| 1. |
- Heijl, Anders, et al.
(författare)
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Nordic research in ophthalmology.
- 2005
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Ingår i: Acta ophthalmologica Scandinavica. - : Wiley. - 1395-3907 .- 1600-0420. ; 83:3, s. 278-88
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Nordic ophthalmologists and vision scientists are active in many fields of eye research. This is most evident at the biannual Nordic Congress of Ophthalmology, most recently held in Malmö in June 2004. The authors here review some of the research in vision and ophthalmology presented at this meeting or published recently by Nordic scientists. This paper does not represent a comprehensive review of all Nordic research in the field, but attempts to give an overview of some of the activities underway in eye research in this part of the world.
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| 2. |
- Crafoord, Sven, 1950-
(författare)
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Experimental transplantation of retinal and iris pigment epithelial cells into the subretinal space
- 2000
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- A dysfunction of the retinal pigment epithelium (RPE) is the main cause for the development of age-related macular degeneration (ARMD) and visual loss in elderly people. For about 10 years experimental and clinical attempts to transplant RPE cells have been performed. The aims of this study were to elucidate the long term results of RPE allografts, to develop an atraumatic transplantation technique, and to explore the cellular response to RPE allografts, melanin granules, and autologous IPE cells.Surgery was performed on rabbits with a follow-up period of up to six months. After a pars plan vitrectomy, a subretinal bleb was created into which a suspension of RPE/IPE donor cells or melanin granules was injected. Pigmented RPE donor cells or preparations of melanin granules were implanted subretinally in albino rabbits. Pigmented rabbits were used in IPE transplantation. The eyes were monitored with ophthalmoscopy, fundus photography, light microscopy, electron microscopy and immunohistochemistry.Transplantation of suspensions of fresh pigmented RPE cells to the subretinal space in rabbits is feasible and induces virtually no complications when an atraumatic surgical procedure is used. The allograft forms a monolayer in conjunction with the native RPE and persists almost intact up to three months. At six months after transplantation, there was a cellular response exhibiting multilayers of cells, such as RPE and macrophages. Damage to adjacent photoreceptors in combination with melanin granules in the subretinal space indicates graft failure. No infiltration of lymphocytes was seen. Whether the cellular response was due to immunological or non-immunological mechanisms could not be determined from this experiment.Cyclosporine (CsA) could not prevent disintegration of the RPE transplant and graft failure. CsA was not capable of promoting graft survival as compared to the controls. The transplant seems to be disrupted either by immunological mechanisms that are not inhibited by CsA, or by non-immunologic events.Implantation of melanin granules to the subretinal space of albino rabbits induces a considerable phagocytic cellular response involving the host’s RPE, macrophages and glial cells. The migration of pigment-laden cells into the neural retina was frequently associated with focal photoreceptor damage. The cellular response was identical to that ensuing RPE cell transplantation. These findings support the concept that non-immunological events have a considerable influence on the outcome.In order to evaluate the impact of non-immunological mechanisms, a technique of transplanting fresh autologous IPE cells to the subretinal space of the same eye was developed. Grafted IPE cells were seen to survive for six months. There was a remodeling of the compound cellular layers in the subretinal space over time where grafted IPE cells joined the native RPE cells. The cellular response that developed exhibited macrophages, but no lymphocytes, and was in this respect similar to that observed following RPE transplantation.In RPE allografts, the photoreceptors appeared normal on light microscopy at three months, but at six months, the photoreceptors overlying the transplants generally exhibited pathological changes. In autologous IPE grafts, on the other hand, the photoreceptors displayed normal outer segment length and outer nuclear layer on top of grafted IPE cells. Focally, multilayers of both grafted IPE and RPE cells, together with macrophages, induce damage to adjacent photoreceptors as observed at 6 months. Cellular multilayers in the subretinal space, irrespective of genesis, are likely to have adverse effects on photoreceptors. The experiments using autologous IPE grafts show that non-immunogenic mechanisms have a decisive impact on the outcome of the transplant in the subretinal space.
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| 3. |
- Kyhn, Maria Voss, et al.
(författare)
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Acute retinal ischemia caused by controlled low ocular perfusion pressure in a porcine model. Electrophysiological and histological characterisation
- 2009
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Ingår i: Experimental Eye Research. - : Elsevier BV. - 0014-4835. ; 88:6, s. 1100-1106
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to establish, and characterize a porcine model of acute, controlled retinal ischemia. The controlled retinal ischemia was produced by clamping the ocular perfusion pressure (OPP) in the left eye to 5 mm Hg for 2 h. The OPP was defined as mean arterial blood pressure (MAP) minus the intraocular pressure (IOP). It was clamped to 0-30 mm Hg by continuous monitoring of MAP and adjustment of the IOP, which was controlled by cannulation of the anterior chamber. Inner retinal function was assessed by induced multifocal electroretinography (mfERG) with comparisons of the amplitudes obtained in the experimental, left eye, and the control, right eye. Quantitative histology was performed to measure the survival of ganglion cells, amacrine cells and horizontal cells 2-6 weeks after the ischemic insult. An OPP of 5 mm Hg for 2 h induced significant reductions in the amplitudes of iN1 to 20% (CI: 13-30%), and iPr2 to 14% (95% CI: 8-22%) of their baseline values. No signs of recovery were found within the 6-week observation period. Quantitative histology revealed a highly significant reduction in the number of ganglion cells, amacrine cells and horizontal cells after the ischemic insult. This model seems to be suitable for investigations of therapeutic initiatives in diseases involving acute retinal ischemia. (C) 2009 Elsevier Ltd. All rights reserved.
