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Biomedical subjects

I Immonen

Publications and source records attributed to I Immonen.

At least 19 recordsLinked to original sources
PubMed2005

Inflammatory markers and retinopathy in pregnancies complicated with type I diabetes.

AIM: The relation of maternal cytokine levels to retinopathy progression during diabetic pregnancy is a less studied subject. Therefore, we investigated levels of systemic proinflammatory markers, C-reactive peptide (CRP), interleukin-6 (IL-6) and circulating vascular cell adhesion molecule-1 (VCAM-1) during pregnancy and postpartum in relation to the progression of diabetic retinopathy (DR). METHODS: A prospective follow-up study of 39 pregnant women with Type I diabetes and eight nondiabetic pregnant women was performed. DR was graded from fundus photographs. Plasma levels of systemic proinflammatory markers were measured by immunofluorometric assay (CRP) and by enzyme-linked immunosorbent assay (IL-6 and VCAM-1) in the first, second (diabetics only), third trimester of pregnancy, and 3 and 6 months postpartum (diabetics only). RESULTS: Our diabetic women had good glycaemic control (HbA1c 6.9 +/- 0.8). The levels of IL-6, VCAM-1, and CRP did not differ between diabetic and nondiabetic women throughout pregnancy and postpartum (repeated measures ANOVA between the groups). An association between CRP and progression of retinopathy was observed in diabetic women (P = 0.037). Additional evidence of inter-relationship could be revealed as CRP was higher in those diabetic women with worse glycaemic control (HbA1c) (P = 0.038). CONCLUSIONS: During pregnancy and postpartum, levels of proinflammatory factors (IL-6, CRP, VCAM-1) seem to be generally similar in Type I diabetic women compared to nondiabetic controls. However, CRP levels were higher in those diabetic women with progression of retinopathy and in those with worse glycaemic control.

Adult↗
PubMed2004

Angiopoietic factors and retinopathy in pregnancies complicated with Type 1 diabetes.

AIMS: To evaluate the role of systemic angiopoietic factors in the progression of diabetic retinopathy during pregnancy. METHODS: In a prospective study of 26 pregnant women with diabetes and eight non-diabetic pregnant women, retinopathy was graded from fundus photographs. Plasma levels of angiopoietin-1, angiopoietin-2, human vascular endothelial growth factor A (hVEGF-A), and total soluble receptor of vascular endothelial growth factor (sVEGF) receptor-1 were measured during the first and third trimester and 3 months postpartum. RESULTS: In diabetic women, levels of angiopoietin-2 were 26.5 ng/ml (12.1-47.7) (median and range) during the first trimester, 2.9 ng/ml (0.6-3.5) during the third trimester, and 0.5 ng/ml (0.3-0.7) 3 months postpartum, compared with 44.3 (38.3-61.9), 5.7 (3.1-8.4) and 0.9 (0.6-4.9) ng/ml, respectively, in non-diabetic women (P = 0.002 between groups). Levels of angiopoietin-1 and sVEGF receptor-1 did not differ between the groups. Postpartum hVEGF-A levels were lowest in women with progression of retinopathy. In logistic regression analyses, progression of retinopathy during pregnancy was not explained by the levels of the angiopoietic factors. CONCLUSIONS: The circulating levels of angiopoietic factors in pregnant diabetic women were either lower than (Ang-2) or similar to (Ang-1, hVEGF-A, VEGFR-1) those levels observed in non-diabetic pregnant women. The levels of angiopoietic factors measured here appear not to be connected with the progression of retinopathy during pregnancy.

Adult↗
PubMed2003

Preliminary experience of combined peri- and retrobulbar block in surgery for penetrating eye injuries.

BACKGROUND AND OBJECTIVE: Regional anaesthesia has not been recommended as an anaesthetic method for penetrating eye injuries because it is suspected to aggravate the injury already present. After having successfully managed the treatment of a penetrating eye injury under combined peri- and retrobulbar block in an ASA IV patient, it was decided to evaluate this anaesthetic method further in the treatment of such emergency cases. METHODS: Twenty adult patients with penetrating eye injuries with a maximum wound length of 8 mm extending up to 4 mm posteriorly from the limbus were operated on under combined peri- and retrobulbar anaesthesia. Eighteen patients receiving general anaesthesia served as controls. RESULTS: The mean (range) volume injected for a satisfactory peribulbar retrobulbar block was 7.4 (6.5-8.0) mL, six patients needed an additional retrobulbar injection before surgery (2.9, range 2-4, mL). All patients receiving regional anaesthesia were satisfied with the anaesthetic method and the surgeons considered the surgical conditions as good. No problems relating to local anaesthesia were observed or reported by any of the patients. CONCLUSIONS: In the hands of an experienced anaesthesiologist and under certain conditions, regional anaesthesia appears to be suitable for adult patients having penetrating eye injuries.

