PubMed Health⌕ Search

Biomedical subjects

I Immonen

Publications and source records attributed to I Immonen.

At least 37 records · Page 2Linked to original sources
PubMed1996

Proteinases in subretinal fluid.

BACKGROUND: Degradation of the extracellular matrix by secreted proteases is connected to cell migration and proliferation in invasive growth and in scar tissue formation. In retinal detachment, retinal pigment epithelium (RPE) cells loosened from their monolayer are often seen in the subretinal fluid (SRF) and the vitreous, where they may participate in the scar tissue formation of proliferative vitreoretinopathy. To evaluate the role of SRF constituents on the release of RPE cells, we analyzed SRF in patients with retinal detachment for the presence of enzymes able to degrade extracellular matrix. METHODS: SRF was collected altogether from 16 patients undergoing retinal reattachment surgery and analyzed for activities against some of the key enzymes in extracellular proteolysis, namely collagenases, gelatinases, elastase and cathepsin G. RESULTS: Seventy-two-kilodalton gelatinase was found in all SRF samples studied, whereas the neutrophil-type 92-kDa gelatinase could not be detected. Low collagenase, elastase and cathepsin G activities could also be detected in some samples. CONCLUSIONS: The predominant type of matrix metalloproteinase present in SRF is the 72-kDa MMP-2. The proteolytic activity in SRF may be connected to the release of RPE cells into SRF and to degradation of components of the vitreous exposed to SRF.

Body Fluids↗
PubMed1996

Identification of individual microaneurysms: a comparison between fluorescein angiograms and red-free and colour photographs.

PURPOSE: To evaluate how often a microaneurysm (MA) seen in a fluorescein angiogram (FAG) is visualized in colour or red-free photographs, and conversely how often a red dot seen in a colour photograph or a red-free photograph is found in an FAG as an MA. METHOD: Sixty-degree FAGs, colour photographs and red free fundus photographs of 24 patients with mild background retinopathy were analysed using a computer-assisted fundus lesion localization system. Only lesions identified similarly in two separate sessions were processed further. The presence of lesions identified by their position was compared in FAGs and colour and red-free photographs. RESULTS: In the whole material 394 MAs were detected in FAGs, 95 in red-free and 62 in colour photographs. Of the MAs in FAGs 26 (6.6%) were seen as a red dot in a colour photograph and 52 (13%) were found in red-free photographs. Of the 95 MAs found in red-free images 52 (55%) were detected in FAGs. Of the 62 MAs in colour photographs, 26 (42%) were seen as a MA in a FAG. A significant correlation existed between MA counts in FAGs and red dot counts in colour or red-free photographs of individual patients. CONCLUSIONS: Although MAs in FAG and red spots in colour or red-free photographs all reflect the degree of retinopathy, about half of the red dots in photographs do not represent open MAs in FAGs.

Adult↗
PubMed1996

Experimental retinal and ciliary body photocoagulation using a new 670-nm diode laser.

PURPOSE: Evaluation of ocular tissue reactions to 670-nm diode laser. METHODS: Twelve eyes of 12 pigmented rabbits were used. Transscleral contact laser delivery of a new 670-nm diode laser was used to produce retinal laser lesions in four rabbits; endolaser application of this laser produced photocoagulation of the retina in another four rabbits; and ciliary body lesions were produced by transscleral application of this laser in a third group of four rabbits. The rabbits were killed either 2 days or 1, 3, or 6 weeks later; lesions were evaluated by gross examination and histology. RESULTS: The mildest visible retinal lesions were produced by transscleral contact application at 0.2 J (2 seconds, 100 mW); explosive lesions began at 0.6 J. The mildest visible lesions were produced by endolaser application at 50 mW (spot size, 0.5 mm); intensive reactions started to occur at 300 mW, but no explosive lesions were produced below 600 mW. With contact transscleral application, substantial ciliary body reactions occurred at 0.5 and 1.0 J. Histologic examination disclosed destruction of the outer retina, pigment epithelium, and parts of the choroid in mild lesions, and of all retinal layers in the intense lesions. CONCLUSIONS: In this experimental study, the 670-nm diode laser appears to be a promising modality for laser photocoagulation of the retina and ciliary body.

Animals↗
PubMed1996

Long-term follow-up of chronic Lyme neuroretinitis.

