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Stefan Seregard

Publications and source records attributed to Stefan Seregard.

At least 19 recordsLinked to original sources
PubMed2004

Incidence of retinoblastoma from 1958 to 1998 in Northern Europe: advantages of birth cohort analysis.

PURPOSE: To assess change in incidence of retinoblastoma in Northern Europe and to compare commonly used methods for calculating its incidence against birth cohort analysis. DESIGN: Retrospective cohort study. PARTICIPANTS: Individual and pooled data of 291 Swedish and 174 Finnish children diagnosed with retinoblastoma between 1958 and 1998. MAIN OUTCOME MEASURES: Incidence per 1 million children younger than 5 years of age (37 812 035 person- years at risk) and per 100 000 live births (7 152 265 live-born children at risk). METHODS: Data were from Swedish and Finnish Cancer Registries and corresponding national referral centers for retinoblastoma. Incidence was calculated both by standard analysis per children younger than 5 years of age and per live births, and by birth cohort analysis. Curves were smoothed with robust, locally weighted regression. Linear regression was used to fit pooled data. RESULTS: The number of new retinoblastoma cases per year ranged from 0 to 13 (1-13 per birth cohort) in Sweden and from 0 to 10 in Finland (1-9 per birth cohort). The mean incidence was 11.8 (95% confidence interval [CI], 10.5-13.1) and 11.2 (95% CI, 9.4-13.0) per 1 million children younger than 5 years of age in Sweden and Finland, respectively, and 6.7 (95% CI, 5.9-7.5) and 6.2 (95% CI, 5.3-7.2) per 100 000 live births, respectively. Analysis based on year of diagnosis suggested moderate increase in incidence since 1990, but by birth cohort analysis, incidence rates were stable for both countries. The pooled incidence by birth cohort was 6.0 (95% CI, 5.4-6.6) per 100 000 live births, corresponding to 1 in 16 642 (95% CI, 15 105-18 528) live births. CONCLUSIONS: The data suggest that the incidence of retinoblastoma is stable in Northern Europe. Analysis based on birth cohort is recommended for future epidemiologic studies, because it minimizes the effect of variable age at diagnosis of this developmental cancer and results in less variable incidence rates than standard analysis based on year of diagnosis.

Adolescent↗
PubMed2004

Characterization of plasminogen variants in healthy subjects and plasminogen mutants in patients with inherited plasminogen deficiency by isoelectric focusing gel electrophoresis.

Plasmin(ogen) plays an important role in fibrinolysis and wound healing. Severe hypoplasminogenemia has recently been linked to ligneous conjunctivitis. Plasminogen (plg) is known as a polymorphic protein and most of these variants have been identified using isoelectric focusing (IEF) gel electrophoresis. Here, we studied common plg variants from healthy subjects and plg mutants from three patients with hypoplasminogenemia and three subjects with dysplasminogenemia by molecular genetic analysis and IEF. Analysis of 24 healthy subjects showed that subjects with the most common IEF plg phenotype A (n=12) were homozygous for aspartate at position 453 (453D), while both subjects with IEF plg phenotype B were homozygous for asparagine at this position (453N). Subjects with IEF plg phenotype AB (n=10) were compound-heterozygous for 453D/453N. Three patients with severe hypoplasminogenemia and different plg gene mutations exhibited characteristic "abnormal" IEF band patterns when compared with IEF plg phenotypes A and B. In all heterozygous family members the observed IEF plg phenotype was derived from the wild type plg molecule only, probably due to low concentration of the mutant plg molecule in plasma. In contrast, in three unrelated subjects with heterozygous dysplasminogenemia an equal "mixture" of wild type and mutant plg was found by IEF analysis. In conclusion, plg phenotyping by IEF in combination with molecular analysis of the plg gene seems to be a useful method for characterization of plg variants and mutants.

Asparagine↗
PubMed2004

c-Kit-dependent growth of uveal melanoma cells: a potential therapeutic target?

