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Biomedical subjects

Kei Shinoda

Publications and source records attributed to Kei Shinoda.

At least 19 recordsLinked to original sources
PubMed2007

Detecting vitreomacular adhesions in eyes with asteroid hyalosis with triamcinolone acetonide.

BACKGROUND: To report the incidence of posterior vitreous detachments (PVDs) and the surgical results of vitrectomy with intravitreal triamcinolone acetonide (TA) to detect vitreomacular adhesions in eyes with asteroid hyalosis (AH). METHODS: Ten eyes of nine patients with AH underwent vitrectomy, six eyes with TA and four without TA. The presence of a PVD was determined preoperatively by ultrasound echography (USE) and intraoperatively by microscopic observations. The postoperative best-corrected visual acuities (BCVA) were evaluated. RESULTS: The BCVA was improved by >2 Snellen lines in nine eyes and maintained at 20/20 with symptomatic improvements in the other eye. A vitreomacular adhesion was clearly seen during TA-assisted vitrectomy, and none was seen when TA was not used, even though preoperative USE showed an incomplete PVD in all eyes. The BCVA was not significantly better in eyes with TA-assisted vitrectomy than without TA-assisted vitrectomy. In one eye with vitrectomy without TA, a second surgery was required for a persistent cystoid macular edema and an epiretinal membrane. The BCVA and the edema in this eye improved after removing the epiretinal membrane. CONCLUSIONS: All (ten) of the eyes with AH were found to have a vitreomacular adhesion by preoperative USE and intraoperative microscopic observations. The residual vitreous over the macula is more easily detected and removed after intravitreally injected TA, but the visual acuities were not significantly different from eyes without TA.

Aged↗
PubMed2006

Phototoxic effects of commercial photographic flash lamp on rat eyes.

BACKGROUND: To determine whether exposure of the cornea and retina of rats to flashes from a commercial photographic flash lamp is phototoxic. METHODS: Sprague-Dawley rats were exposed to 10, 100, or 1,000 flashes of the OPTICAM 16M photographic flash lamp (Fujikoeki, Japan) placed 0.1, 1, or 3 m from the eyes. Corneal damage was assessed by a fluorescein staining score, and the retinal damage by eletroretinography (ERG) and histology before and 24 h after exposure. RESULTS: Exposure of the eyes to 1,000 flashes at 0.1 m increased the fluorescein staining score significantly (P = 0.009, the Mann-Whitney test). Scanning electron microscopy (SEM) of the cornea showed a detachment of the epithelial cells from the surface after this exposure. The amplitude of the a-wave was decreased significantly by 23.0% (P = 0.026) of the amplitude before the exposure, and the b-wave by 19.7% (P = 0.0478) following 1,000 flashes at 0.1 m but not by the other exposures. TUNEL-positive cells were present in the outer nuclear layer only after the extreme exposure, but no significant decrease in retinal thickness was seen under any condition. The fluorescein staining score and ERGs recovered to control levels within 1 week. CONCLUSIONS: Light exposure to a photographic flash lamp does not induce damage to the cornea and retina except when they are exposed to 1,000 flashes at 0.1 m.

Animals↗
PubMed2006

Effect of verteporfin photodynamic therapy on endostatin and angiogenesis in human choroidal neovascular membranes.

AIM: To evaluate the effect of verteporfin photodynamic therapy (PDT) on endostatin with regard to expression of vascular endothelial growth factor (VEGF) in human choroidal neovascular membranes (CNVs) secondary to age-related macular degeneration. METHODS: A retrospective review of an interventional case series of 68 patients who underwent removal of CNV. 29 patients were treated with PDT 3-655 days before surgery. 39 CNVs without previous treatment were used as controls. CNVs were stained for CD34, CD105, Ki-67, cytokeratin 18, endostatin, E-selectin and VEGF. "Predominance score of VEGF over endostatin" (mean) was defined as the difference between VEGF and endostatin staining scores. RESULTS: In four CNVs treated by PDT 3 days previously, PS was significantly higher in the retinal pigment epithelium (mean = 2.5, p = 0.006) and stroma (mean = 2, p = 0.015) than in the control group (mean = 0). At longer post-PDT intervals, PS was significantly decreased in the retinal pigment epithelium (mean = 0, p = 0.019) and stroma (mean = 0, p = 0.015). Proliferative activity was high (p = 0.023), but mostly related to inflammatory cells. PDT did not influence E-selectin expression significantly. CONCLUSIONS: VEGF predominance over endostatin early after PDT might contribute to enhanced angiogenic activity associated with recurrences. Strategies upregulating or replacing endostatin early after PDT might increase the effectiveness of PDT.