PURPOSE: The authors report sequential fluorescein angiographic and color photographic findings of the fundi and response to treatment in a patient with chronic Lyme neuroretinitis. METHODS: A Lyme enzyme-linked immunosorbent assay with purified 41-kd flagellin as antigen was used to detect immunoglobulin G and immunoglobulin M antibodies to Borrelia burgdorferi in serum, cerebrospinal fluid, and vitreous. The changes were documented by fluorescein angiography and color photography tests performed during a 5 1/2 year follow-up. RESULTS: The diagnosis of Lyme neuroretinitis was based on the history of erythema migrans and positive Lyme enzyme-linked immunosorbent assay tests from cerebrospinal fluid and vitreous and by the exclusion of other infectious and systemic diseases and uveitis entities. Fluorescein angiography results disclosed bilateral chronic neuroretinal edema with areas of cystoid, patchy, and diffuse hyperfluorescence peripapillary and in the macular areas. The hyperfluorescent lesions enlarged despite a 9-month period of antibiotic therapy. CONCLUSION: Lyme borreliosis may cause neuroretinitis with unusual angiographic findings. Chronic Lyme neuroretinitis may be unresponsive to antibiotic therapy.

Adult↗
PubMed1996

Disappearance and formation rates of microaneurysms in early diabetic retinopathy.

AIM: To analyse the formation and disappearance rates of individual microaneurysms in mild background retinopathy. METHODS: Three fluorescein angiograms were taken at 1 year intervals during a 2 year follow up from 24 type 1 diabetics with mild background retinopathy. Microaneurysms were identified and localised twice from each angiogram using a computerised system for retrieval of the coordinates for each microaneurysm. Microaneurysms identified similarly in both sessions were then processed further to obtain rates of microaneurysm formation and disappearance, and microaneurysm count changes. RESULTS: In the whole material the total number of microaneurysms increased from 298 to 436 from baseline to 2 years. During the 2 year follow up 395 new microaneurysms formed and 258 microaneurysms disappeared. Of the microaneurysms present at baseline 174 (58%) were still present at the 1 year and 142 (48%) at the 2 year follow up. In patients with good glucose control (HbA1c < or = 7.5 mmol) microaneurysm formation showed a trend of being decreased whereas microaneurysm disappearance did not correlate with glucose control. CONCLUSION: Background diabetic retinopathy is a dynamic process. A significant proportion of microaneurysms present disappear within 2 years. This is compensated for by formation of new microaneurysms, the resultant net changes in microaneurysm counts being small. Microaneurysm formation and disappearance rates are new variables of diabetic retinopathy and may prove to be more sensitive indicators of the progression patterns of background diabetic retinopathy than microaneurysm count changes.

Adult↗
PubMed1996

Radiation related complications after ruthenium plaque radiotherapy of uveal melanoma.

AIMS/BACKGROUND: To analyse radiation related complications and secondary enucleation after irradiation of malignant uveal melanoma with ruthenium-106 plaques. METHODS: A series of 100 consecutive eyes irradiated in 1981-91 was analysed using the life table method and the Cox proportional hazards model. The median apical and scleral tumour dose was 100 Gy (range 15-200 Gy) and 1000 Gy (range 200-1200 Gy), respectively. The median follow up time was 2.8 and 2.0 years (range 1 month to 10 years) for anterior and posterior segment complications, respectively. RESULTS: The 3 and 5 year probabilities of being without radiation cataract were 73% and 63%, without neovascular glaucoma 91% and 81%, without vitreous haemorrhage 83% and 74%, without radiation maculopathy 85% and 70%, and without radiation optic neuropathy 90% and 88%, respectively. The risk of radiation cataract was highest with large tumour size (T1 + T2 v T3, p = 0.0027; height < or = 5 v > 5 mm, p = 0.029; largest basal diameter (LBD) < or = 15 v > 15 mm, p < 0.0001) and location of anterior tumour margin anterior v posterior to the equator (p = 0.0003); the risk of neovascular glaucoma with large size (T1 + T2 v T3, p = 0.039; LBD < or = 15 mm v 15 mm, p = 0.021); and the risk of maculopathy and optic neuropathy with proximity of the posterior tumour margin to the fovea and the optic disc (< or = 1.5 v > 1.5 mm; p = 0.030 and p = 0.0004, respectively). In Cox's multivariate analysis the strongest risk indicator for radiation cataract (RR 1.5, 95% CI 1.4-1.6) and vitreous haemorrhage (RR 1.6, 95% CI 1.4-1.8) was the height of the tumour; for neovascular glaucoma the TNM class (RR 6.2, 95% CI 2.7-13.8); for radiation maculopathy location of posterior tumour margin within 2 mm from the fovea (RR 3.4, 95% CI 2.0-6.0); and for radiation optic neuropathy location of tumour margin within 1 DD of the optic disc (RR 6.1, 95% CI 3.0-12.4). The 3 and 5 year probabilities of avoiding enucleation were 92% and 85%, respectively. Ten eyes were enucleated--six because of recurrent tumour growth, three because of treatment complications, and one because of mistakenly suspected extraocular growth. CONCLUSION: The results suggest that the frequency of radiation related complications after ruthenium brachytherapy of uveal melanoma is acceptable, in particular as regard irradiation of small and medium sized tumours for which ruthenium therapy generally is recommended.

