Biomedical subjects

Taiji Sakamoto

Publications and source records attributed to Taiji Sakamoto.

At least 19 recordsLinked to original sources

PubMed2006

Alteration pattern of tear cytokines during the course of a day: diurnal rhythm analyzed by multicytokine assay.

Our aim was to study the alteration pattern and interaction of inflammatory tear cytokines during the course of a day. Using a prospective, experimental design, tears were collected from 28 healthy volunteers with normal eyes during the period from April 2004 to March 2005. Tears (10 microl) were collected by capillary outflow from each eye at 9:00, 12:00, 16:00, 21:00, and 24:00 h. The concentrations of inflammatory cytokines, IL-1beta, IL-6, IL-8, IL-10, IL-12p70, and TNF-alpha were measured using cytometric bead arrays. Although the concentration of tear cytokines varied widely among eyes, the amount of cytokine had a specific alteration pattern in each eye during the course of a day. IL-1beta, IL-6, IL-10, IL-12p70, and TNF-alpha showed slight increases in the morning and the late evening. IL-8 remained low throughout the day. The alteration pattern of IL-8 was significantly different from those of TNF-alpha and IL-12p70 (P<0.01). The ratio of each pro-inflammatory cytokine to anti-inflammatory cytokine IL-10 did not significantly change throughout the day. The amount of tear cytokines changed during daytime with a specific pattern. This diurnal rhythm may influence symptoms of ocular surface diseases during the course of a day.

Adult↗

PubMed2006

Cellular migration associated with macular hole: a new method for comprehensive bird's-eye analysis of the internal limiting membrane.

OBJECTIVE: To elucidate the pathogenesis of macular hole formation, focusing in particular on the possible role of cellular migration on the cortical vitreous and internal limiting membrane (ILM) around the macular hole. METHODS: To gain a comprehensive overview of the ILM excised in macular hole surgery (n = 36), the ILMs were carefully unfolded and spread out onto glass slides as continuous flat sheets that each contained a macular hole. The specimens were observed by light microscopy and transmission electron microscopy (n = 9), and the cellular distribution was analyzed by scanning electron microscopy in a quantitative manner (n = 27). Immunohistochemistry for glial fibrillary acidic protein and cytokeratin 18 was carried out for cellular characterization. Cellular proliferation was assessed by immunohistochemistry for proliferating cell nuclear antigen and Ki-67. RESULTS: Cellular migration was not apparent around the macular hole in the early stage of development of the macular hole (stage 2, 0 microm). As the macular hole passed through the later stages of development, cellular migration developed around the macular hole (stage 3, 84 microm) and the area of cellular migration gradually enlarged (stage 4, 420 microm). The immunophenotypic analysis showed that these cells were mainly glial fibrillary acidic protein-positive glial cells and cytokeratin 18-positive retinal pigment epithelial cells. The proliferating cell nuclear antigen and Ki-67 immunohistochemistry showed that some of these cells were proliferating on the ILM. CONCLUSIONS: Cellular migration on the ILM is not necessary for the initial formation of a macular break. Cellular migration developed after the macular break occurred, and the migration and proliferation increased gradually from the macular hole. CLINICAL RELEVANCE: This study provides a new method for understanding the ultrastructural analysis of the pathogenesis of the macular hole.

Basement Membrane↗

PubMed2006

Analysis of the retinal nerve fiber layer after indocyanine green-assisted vitrectomy for idiopathic macular holes.

