Investigation of the potential utility of a linomide analogue for treatment of choroidal neovascularization.

The aim of this study was to test the selectivity, in-vivo effectiveness, and potential mechanism of action of a linomide analogue (N-phenyl-1,2-dihydro-4-hydroxyl-2-oxo-quinoline-3-carboxamide, Lin05) for inhibition of choroidal neovascularization. The selectivity of Lin05 was tested in cell proliferation assays with human umbilical vein endothelial cells (HUVEC) and a retinal pigmented epithelial cell line(ARPE-19). In-vivo anti-angiogenic effect of Lin05 was investigated utilizing an experimental laser-induced choroidal neovascularization (ECNV) model in adult Brown Norway rats. Western blot and/or reverse transcriptase-PCR was used to test the effect of Lin05 on potential targets. Our results indicate that Lin05 is at least an 8-fold more selective inhibitor of endothelial cell proliferation compared to RPE cells. Systemic administration of Lin05 in an ECNV model was associated with a significant decrease in both vascular leakage on fluorescein angiography and lesion size by histopathology (p = 0.02). No systemic toxicity was detected for Lin05 in major organs such as the liver, lung and kidneys. Lin05 did not inhibit VEGF-induced VEGFR2 (KDR) phosphorylation in HUVEC nor was associated with decreased VEGF gene expression. Also it did not inhibit insulin-like growth factor (IGF-1) and Epidermal Growth Factor (EGF) induced activation of p42/p44 MAPK activation. It inhibited both PDGF- and bFGF-induced p42/p44 MAPK phosphorylation. However, the effect on PDGF was variable in different HUVEC cells. In conclusion, Lin05 is a potential anti-angiogenic agent for the treatment of eye diseases associated with pathological neovascularization. The anti-angiogenic effect of Lin05 is likely through inhibition of bFGF but not through inhibition of the VEGF/KDR pathway.

Cancer family history characterization in an unselected cohort of 121 patients with uveal melanoma.

Uveal melanoma (UM) is the most common primary intraocular malignancy in adults. The extent of the contribution of familial/hereditary predisposition to the development of uveal melanoma is largely unknown. Thus we sought to ascertain the frequency of cancers in patients with UM and their family members to identify the prevalence of hereditary/familial predisposition to cancer in these patients. An unselected series of 121 patients with UM seen in a university-based tertiary referral program were consented to the study. Cancer histories (site and age of diagnosis) were obtained for all first- and second-degree relatives. Patients/families were classified as being potentially at high risk for hereditary predisposition if they met any of the following criteria: (1) Diagnosis of UM at age 30 or under, (2) Two or more cases of UM in the family, (3) UM plus at least one other primary cancer in the same patient (excluding non-melanoma skin and cervix cancers due to their strong environmental etiological link). (4) Family history meeting high risk criteria for a known hereditary cancer predisposition syndrome as defined by Hampel et al. (J Med Genet 41(2): 81-91, 2004). One patient had a family history of UM (0.8%). Ten patients (8.3%) had a personal and/or family history consistent with predisposition to a known hereditary cancer syndrome including six with possible hereditary breast, two with hereditary colon and two with hereditary melanomas. Twenty three patients (19%) had a personal history of a second cancer after exclusion of non-melanoma skin and cervical cancers. The frequency of cutaneous melanomas was significantly higher in UM patients than the general population (RR: 2.97, 95% CI: 1.00-6.94). Patients with a family history suggestive of a high risk predisposition to a known cancer syndrome had a significantly higher risk for having a second cancer than the remaining UM patients (P = 0.02). Our results indicate that the frequency of UM patients with high risk for a hereditary cancer predisposition is much higher than earlier estimates (0.6%) and that it could be as high as 11.6%. Our results suggest that cancer phenotypes in these patients are diverse and include cancers other than UM. Thus, alerting ophthalmologists to the need for expanding their cancer family history intake to include other cancers is warranted. It also suggests that patients with a hereditary predisposition to UM have a higher risk for the development of other cancers and that characterization of the germline genetic alterations in these patients is highly warranted.

Morphologic studies of the retina in a new diabetic model; SHR/N:Mcc-cp rat.

The pathogenesis of diabetic retinopathy has not been fully explained. The earliest histological lesion is the loss of intramural pericytes and thickening of the basement membrane. Increased activity of the polyol pathway is a probable mechanism for these two abnormalities. Investigations have suffered from the lack of an exact animal model simulating the human condition. Examination of the retina in the spontaneously diabetic SHR/N:Mcc-cp rat demonstrated degeneration and loss of intramural pericytes, a progressive increase in basement membrane thickness, and microinfarctions with an area of non-perfusion. Therefore, this model may be used to clarify the biochemical mechanisms linking the metabolic abnormalities of diabetes and retinopathy.

Bungee cord-associated ocular injuries.

