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Taiji Sakamoto

Publications and source records attributed to Taiji Sakamoto.

At least 37 records · Page 2Linked to original sources
PubMed2004

Weak symptoms of bacterial endophthalmitis after a triamcinolone acetonide-assisted pars plana vitrectomy.

PURPOSE: To report a case of endophthalmitis after triamcinolone acetonide (TA)-assisted par plane vitrectomy (PPV). METHODS: A 60-year-old Japanese man developed endophthalmitis after TA-assisted PPV for diabetic macular edema. Preoperative visual acuity was 20/200. Four days after surgery, endophthalmitis associated with anterior chamber hypopyon was noticed; the patient's vision had deteriorated to hand motion. In spite of severe cell infiltration, the ciliary injection and ocular pain were not significant. RESULTS: The additional PPV with irrigation of cefazolin (40 microg/ml) and gentamicin (8 microg/ml) was performed. Endophthalmitis resolved soon after this treatment. Staphylococcus epidermidis was detected in the intravitreous samples. The patient's visual acuity improved to 20/100. CONCLUSION: Endophthalmitis may be a complication of TA-assisted PPV with unique signs and symptoms.

Anti-Inflammatory Agents↗
PubMed2004

Plasticity of polypoidal lesions in polypoidal choroidal vasculopathy.

PURPOSE: The aim of this study was to describe the clinical course in a patient with polypoidal choroidal vasculopathy (PCV). METHODS: A 68-year-old man with PCV in the left eye was followed up by means of routine examinations including fluorescein angiography and indocyanine green angiography for over 60 months. RESULTS: Throughout the follow-up period, the patient experienced repeated lesions in the macula, such as serosanguineous detachment of the retinal pigment epithelium and neurosensory retina, but retained good visual acuity. Indocyanine green angiography disclosed spontaneous regression of polypoidal vessels followed by significant changes in the choroidal circulation: a group of polypoidal structures disappeared, and after several months a small choroidal vessel became apparent that was distant from the previously observed polypoidal structure rather than representing an extension of the original lesion. CONCLUSION: The clinical observation suggests that in some cases of PCV the choroidal vasculature may be altered with time, in that some vessels in the inner choroid and even the choriocapillaris may close and collateral vessels and/or new vessels may develop to form complex such as that described here.

Aged↗
PubMed2004

Visual field defects after intravitreous administration of indocyanine green in macular hole surgery.

OBJECTIVES: To report the findings on a patient cohort with visual field defects after macular hole surgery with indocyanine green (ICG)-assisted internal limiting membrane peeling and to investigate the correlation between the defects and the use of ICG. DESIGN: Retrospective, noncomparative interventional case series. PARTICIPANTS: Thirty-nine eyes of 38 patients having the clinical diagnosis of a macular hole who underwent pars plana vitrectomy between January 1, 2001, and December 31, 2002, were enrolled in this study. INTERVENTION: Indocyanine green-assisted internal limiting membrane peeling was performed on a series of 22 eyes: 12 eyes using a 0.5% ICG solution and 3-minute exposure to the retina (group 1), 4 eyes using a 0.5% ICG solution and immediate washout (group 2), and 6 eyes using a 0.25% ICG solution and immediate washout (group 3). The remaining 17 eyes underwent vitrectomy without ICG-assisted internal limiting membrane peeling (group 4). MAIN OUTCOME MEASURES: Visual field, best-corrected visual acuity, and fundus photography were evaluated. RESULTS: Postoperatively, all patients (100%) in group 1 and 1 (25%) of 4 eyes in group 2 had visual field defects. None of the patients in group 3 had a visual field defect. The visual field defects included 10 eyes (84%) with nasal defects, 1 eye (8%) with an inferotemporal defect, and 1 eye (8%) with an extensive visual field defect. Ophthalmoscopy revealed mild to moderate optic disc pallor in 8 (62%) of 13 eyes with postoperative visual field defects. Only 1 patient in group 4 had an inferotemporal defect; none of the other patients in group 4 had visual field defects. There was no statistically significant difference in postoperative visual acuity between patients with and without postoperative visual field defects. CONCLUSIONS: Although this study was limited by the few patients enrolled, our experience indicates that visual field defects, specifically nasal defects, can occur after macular hole surgery with ICG-assisted internal limiting membrane peeling, and that the incidence depends on the concentration of the ICG solution and/or the exposure time to the retina. Further studies are needed to clarify the pathomechanism of visual field defects.