PURPOSE: To analyze retinal nerve fiber layer (RNFL) thickness in eyes with or without visual field (VF) defects after indocyanine green-assisted vitrectomy for idiopathic macular holes using optical coherence tomography (OCT) and to investigate the relationship between postoperative VF defects and RNFL damage. DESIGN: Retrospective interventional case series. PARTICIPANTS: Thirty-four eyes of 32 patients with idiopathic macular holes that underwent vitrectomy between January 2001 and March 2003 were included in this study. Eyes were divided into 3 groups according to the occurrence of postoperative VF defects and the use of indocyanine green for internal limiting membrane peeling during surgery: 11 eyes with VF defects after indocyanine green-assisted vitrectomy (group 1), 9 eyes without VF defects despite the use of indocyanine green (group 2), and 14 eyes without VF defects that underwent vitrectomy without indocyanine green (group 3). METHODS: Retinal nerve fiber layer thickness in each of 4 quadrants (superior, inferior, nasal, temporal) was measured with OCT. MAIN OUTCOME MEASURE: Retinal nerve fiber layer thickness around the optic disc. RESULTS: The mean RNFL thickness in 3 of 4 quadrants (superior, nasal, inferior) in group 1 was significantly less than that in the corresponding quadrant in groups 2 and 3 (P<0.01). In the temporal quadrant, there was a significant difference between groups 1 and 3 (P = 0.02), but not between groups 1 and 2. The RNFL thickness in group 1 was significantly less in 3 quadrants in operated eyes than in fellow eyes (P<0.05). CONCLUSIONS: The RNFL thickness was reduced in eyes with VF defects after indocyanine green-assisted vitrectomy for macular holes, suggesting that the postoperative VF defects may have been caused by RNFL damage relating to the use of indocyanine green.

Aged↗

PubMed2006

Evaluating adjunctive surgical procedures during vitrectomy for diabetic macular edema.

PURPOSE: To evaluate the long-term outcomes of adjunctive surgical procedures during pars plana vitrectomy (PPV) for the treatment of diabetic macular edema (DME). METHODS: In this nonrandomized study, we retrospectively analyzed 57 eyes of 54 patients who had DME and had undergone PPV. We performed PPV using three different surgical procedures: conventional PPV (group PVD; 13 eyes), triamcinolone acetonide (TA)-assisted PPV (group TA; 22 eyes), and TA-assisted PPV combined with internal limiting membrane (ILM) peeling (group ILM; 22 eyes). We also evaluated the preoperative and postoperative best-corrected visual acuity (BCVA) results. RESULTS: The overall mean preoperative BCVA was 0.86 logarithm of the minimal angle of resolution unit. In groups PVD, TA, and ILM, BCVAs were 0.99, 0.90, and 0.74 (P = 0.310), respectively. The mean postoperative BCVA for all patients improved to 0.68 (P = 0.005). The postoperative BCVA improved in 47% of the treated eyes, it remained unchanged in 37% of the treated eyes, and it deteriorated in 16% of the treated eyes. However, we observed no significant difference in the mean postoperative BCVAs between the three groups. Furthermore, we found that there was no significant difference in postoperative BCVA improvements between any of the groups (P = 0.450). CONCLUSION: The present study suggests that these 3 PPV approaches do not significantly affect postoperative BCVAs after 18 months of DME treatment.

Adult↗

PubMed2006

Ultrastructure of the trabecular meshwork in secondary glaucoma eyes after intravitreal triamcinolone acetonide.

PURPOSE: To study the histology of the trabecular meshwork of eyes with glaucoma by intravitreal injection of triamcinolone acetonide (TA). DESIGN: Two cases report. PARTICIPANTS/METHODS: A 68-year-old Japanese man with branch retinal vein occlusion and a 48-year-old Japanese woman with uveitis were treated by cataract surgery, intraocular lens implantation, and TA-assisted pars plana vitrectomy. At the end of surgery, TA suspension (4 mg) was intravitreously injected. During the follow-up period, the intraocular pressure (IOP) of the patients increased over 30 mm Hg even with full medication. Trabeculectomy was performed at 4 months after TA injection in case 1 and at 6 months in case 2, and intraocular pressure returned to the normal range in both cases. Light and electron microscopic studies of the resected trabecular tissue were carried out. RESULTS: The histology showed minimal deposition of extracellular matrix in the trabecular meshwork in case 1. Case 2 showed the beginnings of deposition of extracellular matrix including fingerprintlike material in the trabecular meshwork with decreased intertrabecular spaces. CONCLUSIONS: The ultrastructural changes in the trabecular meshwork of eyes with glaucoma after treatment with intravitreal TA might resemble those with glaucoma after topical corticosteroid treatment.

Extracellular Matrix↗

PubMed2006

Endoscopy-guided subretinal fluid drainage in vitrectomy for retinal detachment.