Aged↗
PubMed2006

Drusen, choroidal neovascularization, and retinal pigment epithelium dysfunction in SOD1-deficient mice: a model of age-related macular degeneration.

Oxidative stress has long been linked to the pathogenesis of neurodegenerative diseases; however, whether it is a cause or merely a consequence of the degenerative process is still unknown. We show that mice deficient in Cu, Zn-superoxide dismutase (SOD1) have features typical of age-related macular degeneration in humans. Investigations of senescent Sod1(-/-) mice of different ages showed that the older animals had drusen, thickened Bruch's membrane, and choroidal neovascularization. The number of drusen increased with age, and exposure of young Sod1(-/-) mice to excess light induced drusen. The retinal pigment epithelial cells of Sod1(-/-) mice showed oxidative damage, and their beta-catenin-mediated cellular integrity was disrupted, suggesting that oxidative stress may affect the junctional proteins necessary for the barrier integrity of the retinal pigment epithelium. These observations strongly suggest that oxidative stress may play a causative role in age-related retinal degeneration, and our findings provide evidence for the free radical theory of aging. In addition, these results demonstrate that the Sod1(-/-) mouse is a valuable animal model to study human age-related macular degeneration.

Animals↗
PubMed2006

Expression of endostatin in human choroidal neovascular membranes secondary to age-related macular degeneration.

Endostatin is an endogenous angiogenesis inhibitor which requires E-selectin for its antiangiogenic activity. The aim of this study was to investigate the expression of endostatin in human choroidal neovascular membranes (CNV) secondary to age-related macular degeneration (AMD) with regard to vascularization and proliferative activity. An interventional case series of 36 patients who underwent removal of CNV were retrospectively investigated. Thirty-six CNV were analyzed by light microscopic immunohistochemistry for the expression of CD34 (endothelial cells, EC), CD105 (activated EC), Ki-67 (cell proliferation), Cytokeratin 18 (epithelial cells), VEGF (vascular endothelial growth factor), E-selectin and endostatin. Donor eyes (n=7) including one with AMD were used as controls. Endostatin immunoreactivity was present in choroidal vessels of five as well as in the retinal pigment epithelium (RPE)-Bruch's membrane complex of two donor eyes without AMD. In one eye with AMD, endostatin was detected in RPE, Bruch's membrane and choroidal vessels. Ninety-two percent (33/36) of CNV disclosed endostatin staining. RPE-Bruch's membrane complex, choroidal vessels and stroma were positive in 50% (18/36), 72% (26/36), and 78% (28/36) of the membranes, respectively. Both control eyes and CNV expressed all the investigated markers except E-selectin being positive only in membranes. Endostatin, an endogenous angiogenesis inhibitor, is expressed in CNV and its therapeutic up-regulation may be a new strategy in the treatment of neovascular AMD.

Adult↗
PubMed2006

Consequences of verteporfin photodynamic therapy on choroidal neovascular membranes.

OBJECTIVE: To examine the impact of photodynamic therapy (PDT) on angiogenesis in human choroidal neovascular membranes with respect to vascular endothelial growth factor (VEGF) expression, proliferation, and vascularization. METHODS: Retrospective review of an interventional case series of 50 patients (50 eyes) who underwent removal of choroidal neovascular membranes. Choroidal neovascularization was secondary to age-related macular degeneration. Twenty patients were treated with PDT 3 to 655 days before surgery. Choroidal neovascular membranes were stained for CD34, CD105, Ki-67, cytokeratin 18, and VEGF. Thirty choroidal neovascular membranes secondary to age-related macular degeneration without previous treatment were used as controls. RESULTS: Specimens without pretreatment disclosed varying degrees of vascularization, proliferative activity, and VEGF expression by different cells. Specimens treated with PDT 3 days earlier showed mostly occluded vessels, damaged endothelial cells, and low proliferative activity. In contrast, specimens excised at later time points after PDT were highly vascularized and proliferating. This chronology was associated with an impressive VEGF immunoreactivity unique to retinal pigment epithelial cells shortly after PDT that also shifted to other cells at later time points. CONCLUSIONS: Photodynamic therapy induces selective vascular damage in choroidal neovascular membranes. The effectiveness and selectivity of this treatment, however, seem to be jeopardized by a rebound effect initiated by enhanced VEGF expression in retinal pigment epithelial cells.