Coloring Agents↗
PubMed2004

Incidence of acute endophthalmitis after triamcinolone-assisted pars plana vitrectomy.

PURPOSE: To report the incidence of acute endophthalmitis after triamcinolone acetonide-assisted pars plana vitrectomy (PPV). DESIGN: A retrospective multicenter interventional case series collected over 23 months. METHODS: We retrospectively reviewed the charts of all patients who underwent triamcinolone-assisted PPV at seven academic clinical centers or eye hospitals from January 2002 to November 2003. RESULTS: Of a total of 1,886 cases, only 1 case showed acute endophthalmitis due to Staphylococcus epidermidis (0.053%). No other cases showed any signs of postoperative endophthalmitis. CONCLUSION: Intraoperative use of triamcinolone during PPV is not a high risk factor for acute endophthalmitis.

Acute Disease↗
PubMed2004

Intracameral triamcinolone helps to visualize and remove the vitreous body in anterior chamber in cataract surgery.

AIM: To study the effects of intracameral injection of triamcinolone acetonide on visualizing and removing the vitreous body from the anterior chamber in cataract surgery. DESIGN: Observational case series. METHODS: Six eyes of six patients had the posterior capsule ruptured and the vitreous body prolapsed or incarcerated into the anterior chamber during cataract surgery. To visualize vitreous body, triamcinolone acetonide solution was injected into the anterior chamber and the vitreous body was resected. The intraoperative findings, results, and complications were evaluated. RESULTS: Vitreous body was well observed under surgical microscopy and was resected safely and completely. Minimum inflammation was observed postoperatively, and the patients obtained good visual acuity. No serious complications were found. One eye showed increased intraocular pressure (40 mm Hg), which was normalized by additional washing of the anterior chamber. CONCLUSIONS: Appropriate use of intracameral triamcinolone acetonide is beneficial to visualize and remove the vitreous body from the anterior chamber during cataract surgery, and sufficient washing of the anterior chamber is necessary to avoid complications.

Aged↗
PubMed2004

Residual vitreous cortex after surgical posterior vitreous separation visualized by intravitreous triamcinolone acetonide.

OBJECTIVE: To visualize the residual vitreous cortex (VC) on the retinal surface after surgical posterior vitreous separation (PVS) during a pars plana vitrectomy (PPV), especially in patients with diabetic retinopathy. DESIGN: Case-control study. PARTICIPANTS: Patients with proliferative diabetic retinopathy (PDR), diabetic macular edema (DME), branch retinal vein occlusion (BRVO), and rhegmatogenous retinal detachment (RRD). METHODS: A triamcinolone acetonide (TA)-assisted vitrectomy was performed on patients with the following diseases: PDR (40 eyes), DME (26 eyes), BRVO (11 eyes), and RRD (17 eyes). Eyes with no apparent preoperative posterior vitreous detachment were enrolled in this study. After performance of surgical PVS, the residual VC was visualized as a white gel highlighted by TA. Based on this finding, the residual VC pattern was then divided into 3 groups: (1) diffuse type (VC was diffusely present in the temporal vascular arcade), (2) focal type (a small island of VC was left), and (3) no residual VC. A multivariate analysis using analysis of variance was performed regarding the residual VC pattern, disease type, age, and the 3 different surgeons. MAIN OUTCOME MEASURES: Each surgeon determined the type of residual VC during the operation, and the results were confirmed by a postoperative review of the videotape records judged by the other 2 surgeons. RESULTS: Eighty percent of the PDR eyes demonstrated the diffuse type; 10%, the focal type; and 10%, no residual VC. Fifty-eight percent of the eyes with DME demonstrated the diffuse type; 19%, the focal type; and 23%, no residual VC. Eighteen percent of the BRVO eyes showed the diffuse type; 24%, the focal type; and 59%, no residual VC. Thirty percent of the RRD eyes showed the diffuse type; 30%, the focal type; and 40%, no residual VC. A multivariate logistic regression analysis showed that PDR was a predictor of the diffuse type of residual VC in comparison to RRD (odds ratio = 8.42, 95% confidence interval = 2.07-34.3). Neither age nor the surgeon was a significant factor for a specific type of residual VC. CONCLUSIONS: Diabetic eyes more often demonstrated the diffuse type of residual VC, even after surgical PVS. This information may be valuable for surgeons performing a PPV on patients with diabetic retinopathy.