PURPOSE: This study was conducted to investigate the expression and functional impact of the proto-oncogene c-kit in uveal melanoma. METHODS: Based on immunohistochemical (IHC) study of paraffin-embedded specimens from 134 uveal melanomas and Western blot analysis on eight fresh-frozen samples the expression of c-kit in uveal melanoma was studied. Furthermore, the phosphorylation of c-kit and the impact of the tyrosine kinase inhibitor STI571 was examined in the three uveal melanoma cell lines OCM-1, OCM-3, and 92-1. RESULTS: Eighty-four of 134 paraffin-embedded samples and six of eight fresh-frozen samples expressed c-kit. c-Kit was strongly expressed and tyrosine phosphorylated in cultured uveal melanoma cells compared with cutaneous melanoma cells. Moreover, in contrast to cutaneous melanoma cell lines c-kit maintained a high phosphorylation level in serum-depleted uveal melanoma cells. No activation-related mutations in exon 11 of the KIT gene were found. On the contrary, expression of the stem cell growth factor (c-kit ligand) was detected in all three uveal melanoma cell lines, suggesting the presence of autocrine (paracrine) stimulation pathways. Treatment of uveal melanoma cell lines with STI571, which blocks c-kit autophosphorylation, resulted in cell death. The IC(50) of the inhibitory effects on c-kit phosphorylation and cell proliferation was of equal size and less than 2.5 microM. CONCLUSIONS: The results confirm that c-kit is vastly expressed in uveal melanoma, suggest that the c-kit molecular pathway may be important in uveal melanoma growth, and point to its use as a target for therapy with STI571.

Adult↗
PubMed2004

Subthreshold transpupillary thermotherapy reduces experimental choroidal neovascularization in the mouse without collateral damage to the neural retina.

PURPOSE: Transpupillary thermotherapy (TTT) is currently being evaluated for treatment of choroidal neovascularization (CNV) in age-related macular degeneration. To optimize TTT for CNV, the effect was analyzed of invisible (subthreshold) or visible (threshold) doses of TTT on the normal mouse retina and on experimental CNV. METHODS: TTT was delivered to the normal retina of 42 mice with a diode laser at increasing power settings (50, 60, 70, or 80 mW), to obtain thermal lesions ranging from invisible (subthreshold) to visible (threshold) burns. CNV was induced in 53 mice by krypton laser photocoagulation of the fundus, after which the CNV lesions were treated with TTT (50, 60, or 80 mW). Eyes were enucleated 7 days after TTT and prepared for histology, and the CNV complex was evaluated on hematoxylin-eosin stained serial sections by measuring the maximum height of the CNV lesions. Ultrastructural changes were examined by transmission electron microscopy. RESULTS: Increasing the TTT laser power yielded gradually more visible effects. At 50 mW, which induced subthreshold burns, no damage was seen in the neural retina, retinal pigment epithelium (RPE), or choroid at any time point. By contrast, eyes treated with higher power exhibited progressively more damage to the neural retina, including a complete disruption of the outer nuclear layer. When TTT was applied to the laser-induced CNV lesions, the height of lesions was significantly reduced (P < 0.001) in response to all three power settings at 7 days after treatment. The mean relative thickness of the CNV lesion was 3.29 +/- 0.89 in untreated mice, whereas in TTT-treated mice it was 1.69 +/- 0.35, 1.69 +/- 0.41 and 1.70 +/- 0.17 at power settings of 50, 60, and 80 mW, respectively. The overlying neural retina showed no apparent damage with the 50- or 60-mW settings, whereas outer nuclear layer disruption occurred with a power of 80 mW. Electron microscopy confirmed the presence of vascular occlusion at 1 day and a fibrotic scar at 7 days after TTT. CONCLUSIONS: Subthreshold TTT can effectively occlude newly formed vessels and cause regression of the experimental CNV complex without damaging the neural retina. The results demonstrate the importance of using subthreshold laser power in experimental and clinical evaluation of TTT.

Animals↗
PubMed2003

TIMP-3 mRNA is not overexpressed in Sorsby fundus dystrophy.

PURPOSE: To assess the expression of MMP (matrix metalloproteinase)-2 and -9 and TIMP (tissue inhibitors of metalloproteinases)-1, -2, and -3 in Sorsby fundus dystrophy. DESIGN: Cliniciopathological report. METHODS: A donor eye with a confirmed S181C mutation in the TIMP-3 gene and an age-matched normal donor eye were studied using in situ hybridization technique with MMP -2 and -9 and TIMP -1, -2, and -3 probes. RESULTS: There is a reduction of mRNA expression of MMP-2 and TIMP-3 in the Sorsby retinal pigment epithelium cells. CONCLUSIONS: Increased expression of TIMP-3 mRNA does not cause accumulation of TIMP-3 in the Bruch membrane of Sorsby fundus dystrophy nor is it likely to cause age-related macular degeneration.