Adolescent↗
PubMed2000

Retinal breaks before and after neodymium:YAG posterior capsulotomy.

PURPOSE: To determine the frequency of asymptomatic retinal breaks before and after neodymium:YAG (Nd:YAG) laser posterior capsulotomy. SETTING: Department of Ophthalmology, Helsinki University Central Hospital, Helsinki, Finland. METHODS: Of 350 consecutive patients referred for their first laser Nd:YAG posterior capsulotomy, 235 eligible eyes were enrolled and 220 eyes completed the study. A vitreoretinal surgeon looked for retinal breaks using binocular indirect ophthalmoscopy with scleral indentation. The eyes were examined 1 week before and 1 hour and 1 month after the posterior capsulotomy. The number, type, and location of retinal breaks were recorded. RESULTS: The median age of eligible patients who did not participate in the study was higher than that of enrolled patients (79.6 versus 74.4 years; P =.0005). The mean axial length, median time from cataract surgery, and the course of cataract surgery were comparable in both groups. Before the posterior capsulotomy, an untreated retinal break was diagnosed in 4 of the 235 eyes (1.7%; 95% confidence interval [CI] 0 to 4) scheduled for surgery and an undiagnosed retinal detachment was present in 2 additional eyes (0.9%; 95% CI 0 to 3). An asymptomatic retinal break was also present in 4 fellow eyes (1.7%, 95% CI 0 to 4). No new breaks developed during Nd:YAG posterior capsulotomy using a median total energy of 51 mJ (range 10 to 901 mJ) and a median number of 22 applications (range 4 to 341 applications) and resulting in an opening with a median largest diameter of 3.4 mm (range 2.0 to 4.6 mm). In 1 treated eye (0.4%; 95% CI 0 to 2), a new retinal break had developed by 1 month postoperatively. CONCLUSIONS: The observed 2.1% frequency of asymptomatic retinal breaks that had escaped the attention of the referring ophthalmologist or had developed by 1 month after Nd:YAG posterior capsulotomy can be contrasted with the 0.5% to 2.0% frequency of retinal detachment reported in the literature. However, it is not known which proportion of such asymptomatic breaks, if any, will progress to detachment after Nd:YAG laser posterior capsulotomy.

Adolescent↗
PubMed1999

The use of confocal scanning laser tomography in the evaluation of retinal elevation in age-related macular degeneration.

OBJECTIVE: To evaluate the feasibility of using confocal scanning laser tomography in the analysis of macular topography in patients with subfoveal choroidal neovascularization associated with age-related macular degeneration (AMD) and to analyze quantitatively the changes in topography after local strontium-plaque radiation therapy. DESIGN: Prospective case series. PARTICIPANTS: A total of 16 eyes with subfoveal choroidal neovascular membranes (CNVM) treated with strontium-90 (90Sr)-plaque radiation therapy and 16 fellow eyes of 16 patients were examined. INTERVENTION: Confocal scanning laser analysis of macular surface topography before and after irradiation of the macula was performed. MAIN OUTCOME MEASURES: Parameters describing the height and volume of the retinal elevation in the macula were measured. RESULTS: The maximum height of the macular lesion at baseline was 0.25 mm (standard deviation [SD], 0.12 mm) in eyes showing regression of the CNVM during follow-up and 0.34 mm (SD, 0.19 mm) in eyes showing continued growth of the CNVM. During follow-up, a mean decrease in the maximum height of the macular lesion ranging from 0.03 to 0.10 mm occurred in eyes with regression of the CNVM, whereas the mean maximum height increased by 0.07 to 0.15 mm during follow-up visits in eyes with continued growth of the CNVM. All parameters describing the mean height and volume of the lesion also decreased significantly in patients showing angiographic regression, whereas they increased or remained unchanged in patients with continuous growth of the CNVM despite irradiation. The corresponding parameters also were higher in fellow eyes with untreated CNVM than in eyes without exudative AMD. CONCLUSIONS: Confocal scanning laser tomography can be used to monitor the amount of the change in neurosensory detachment in AMD. The parameters obtained by confocal scanning laser tomography correlate with CNVM perfusion after 90Sr-plaque radiation therapy. This technology is a useful tool for objective evaluation of morphologic change after institution of new therapeutic methods for the treatment of AMD.

