Photodynamic therapy for AMD: smaller is better!
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Humans↗
Biomedical subjects
Morten la Cour
Publications and source records attributed to Morten la Cour.
Cotransport of H+, lactate, and H2O in porcine retinal pigment epithelial cells.
The retinal pigment epithelium (RPE) of the eye transports water and lactate ions in the direction from retina to choroid. The water transport is important in maintenance of retinal adhesion and the transport of lactate ions serves to regulate the lactate levels and pH of the subretinal space. This study investigates by means of a non-invasive technique the mechanism of coupling between transport of H(+), lactate ion, and water in the monocarboxylate transporter (MCT1) located in the apical (retinal) membrane of a mammalian RPE. Primary cultures of porcine RPE cells were grown to confluence and placed in a perfusion chamber in which the solution facing the retinal membrane could be changed rapidly. Two types of experiments were performed: Changes in cell water volume were measured by self-quenching of the fluorescent dye Calcein, and changes in intracellular pH were measured ratiometrically using the fluorescent dye BCECF. In lactate-free solutions, mannitol addition to the retinal bath caused intracellular acidification and cell shrinkage, given by a single osmotic water permeability of 1.2+/-0.1 x 10(-4)cmsec(-1) (osmoll(-1))(-1). In solutions containing 50 mmoll(-1) lactate, however, the mannitol-induced cell shrinkage was faster and the cells alkalinized. These effects were not linear functions of the magnitude of the imposed osmotic gradients: Both volume effects and changes in intracellular pH showed apparent saturation with increasing gradients. Abrupt isosmotic replacement of Cl(-) with lactate in the concentration range from 3 to 50 mmoll(-1) caused an immediate cell swelling as well as an immediate intracellular acidification; both effects showed apparent saturation with increasing lactate concentration. The K(m) values were: 11+/-2 mmoll(-1) for the water fluxes and 13+/-4 mmoll(-1) for the H(+) and lactate fluxes. The data suggest that H(2)O is cotransported along with H(+) and lactate ions in MCT1 localized to the retinal membrane. The study emphasizes the importance of this cotransporter in the maintenance of water homeostasis and pH in the subretinal space of a mammalian tissue and supports our previous study performed by an invasive technique in an amphibian tissue.
Animals↗
Eales' disease in Inuit: report of four cases.
PURPOSE: To report four cases of Eales' disease in Inuit from Greenland diagnosed within a 6.5-year period. There are no previous reports on Eales' disease among Greenlanders. METHODS: Four younger Inuit, three males and one female, were diagnosed with Eales' disease based on fundus changes and exclusion of possible differential diagnoses. Several studies point to a possible relation between Eales' disease and tuberculosis (TB); examination of possible exposure to TB was part of the clinical investigation. RESULTS: Retinal changes made panretinal laser photocoagulation necessary in all cases. Four eyes in three patients were vitrectomized. Three patients received oral corticosteroid treatment. The final visual outcome was relatively good, with a visual acuity below 6/60 (3/36) in only one vitrectomized eye. All patients had been exposed to TB. CONCLUSION: Eales' disease seems to be rather common in the small population of Inuit (56,000) in Greenland. Attention is required to ensure diagnosis and appropriate treatment, including laser photocoagulation, leading to a reasonably good prognosis.
Adult↗
Nordic research in ophthalmology.
PURPOSE: To provide an overview of some of the current activities in eye research in the Nordic countries. METHODS: The presentations at the biannual Nordic Congress of Ophthalmology, held in Tampere, Finland in 2002, were reviewed and the contributions found most noteworthy are included in this article along with a limited discussion of each research field. However, space requirements prevented the inclusion of many interesting scientific contributions. RESULTS: Important contributions in various subfields of eye research and ophthalmology are reviewed. These include cornea, cataract, paediatric ophthalmology, glaucoma, diabetic eye disease, age-related macular degeneration, physiology and pharmacology and oncology. CONCLUSIONS: Eye research is very active in the Nordic countries and significant contributions are being made to ophthalmology in several fields on a world scale. We hope to continue to review Nordic contributions to eye research after each Nordic Congress of Ophthalmology and plan to make the reviews more systematic and comprehensive in the future.
Biomedical Research↗
Transplantation of allogenic anterior lens capsule to the subretinal space in pigs.