DNA Probes↗
PubMed2003

Transpupillary thermotherapy of predominantly occult choroidal neovascularization in age-related macular degeneration with 12 months follow-up.

PURPOSE: To perform a phase I/II safety and efficacy study in order to assess the outcome following transpupillary thermotherapy (TTT) for occult choroidal neovascularization (CNV) with no or minimally classic CNV in age-related macular degeneration. METHODS: The study comprised 113 referred patients (79 females, 34 males) aged 59-89 years (mean 77.7 years) with predominantly occult CNV. There were 49 cases of occult with no classic CNV and 64 of occult with minimally classic CNV. According to their greatest linear dimension, lesions were classified as being < 3.0 mm or > 3.0 mm. Transpupillary thermotherapy was delivered with a diode laser, emission at 810 nm, duration 60 seconds, laser power 500-800 mW. Clinical examination, ETDRS logMAR visual acuity and fluorescein angiography were carried out at baseline, and at 3, 6 and 12 months in all cases. RESULTS: The average baseline visual acuity was 0.20 (50.6 letters). Following TTT, it was 0.12 (42.0 letters) at 6 months and 0.12 (38.0 letters) at 12 months. Visual acuity improved in 9/113 eyes (8.0%), remained unchanged in 46 (40.7%) eyes, and deteriorated in 58 (51.3%) eyes. There was no significant difference in the proportion of eyes that had lost at least 15 letters at 12 months in the subgroup of occult with no classic CNV (18/49; 36.7%) versus those with minimally classic lesions < 3.0 mm (15/39; 38.5%). However, 13/25 (52.0%) of cases with minimally classic lesions > 3.0 mm had lost at least 15 letters at 12 months (p = 0.31). The most common complications in the 46 eyes that suffered visual loss comprised subretinal progressive fibrosis (18 eyes) and atrophy of the retinal pigment epithelium (13 eyes). CONCLUSIONS: This study shows that TTT generally prevents moderate and severe visual loss at 12 months follow-up in occult CNV with no classic CNV. Eyes with minimally classic lesions with a greatest linear dimension of < 3.0 mm also show the same positive outcome. These results compare favourably with published data on the natural course of the disease. However, minimally classic lesions of > 3.0 mm responded poorly in this treatment setting.

Aged↗
PubMed2003

Reduced choroidal neovascular membrane formation in matrix metalloproteinase-2-deficient mice.

PURPOSE: Findings in studies have suggested a role for matrix metalloproteinase (MMP)-2 in angiogenesis, including choroidal neovascularization (CNV). To investigate further, the current study was conducted to observe the formation of experimental CNV in MMP-2-deficient mice. METHODS: CNV was induced in wild-type and MMP-2-deficient mice by krypton laser photocoagulation of the fundus. The time-course of expression of MMP-2 mRNA after laser treatment was determined by in situ hybridization with anti-sense and sense cRNA probes. MMP-2 protein distribution was determined by immunohistochemistry. Ten days after treatment, the extent of CNV was evaluated on hematoxylin-eosin stained serial sections. The maximum height of the CNV lesions was calculated by image analysis of digitized histologic images. RESULTS: Expression of MMP-2 mRNA was detected in the CNV lesions at day 3 after laser treatment and peaked at day 5, after which it slowly declined. MMP-2 mRNA expression appeared to be highest at the margins of the membrane. Immunostaining for MMP-2 confirmed the presence of MMP-2 protein in the CNV lesions. The CNV lesions of MMP-2-deficient mice showed that relative thickness was reduced by 31% compared with wild-type mice (P = 0.006). CONCLUSIONS: The present study demonstrated that MMP-2 mRNA and protein are upregulated during experimental CNV in the mouse. The marked difference in thickness of the CNV membrane between wild-type and MMP-2-deficient mice shows that MMP-2 is involved in the formation of experimental CNV in the mouse. These results suggest that pharmacologic targeting of MMPs, including MMP-2, may reduce formation of CNV in conditions such as age-related macular degeneration.

