Miki Miyashiro

The second eye of Japanese patients with unilateral exudative age related macular degeneration

AIM To clarify the incidence of choroidal neovascularisation (CNV) and predisposing findings for development of CNV in the second eye of Japanese patients with unilateral exudative age related macular degeneration (AMD). METHODS The second eyes of unilaterally affected patients with exudative (neovascular) AMD treated in our clinic during the past 10 years (1988–97) were carefully followed up for more than a year. Evidence of CNV was confirmed by fluorescein and indocyanine green angiography. Macular lesions in patients, in whom CNV developed in the second eye, were retrospectively evaluated from patient records. RESULTS 170 patients met the criteria. The average follow up period was 47 months (range 12–108 months). All patients were Japanese. CNV developed in the second eye in 12 (7%) of 170 patients, 30.3 months on average after the first examination. Cumulative incidence of developing CNV in the second eye using Kaplan–Meier life table analysis was: 0.6% by 1 year, 5.6% by 3 years, and 12.3% by 5 years, and was relatively low compared with that in white patients. CNV developed most frequently from serous pigment epithelial detachment (PED) in the macula (58%). Soft drusen were not prevalent and risk of developing CNV was not very high (18%). CONCLUSION It was confirmed that there were some differences in the incidence and predisposing findings for CNV developing in AMD among Japanese and other Asian patients compared with those in white people. It is important to recognise these differences between the two populations to understand the pathogenesis and epidemiology of AMD.

Immunolocalization of basic fibroblast growth factor during wound repair in rat retina after laser photocoagulation.

Abstract•Background: Basic fibroblast growth factor (bFGF) stimulates the mitogenesis of various cells and plays a key role in wound repair. We studied the immunohistochemical localization of bFGF during wound repair in the rat retina after laser photocoagulation.• Methods: Krypton laser photocoagulation was performed on the eyes of pigmented rats. The eyes were enucleated on days 1, 3, 7, 14 and 28 after the photocoagulation, and the immunohistochemical localization of bFGF was assessed. Two different monoclonal antibodies and one polyclonal antibody against bFGF as first antibodies were used.• Results: Marked immunoreactivity for bFGF was found in the ganglion cell layer, and weak immunoreactivity for bFGF was found in the retinal pigment epithelial (RPE) cells of the normal adult rat retina. On day 3 after laser photocoagulation, the nuclei and cytoplasm of proliferating RPE cells at the center of the photocoagulated lesion showed intense bFGF immunoreactivity. The nuclei of RPE cells around the lesion showed intense bFGF immunoreactivity. Macrophages that migrated into the lesion showed positive staining for bFGF. These immunoreactivity decreased with time. Controls (0.05 M Tris-HCl buffer, normal serum, or these same antibodies preabsorbed with bFGF) did not show positive staining.• Conclusion: The finding of an elevated expression of bFGF immunoreactivity in the photocoagulated lesion suggests that bFGF may play a role in wound repair in the rat retina after laser photocoagulation.

Immunolocalization of transforming growth factor β during wound repair in rat retina after laser photocoagulation

Abstract• Background: Scatter photocoagulation induces regression of retinal neovascularization, but the mechanism of its therapeutic effect is incompletely understood. To elucidate the mechanism of therapeutic effect of photocoagulation is the main focus of our research. We have already demonstrated basic fibroblast growth factor (bFGF) immunolocalization during retinal wound repair following laser photocoagulation. Transforming growth factor beta (TGF β) reportedly inhibits endothelial cell growth and bFGF-induced cell proliferation in vitro. In the present study, we evaluated the immunohistochemical localization of TGF-β1 and -β2 during wound repair in the rat retina following laser photocoagulation. • Methods: Krypton laser photocoagulation was performed on the eyes of pigmented rats. The eyes were then enucleated on day 1, 3, 7, 14, 28 or 56 following the photocoagulation and enrolled into the analysis of immunohistochemical localization of TGF-β1 and -β2. • Results: Immunoreactivity for TGF-β1 and -β2 was present in the ganglion cell layer and photoreceptor outer segments of the normal adult rat retina. The cytoplasm of RPE cells at the photocoagulated lesion showed intense TGF-β1 and -β2 immunoreactivity on day 3 after laser photocoagulation. Macrophages that migrated into the lesion lacked positive staining for TGF-β1 and -β2. TGF-β immunoreactivity in RPE cells continued to be upregulated for more than 1 month compared with that in normal RPE cells. Controls did not exhibit any positive staining. • Conclusion: An elevated expression of TGF-β immunoreactivity for a longer period of time than bFGF was observed in RPE cells at the photocoagulated lesion in vivo. In the late phase of retinal wound repair, TGF-β may inhibit cell proliferation induced by mitogens, introduce an end stage of cellular events, and induce extracellular matrix induction.

Expression of basic fibroblast growth factor and its receptor mRNA in retinal tissue following ischemic injury in the rat

Abstract · Background: Our purpose was to determine the time-dependent changes of expression of basic fibroblast growth factor (bFGF) and its receptor in pressure-induced retinal ischemia in rats. · Methods: Retinal ischemia was induced in Wistar rats by increasing the intraocular pressure to 110 mmHg for 45 min by cannulation into the eyes. At the end of the ischemic period, reperfusion of the retinal vasculature was confirmed. Localization of bFGF and FGF receptor-1 (FGF-R) mRNAs were evaluated by in situ hybridization at various times after reperfusion. The reverse-transcription polymerase chain reaction (RT-PCR) method was used to detect the expression of bFGF and FGF-R mRNA in the sensory retina. · Results: In normal sensory retina, bFGF and FGF-R mRNAs were observed in the ganglion cell layer and inner nuclear layer. bFGF gene expression in the sensory retina increased within 24 h, particularly at 6–12 h. FGF-R gene expression increased earlier than that of bFGF. By RT-PCR, expression of bFGF gene reached a peak at 6–24 h, and FGF-R reached a peak at 3–12 h. These RT-PCR results are comparable to those of in situ hybridization. · Conclusions: These results demonstrate that transient retinal ischemia leads to the induction of bFGF mRNA synthesis, and suggest that bFGF has a protective role, e.g., a defense mechanism for the sensory retina.

Linezolid-Associated Optic Neuropathy in a Patient with Ocular Sarcoidosis

BackgroundWe describe a case of bilateral linezolid-associated optic neuropathy in a patient with ocular sarcoidosis.CaseA 70-year-old woman with sarcoidosis noted foggy vision in both eyes. Best-corrected visual acuity was 0.5 in the right eye and 0.9 in the left. No abnormality other than slight optic disc hyperemia was visible in either eye. A central scotoma in both eyes and enlargement of the blind spot in the right eye were detected by Goldmann perimetry examination, and magnetic resonance imaging demonstrated an edematous optic nerve in the right eye. Therefore, retrobulbar optic neuritis resulting from sarcoidosis was initially suspected. Sub-Tenon’s capsule injection of triamcinolone acetonide along with steroid pulse therapy was given; however, best-corrected visual acuity worsened to 0.06 in the right eye and 0.08 in the left. Pulse therapy was discontinued on day 1, and the possibility of linezolid-associated optic neuropathy was speculated because linezolid had been given for methicillin-resistant Staphylococcus aureus osteomyelitis 2 years before by an orthopedist. After discontinuation of linezolid, best-corrected visual acuity improved to 0.8 in the right eye and 0.9 in the left, and the optic disc hyperemia in both eyes disappeared.ConclusionOur findings demonstrate that it is important for ophthalmologists as well as physicians and orthopedists to consider the possibility of optic neuropathy caused by long-term use of linezolid.