Aged↗
PubMed1999

Biodegradable tube implants in experimental glaucoma surgery in the rabbit.

Although ocular drainage implants are manufactured from biocombatible materials to reduce foreign-body reaction, the formation of excessive scar tissue around the implant is a common cause for implant failure. In this study, the suitability of poly(D, L-lactide-co-glycolide) copolymer, impregnated with an antiproliferative agent retinoic acid, was evaluated as a material for biodegradable tubular implants, as well as the duration and magnitude of the intraocular pressure reduction obtained with the prototype implant. Subconjunctivally placed retinoid-impregnated polymer particles caused a milder inflammatory reaction than plain polymer, and the layer of connective tissue around the material was thinner after the follow-up period of 60 d. In the anterior chamber, the inflammatory response elicited by the material was milder than subconjunctivally. The plain polymer caused a transiently stronger reaction than the retinoid-impregnated polymer, but after 60 d no difference was evident between the two materials. In all operated eyes with the tubular implant, the intraocular pressure was statistically significantly lower (p<0.05) than in control eyes for 9 wk after the operation. The intraocular pressure of the eyes with the retinoid-impregnated implant was statistically significantly lower (p<0.05) than in eyes with a plain polymer implant for up to 7 wk post-operatively. However, the use of retinoid did not prolong the effective functioning time of the implants.

Journal Article↗
PubMed1999

Visual function after strontium-90 plaque irradiation in patients with age-related subfoveal choroidal neovascularization.

PURPOSE: To report 2-year visual and angiographic results in eyes treated with strontium plaque irradiation for subfoveal choroidal neovascular membranes (CNVM) in age-related macular degeneration. METHODS: Twenty eyes with recent subfoveal CNVM were treated with local irradiation. The impact of the treatment on visual function was evaluated by visual acuity, contrast sensitivity and reading speed testing. RESULTS: At 12 months visual acuity had improved or remained the same in 9/ 20 eyes (45%). At 24 months visual acuity was stable in 5/18 eyes (28%). Eyes with signs of CNVM regression (13/18, 72%) lost a mean of 3.3 lines, but eyes with recurrent CNVM lost a mean of 5.1 lines of vision. The mean contrast sensitivity was better in the irradiated eyes than in the fellow eyes with late age-related macular degeneration at 24 months. Six of 17 irradiated eyes (35%) could read at least some words at 24 months. CONCLUSIONS: Visual function decreases in patients treated with strontium irradiation, but less in eyes showing regression of the CNVM than in eyes with further growth of the CNVM.

Aged↗
PubMed1999

Transforming growth factor beta induces urokinase receptor expression in cultured retinal pigment epithelial cells.

The effect of transforming growth factor-beta1 (TGF-beta1) and interferon-gamma (IFN-gamma) was studied on urokinase receptor (uPAR) expression of cultured human retinal pigment epithelial (RPE) cells. Human RPE cells were incubated with 1, 5 or 10 ng/ml of TGF-beta1 or with 10, 100 or 1,000 IU/ml of IFN-gamma to measure total cellular uPAR protein and released uPAR by enzyme immunoassay. uPAR at cell surface was measured by flow cytometric analysis at 8, 12, 24 and 48 h. uPAR mRNA levels were assayed by Northern blotting at 2, 6, 12 and 24 h. The increase in uPAR gene expression in RPE cells exposed to TGF-beta1 paralleled enhanced uPAR level at the cell surface and in conditioned medium. TGF-beta appeared to induce also membrane-bound uPA activity and the release of active plasminogen activator inhibitor-1, indicating that TGF-beta has the potential to regulate plasminogen activation at the RPE cell surface. The increase in uPAR gene expression by IFN-gamma did not seem to translate into the protein level. We conclude that TGF-beta regulates the pericellular proteolysis in RPE cells by increasing uPAR expression.

Cell Membrane↗
PubMed1998

Strontium plaque irradiation of subfoveal neovascular membranes in age-related macular degeneration.