Animals↗
PubMed2003

Uveal melanoma survival in Sweden from 1960 to 1998.

PURPOSE: To investigate the crude and relative survival rates in patients with uveal melanoma in Sweden during the period from 1960 to 1998. METHODS: A population-based national survey revealed 2997 cases of uveal melanoma in the Swedish Cancer Registry. The survival rates were calculated by the Hakulinen life-table method, using relative survival as an estimate for deaths due to uveal melanoma. The excess mortality rates were calculated with confidence intervals for the first 15 years after diagnosis. Multivariate regression analysis was undertaken to evaluate the influence of gender, age, and calendar period on relative survival the first 5 years after diagnosis. The underlying causes of deaths in the patients with uveal melanoma, as found in the Cause of Death Registry were also investigated. RESULTS: Up to December 31, 1998, 2003 patients had died. The 5-year crude survival rate was 60.3% and the relative survival 70.1%. After 10 years, the rates were 42.5% and 59.4%, respectively. Significant excess mortality existed up to 5.5 years after diagnosis. In the multivariate model, younger age (P < 0.001) and later calendar period (P = 0.002), but not gender (P = 0.117), were associated with better relative survival. Deaths due to uveal melanoma were misclassified in the Cause of Death Registry in more than half of the cases. CONCLUSIONS: This study, covering more than 95% of the uveal melanoma cases in the Swedish population revealed an improvement in relative survival rates for patients with uveal melanoma over time and a significant excess mortality up to 5.5 years after diagnosis.

Adolescent↗
PubMed2002

Age-related maculopathy: pathogenetic features and new treatment modalities.

A considerable amount of new information on putative pathogenetic mechanisms in age-related maculopathy and degeneration has emerged in recent years. This comprises experimental studies on retinal pigment epithelium (RPE) and rod photoreceptor ageing, lipofuscin accumulation, the roles of oxidative stress and free radical formation, as well as antioxidants and other defensive mechanisms operating against environmental factors and ageing. The current application of photodynamic therapy (PDT) using verteporfin marks a new era in the treatment of subfoveal classical choroidal neovascularization. Several new treatment modalities, such as transpupillary thermotherapy (TTT) and anti-vascular endothelial growth factor (VEGF) agents for inhibition of neovascularization, have emerged and are undergoing multicentre clinical trials. A period of dynamic development in this field has commenced.

Aging↗
PubMed2002

A prospective study of children treated for retinoblastoma: cognitive and visual outcomes in relation to treatment.

PURPOSE: : To assess cognitive and visual outcomes in children treated for retinoblastoma. PATIENTS AND METHODS: A population-based group of 22 children treated for retinoblastoma were followed in a longitudinal, prospective study. Eleven children had unilateral tumours, all of which had been enucleated. The remaining 11 had bilateral tumours. Seven of these had undergone unilateral enucleation and local or external beam radiation to the other eye. Four children had been treated with local or external beam radiation only. Cognitive outcome and visual function was assessed at 4 and 6 years of age. RESULTS: We found no general delay in cognitive or motor development at 4 or 6 years of age. Better cognitive capacities were found in the bilateral/irradiated retinoblastoma patients than in unilateral/non-irradiated patients. However, two of the irradiated children, both of whom had been treated at 1 month of age, performed below group mean. None of the children was totally blind. Three children were visually impaired due to tumours affecting the macular area in the remaining eye; another three had subnormal visual acuity but no macular pathology. A total of 14 children had been enucleated and had normal vision in the remaining eye. Visual fields and dark adaptation were adversely affected in a few cases, but colour vision was normal in all. CONCLUSION: Bilateral retinoblastoma seems to be associated with superior cognitive capacities. Few children were visually impaired according to WHO criteria. We speculate that children treated during the first months of life may be at risk of adverse cognitive and visual outcomes. The immature brain may be affected by radiation treatment, causing both cognitive and visual deviations.

Brachytherapy↗
PubMed2002

Photoreceptor survival in transplantation of autologous iris pigment epithelial cells to the subretinal space.