PURPOSE: To study the usefulness of endoscopy-guided subretinal fluid drainage in pars plana vitrectomy (PPV) for rhegmatogenous retinal detachment (RRD). PARTICIPANTS/METHODS: A prospective non-comparative study of a small number of RRD cases. The study involved examining 10 eyes of 10 patients with RRD that received PPV. Two eyes had hazy corneas, which hindered the observation by surgical microscopy. Fluid-gas exchange was performed and then subretinal fluid was drained through a primary retinal break guided by an endoscope. No drainage retinotomy was made. Each clinical feature was studied and the surgical outcome and complications were evaluated. RESULTS: All eyes had retinal reattachment by a single operation. No serious complication related to surgery was experienced. CONCLUSIONS: Endoscopy-guided subretinal fluid drainage is the safe and effective procedure in PPV for RRD.

Aged↗

PubMed2006

Intravitreal triamcinolone acetonide for exudative age-related macular degeneration among Japanese patients.

AIM: To study the results of intravitreal triamcinolone acetonide (TA) for exudative age-related macular degeneration (AMD) among Japanese patients. METHODS: 13 eyes of 12 Japanese patients (9 males and 3 females) with subfoveal choroidal neovascularization (CNV) of exudative AMD received intravitreal TA (8 mg). Visual acuity, size of CNV and serous retinal detachment, and complications related to treatment were evaluated for 6 months or longer. RESULTS: Postoperative maximum visual acuity significantly improved (p < 0.05). Postoperative eyes had a greater probability of a reduced size of CNV and/or retinal detachment compared to preoperative eyes. Seven eyes showed increased intraocular pressure (21 mm Hg or over), which was controlled well by medication. Cataract development and advancement were observed in 90% of phakic eyes. No other serious complications were found. CONCLUSIONS: Intravitreal TA might be an effective treatment for subfoveal CNV of exudative AMD among Japanese as well as Caucasian patients for a comparatively short period.

Aged↗

PubMed2006

Gene transfer to corneal epithelium and keratocytes mediated by ultrasound with microbubbles.

PURPOSE: The cornea is an ideal organ for evaluating gene transfer because it can be treated noninvasively and monitored easily. The present study was performed to investigate the practical efficacy and safety of ultrasound (US) plus microbubble (MB)-mediated gene transfer to cornea. METHODS: Cultured rabbit corneal epithelial (RC-1) cells were incubated in 24-well dishes with plasmid DNA having a green fluorescent protein (GFP) gene under a cytomegalovirus promoter. The cells were exposed to US under different intensities (1 MHz; power, 0.5 approximately 2 W/cm2; duration, 15-120 seconds; duty cycle, 20%-100%). The effect of simultaneous stimulation with MBs was also examined. Gene transfer was quantified by counting the number of GFP-positive cells under microscopy. Furthermore, in vivo gene transfer was examined by GFP plasmid injection into rabbit cornea and US exposure with MBs. RESULTS: In the in vitro study, DNA exposure alone could not transfer gene into cultured RC-1 cells; US enhanced gene transfer slightly. Coexposure with MBs significantly increased gene transfer efficiency. In the in vivo study, DNA injection alone could transfer the gene to a limited degree, but plasmid injection plus US with MBs strongly increased gene transfer efficiency without apparent tissue damage, and gene transfer was achieved two dimensionally. CONCLUSIONS: US with MBs greatly increases gene transfer to in vivo and in vitro corneal cells. This noninvasive gene transfer method may be a useful tool for clinical gene therapy.

Animals↗

PubMed2006

[A case of anterior ischemic optic neuropathy associated with Vogt-Koyanagi-Harada disease].