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| 4. |
- Kyhn, Maria Voss, et al.
(författare)
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Delayed administration of glial cell line-derived neurotrophic factor (GDNF) protects retinal ganglion cells in a pig model of acute retinal ischemia
- 2009
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Ingår i: Experimental Eye Research. - : Elsevier BV. - 0014-4835 .- 1096-0007. ; 89:6, s. 1012-1020
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Tidskriftsartikel (refereegranskat)abstract
- This study investigates whether intravitreal administration of glial cell line-derived neurotrophic factor (GDNF) enhances survival of NeuN positive retinal cells in a porcine model of retinal ischemia. 16 pigs were subjected to an ischemic insult where intraocular pressure was maintained at 5 mmHg below mean arterial blood pressure for 2 h. The mean IOP during the ischemic insult was 79.5 mmHg (s.e.m. 2.1 mmHg, n = 15). Three days after the insult the pigs received an intravitreal injection of GDNF microspheres or blank microspheres. The pigs were evaluated by way of multifocal electroretinography (mfERG), quantification of NeuN positive cells and evaluation of the degree of retinal perivasculitis and inflammation 6 weeks after the insult. In the post-injection eyes (days 14, 28 and 42), the ratios of the iN1 and the iP2 amplitudes were 0.10 (95% CI: 0.05-0.15) and 0.09 (95% CI: 0.04-0.16) in eyes treated with blank microspheres, and 0.24 (95% CI: 0.18-0.32) and 0.23 (95% CI: 0.15-0.33) in eyes treated with GDNF microspheres. These differences were statistically significant (P < 0.05). The number of NeuN positive cells in the area of the visual streak area was significantly higher in eyes injected with GDNF microspheres compared to eyes injected with blank microspheres. In eyes injected with GDNF microspheres the ganglion cell count was 9.5/field (s.e.m.: 2.1, n = 8), in eyes injected with blank microspheres it was 3.5/field (s.e.m.: 1.2, n = 7). This difference was statistically significant (P < 0.05). There was also a significant difference (P < 0.01) in the degree of perivasculiitis between GDNF treated eyes (median perivasculitis score 1.5) and blank treated eyes (median perivasculitis score 3.0). In conclusion, injection of GDNF microspheres 3 days after an ischemic insult results in functional and morphological rescue of NeuN positive cells in a porcine model of acute ocular ischemia. (C) 2009 Elsevier Ltd. All rights reserved.
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| 5. |
- von Holstein, Sarah Linéa, et al.
(författare)
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Lacrimal gland lesions in Denmark between 1974 and 2007.
- 2013
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Ingår i: Acta ophthalmologica. - : Wiley. - 1755-3768 .- 1755-375X. ; 91:4, s. 349-354
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To evaluate the incidence rate, distribution, patient characteristics and indications for surgical intervention of lacrimal gland lesions in Denmark between 1974 and 2007. Material and methods: All biopsied/surgically removed lacrimal gland lesions in Denmark during the period 1974-2007 were identified by searching two population-based registries. Specimens were collected and re-evaluated. The following data were collected: age, gender, indications for surgical intervention and local recurrence. Results: A total of 232 lesions from 210 patients with a histologically verified lesion of the lacrimal gland were included. The incidence rate of lacrimal gland lesions was 1.3/1000000/year. The overall annual age- and gender-adjusted incidence rate more than doubled during the study period, owing to an increase in non-malignant lesions. Approximately half of the lesions were neoplasms (119) and 55% (66) of these were malignant. Dacryops constituted 10% (24), inflammatory lesions 27% (62), normal tissue 12% (27), benign tumours 23% (53) and malignant tumours 29% (66). Patients with malignant neoplasms were significantly older than patients with benign neoplasms (63 versus 48years, p<0.001). The indication for surgical intervention was suspicion of a tumour in more than 90% of the neoplastic lesions and in 30% of the non-neoplastic lesions. Conclusion: Lacrimal gland lesions that require surgical evaluation are rare in the Danish population and represent a wide spectrum of diagnoses, mostly benign. The overall incidence rate of biopsied lacrimal gland lesions is increasing.
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