PURPOSE: To investigate photoreceptor survival in transplantation of non-cultured iris pigment epithelial (IPE) cells to the subretinal space in a prospective experimental study. METHODS: Upper iridectomies were carried out in the right eyes of 37 pigmented rabbits. Suspensions of freshly harvested autologous IPE cells (without culturing) were prepared and injected into the subretinal space of the same eye. Follow-up examinations were carried out using ophthalmoscopy and colour fundus photography. The rabbits were killed at 1, 2, 3 and 6 months, respectively, and the eyes examined with light and electron microscopy. RESULTS: On histological examination, the photoreceptor cells were found to be well-preserved in grafted areas at 1-3 months. At 6 months, the photoreceptors generally disclosed a normal nuclear layer and long outer segments when overlying areas with single cells or clusters of transplanted IPE cells. Multilayers of cells in abundance, including native RPE cells and macrophages (stained with RAM 11), particularly under microfolds of the neural retina, were occasionally associated with photoreceptor damage and nuclear drop out from the outer retinal layer. There was no inflammatory response in the choroid and the choriocapillaris remained patent. CONCLUSION: The experiments show that grafting freshly harvested autologous IPE cells to the subretinal space is feasible and that the photoreceptors generally survive for at least 6 months when overlying the transplanted areas. Multilayers of abundant cells in the subretinal space may induce adverse focal effects on adjacent photoreceptors.

Animals↗
PubMed2002

Photodynamic therapy for circumscribed choroidal haemangioma.

PURPOSE: To assess the efficacy of photodynamic therapy (PDT) as a new treatment for circumscribed choroidal haemangioma (CCH). METHODS: Eight patients with CCH were treated with PDT using a protocol similar to that used in the standard treatment of neovascular age-related macular degeneration. RESULTS: Visual acuity improved in six of eight eyes, remained unchanged in one eye and deteriorated in one eye after 3-15 months (median 7 months) follow-up. Pre-treatment metamorphopsia disappeared in all but two cases. The thickness of the CCH measured with standardized echography showed marked regression within 1 month after PDT. In six eyes there was no remaining protrusion after PDT and one lesion was barely detectable. One patient experienced a transient choroidal effusion and perifoveal haemorrhage. CONCLUSION: Photodynamic therapy is a promising new treatment for CCH as it restores visual function in most cases without causing apparent ocular or systemic side-effects.

Adult↗
PubMed2002

Insulin-like growth factor-1 receptor in uveal melanoma: a predictor for metastatic disease and a potential therapeutic target.

PURPOSE: To investigate the expression of the insulin-like growth factor-1 receptor (IGF-1R) with special focus on its role in cell growth in uveal melanoma. METHODS: Paraffin material from 36 clinicopathologically well characterized cases of primary uveal melanomas (18 of which had metastasized to the liver) with more than 15 years' follow-up was used for immunohistochemical analysis. In the experimental studies, three uveal melanoma cell lines (OCM-1, OCM-3, and 92-1) were used. The expression level of IGF-1R in the cell lines was modulated by glycosylation inhibitors, and the IGF-1R was neutralized with the antibody alphaIR-3. Expression of IGF-1R was assayed by Western blot analysis and immunohistochemistry. Cell growth and survival were analyzed by cell counting, thymidine incorporation, and viability assays. RESULTS: Western blot analysis and immunohistochemistry confirmed that IGF-1R is expressed in uveal melanoma. Although 10 of 18 patients who died of metastasizing disease showed high IGF-1R expression, only 5 of 18 tumors from patients who survived for 15 years or more after enucleation exhibited a high IGF-1R expression. Kaplan-Meier analysis showed a significant association (P = 0.035) between a high IGF-1R expression and death due to metastatic uveal melanoma. Using in vitro experimental models, we found that inhibition of the IGF-1R activity (tyrosine phosphorylation) was associated with a drastic decrease in uveal melanoma cell viability. CONCLUSIONS: These data suggest an important role of IGF-1R in uveal melanoma. The significant association between high IGF-1R expression and death due to metastatic disease may be explained by the fact that IGF-1 is mainly produced in the liver, which is the preferential site for uveal melanoma metastases. These data also point to the possibility of therapeutically interfering with IGF-1R, which appears to be expressed preferentially in uveal melanomas that appear to follow an aggressive clinical course.