PURPOSE: To investigate the consequences of transplantation of a new basement membrane to the subretinal space (SRS) as a substitution of Bruch's membrane. METHODS: Porcine anterior lens capsules (ALC) were transplanted to the subretinal space of 20 eyes from 19 young Danish landrace pigs. All pigs underwent a three port localized pars plana vitrectomy. Seventeen eyes received naked ALC. In three experiments the ALC was embedded in gelatine, in order to prevent curling of the ALC. The observation period varied between zero and 49 days. The pigs were examined by ophthalmoscopy and fundus photography. Histopathological examination of enucleated eyes was performed at the end of the experiment. RESULTS: ALCs transplanted to the subretinal space were well-tolerated and caused no inflammation when Bruch's membrane was left undamaged. After 11 days host RPE and glial cells started to cover the ALC in a competitive fashion. When Bruch's membrane was damaged, ingrowths of choroidal vessels and fibroblasts was prominent. The use of gelatine to flatten the ALC did not prevent curling, and gelatine caused pronounced inflammation. CONCLUSIONS: It is possible to transplant porcine ALC to the SRS of the pig. ALCs are well-tolerated in the SRS and are covered with well-differentiated monolayers of host RPE-cells, if Bruch's membrane is left intact.
Animals↗
A case of central visual loss in a child due to macular cavernous haemangioma of the retina.
PURPOSE: To report a case of retinal cavernous haemangioma localized to the fovea. METHODS: Clinical examination, fluorescein angiographic study and magnetic resonance imaging are reported. RESULTS: A 9-year-old girl presented with acute loss of vision in the right eye. Ophthalmoscopy showed intraretinal bleeding in the macula, while fluorescein angiography showed a lesion typical of a small cavernous retinal haemangioma, localized in the central macula. Family history was negative. CONCLUSION: Central cavernous retinal haemangioma is a rare cause of central visual loss and should be distinguished from other retinal vascular abnormalities with more profound systemic implications for the patient.
Acute Disease↗
Macular holes: classification, epidemiology, natural history and treatment.
BACKGROUND: Macular hole is a retinal disease primarily affecting elderly women. Its overall prevalence in the Danish population is estimated to be 0.14%. The majority of cases are unilateral. The fully developed macular hole evolves through a series of stages starting with an impending hole. About half of impending macular holes regress spontaneously. The remaining half progress to full thickness macular holes. In a patient with a macular hole in one eye, the risk of development of a macular hole in the fellow eye is less than 2% if posterior vitreous detachment is present. If the posterior vitreous is attached, the risk is approximately 15%. If an impending hole is found in the other eye, the risk rises to 50%. TREATMENT AND OUTCOMES: Macular hole surgery is able to close full thickness macular holes in approximately 90% of cases. Visual acuity of 20/50 or better can be obtained in approximately half of patients with recent onset of symptoms. Complications include retinal detachment, endophthalmitis, late reopening of an initially successfully closed hole and retinal pigment epithelial abnormalities. Retinal detachment should be expected in less than 5% of cases.
Denmark↗
Age-related macular degeneration: epidemiology and optimal treatment.
Age-related macular degeneration (AMD) is a common macular disease affecting elderly people in the Western world. It is characterised by the appearance of drusen in the macula, accompanied by choroidal neovascularisation (CNV) or geographic atrophy. The disease is more common in Caucasian individuals than in pigmented races. In predominantly Caucasian populations, the age-standardised prevalence of AMD in at least one eye is 7760 cases per million. The age-standardised cumulated 1-year incidence of AMD in at least one eye is 1051 cases per million individuals. AMD is the most important single cause of blindness among Caucasian individuals in developed countries. Blindness resulting from AMD rarely occurs before age 70, and most cases occur after age 80. The age-standardised 1-year incidence of legal blindness resulting from AMD is 212 cases per million. Two-thirds of AMD cases have CNV (exudative cases); the remainder has only geographic atrophy. In cross-sectional population-based studies about 45% of eyes with AMD have visual acuity reduced to 20/200 or worse. This is true both for exudative AMD and pure geographic atrophy. Age and genetic predisposition are known risk factors for AMD. Smoking is probably also a risk factor. Preventive strategies using macular laser photocoagulation are under investigation, but their efficacy in preventing visual loss is as yet unproven. There is no treatment with proven efficacy for geographic atrophy. Optimal treatment for exudative AMD requires a fluorescein angiographic study and a physician capable of interpreting it. For CNV not involving the foveal centre, the only evidence-based treatment is laser photocoagulation. For AMD cases with subfoveal CNV, good visual acuity, and predominantly classic fluorescence pattern on fluorescein angiography, photodynamic therapy with verteporfin is the treatment of choice. Photodynamic therapy is also effective in eyes with pure occult CNV and evidence of recent disease progression. For new subfoveal CNV with poor vision and recurrent CNV, laser photocoagulation can be considered.
Age Factors↗