distributed over a large diseased area.
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- Ederoth, Per, et al.
(författare)
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Blood-brain barrier transport of morphine in patients with severe brain trauma
- 2004
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Ingår i: British Journal of Clinical Pharmacology. - : Wiley. - 0306-5251 .- 1365-2125. ; 57:4, s. 427-435
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Tidskriftsartikel (refereegranskat)abstract
- AIMS: In experimental studies, morphine pharmacokinetics is different in the brain compared with other tissues due to the properties of the blood-brain barrier, including action of efflux pumps. It was hypothesized in this clinical study that active efflux of morphine occurs also in human brain, and that brain injury would alter cerebral morphine pharmacokinetics. METHODS: Patients with traumatic brain injury, equipped with one to three microdialysis catheters in the brain and one in abdominal subcutaneous fat for metabolic monitoring, were studied. The cerebral catheter locations were classified as 'better' and 'worse' brain tissue, referring to the degree of injury. Morphine (10 mg) was infused intravenously over a 10-min period in seven patients in the intensive care setting. Tissue and plasma morphine concentrations were obtained during the subsequent 3-h period with microdialysis and regular blood sampling. RESULTS: The area under the concentration-time curve (AUC) ratio of unbound morphine in brain tissue to plasma was 0.64 (95% confidence interval 0.40, 0.87) in 'better' brain tissue (P < 0.05 vs. the subcutaneous fat/plasma ratio), 0.78 (0.49, 1.07) in 'worse' brain tissue and 1.00 (0.86, 1.13) in subcutaneous fat. The terminal half-life and T(max) were longer in the brain vs. plasma and fat, respectively. The relative recovery for morphine was higher in 'better' than in 'worse' brain tissue. The T(max) value tended to be shorter in 'worse' brain tissue. CONCLUSIONS: The unbound AUC ratio below unity in the 'better' human brain tissue demonstrates an active efflux of morphine across the blood-brain barrier. The 'worse' brain tissue shows a decrease in relative recovery for morphine and in some cases also an increase in permeability for morphine over the blood-brain barrier.
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- Elmqvist, Thomas, et al.
(författare)
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The Dynamics of Social-Ecological Systems in Urban Landscapes
- 2004
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Ingår i: Annals of the New York Academy of Sciences. - : Wiley. - 0077-8923 .- 1749-6632. ; 1023, s. 308-322
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Tidskriftsartikel (refereegranskat)abstract
- This study addresses social-ecological dynamics in the greater metropolitan area of Stockholm County, Sweden, with special focus on the National Urban Park (NUP). It is part of the Millennium Ecosystem Assessment (MA) and has the following specific objectives: (1) to provide scientific information on biodiversity patterns, ecosystem dynamics, and ecosystem services generated; (2) to map interplay between actors and institutions involved in management of ecosystem services; and (3) to identify strategies for strengthening social-ecological resilience. The green areas in Stockholm County deliver numerous ecosystem services, for example, air filtration, regulation of microclimate, noise reduction, surface water drainage, recreational and cultural values, nutrient retention, and pollination and seed dispersal. Recreation is among the most important services and NUP, for example, has more than 15 million visitors per year. More than 65 organizations representing 175,000 members are involved in management of ecosystem services. However, because of population increase and urban growth during the last three decades, the region displays a quite dramatic loss of green areas and biodiversity. An important future focus is how management may reduce increasing isolation of urban green areas and enhance connectivity. Comanagement should be considered where locally managed green space may function as buffer zones and for management of weak links that connect larger green areas; for example, there are three such areas around NUP identified. Preliminary results indicate that areas of informal management represent centers on which to base adaptive comanagement, with the potential to strengthen biodiversity management and resilience in the landscape.
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