BACKGROUND: Although optic disc swelling is one of the common findings of Vogt-Koyanagi-Harada (VKH) disease, severe visual field loss from optic disc involvement is not common. We report a case of severe visual field contraction from optic disc involvement in VKH disease. CASE REPORT: A 51-year-old woman was diagnosed as having VKH disease and was treated with intravenous pulse methylprednisolone. Exudative retinal detachments disappeared and visual acuity improved, but optic disc swelling was persistent in both eyes. Ten weeks after VKH disease onset, she claimed acute visual field loss in the right eye. Marked optic disc swelling with peripapillary hemorrhages and severe visual field loss were observed in the right eye. Fluorescein angiography showed filling delay and late leakage of the optic disc in the right eye. One month later, right optic disc swelling disappeared, but visual field loss remained. In addition, 5.5 months later, the left optic disc swelled further, and the left visual field was markedly contracted. Hyperbaric oxygen therapy was added. The swelling in the left optic disc gradually decreased and disappeared in one month, but the visual field loss remained. CONCLUSIONS: The optic disc involvement with irreversible visual field loss in this case is thought to be due to anterior ischemic optic neuropathy, which may be a possible complication of VKH disease.

Female↗

PubMed2005

Alteration of tear cytokine balance by eye closure: analysis by multicytokine assay.

PURPOSE: To study the effects of eye closure on the balance of tear cytokines. METHODS: A total of 17 healthy volunteers with normal eyes were recruited. Tears (10 microl) were collected by capillary outflow at 09:00. The right eyes were closed with cotton bandages for 3 h, then tears were collected from each eye separately. The concentrations of inflammatory cytokines, interleukin (IL)-1beta, IL-6, IL-8, IL-10, IL-12p70, and tumor necrosis factor (TNF)-alpha were measured by cytometric bead array. RESULTS: Although the concentration of each cytokine varied between eyes, the increasing ratio for 3 h showed a similar pattern in each cytokine. IL-1beta, IL-6, IL-10, IL-12p70, and TNF-alpha increased and IL-8 decreased in normal eyes. After eye closure, the increase of IL-10 significantly diminished (P=0.037); however, the other cytokines were not affected. CONCLUSIONS: Eye closure decreased the concentration of IL-10 in tears, which might cause a potentially pro-inflammatory status of the ocular surface.

Adult↗

PubMed2005

Visual improvement following trans-Tenon's retrobulbar triamcinolone acetonide infusion for polypoidal choroidal vasculopathy.

PURPOSE: To report a case of polypoidal choroidal vasculopathy (PCV) that was successfully treated by sub-Tenon's infusion of triamcinolone acetonide (TA). METHODS: A 56-year-old Japanese man had PCV in his left eye with vision of 20/32. Fluorescein angiography demonstrated a hyper-fluorescent spot, and indocyanine green angiography showed marked leakage of dye from the polypoidal vessel. Optical coherence tomography showed anterior protrusion of highly reflective layers and subretinal fluid. RESULTS: The patient underwent trans-Tenon's retrobulbar infusion of 12 mg TA. Subsequently, the reddish-orange lesion decreased in size and elevation with complete resolution of the serous retinal detachment, and visual acuity improved to 20/20. Visual acuity remained good through a 15-month follow-up during which the patient was free of endophthalmitis and elevated intraocular pressure. CONCLUSIONS: Trans-Tenon's retrobulbar TA infusion is potentially effective in treating PCV.

Choroid↗

PubMed2005

A new method for comprehensive bird's-eye analysis of the surgically excised internal limiting membrane.

PURPOSE: To investigate the role of cells and extracellular matrix on the internal limiting membrane (ILM), we demonstrated a new method for a comprehensive bird's-eye analysis of surgically excised ILM. DESIGN: Laboratory investigation. METHODS: The ILM of an idiopathic epiretinal membrane was fixed and spread out onto a glass slide, using fine needles under a biomicroscope. The expanded ILM was analyzed by light microscopy, immunohistochemistry, and scanning electron microscopy. RESULTS: The excised ILM could be unfolded and spread out as a flat sheet onto the glass slide. Immunohistochemistry revealed that most migrating cells were glial cells. Scanning electronmicroscopy revealed that the vitreous surface of the ILM was smooth, in contrast to the rough retinal surface. The ILM showed abundant cellular migration as a continuous stratified cellular sheet. CONCLUSIONS: This new bird's-eye-view observation of excised ILM enables us to carry out comprehensive analysis of cellular distribution from a temporal and spatial perspective.

Basement Membrane↗

PubMed2005

Pars plana vitrectomy with gas tamponade for lamellar macular holes.