Adult↗
PubMed2002

Structure and function of the N-cadherin/catenin complex in retinoblastoma.

PURPOSE: To identify in human retinoblastoma and normal retinal tissue the type of cadherin, its relationship with cytoplasmic catenins, and its participation in invasion. METHODS: The cadherin/catenin complex was characterized in surgical retinoblastoma specimens from five patients and human retinas from four donor eyes by immunocytochemistry, flow cytometry, and coimmunoprecipitation with antibodies against N-cadherin, alpha-catenin, and beta-catenin, followed by Western blot analysis or autoradiography. Y79 and WERI-Rb-1 retinoblastoma cell lines serve the evaluation of the cadherin/catenin complex in aggregation and collagen type I invasion in vitro. The association of the cadherin/catenin complex with the cytoskeleton was examined by an antibody-capping assay. RESULTS: In retinoblastoma and normal retina N-cadherin associated with alpha-catenin and beta-catenin but not E- or P-cadherin. The N-cadherin/catenin complex formed a regular, linear, and continuous honeycomb pattern in normal retina that was irregular, clustered, and interrupted in retinoblastoma. The N-cadherin/catenin complex was found also in the retinoblastoma cell lines WERI-Rb and Y79, in which it also showed an irregular pattern. Both cell lines were invasive in collagen type I, and invasion was inhibited by the GC-4 antibody, which functionally neutralizes N-cadherin. Less GC-4 antibody was needed to inhibit invasion of Y79 cells, which expressed N-cadherin at a lower level, than to inhibit invasion of WERI-Rb-1 cells. In both cell lines, antibody capping of the N-cadherin/catenin complex indicated that its linkage with the cytoskeleton were weak or absent. CONCLUSIONS: Retinoblastoma cells, in contrast with normal retina, express an N-cadherin/catenin complex that is irregularly distributed and weakly linked to the cytoskeleton. In retinoblastoma, this complex acts as an invasion promoter.

Autoradiography↗
PubMed2002

Incidence of uveal melanoma in Sweden from 1960 to 1998.

PURPOSE: To investigate the incidence of uveal melanoma in Sweden during the period from 1960 to 1998, with respect to age distribution, gender, and changes in incidence over time. METHODS: The Swedish Cancer Registry was searched for patients with uveal melanoma and cross-checked against hospital files over patients where an eye-sparing treatment had been applied, to ensure inclusion in the Registry even when no histologic specimen was available. The crude and age-standardized incidence was estimated separately for each gender. The Swedish population of 1970 to 1974 was used as a standard, and the annual change in incidence was calculated by using a regression model with logarithmic incidence numbers. RESULTS: In total, 2997 patients met the criteria, of whom 1542 were males and 1455 females. During the 39-year period, the age-standardized incidence of uveal melanoma declined significantly in the male population, from 11.7 cases/million to 8.4 cases/million (P = 0.002). The trend toward reduced incidence in females, from 10.3 to 8.7 cases/million did not reach statistical significance (P = 0.108). The annual relative change in incidence was 1% (95% CI, 0.8%-1.2%) in males and 0.7% (95% CI, 0%-1.3%) in females. The age-specific incidence revealed a significantly higher incidence among men older than 45 years (23.5 cases/million) compared with the incidence in women of the same age group (19.2 cases/million; P < 0.001). CONCLUSIONS: A Swedish national survey performed to establish the incidence of uveal melanoma during the period from 1960 to 1998 revealed a decreasing incidence in the male and a stable incidence in the female population.

Adolescent↗
PubMedDate not supplied

Sunlight exposure and pathogenesis of uveal melanoma.

Uveal melanoma is the most frequent primary malignant intraocular tumor of adults. Among various non-modifiable risk factors, Caucasian race seems to be the most significant with light skin color, blond hair, and blue eyes being specific risk factors. The racial predisposition to uveal melanoma have been explained on the basis of susceptibility of Caucasian race to oncogenic effects of sunlight. Although there is ample evidence in support of this hypothesis in regard to skin melanoma, the evidence in regard to uveal melanoma is insufficient and contradictory. In the following review, we examine physiologic, epidemiological, and genetic data in order to determine the role of sunlight exposure in the pathogenesis of uveal melanoma.

Environmental Exposure↗