Yutaka Shirao

Development of Electroretinographic Alterations in Streptozotocin-lnduced Diabetes in Rats

Development of electroretinographic alterations in 9-week-old experimental diabetic rats was studied for up to 6 weeks after a single intraperitoneal injection of streptozotocin (STZ, 60 mg/kg). The amplitudes and the peak latencies of the a and b waves in the diabetic rats did not differ significantly from those in the control rats. In contrast, the diabetic rats showed a significantly smaller amplitude of the second oscillatory potential (OP) 6 weeks after STZ treatment, and furthermore significantly delayed OP peaks as early as 2-3 weeks after STZ treatment. Vitreous fluorophotometric abnormality developed 6 weeks after STZ treatment. None of the diabetic rats had fundus angiographic changes. These results suggest that hyperglycemia or its related changes rapidly affects the light-induced electrical activities of the retina.

Upregulation of Retinal Vascular Endothelial Growth Factor mRNAs in Spontaneously Diabetic Rats without Ophthalmoscopic Retinopathy

Vascular endothelial growth factor (VEGF) has recently been shown to be involved in the pathogenesis of proliferative diabetic retinopathy. However, its involvement in the development of the early phase of diabetic retinopathy is not fully understood. In this study we investigated the retinal VEGF mRNA level in spontaneously diabetic Otsuka Long-Evans Tokushima fatty (OLETF) rats, a model of non-insulin-dependent diabetes, without overt retinopathy, using quantitative reverse-transcription polymerase chain reaction. The retinal VEGF mRNA level was 2.2 times higher (p < 0.0005) in OLETF rats than in control rats at the age of 60 weeks. Moreover, their retinal mRNA level was positively correlated with serum concentration of advanced glycation end products (AGEs) but not to serum glucose concentration. Furthermore, the peak latency of the oscillatory potentials in the electroretinogram, one of the most sensitive markers for the early phase of diabetic retinopathy, was significantly prolonged in OLETF rats (p < 0.05), being also correlated with the serum AGE concentration. The results thus suggest that AGEs, which are formed acceleratedly in diabetic conditions, are involved in the development of the early phase of diabetic retinopathy probably through the induction of retinal VEGF mRNAs.

Isolating triamcinolone acetonide particles for intravitreal use with a porous membrane filter.

Purpose To report a new, simple, rapid method to isolate triamcinolone acetonide particles and to remove additives from its commercially available suspension (Kenacort-A) for intravitreal use. Methods The contents of a Kenacort-A vial (40 mg triamcinolone acetonide suspended in 1.0 mL vehicle) were loaded into a syringe and passed through a porous membrane filter with 0.45-&mgr;m pores. The filter was then backflushed with distilled water to yield a vehicle-poor suspension of triamcinolone acetonide in the initial syringe. This filtration and backflush procedure was repeated four times, and each waste filtrate was subjected to high-performance liquid chromatography to identify benzyl alcohol, a preservative in the vehicle. Gel permeation chromatography was also used to determine the degree to which carboxymethylcellulose, one of the two suspending agents in the vehicle, permeated the membrane filter. Although 7.5 mg/mL high-viscosity carboxymethylcellulose hardly passed through the 0.45-&mgr;m pore filter, it passed through the 5.0-&mgr;m pore filter easily. Therefore, a 5.0-&mgr;m pore filter was used in this study. Results By using a 0.45-&mgr;m porous membrane filter, 99.7% of the benzyl alcohol can be eliminated. By using a 5.0-&mgr;m porous membrane filter, but not by using a 0.45-&mgr;m porous membrane filter, 88.1% of the high-viscosity carboxymethylcellulose can be eliminated. Conclusions The filtration and backflush procedure using the 5.0-&mgr;m porous membrane filters is useful during vitrectomy to reduce the preparation time of triamcinolone acetonide suspension. Also, this method of reducing additives may be more helpful when using triamcinolone as a therapeutic agent for intravitreal depot use, because there is no washout effect when it is used in this manner.

Endophthalmitis Caused by Enterococcus mundtii

ABSTRACT Enterococcus mundtii has rarely been isolated from environmental or human sources. We report the identification of E. mundtii as a pathogen of human infectious disease by DNA sequencing of 16S rRNA and sodA genes in a case of endophthalmitis developed in a 66-year-old immunocompetent gardener.