Adult↗
PubMed1995

Clinically successful contact transscleral krypton laser cyclophotocoagulation. Long-term histopathologic and immunohistochemical autopsy findings.

OBJECTIVE: To report long-term histopathologic findings 10 months after contact transscleral krypton cyclophotocoagulation. METHODS: The tissue response in a successfully treated eye was analyzed by light microscopy and a panel of 11 antibodies to epithelial, mesenchymal, and inflammatory cells. RESULTS: A 75-year-old man with uncontrolled angle recession glaucoma was treated with transscleral contact krypton cyclophotocoagulation (17 burns, 3.5 J each) 10 months before his death. The intraocular pressure fell from 28 to 17 mm Hg 6 months after therapy. Confluent scars straddled the posterior pars plicata and the anterior pars plana. The ciliary processes were destroyed, but the sclera and zonules were intact. Vimentin and cytokeratin 8 and 18 persisted in the degenerated ciliary epithelium. The inner connective-tissue layer and the ciliary muscle had atrophied, as shown with antibodies to the HNK-1 epitope, desmin, and alpha-smooth-muscle actin. Macrophages with phagocytized pigment and single T cells were present instead. No unusual inflammatory infiltrate was present in the choroid of either eye. CONCLUSIONS: Clinically effective ablation of ciliary processes is achieved with contact krypton laser. Little chronic inflammation and no signs of sympathetic ophthalmia were present. Atrophy of the ciliary muscle may reduce accommodative capacity in younger patients undergoing cyclophotocoagulation.

Actins↗
PubMed1995

Cellular fibronectin and tenascin in experimental perforating scleral wounds with incarceration of the vitreous.

BACKGROUND: Posterior perforating eye injury carries a high risk of visual loss due to the formation of intravireal and epiretinal scar tissue. Intraocular scar formation in patients with retinal detachment has been shown to be associated with elevated intravitreal FN levels. The extracellular matrix glycoproteins fibronectin (FN) and tenascin (TN) have been located in epiretinal scar membranes. As both FN and TN are also involved in healing of cutaneous and corneal wounds, we undertook to study their expression in rabbit perforating scleral wounds with vitreous incarceration. METHODS: A perforating scleral wound was produced and sutured without removal of vitreous from the wound in 18 pigmented rabbits. The rabbits were killed at various times (1 h to 21 days) after the operation, and the indirect immunohistochemical method was used for demonstration of FN and TN. Monoclonal mouse hybridoma antibodies 52 DH1 and 100 EB2, recognizing the cellular form of FN (cFN) and TN, respectively, were used. RESULTS: During the first post-operative week immunoreaction for glycoproteins, both the locally produced cFN and TN, were observed at the scar tissue containing the prolabed vitreous and the adjacent sclera. Subsequently, the reaction gradually shifted to the vitreal side of the wound, and 3 weeks after the operation it was almost completely restricted to a separated mass of vitreous beneath the scar. CONCLUSION: The expression of cFN and TN in the scleral scar and vitreous is indicative of their local synthesis. The shift of the expression of those proteins to the vitreal side of the wound with time suggests that the scarring process in the vitreous is delayed compared to the sclera.

Animals↗
PubMed1995

Dislocated nuclear fragments after cataract surgery.

Posterior nuclear dislocation is a serious complication of cataract surgery, especially when using the phacoemulsification technique. So far, there have been only a few reports concerning the indications and timing of vitrectomy with nuclear removal as well as long-term visual outcome of these eyes. We analysed 23 consecutive patients (follow-up at least 3 months) with intravitreal nuclear remnants after cataract surgery treated with vitrectomy and removal of posteriorly dislocated nuclei. All the eyes had increased intraocular pressure pre-vitrectomy, 63% had corneal oedema, 67% marked uveitis and 26% either retinal tear or detachment. Vitrectomy was performed within 1 week in 70% of eyes. In 14 eyes (61%) the final visual acuity was 20/40 or more. The main reason for poor visual outcome was retinal detachment (9%). These results indicate that with vitrectomy and removal of the nucleus good visual results can be achieved in a large proportion of eyes with posterior dislocation of nuclear remnants.