Aged↗
PubMed2004

Two patients with severe corneal disease in KID syndrome.

PURPOSE: To report two independent Japanese patients with keratitis, ichthyosis, and deafness (KID) syndrome and severe corneal disorder. DESIGN: Observational case reports. METHODS: Clinical observation of a 5-year-old boy (Patient 1) and a 64-year-old man (Patient 2) with KID syndrome, presenting prominent corneal diseases. Molecular genetic assessment of the GJB2 gene encoding connexin-26 was performed. RESULTS: Patient 1 had bilateral diffuse superficial punctuate keratopathy with severe corneal neovascularization. He had a missense mutation of the GJB2 gene. Patient 2 had bilateral corneal stromal keratitis and right corneal ulceration with rupture of the Descemet membrane. He did not have any pathologic mutation of the GJB2 gene. The area of palisades of Vogt was diminished and tear production reduced in both patients. Topical eye drops, and corticosteroid or antibiotics, respectively, relieved them effectively. CONCLUSION: The impaired ocular surface regulating system might be a cause of corneal disease in KID syndrome and it can be treated by eye drops.

Anti-Bacterial Agents↗
PubMed2004

Functional properties of hyalocytes under PDGF-rich conditions.

PURPOSE: To investigate the functional properties and intracellular signaling of hyalocytes under platelet-derived growth factor (PDGF)-rich conditions. METHODS: The hyalocytes were isolated from bovine eyes and identified by immunocytochemistry and electron microscope. The expression of PDGF receptor alpha/beta and its phosphorylation in response to PDGF-BB was analyzed by Western blot analysis. PDGF-BB-induced proliferation and migration were evaluated by thymidine uptake and Boyden's chemotaxis assay. The expression of the urokinase-type plasminogen activator (uPA) gene and the fibrinolytic activity were assessed by Northern blotting and fibrin zymography. An in vitro type I collagen gel contraction assay was performed to determine the effect of PDGF-BB on cellular contraction. RESULTS: The hyalocytes were immunocytochemically positive for S-100 and negative for glial fibrillary acidic protein (GFAP) and cytokeratin, as previously described. The electron microscope demonstrated that hyalocytes possess lysosome-like granules, mitochondria, and micropinocytotic vesicles in their cytoplasm. The hyalocytes expressed PDGF receptor alpha and beta, both of which were immediately phosphorylated in response to PDGF-BB. PDGF-BB also activated p85 PI3-kinase, p44/p42 mitogen-activated protein (MAP) kinase and p38 MAP kinase. PDGF-BB induced thymidine uptake and migration in a concentration-dependent (0-10 ng/mL) manner. Inhibitors of the respective kinases prohibited PDGF-BB-dependent thymidine uptake and migration with the exception of the p44/p42 MAP kinase inhibitor, which displayed no inhibitory effects on migration. PDGF-BB increased uPA gene expression and fibrinolytic activity. Collagen gel contraction observed under PDGF-BB-rich conditions was not prohibited by the respective inhibitors investigated. CONCLUSIONS: The hyalocytes demonstrated macrophage-like characteristics and may have both physiologic and pathologic roles, such as the maintenance of vitreous transparency through fibrinolytic activity and the pathogenesis of proliferative-vitreoretinal diseases through cellular proliferation and vitreous hyper-contraction.

Animals↗
PubMed2003

Immunoregulatory role of ocular macrophages: the macrophages produce RANTES to suppress experimental autoimmune uveitis.

Murine experimental autoimmune uveitis (EAU) is a model of human uveitis. Ocular-infiltrating macrophages play a crucial role in the generation of tissue damage in EAU. In fact, several chemokines are actually produced in the inflamed eye. The aim of this study was to elucidate the role of ocular macrophage-derived chemokines in EAU. C57BL/6 mice were immunized with human interphotoreceptor retinoid binding protein peptide 1-20, and the EAU severity was scored at multiple time points based on microscopic fundus observations (retinal vascular dilatation and exudates) and histological examinations. The peak inflammatory response was observed 1 wk (day 16) after the beginning of macrophage infiltration to the eye (day 9). Ocular-infiltrating cells were enriched or depleted of macrophages by magnetic beads and analyzed by real-time RT-PCR for chemokine mRNA production. We found that only the macrophage-enriched cells from the eye produced RANTES, and thus proposed that macrophage-derived RANTES facilitated the ocular inflammations. In contrast to our postulate, neutralization of RANTES by specific Ab in vivo on days 9 and 13 exacerbated EAU. We also found that the ratio of ocular CD4/CD8 T cells was markedly increased after treatment. As a result, RANTES neutralization might exacerbate EAU by modulating the type of T cell subsets recruited to the eye. In conclusion, our data provide insight into the immunoregulatory role of macrophages and RANTES in the pathogenesis of ocular inflammation. Not all macrophage-derived chemokines cause local inflammation, since RANTES produced by ocular macrophages appears to suppress EAU.