PURPOSE: To report ocular injuries associated with the use of bungee cords. METHOD: Four patients with bungee cord-associated ocular trauma are presented. RESULTS: Four eyes of four patients demonstrated severe contusion injuries associated with bungee cord trauma. Ocular injuries in the four eyes included a variable combination of corneal abrasion, hyphema, iridodialysis, anterior chamber angle recession, secondary glaucoma, lens subluxation, vitreous hemorrhage, and retinal detachment. Three of the four eyes required ophthalmic surgery. All eyes had anterior chamber angle recession and required continuing ophthalmic care. CONCLUSION: Bungee cords may be associated with severe ocular injury and should be used with caution.

Interferon alfa-associated retinopathy.

Interferon alfa and its related compounds have been used for more than 10 years in the treatment of a number of conditions including viral illnesses, childhood hemangiomas, various cancers, and leukemia. The potential applications for this class of medication continue to grow. The use of interferon alfa in experimental protocols has also increased, thus making it more likely that new indications will be discovered. It is probable that primary care physicians will be called on to initiate therapy or will see patients being treated with interferon in their practice. We report the development of interferon-related retinopathy in a 43-year-old man while he was receiving experimental treatment with interferon alfa for hepatitis B virus and hepatitis C virus infection. The vision loss was acute and only partially reversible. Interferon, its mechanism of action, and the past literature are briefly discussed.

Altered membrane fatty acids of cultured human retinal pigment epithelium persistently infected with rubella virus may affect secondary cellular function.

Persistent infection with rubella virus (RV) can alter secondary functions of host cells. Previously we had documented defective phagocytosis of latex beads by cultured human retinal pigment epithelial cells (RPE), persistently infected with M-33 RV (RPE/RV). Here, examining possible mechanisms for altered function, we reported significant differences between the total esterified fatty acids (FA) of RPE and RPE/RV membranes, measured by gas liquid chromatography. RPE/RV contained an increased proportion of saturated FA, particularly palmitic acid, with a presence of unusual chromatographic FA peaks co-eluting with odd-numbered long-chain carbon atom FA not normally found in human cells. Apical membrane microvilli, structures essential to phagocytic activity of RPE and RPE/RV, observed by scanning and transmission electron microscopy, were similar in number and appearance between uninfected RPE and RPE/RV cells before and after latex bead addition. However, RPE/RV microvilli, possibly reflecting altered membrane FA composition, engaged latex beads less effectively than uninfected RPE microvilli. In addition, microvilli remained abnormally distributed on RPE/RV cell surfaces at 48 h after latex addition. Thus, RV persistent infection may affect the cellular membrane fluidity and functional activity of human cells with increased saturated FA proportions and altered FA components of membrane phospholipids. These changes may participate in the defective phagocytosis of RPE/RV.

Diabetic retinopathy during pregnancy.

This article outlines the pathophysiology of diabetic retinopathy, its epidemiology, and its diagnosis. Recommendations for management of the pregnant diabetic patient through the team approach has resulted in a dramatic improvement in maternal and fetal complications during pregnancy. By including a retinal specialist in the team during each trimester, the effects of pregnancy on the progression of diabetic retinopathy should be nearly identical to that of the non-pregnant patient.

Phagocytosis of latex beads is defective in cultured human retinal pigment epithelial cells with persistent rubella virus infection.

Phagocytosis, a secondary function of retinal pigment epithelial (RPE) cells essential to sight, was significantly decreased, when measured with latex beads, during persistent rubella virus (RV) infection of human cultured RPE cells. A target for RV in vivo, RPE cells infected with RV (RPE/RV) ingested fewer fluorescent microspheres (26%) than did uninfected RPE cells (68%) (P < 0.001), as measured by flow cytometry. In RPE/RV cells, with characteristic RPE monolayer appearance and normal growth during subculturing over 6 months, persistent RV infection was shown by specific RV antigen immunofluorescence, by the presence of the RV genome in RPE/RV cell messenger RNA, and by recovery of cell-free RV after cocultivation with Vero cells. The adhesion of latex beads to apical cell surfaces of RPE/RV and uninfected RPE cells appeared similar, as imaged by scanning electron microscopy. Cytoskeletal actin, a component of phagocytosis in RPE, appeared altered in 60 to 75% of RPE/RV cells by antiactin immunofluorescence staining, as previously described in other RV-infected cells, but its role in the disturbed phagocytosis of latex beads was not determined. Persistently RV-infected human RPE is an additional example of RV-associated secondary cellular dysfunction in the absence of cytopathic effects.

False-positive magnetic resonance imaging of a metastatic carcinoma simulating a malignant melanoma.

Previous studies have shown the value of magnetic resonance imaging (MRI) in the diagnosis of malignant melanoma of the choroid. We describe the case of a patient with a choroidal mass whose MRI study was characteristic of malignant melanoma. Subsequently the eye was enucleated. However, on histopathologic examination, the mass was a metastatic carcinoma to the choroid. This false-positive study makes us question the value of MRI in the diagnosis of malignant melanoma of the choroid.

Activated retinitis pigmentosa peripheral lymphocytes adhere to and alter cultured human retinal pigment epithelial cells.