Aged↗
PubMed1994

A computerized system for localization of diabetic lesions from fundus images.

A computerized system for the localization of diabetic lesions from fundus photographs is described. The coordinates for each lesion in relation to reference points are determined from fundus images projected on a digitizing table. The program accepts some variation in coordinates for a single lesion, still to be recorded as the same lesion in a series of photographs, and the magnitude of this variation is adjustable. The data obtained from the localization program are transferred to a register program yielding the following parameters: number of lesions, new lesions, lost lesions, variable lesions, time of presence for lost lesions. These data can be further exported into Microsoft Excel 4, for analysis of large patient materials. An intra-observer error of 0% and an inter-observer error of 1.1% was found in localization of lesions from fundus images. The program was insensitive to small variations in the fundus pictures, but comparisons of 30 degrees and 60 degrees photographs of the same fundus, or 20 degrees deviation of gaze, induced identification errors in 2.9% and 11.9% of localizations, respectively. With this system new parameters on diabetic fundus images can be obtained. The significance of these parameters in the progression of diabetic retinopathy will be analyzed in further studies.

Aneurysm↗
PubMed1994

Secretion of plasminogen activators by cells cultured from subretinal fluid.

Secretion of plasminogen activators was examined in 11 cells cultures from subretinal fluid of patients with retinal detachment. The plasminogen activator production was compared to 4 retinal pigment epithelial cell cultures from post-mortem donors with no known retinal pathology. Plasminogen activator activity was evaluated by zymography and was corrected for the total cell protein in the cultures. Cells from subretinal fluid had more proteolytic activity and secreted more active urokinase-type plasminogen activator than retinal pigment epithelial cells of donor origin. It is possible that cells from subretinal fluid are modulated by the conditions in subretinal fluid to secrete more urokinase-type plasminogen activator, generally considered to be a sign of invasive growth or that the subretinal fluid cultures contain other cell types than solely retinal pigment epithelial cells, such as pigmented macrophages, with an active plasminogen activator production. Alternatively, retinal pigment epithelial cells detached into the subretinal fluid may represent a selected population of retinal pigment epithelial cells with a more active extracellular proteolysis.

Adolescent↗
PubMed1994

Interferon alpha-2a in the treatment of exudative senile macular degeneration.

We performed a pilot study of 10 patients with the objective to determine the efficacy of interferon alpha-2a in the treatment of age-related macular degeneration with freshly diagnosed choroidal neovascular membrane. Interferon was given at a dose of 3 MIU/m2 three times a week for 8 weeks. Mean age of the patients was 74 years. In 3 patients we combined laser photocoagulation of extrafoveal part of the choroidal neovascular membrane to interferon therapy. The patients were followed up for 1 year after termination of interferon treatment. In 1 patient a visual improvement of two Snellen lines was noted, while in 7 patients visual acuity remained the same during the treatment (includes 3 patients treated with combined Krypton-laser photocoagulation). In 2 patients there was a decrease in acuity of one line. Six months later visual acuity had deteriorated in 7 patients and 1 year later all the patients had visual acuity < or = 20/200. We did not find any regression of choroidal neovascular membrane in fluorescein angiography in any of the patients during the treatment except the laser-treated area. At the 6-month follow-up there was still leakage or choroidal neovascular membrane growth in 6 patients. Combined interferon-laser therapy did not prove to be more effective in preventing the membrane growth. Side-effects included weakness, apathy, and fatigue in this elderly population. Our results indicate that treatment with 3 MIU/m2 interferon for 8 weeks is not an effective treatment for subfoveal choroidal neovascular membranes.

Aged↗
PubMed1994

Alpha- and gamma-interferon inhibit plasminogen activator inhibitor-1 gene expression in human retinal pigment epithelial cells.

The effect of interferons IFN-alpha and IFN-gamma on the production of plasminogen activators (PAs) and plasminogen activator inhibitors (PAIs) was examined in human retinal pigment epithelial (RPE) cells in culture. Cultures of human RPE cells were incubated with either of the interferons for 48-96 h. The cell cultures were assayed using mRNA analysis and solid-phase immunocapture assay. Both interferons caused a marked decrease in PAI-1 mRNA expression after 48 h with no change in urokinase-type plasminogen activator (u-PA) mRNA expression. A marked decrease in PAI-1 activity and concomitant increase in u-PA activity in the culture medium appeared only after 72-96 h. We conclude that IFN-alpha and IFN-gamma stimulate plasminogen-mediated pericellular proteolysis of human RPE cells in culture by inhibiting PAI-1 gene expression.