PURPOSE: To determine the effect of focal strontium-90 plaque radiotherapy on subfoveal choroidal neovascularization in patients with age-related macular degeneration. METHODS: Twenty patients with age-related macular degeneration, presenting with a recent subfoveal neovascular membrane, were treated with local episcleral radiotherapy using a strontium-90 applicator. The applicator was applied to the sclera under the macular region and held there tightly for 54 min to obtain a dose of 15 Gy at a depth of 1.75 mm. The main parameters evaluated at follow-up after 3, 6 and 12 months were visual acuity and changes in fluorescein angiography. Twelve untreated patients with the same criteria were followed as controls. RESULTS: Early effects of radiation could be seen at 3 months, but became more obvious after follow-up for 6 and 12 months. At 6 months, regression of the choroidal neovascularization was detected in 14/19 patients (74%) as a decrease in the size of the lesion or as diminished leakage in late-phase fluorescein angiography. Likewise, in 14/19 patients (74%) at 12 months the neovascular membrane was partially or totally occluded. In all patients showing regression of the choroidal neovascular membrane, the neurosensory detachment had also dried. Visual acuity was unchanged (within 1 line) or improved in 11/20 (55%) and 9/20 (45%) treated patients after 6 and 12 months, respectively. In the controls, the choroidal neovascularization had increased in size in 9/12 patients (75%) at the last follow-up (mean 12.0 months). Visual acuity was unchanged in 3/12 patients (25%). CONCLUSION: Local low-energy beta irradiation with a strontium-90 applicator can induce regression of choroidal neovascularization. The effect of irradiation is seen as a decrease in the size of the choroidal neovascular membrane and disappearance of the neurosensory detachment and exudates.

Aged↗
PubMed1998

Correlation between Octopus perimetry and fluorescein angiography after strontium-90 plaque brachytherapy for subfoveal exudative age related macular degeneration.

AIM: To evaluate the correlation between the central visual field and changes in fluorescein angiography and fundus photography in patients treated with strontium plaque radiotherapy for subfoveal exudative age related macular degeneration (AMD). METHODS: Octopus program 34 automated static perimetry, fluorescein angiography, and colour fundus photography were performed on 19 patients at baseline and at 12 months after strontium-90 plaque therapy. A schematic picture outlining the areas of hyperfluorescent neovascular membranes and subretinal blood was drawn of a projected 30 degrees fundus fluorescein angiogram. This drawing was superimposed on the size adjusted Octopus visual field. The changes in retinal sensitivity were calculated and related to angiographic changes. RESULTS: Three of the 19 patients had a reliability factor (RF) > 15% and were excluded from further analysis. In the remaining 16 patients the mean defect (MD) and loss variance (LV) values remained unchanged in patients showing regression of the choroidal neovascular membrane (CNVM) to irradiation at 12 months. MD was 7.7 (SD 1.7) at baseline and 7.6 (1.9) at 12 months (p = 0.86), and LV was 32.6 (13.9) at baseline and 32.4 (15.7) at 12 months (p = 0.94). However, in patients with progression of the CNVM at 12 months, both the MD and LV increased significantly during the 12 month follow up (MD from 7.3 (2.9) to 13.1 (3.6) (p = 0.05) and LV from 31.0 (22.9) to 71.8 (24.1) (p = 0.017)). When comparing the mean retinal sensitivity in the area of the primary CNVM (including classic, occult, and haemorrhagic components), the results were analogous: in patients with a regression of the CNVM after irradiation the mean sensitivity remained almost unchanged. It was 10.3 (6.4) dB at baseline and 9.4 (7.3) dB at 12 months (p = 0.58). In five out of 11 patients (45%) with regression of the CNVM, the mean retinal sensitivity even improved by 2.0-5.0 dB in the area of the original lesion during follow up. Instead, in patients showing progression of the CNVM at 12 months, there was a significant loss in mean retinal sensitivity--from 9.9 (4.6) dB at baseline to 1.0 (1.1) dB at 12 months (p = 0.019). The mean retinal sensitivity in the area of the irradiated but clinically normal retina during follow up was not significantly altered (21.5 dB at baseline, 19.7 dB at 12 months (p = 0.10)). CONCLUSIONS: Regression of subfoveal choroidal membranes in AMD after focal strontium irradiation is connected with stabilisation or even improvement of retinal sensitivity in central visual field measured by automated perimetry. Strontium plaque irradiation does not change the sensitivity in clinically normal paramacular retina during a 12 month follow up.

Aged↗
PubMed1997

Contrast sensitivity in diabetic pregnancy.