Optical coherence tomographic and angiographic findings of a case with subretinal toxocara granuloma

PURPOSE To study a case with a subretinal Toxocara granuloma. DESIGN Interventional case report. METHODS A patient with a exudative macular lesion, diagnosed as ocular toxocariasis, was examined with optical coherence tomography (OCT) and angiography before and after systemic corticosteroid and anthelminthic therapy. RESULTS In OCT images, the macular granuloma initially appeared as a highly reflective mass protruding above the retinal pigment epithelium and showed dye leakage by angiography. Posttherapy, the lesion was no longer exudative, was less elevated, and was covered by the retinal pigment epithelium. There was reticular hyperfluorescence surrounded by a hypofluorescent rim in the angiograms. CONCLUSIONS Subretinal Toxocara granuloma may have a presentation similar to idiopathic choroidal neovascularization (CNV) and should be included in the differential diagnosis of the idiopathic CNV.

Remission of antiepiligrin (laminin-5) cicatricial pemphigoid after excision of gastric carcinoma.

Purpose. To describe a case of antiepiligrin cicatricial pemphigoid with unusual ocular manifestations and its remission after surgical removal of gastric carcinoma. Methods. We describe a 61-year-old Japanese man with antiepiligrin cicatricial pemphigoid. Results. He presented with conjunctival injection and discharge preceded by a 6-month period of erosive lesions in the oral mucosa and the truncal skin. An advanced gastric carcinoma was found and his serum immunoprecipitated laminin-5. Despite topical treatment with betamethasone, ofloxacin, and artificial tear solutions, serious symblepharon along the Meibomian line developed with little shortening of the inferior conjunctival sac. Following radical gastrectomy, the ocular and cutaneous lesions turned completely quiet. Conclusion. The present case differed from past cases by lacking inferior conjunctival sac shortening and by showing erosive lesions solely at the mucocutaneous junctions. The ocular involvement in this case correlated very well with the severity of gastric carcinoma.

Evaluation of retinal integrity in eyes with retained intraocular metallic foreign body by ERG and EOG

In three eyes with a retained intraocular metallic foreign body, the neural retina and retinal pigment epithelial (RPE) integrity were evaluated by means of ERG (a-wave, b-wave, oscillatory potentials) and non-photic EOG responses from the RPE (hyperosmolarity response, Diamox response, bicarbonate response). All three cases were judged in an early stage of retinal impairment on the basis of a well-preserved or supernormal b-wave amplitude and showed good postoperative prognosis. Out of three non-photic responses from the RPE, only the bicarbonate response was preoperatively reduced in two out of the three eyes.

Temporary use of a customized, glued-on hard contact lens before penetrating keratoplasty for descemetocele or corneal perforation

Descemetocele or corneal perforation makes it difficult to perform penetrating keratoplasty (PKP). To circumvent this difficulty, a polymethylmethacrylate hard contact lens with a diameter of 4.0 mm was customized and applied to the cornea with tissue adhesive prior to PKP in three patients, one with corneal perforation and two with descemetoceles. The results showed that this modified method facilitated trephination during PKP without complications in all three patients, suggesting that it may be applicable to other similar clinical situations.

Perfluorocarbon Liquid Assists in Stripping the ILM to Treat Detached Retina Caused by Macular Hole

Stripping the internal limiting membrane (ILM) is supposed to be beneficial in attaching the retina in retinal detachment because of macular hole. However, it is difficult to lift up and strip the ILM over extensively detached retinas because such retinas are very mobile. To evade this difficulty, we flattened the detached retina with perfluorocarbon liquid (PFCL) and peeled the ILM in the presence of PFCL. The ILM flap was easily turned up and enlarged with the posterior counter traction by PFCL. Intraoperative flattening of the retina with PFCL is useful in peeling the ILM from detached retinas.

Fornix and conjunctiva reconstruction by amniotic membrane in a patient with conjunctival mucosa-associated lymphoid tissue lymphoma.

BACKGROUND Conjunctival mucosa-associated lymphoid tissue (MALT) lymphoma is a rare, low-grade, non-Hodgkins B-cell lymphoma. Herein, we report our successful management of the large conjunctival defect caused by resection of conjunctival MALT lymphoma by covering it with transplanted amniotic membrane. CASE A 28-year-old Japanese man, who had been diagnosed histologically as having conjunctival MALT lymphoma in his left eye, was referred to us for treatment. The tumor was located on the lower bulbar and palpebral conjunctiva, and involved the fornix. Extensive resection of the conjunctival lesion was performed. Two pieces of amniotic membrane were used to reconstruct the fornix, bulbar, and palpebral conjunctival defect. OBSERVATIONS Epithelialization over the transplantation was completed within 3 weeks when all sutures were removed. During the 6 months of follow-up, there was no recurrence or any postoperative complication, such as graft rejection, symblepharon, or chronic inflammation. CONCLUSIONS We demonstrated for the first time that amniotic membrane can be used to cover a large defect on both bulbar and palpebral conjunctiva when such a low-grade malignancy as MALT lymphoma is extensively excised. Amniotic membrane transplantation was quite effective for the fornix and conjunctival reconstruction.