Adolescent↗
PubMed1993

Isolated congenital heart block. Long-term outcome of mothers and characterization of the immune response to SS-A/Ro and to SS-B/La.

OBJECTIVE: To study the long-term outcome of mothers of children with isolated congenital heart block (CHB) and to characterize the maternal autoantibody response to SS-A/Ro and SS-B/La. METHODS: A retrospective clinical study of 33 mothers a mean of 11.2 years (SD 9.2 years, range 0-32 years) after the delivery of their first child with CHB. A clinical and immunologic study of 31 of these mothers, compared with 89 healthy mothers, 45 mothers with systemic lupus erythematosus (SLE), and 19 mothers with primary Sjögren's syndrome (SS), all of whom had healthy children. The specificity of the autoantibody responses to SS-A/Ro and SS-B/La was studied by enzyme-linked immunosorbent assays using purified human recombinant antigens and affinity-purified antigens. RESULTS: By the time of the analysis, 2 (6%) of the 33 mothers of CHB children had died and 6 (18%) had met the criteria for SLE. As a group, mothers of CHB children had clinical and immunologic characteristics more closely related to primary SS than to SLE or any other connective tissue disease. The predominant autoantibody response was to the SS-A/Ro antigens, notably to the 52-kd SS-A/Ro protein (prevalence 97%). Compared with controls with SLE, mothers of CHB children had higher titers of antibodies to recombinant 52-kd and 60-kd SS-A/Ro proteins and to the affinity-purified SS-A/Ro antigen (P < 0.05, P < 0.01, and P < 0.001, respectively). Compared with controls with primary SS, the autoantibody responses were similar. CONCLUSION: The predominant autoimmune disorder in mothers of children with CHB is subclinical primary SS. Antibodies to SS-A/Ro appear to be a prerequisite for the development of CHB.

Adolescent↗
PubMed1993

Energy levels needed for cyclophotocoagulation: a comparison of transscleral contact cw-YAG and krypton lasers in the rabbit eye.

The energy levels needed for cyclophotocoagulation using either transscleral contact krypton or cw-YAG lasers were compared in pigmented rabbits. The same transscleral laser probe was used for both lasers. With the krypton laser, 0.25 J of energy caused macroscopically detectable lesions, and 1.5 J led to widespread destruction of the ciliary body. With the cw-YAG laser, the first detectable lesions were produced at 0.5 J. Similarly, at higher energies, twice as much energy was required using the cw-YAG as compared with using the krypton laser to produce comparable lesions. Histologically, lesions of the same macroscopic severity made with the two lasers were similar. We conclude that the transscleral contact krypton laser is an efficient instrument for cyclophotocoagulation. Although these results may not be directly applied to human eyes, it appears that the poorer scleral transmission of the krypton beam is offset by its higher level of absorption in the pigmented epithelium of the ciliary body.

Animals↗
PubMed1993

Survival of patients and metastatic and local recurrent tumor growth in malignant melanoma of the uvea after ruthenium plaque radiotherapy.

A series of 100 consecutive patients treated by ruthenium plaque radiotherapy for uveal malignant melanoma from 1981 to 1991 was studied to evaluate local recurrences, metastases, and melanoma-specific mortality. Follow up ranged from 1.0 to 10.1 years (mean, 3.3; median, 3.0 years). Local relapse was observed in 19 patients from 0.1 to 2.7 years (median, 0.7 years) after therapy. Six of these eyes were enucleated. The 5-year probability of local tumor control was 59%. Seven patients with local relapse developed metastasis 0 to 4.3 years (median, 1.4 years) later. Altogether, 18 patients developed metastases 0.9 to 4.6 years (median, 2.0 years) after the irradiation, and 15 of them died of melanoma 5 days to 3.3 years (median, 0.5 years) after detection of metastases. The 5-year probability of metastasis not developing was 61%. The overall 5-year survival was 78%, excluding causes other than malignant melanoma. Large tumor size and anterior tumor location, with or without ciliary body involvement, predicted poor prognosis both in terms of local growth, metastases, and melanoma-specific mortality. Local recurrent tumor growth was associated with a significant increase in metastasis but a nonsignificant increase in melanoma-specific mortality.

Aged↗