Aged↗
PubMed2006

Subjective visual sensation during vitrectomy under retrobulbar anesthesia.

PURPOSE: To report a precise illustrated image of patient's view during vitrectomy. DESIGN: Interventional case report. METHODS: A 56-year-old male with cystoid macular edema (CME) associated with epiretinal membrane underwent vitrectomy. The patient seemed to find gratification in being operated on because he was able to see what was going on. He was a professional artist in computer graphics, and he drew three different pictures depending on the surgical procedures. RESULTS: These pictures depicted the moving of pasty, whirling fluid during core vitrectomy, numerous black or gray spots like snowflakes by intravitrealy injected crystals of triamcinolone acetonide, and a sharp tapered instrument coming into the center and membrane-like material being peeled off. CONCLUSIONS: Patients may see a precise shape in a constant size, scale, and detailed movement as well, focused on the retina without described optics. Further investigation will be required to determine this mechanism.

Anesthesia, Local↗
PubMed2006

Expression of VEGF and PEDF in choroidal neovascular membranes following verteporfin photodynamic therapy.

PURPOSE: To examine the impact of photodynamic therapy (PDT) on pigment epithelium derived factor (PEDF) expression in human choroidal neovascularization (CNV) membranes with regard to vascular endothelial growth factor (VEGF) expression. DESIGN: Interventional case series. METHODS: Retrospective review of interventional case series of 42 patients (42 eyes) who underwent removal of CNV. CNV was secondary to age-related macular degeneration (AMD) in all cases. Fifteen patients were treated with PDT, 3 to 246 days before surgery. CNV were stained for CD34, CD105, cytokeratin 18, VEGF, and PEDF. Twenty-seven CNV without previous treatment were used as control. RESULTS: Specimens without pretreatment disclosed varying degrees of vascularization, VEGF, and PEDF expression by different cells. Specimens treated by PDT, three days previously showed mostly occluded vessels lined with damaged endothelial cells (EC). In contrast, specimens excised at later time points after PDT were highly vascularized with healthy EC. This chronology was associated with an impressive VEGF immunoreactivity increased considerably in retinal pigment epithelial cells as well as significantly reduced PEDF expression in EC and stroma. CONCLUSIONS: PDT induces a selective vascular damage in CNV. The effectiveness of PDT, however, seems to be jeopardized by a rebound effect initiated by an enhanced VEGF and reduced PEDF expression in CNV.

Aged↗
PubMed2006

Microcirculation at optic disc rim is correlated with visual field defects in cases of anterior ischaemic optic neuropathy.

We report two cases of anterior ischaemic optic neuropathy in whom tissue blood flow at the disc rim was correlated with the visual field defect. Tissue blood flow of each eye was evaluated with Heidelberg retina flowmeter. Both cases experienced acute visual loss and an altitudinal hemianopsia associated with optic disc oedema in the affected eye. In each case, the tissue blood flow at the affected (upper or lower half) disc rim corresponding to visual field deficit was reduced compared with that at the opposite-sided half disc rim in the affected eye and with the corresponding area in the fellow eye. The reduction of blood flow in the affected half disc rim associated with the visual field defect demonstrated that retina flowmetry can detect differences in tissue blood flow between superior and inferior sectional disc rim areas as well as between eyes non-invasively.

Blood Flow Velocity↗
PubMed2005

Decreased blood flow at neuroretinal rim of optic nerve head corresponds with visual field deficit in eyes with normal tension glaucoma.