Adjuvants, Immunologic↗
PubMed2003

Suppression of experimental choroidal neovascularization utilizing KDR selective receptor tyrosine kinase inhibitor.

BACKGROUND: We investigated the role of the VEGF-VEGF receptor 2 (KDR) system in the development of choroidal neovascularization (CNV) and its possibility as a therapeutic target utilizing KDR selective receptor tyrosine kinase (RTK) inhibitor (SU5416) both in vitro and in an experimental CNV model. METHODS: VEGF-induced phosphorylation of KDR and p44/p42 MAPK in cultured bovine choroidal endothelial cells (BCECs) was determined by Western blot analysis. The proliferation and in vitro tube formation were analyzed by [3H]thymidine uptake and three-dimensional collagen gel model. For experimental CNV model, intense fundus laser photocoagulation was performed on pigmented rats. The anti-angiogenic efficacy of intraperitoneally injected SU5416 on experimental CNV was evaluated by fluorescein angiography and histology. The extent of fluorescein leakage on late-phase angiograms was scored, and the thickness of CNV membrane was histologically measured under a light microscope. RESULTS: VEGF-induced KDR phosphorylation in cultured BCECs was inhibited by SU5416 in a dose-dependent manner (0-3 microM) with IC50 of 0.29 +/- 0.071 microM. SU5416 treatment also resulted in a dose-dependent prohibition of VEGF-induced p44/p42 MAPK phosphorylation, [3H]thymidine uptake and in vitro tube formation with corresponding concentrations that inhibited KDR phosphorylation. The leakage score on fluorescein angiography for experimental CNV was significantly lower in the SU5416-treated group than in the control group (P<0.01). Histologically, the CNV membranes in the SU5416-treated group were 31.6% thinner than those in the control group (P<0.01). CONCLUSION: These results strengthen the evidence for a critical role of the VEGF-KDR system in the development of CNV, indicating that KDR selective inhibitor might be beneficial for the treatment of intraocular angiogenic diseases, including age-related macular degeneration.

Animals↗
PubMed2003

Submacular deposition of triamcinolone acetonide after triamcinolone-assisted vitrectomy.

PURPOSE: We describe a case demonstrating a submacular deposition of triamcinolone acetonide (TA) after a TA-assisted vitrectomy for retinal detachment. DESIGN: Interventional case report. METHODS: A 48-year-old Japanese man with rhegmatogenous retinal detachment in his left eye underwent a TA-assisted vitrectomy, endolaser photocoagulation, and sulfur hexafluoride (SF(6)) gas tamponade. RESULTS: At the end of the surgery and the day after undergoing vitrectomy, the deposition of TA was observed between the retinal pigment epithelium and neurosensory retina in the submacular area. These TA granules disappeared after 2 weeks. Two months after the operation, the retina was observed to be successfully attached and no abnormality was observed in the macula. The patient's visual acuity improved to 20/16, and no ophthalmoscopic or functional damage was observed. CONCLUSION: No apparent adverse effect was found in this case demonstrating a submacular deposition of TA.

Fluorescein Angiography↗
PubMed2003

Clearance of apoptotic photoreceptors: elimination of apoptotic debris into the subretinal space and macrophage-mediated phagocytosis via phosphatidylserine receptor and integrin alphavbeta3.