PURPOSE: To report anatomic and visual improvement after pars plana vitrectomy with gas tamponade for a lamellar macular hole with poor central visual acuity. DESIGN: Two interventional case reports. METHODS: Two patients with a lamellar macular hole underwent vitrectomy, internal limiting membrane peeling, and long-acting gas injection. Main outcome measures included best-corrected visual acuity, biomicroscopic appearance, and optical coherence tomography findings. RESULTS: Vitrectomy with gas tamponade resulted in biomicroscopic, functional, and tomographic improvement in both patients for follow-up periods of 12 months. CONCLUSIONS: Vitrectomy with gas tamponade may be an effective method for a lamellar macular hole with poor visual acuity.

Aged↗

PubMed2005

Effects of volcanic ash on ocular symptoms: results of a 10-year survey on schoolchildren.

OBJECTIVE: To study the effects of volcanic ash on the ocular symptoms of schoolchildren ages 6 to 15 residing near Mt. Sakurajima, an active volcano. DESIGN: Retrospective, cross-sectional study. PARTICIPANTS: A total of 10,380 children ages 6 to 15, 1175 in a high-exposure area and 9205 in a low-exposure area, were studied. METHODS: High- and low-exposure areas for volcanic ash were selected. All subjects in both areas were examined annually each September in the decade from 1994 to 2003. MAIN OUTCOME MEASURES: The frequency of positive ocular symptoms in years with and without active volcanic eruptions was compared. The association of ocular symptoms with volcanic ash dispersal was assessed with the Mantel-Haenszel test or chi-square test. RESULTS: Subjects in the high-exposure area showed ocular symptoms more often than those in the low-exposure area (P<0.0001). Years of active volcanic eruptions (volcanic ash of 5000 g/m2/year or more) were closely related to years with a high frequency of ocular symptoms in subjects in the high-exposure area (P<0.05) but related conversely in subjects in the low-exposure area (P<0.01). Major ocular symptoms were redness, discharge, foreign body sensation, and itching, all treated effectively with eyedrops. CONCLUSIONS: Ocular symptoms in subjects were strongly influenced by volcanic eruptions in the Mt. Sakurajima area, but direct influence was limited to those living in areas very near the volcano (i.e., 4 km from the volcano's crater).

Adolescent↗

PubMed2005

Pulsatile blood flow in the polypoidal choroidal vasculopathy.

OBJECTIVE: To describe patients with pulsatile polypoidal vessels in polypoidal choroidal vasculopathy (PCV). DESIGN: Retrospective, observational case series. PARTICIPANTS: Eighty-four eyes of 74 patients with PCV. METHODS: The medical records of patients diagnosed with PCV between 1998 and 2004 at Kagoshima University Hospital were reviewed. MAIN OUTCOME MEASURES: A pulsatile polypoidal vessel (PV) on indocyanine green angiography (ICGA). RESULTS: Seven of 74 patients (9.5%) had PVs in the macula. Four eyes revealed pulsatile PVs on the day the diagnosis of PCV was first made, and PVs in the other 3 eyes showed pulsatile movement during the follow-up period. Two patterns of pulsatile movement were observed on ICGA: (1) a rhythmic variation in the caliber of a choroidal vessel (caliber variation pattern) and (2) a pulsatile blood flow in a tortuous and relatively narrow choroidal vessel (pulsatile blood flow pattern). Both patterns of pulsatile PVs appeared in the early frames of the ICGA, and some of them were observable even during the first 15 minutes after the ICG dye injection. The pulsatile movement disappeared spontaneously without treatment in some patients, and the period in which pulsatile PVs was detectable on ICGA was limited in each patient. CONCLUSIONS: We report the features of pulsatile PV in PCV. It is a unique and important characteristic that has not been reported with any other chorioretinal diseases and may provide a clue to understanding the pathogenesis of PCV.

Aged↗

PubMed2005

Vitreomacular adhesion and the defect in posterior vitreous cortex visualized by triamcinolone-assisted vitrectomy.