PURPOSE: To evaluate the correlation between the changes in contrast sensitivity and retinopathy throughout pregnancy in diabetic women with mild background diabetic retinopathy. METHODS: Contrast sensitivity (Vistech 6500 Contrast Test System) was measured in 22 type I diabetic women with mild background retinopathy [0-16 microaneurysms (MAs)/eye and occasional small intraretinal hemorrhages] and 10 healthy pregnant women at the 12th and 32nd weeks of pregnancy and 3 months after delivery. Red-free fundus photography was also performed at all visits. RESULTS: Throughout pregnancy contrast sensitivity was lower in the diabetics than in the controls at 1.5, 3.0, and 6.0 cycles per degree (cpd). During the course of pregnancy, contrast sensitivity decreased at 1.5 and 6.0 cpd in patients with more than five new MAs compared to those with fewer than five new MAs during pregnancy. Likewise, contrast sensitivity decreased at 6 cpd in patients with an increase in MA count during pregnancy and at 6 and 12 cpd in patients with a baseline MA count of two or more MAs. CONCLUSIONS: Contrast sensitivity, especially at low to mid-range spatial frequencies, is decreased in diabetic women with mild retinopathy. Even small changes in retinopathy are reflected in a decrease in contrast sensitivity during and after pregnancy. Thus, contrast sensitivity seems to be a sensitive indicator of changes in minimal background retinopathy.

Adult↗
PubMed1997

The effect of pregnancy on mild diabetic retinopathy.

PURPOSE: To study microaneurysm (MA) formation and disappearance rates during pregnancy and postpartum in diabetic women with mild diabetic retinopathy. METHODS: Red-free photographs were taken at the 12th, 24th and 32nd-36th weeks of pregnancy and 3 and 6 months postpartum from 21 type 1 diabetics with mild diabetic retinopathy. In a subset of 13 patients follow-up was continued until 1 year after pregnancy. Fundus photographs were analysed using a computer-assisted fundus lesion localization system. RESULTS: In the whole material the total MA count was 3.1 +/- 3.6 (mean +/- SD) at the 12th week, 3.4 +/- 3.1 at the 24th week, 4.1 +/- 4.9 at the 32nd-36th week, 5.4 +/- 6.2 at 3 months postpartum and 5.2 +/- 5.8 at 6 months postpartum. We found that MA count increased during pregnancy, but it was highest 3 months postpartum. Both the rate of MA formation and the rate of MA disappearance increased during pregnancy, with the disappearance rate exceeding the formation rate 6 months postpartum. In patients having mean HbA1c levels below the median value of 6.38 mmol/l there was a flare-up of MAs during pregnancy, levelling by 3 months postpartum. Patients with a higher than the median (0.76 mmol/l) decrease in HbA1c level compared to pre-pregnancy HbA1c also developed more MAs during the course of pregnancy. CONCLUSIONS: These data suggest that there is continuous turnover of MAs during pregnancy. MA count increases during pregnancy but the MA count was highest 3 months postpartum, after which the formation rate started to decline. Temporary aggravation of mild retinopathy occurs in diabetic patients after normalization of blood glucose levels.

Adult↗
PubMed1997

The etiology of uveitis: the role of infections with special reference to Lyme borreliosis.

PURPOSE: To assess the distribution of different uveitis entities and to evaluate their associations with infections, especially Lyme borreliosis. METHODS: During a one-year period 160 consecutive uveitis patients were evaluated in a university clinic. Selected tests were performed depending on the medical history of the patient and the clinical picture of the ocular inflammation. RESULTS: Uveitis was classified into selected entities for 74.4% of the patients. A direct infection was suggested to be linked with uveitis in 23 patients (14.4%). Lyme borreliosis, toxoplasmosis, and herpetic infections were the most frequently seen, in seven patients (4.3%) each. All patients with Lyme uveitis had manifestations of the posterior segment of the eye, such as vitritis, retinal vasculitis, neuroretinitis, chorioretinitis, or optic neuropathy. CONCLUSION: Infections are an important cause of uveitis in a university clinic. Lyme borreliosis is a newly recognised uveitis entity which should be kept in mind in the differential diagnosis of intermediate or posterior uveitis in areas endemic for Lyme borreliosis.

Adolescent↗
PubMed1996

Long-term effects of pregnancy on diabetic complications.