The effective phagocytotic clearance of apoptotic debris is fundamental to the maintenance of neural tissues during apoptosis. Retinal photoreceptors undergo apoptosis after retinal detachment. Although their induction phase of apoptosis has been well discussed, their phagocytotic process remains quite unclear. We herein demonstrate that apoptotic photoreceptors are selectively eliminated from their physiological localization, the outer nuclear layer, to the subretinal space, and then phagocytosed by monocyte-derived macrophages. This could be shown by an ultrastructural and immunophenotypic analysis. Moreover, in chimera mice expressing transgenic green fluorescent protein in bone marrow-derived cells, the local infiltration of macrophages could be detected after retinal detachment-induced photoreceptor apoptosis. The local injection of an antibody blocking the phosphatidylserine receptor (PSR) or a peptide (GRGDSP)-blocking integrin alphavbeta3 revealed that phagocytotic clearance involves the PSR as well as integrin alphavbeta3 in vivo. Importantly, the level of blockade obtained with these reagents was different. Although anti-PSR increased the frequency of apoptotic cells that fail to bind to macrophages, GRGDSP prevented the engulfment (but not the recognition) of apoptotic photoreceptor cells by macrophages. To our knowledge, this is the first report describing the mechanisms through which apoptotic photoreceptors are selectively eliminated via a directional process in the subretinal space.

Animals↗
PubMed2003

Ultrastructure of the vitreoretinal interface following the removal of the internal limiting membrane using indocyanine green.

PURPOSE: To investigate the morphological changes of the vitreoretinal interface following the removal of the internal limiting membrane (ILM) using indocyanine green (ICG). METHODS: In 10 primate eyes, a pars plana vitrectomy was performed followed by ICG-assisted peeling of the ILM. Morphological changes in the exposed inner surface of the retina were investigated by electronmicroscopy immediately, 3, 6 and 12 months after the ILM removal. RESULTS: The excised ILM was associated with fragments of glial tissue. The Muller cell processes were damaged and removed at the corresponding region of the retina. Regenerative spindle-shaped Muller cell processes were observed focally showing a meshwork like configuration at 3 and 6 months. Flattened and stretched processes were observed at 12 months; however, there was no apparent ILM regeneration. CONCLUSIONS: ICG assisted ILM peeling was observed to cause mild damage to the vitreoretinal interface, which did not completely recover within 12 months.

Animals↗
PubMed2003

Possible benefits of triamcinolone-assisted pars plana vitrectomy for retinal diseases.

PURPOSE: To study the advantages and complications of triamcinolone acetonide (TA)-assisted pars plana vitrectomy (PPV) for various retinal diseases. METHODS: This report is an interventional case series and nonrandomized study. One hundred seventy-seven eyes from 158 patients underwent PPV with or without TA. Group TA(+) consisted of 94 eyes and group TA(-) consisted of 83 eyes. The improvement in vision and postoperative complications were prospectively studied. RESULTS: Sixty-two percent of the eyes in group TA(+) and 49% of the eyes in group TA(-) had improved vision after surgery (P = 0.34). Twelve eyes in group TA(+) and 12 eyes in group TA(-) had an intraocular pressure higher than 21 mmHg after the operation, with no statistically significant difference (P = 0.63). Four eyes with proliferative diabetic retinopathy in group TA(+) and five eyes with proliferative diabetic retinopathy in group TA(-) needed an additional filtering surgery. Group TA(+) (five eyes) had a lower incidence (P = 0.041) of reoperation caused by preretinal fibrous membrane formation than group TA(-) (13 eyes). No apparent corneal disorder or infectious signs were found in any eyes. CONCLUSIONS: Triamcinolone acetonide-assisted PPV appears to be potentially useful to reduce the incidence of reoperation owing to preretinal fibrosis with no serious complications.

Aged↗
PubMed2003

The critical role of ocular-infiltrating macrophages in the development of choroidal neovascularization.

Choroidal neovascularization (CNV) is directly related to visual loss in some eye diseases, such as age-related macular degeneration. Although several human histological studies have suggested the participation of macrophages in CNV formation, the precise mechanisms are still not fully understood. In this study, we elucidated the role of ocular-infiltrating macrophages in experimental CNV using CCR2 knockout (KO) mice, wild-type mice, and C57BL/6 (B6) mice. CCR2 is the receptor of monocyte chemoattractant protein-1, and the number of infiltrating macrophage and the area of CNV were significantly reduced in CCR2 KO mice. Enriched ocular-infiltrating macrophages from B6 mice actually showed angiogenic ability in a dorsal air sac assay. Moreover, their expression of class II, CD40, B7-1 and B7-2 molecules, and the mRNA for potential angiogenic factors, such as vascular endothelial growth factor, basic fibroblast growth factor, and tumor necrosis factor alpha, was also observed. Collectively, we conclude that ocular-infiltrating macrophages play an important role in CNV generation.

Animals↗