PURPOSE: To study the vitreomacular adhesion and the contractile force of posterior hyaloid, which are shown in triamcinolone acetonide (TA)-assisted pars plana vitrectomy (PPV). DESIGN: Interventional case series. METHODS: Twenty-eight eyes with diabetic macular edema (DME) without posterior vitreous detachment (PVD) received TA-assisted PPV. Surgical PVD was performed by an aspiration of vitrectomy probe, and the dynamic changes of posterior vitreous cortex and residual vitreous cortex were evaluated. RESULTS: A premacular defect was formed in the detached posterior vitreous cortex during surgical PVD in 27 of 28 eyes. Immediately thereafter, the small defect expanded into a large hole in the detached posterior vitreous cortex in all cases. A residual vitreous cortex was left on the macula in 22 eyes. CONCLUSIONS: These observations demonstrate a firm vitreoretinal adhesion in the central macula and suggest that the enlargement of the defect of posterior vitreous cortex may be extrusion of vitreous out through the premacular dehiscence into the preretinal space, or a tangentially contractile force may exist in the posterior vitreous cortex. Both macular adhesion and the traction of vitreous cortex might contribute to the pathogenesis of DME and other vitreomacular disease.

Diabetic Retinopathy↗

PubMed2005

The analysis of systemic tolerance elicited by antigen inoculation into the vitreous cavity: vitreous cavity-associated immune deviation.

The immune privilege that exists in the eye is maintained by various mechanisms. One of the best studied is a form of systemic tolerance termed anterior chamber-associated immune deviation (ACAID). We have investigated the mechanisms by which ocular inflammation associated with the vitreous cavity (VC) is reduced, by injecting either ovalbumin (OVA) or allogeneic splenocytes into the VCs of mice, and assessed the effect of this on delayed type hypersensitivity (DTH) responses. After antigen inoculation into the VC, antigen-specific DTH responses were significantly impaired and we named this phenomenon 'vitreous cavity-associated immune deviation' (VCAID). VCAID could also be induced by inoculating antigen-pulsed macrophages into the VC. However, VCAID did not develop either in mice with inflamed eyes, whether as a result of experimental autoimmune uveitis or coadministration of interleukin (IL)-6 in the VC, or in knockout mice deficient for natural killer T (NKT) cells. Finally, we found that so-called 'hyalocytes' are the only cells present in the VCs of normal mice, uniformly distributed on the retinal surface. Interestingly, they express F4/80, suggesting that hyalocytes are candidate antigen-presenting cells (APCs) responsible for mediating VCAID. As for the anterior chamber model, systemic tolerance can be induced in the VC in non-inflamed eyes and in the presence of invariant NKT cells.

Animals↗

PubMed2004

Fibrous proliferation of the pre-papillary canal in proliferative diabetic retinopathy: Cloquet's canal as a scaffold for proliferative diabetic retinopathy.

BACKGROUND: The structure of the vitreous body is known to play an important role in the pathogenesis of proliferative diabetic retinopathy (PDR). The purpose of this study was to ascertain the pattern of fibrous membrane proliferation in PDR focusing on pre-optic disc canal-like fibrous proliferation. METHODS: The investigation comprised two parts. The first, prospective study involved examining ten eyes of ten patients with PDR who underwent triamcinolone acetonide-assisted pars plana vitrectomy (TA-PPV). The presence of canal-like intravitreous structures was determined during TA-PPV. The second, retrospective study included analysis of photographs and clinical records of 235 eyes examined in 207 patients with PDR. The clinical and surgical records of the 235 eyes treated with PPV were reviewed and were categorized into four groups based upon the pattern of fibrous proliferation (optic disc type, pre-cortical pocket type, mixed type, or other). Each clinical feature was studied. The clinical features of the four groups of PDR were compared. RESULTS: A pre-optic disc canal-like structure was observed in seven of the ten eyes. In the retrospective study, 25 eyes (10.7%) were classified as optic disc type, 16 eyes (6.9%) as pre-cortical pocket type, 68 eyes (29.1%) as mixed type, and 126 eyes (53.4%) as other types. The patients with the optic disc type were significantly younger than the other three groups (P = 0.02). Other clinical features and post-operative outcome were not significantly different between the groups. CONCLUSIONS: A pre-optic disc canal-like structure, probably Cloquet's canal and the area of Martegiani, was present in PDR eyes. The PDR patients with fibrous proliferation of this structure were younger than those with other patterns of fibrous proliferation.

Adult↗