PURPOSE: To determine the relationship between the blood flow parameters of the optic disc rim and the glaucomatous visual field changes. DESIGN: Observational cross-sectional study. METHODS: Tissue blood flow in the neuroretinal rim within the optic disc was determined with the Heidelberg retina flowmeter(HRF) in 54 eyes of 54 patients with normal tension glaucoma (NTG). Patients were selected whose visual field defects were confined to either the superior or inferior hemifield. Blood flow measurements were made in a 10 degrees x 2.5 degrees area of the superior and inferior neuroretinal rim within the optic disc. The mean blood flow (MBF) was calculated by the automatic full-field perfusion image analyzer program, and the ratio of the MBF in the superior to the inferior rim areas (the S/I ratio) was calculated from the same HRF image in order to minimize the variation of measurement condition. RESULTS: Inferior rim blood flow is less than superior rim blood flow in patients with superior hemifield defect, and superior rim blood flow is reduced compared to inferior in patients with inferior hemifield defect. The mean S/I ratios of the MBF in the patients with superior hemifield defect (1.46, n=37) was significantly higher than that in the patients with inferior hemifield defect (0.79, n=17; P<0.0001, Mann-Whitney U-test). CONCLUSIONS: The blood flow in the neuroretinal rim was found to correspond to the regional visual field defect in eyes with NTG. Reductions in flow were associated with reductions in function.

Adult↗
PubMed2005

Scotopic threshold responses to infrared irradiation in cats.

Infrared (IR) irradiation is frequently used in ophthalmological diagnosis and treatment. It has been used to selectively stimulate photodiode-based retinal prostheses to prove their function. Data concerning the natural IR-sensitivity of the retina are contradictory. In our experiments in dark-adapted cats an IR-laser (826 nm) and IR emitting diodes (875 nm) elicited clear scotopic threshold responses. Comparison of the two lasers (IR and a visible laser at 670 nm) using Lambs template and our experimental data revealed very similar differences in retinal sensitivity (4.28 and 3.94+/-0.29 log units, respectively). The fact that the cat retina is sensitive to IR-irradiation under certain conditions has important implications in interpreting the results from retinal prostheses and rewards further attention in its use in many ophthalmological applications.

Animals↗
PubMed2005

Massive bilateral vitreoretinal hemorrhage in patient with chronic refractory idiopathic thrombocytopenic purpura.

BACKGROUND: We describe a patient with chronic, refractory idiopathic thrombocytopenic purpura (ITP) who developed massive vitreoretinal hemorrhages in both eyes. METHODS: A 49-year-old woman complained of an acute decrease of vision, and ophthalmoscopy revealed bilateral preretinal and subretinal hemorrhages around the optic disc. Her platelet counts were less than 5000/mul in spite of repetitive administration of corticosteroids and immunoglobulins with splenectomy for the chronic refractory ITP. One month later, she developed massive vitreoretinal hemorrhages bilaterally, and vision decreased to hand-motion. RESULTS: Vitrectomy was performed on both eyes after medical treatment to increase platelet counts. The intraretinal hemorrhages were absorbed from the area around the disc and vision recovered to 20/100 in the right eye and 20/2000 in the left after one month. CONCLUSION: Massive vitreoretinal hemorrhages can develop in patients with chronic refractory ITP, and vitrectomy can be beneficial for this condition.

Chronic Disease↗
PubMed2005

Intraocular lens implantation after atopic cataract surgery decreases incidence of postoperative retinal detachment.