The aim of our study was to establish whether pregnancy affects long-term development and progression of retinopathy and nephropathy in diabetic women compared to nulliparous diabetic women. Twenty-eight diabetic women who had delivered in 1983-85 at Helsinki University Central Hospital and 17 nulliparous controls matched according in age, duration of diabetes, and degree of vascular complications were personally interviewed and the current retinal status and renal function were assessed 7 years later, in 1990-92. Serum creatinine, creatinine clearance, nocturnal albuminuria, and HbA1c were measured and colour fundus photography carried out. The results were compared to the status in 1983-85. Of those who had been pregnant, 5 of 26 (19.2%) had experienced worsening of retinopathy. In 3 of these, proliferative retinopathy had developed from only minimal background changes. In the control group, progression had occurred in 8 cases of 16 (50%, p < 0.05). The groups did not differ from each other regarding progression or development of nephropathy. This suggests that pregnancy does not seem to affect development or progression of diabetic nephropathy whereas progression of retinopathy seems to occur less often after pregnancy compared to nulliparous women.

Adult↗
PubMed1996

Macular blood flow during pregnancy in patients with early diabetic retinopathy measured by blue-field entoptic simulation.

PURPOSE: To study macular capillary blood flow velocity during pregnancy and postpartum in diabetic women with minimal diabetic retinopathy. METHODS: Macular capillary blood velocity was measured using the blue-field entoptic simulation technique in 17 type I diabetic pregnant women with minimal background retinopathy and 10 healthy pregnant women at the 12th and 32nd-36th weeks of pregnancy and 3 months after delivery. Red-free fundus photography was also performed at all visits. RESULTS: Capillary blood velocities at the 12th week of pregnancy were 1.09 +/- 0.37 mm/s in the diabetic women and 0.81 +/- 0.21 mm/s in the controls(P = 0.017), at the 32nd week 0.93 +/- 0.19 mm/s and 0.94 +/- 0.24 mm/s (P = 0.880), and 3 months postpartum 0.98 +/- 0.25 mm/s and 0.75 +/- 0.17 mm/s (P = 0.016), respectively. Analysis of variance indicated that there was a significant difference in leukocyte velocities during the course of pregnancy, with the flow being constantly elevated in diabetic women, but increasing by term in nondiabetic women (P = 0.039). Capillary flow velocity showed a statistically non-significant tendency to be higher in patients with HbA1c levels > 6.4%. Capillary flow velocity levels were not connected with changes in the number of microaneurysms. Capillary leukocyte density in the pregnant diabetic women did not differ from that of nondiabetic pregnant women. CONCLUSIONS: These data suggest that during pregnancy there is a difference in retinal capillary blood flow between diabetic women with minimal background retinopathy and normal women. The lack of increase in blood flow in macular capillaries during diabetic pregnancy may reflect redistribution of retinal capillary flow during diabetic pregnancy or be due to altered rheological properties of blood components in diabetic pregnancy.

Adult↗
PubMed1996

Plasminogen activation in epiretinal membranes.

BACKGROUND: Formation of epiretinal membranes occurs in proliferative vitreoretinopathy, macular pucker and after penetrating trauma. Epiretinal membrane formation includes cell migration and proliferation, extracellular matrix formation and tissue contraction. Generally in scar tissue formation, the production of new extracellular matrix occurs concomitantly with its proteolytic degradation, resulting in continuous tissue remodelling. The plasminogen activator-mediated proteolytic cascade is an important mechanism for pericellular degradation of the extracellular matrix. Therefore we wanted to study the presence of the plasminogen activator-mediated proteolytic cascade in epiretinal membranes. METHODS: Specimens of 18 epiretinal and 3 subretinal membranes were obtained during vitreous surgery for retinal detachment with proliferative vitreoretinopathy or macular pucker. Plasminogen activators and plasmin were characterized in frozen sections of epiretinal membranes by in situ zymography and in membrane lysates by zymography. Indirect immunofluorescence staining was performed to localize urokinase in epiretinal membranes. RESULTS: Urokinase was present in 17/21 and tissue-type plasminogen activator in 12/21 of the membranes studied. Active plasmin was not detected in the frozen sections of epiretinal membranes. Immunofluorescence staining localized urokinase predominantly in the areas invaded by macrophages and cells of retinal pigment epithelial origin. CONCLUSION: Our results demonstrate the presence of proteolytic activity in periretinal scar tissue. Urokinase was more consistently present, but smaller amounts of tissue-type plasminogen activator were also found in the specimens. These results indicate that continuous tissue remodelling with simultaneous extracellular matrix production and breakdown regulates the growth of epiretinal membranes.

Adult↗