Interleukin-2 receptor (IL-2R) is an activation molecule that, when expressed on peripheral blood lymphocyte (PBL) membranes, indicates the secretion of IL-2 and initiation of an immune system activation cascade. Comparing the average of IL-2R expression in 34 patients with retinitis pigmentosa (RP) syndrome (561 +/- 282 cells/mm3; mean +/- standard deviation) with 35 age-matched normal subjects (194 +/- 39 cells/mm3), it was found that those with RP had greater numbers of IL-2R-positive cells (P less than 0.001). The increased amounts of IL-2R on PBL of 29 RP and the homotypic self-aggregation of RP PBL by phase and scanning electron microscopy led to the study of the interaction of RP PBL with cultured human postmortem retinal pigment epithelial cells (RPE). A direct correlation was found between the amount of IL-2R expression and the numbers of RP lymphocytes adhering to RPE monolayers. However, the adherence effect was not unique to RP syndrome but appeared to be a nonspecific result of lymphocyte activation. Greater adherence to RPE than normal also was observed in PBL from disease control subjects with elevated IL-2R values and in PBL stimulated by the mitogen, concanavalin A (Con-A). In addition, RPE monolayers were destroyed by Con-A-stimulated PBL that showed 95-98% IL-2R expression. Similar, but less serious effects, occurring in RPE cells after 1 wk's cocultivation with RP PBL, suggested that activated RP lymphocytes can be cytotoxic to RPE during prolonged contact. Because macrophage-like cells and class II major histocompatibility complex expression have been found in RP-affected retinas, immune-mediated cytopathologic effects may contribute to retinal degeneration in RP.

Retinoblastoma, microphthalmia, coloboma, and neuroepithelioma of the pineal body.

A one-month-old infant boy was examined early in life because his mother had bilateral retinoblastoma and his father had bilateral microphthalmia. The ophthalmologist found his right eye was normal size with a coloboma of the iris, choroid, and retina. The left eye was microphthalmic with a coloboma of the uveal tract and retina. A vascularized fluffy white mass in the posterior pole was diagnosed clinically as a retinoblastoma. The tumor regressed with radiation. When the patient was four years of age, a large tumor was found in the region of the pineal recess, causing hydrocephalus and seizures. A biopsy showed an undifferentiated malignant neuroepithelial neoplasm. The patient died within three months of diffuse central nervous system tumor. The unusual findings of a retinoblastoma in a microphthalmic eye with bilateral colobomas and a neuroepithelial neoplasm of the pineal gland are discussed.

Systemic immunostimulation after retinal laser treatment in retinitis pigmentosa.

Systemic immunostimulation followed an experimental treatment trial of scatter argon laser photocoagulation directed to the retina of one eye of 10 patients with heredo-degenerative retinitis pigmentosa (RP). Significantly increased RP lymphocyte CD25, CD26, and CD4/CD26 activation epitope expressions over prelaser values and controls were found with a normalization of soluble interleukin-2 receptor secretion after laser treatment. Serum interferon-gamma was low both pre- and postlaser. Interestingly, when a panel of viral antibodies was tested, only those to rubella virus were elevated in the early postlaser period. The character of RP immunostimulation after laser-induced inflammation could be consistent with an antigenic stimulus from laser-released retinal proteins which might be of autoimmune or latent infectious origin. Enhanced immune responses may be a common but unrecognized sequellae of retinal laser.

Modified vitrectomy for impending macular holes.

We report a consecutive series of 13 eyes (11 patients) treated with pars plana vitrectomy, in which surgical manipulation of the prefoveal layer of cortical vitreous was avoided, for stage I (eight eyes) and stage II (five eyes) macular hole formation. Average follow up was 8.1 months (range, 2 to 13 months). There was no significant improvement in vision in the patients with stage II macular holes; however, vision in these patients stabilized and did not fall below 20/400. Visual acuity improved in seven of the eight patients with stage I holes. The results for both these groups achieved by our modified vitrectomy, which is relatively easy to perform and involves minimal intraoperative manipulation of the fovea, are consistent with those obtained by methods involving more aggressive cortical vitreous stripping of the fovea.

Scanning electron microscopic study of microaneurysms in the diabetic retina.

We describe the clinical and pathologic appearance of the retinal microcirculation in a patient with a 22-year history of diabetes mellitus. A vascular cast of one eye was prepared and studied with scanning electron microscopy. The three-dimensional views obtained give insight into the pathogenesis of microaneurysms.

Pathogenesis of retinal dystrophy in the Royal College of Surgeons rat.

The Royal College of Surgeons (RCS) rat is an animal with genetically transmitted progressive retinal dystrophy. We compared histopathologically the RCS rat retina with normal age-matched control retinas (Long-Evans rats) using light and scanning electron microscopy. Retinal degeneration begins with alteration of the rod outer segments. There is a progressive involvement of the entire retina, with all layers affected by 45 days. The three-dimensional view obtained with scanning electron microscopy provides another perspective on the pathogenetic changes of the RCS retina.