PURPOSE: To investigate the efficacy of intraocular lens (IOL) implantation in reducing the incidence of postoperative retinal detachment after cataract surgery in patients with atopic dermatitis. DESIGN: Retrospective review. PARTICIPANTS: One hundred sixty-nine eyes of 126 patients who underwent cataract surgery for atopic cataract were followed for more than 1 year. None of the eyes previously had a retinal detachment or retinal detachment surgery. METHODS: The eyes were divided into 132 eyes of 95 patients with an IOL implantation (IOL group) and 37 eyes of 31 patients without an IOL implantation (aphakia group). The postoperative visual acuity and incidence of postoperative retinal detachment were compared between the 2 groups. The effects of the location of the causative retinal breaks, intraoperative posterior capsule rupture, and postoperative posterior capsulotomy on the incidence of retinal detachments were evaluated. MAIN OUTCOME MEASURES: The postoperative corrected visual acuity, incidence of postoperative retinal detachment, and influence of intraoperative posterior capsule rupture on the retinal detachment. RESULTS: The final visual acuity was better than or equal to 20/20 in 128 eyes (97.0%) of the IOL group and in 29 eyes (78.4%) of the aphakia group (P = 0.0007). Retinal detachment after an uncomplicated cataract surgery occurred in 3 eyes (2.3%) of the IOL group and in 8 eyes (25.8%) of the aphakia group (P<0.0001, Mantel-Cox). Two of 3 eyes (66.7%) in the IOL group and 1 of 8 eyes (16.7%) in the aphakia group that later developed a retinal detachment had an intraoperative posterior capsule rupture. Posterior capsulotomy by yttrium-aluminum-garnet laser did not seem to alter the incidence of postoperative retinal detachment in either the IOL (2.0%) or the aphakia group (25.0%). CONCLUSIONS: The rate of postoperative retinal detachment in eyes with IOL and no intraoperative posterior capsule rupture seems to be low. Intraocular lens implantation with capsular bag fixation may reduce the incidence of postoperative retinal detachment triggered by lens surgery for atopic cataract.

Adolescent↗
PubMed2005

Toxicity study of erucylphosphocholine in a rat model.

PURPOSE: To investigate the effect of intraocular erucylphosphocholine (ErPC) on the retina, the retinal pigment epithelium (RPE), and the choroid in an in vivo rat model. METHODS: Adult male Brown Norway rats were injected intravitreally with ErPC dissolved in balanced salt solution (BSS) at a final concentration of 10 or 100 microM with BSS serving as control. Adverse effects on the anterior and posterior segment were assessed by slit-lamp biomicroscopy and ophthalmoscopy. Retinal toxicity was assessed by electroretinography (ERG), retinal ganglion cell (RGC) quantification, and histology 7 days after intravitreal administration of ErPC. RESULTS: There was neither a statistically significant difference in the clinical examination nor in the ERG waves of treated versus control rats 7 days after intravitreal administration of ErPC. Correspondingly, the number of RGC after BSS injection did not differ significantly from ErPC-injected animals. Histologic sections of the posterior segment of 10 and 100 microM ErPC-injected rats did not show any signs of retinal toxicity. Electron microscopy did not display a difference between the 10 microM and the control group. Only the 100 microM-injected animals showed a discrete irregularity of the Müller cell and the retinal ganglion cell cytoplasm at the ultrastructural level. CONCLUSIONS: ErPC can safely be injected into the vitreous of adult rats at a concentration of 10 microM without any retinal toxicity. Even a 10-fold increase in ErPC concentration leads only to a discrete cytoplasmic irregularity of the innermost retinal layers.

Animals↗
PubMed2005

Selective suppression of pathologic, but not physiologic, retinal neovascularization by blocking the angiotensin II type 1 receptor.

PURPOSE: To investigate the anti-inflammatory and anti-angiogenic effects of telmisartan, an angiotensin II type 1 receptor (AT1-R) antagonist, on ischemia-induced retinal neovascularization. METHODS: C57BL/6 neonatal mice were reared in an 80% concentration of oxygen from postnatal day (P)7 to P12, followed by room-air breathing until P17, to induce ischemia-initiated retinal neovascularization (i.e., a murine model of ischemic retinopathy). Tissue localization of AT1-R was examined by immunohistochemistry for murine retinal wholemounts and human fibrovascular tissues excised at vitrectomy for proliferative diabetic retinopathy. Animals received intraperitoneal injection of telmisartan or vehicle. A concanavalin A lectin perfusion-labeling technique was used to evaluate the areas of physiological and pathologic retinal new vessels and the number of leukocytes adhering to the vasculature. Retinal mRNA and protein levels of intercellular adhesion molecule (ICAM)-1, vascular endothelial growth factor receptor (VEGFR)-1, and VEGFR-2 were examined by RT-PCR and ELISA. RESULTS: Vessels in human fibrovascular tissues and the murine retinas were positive for AT1-R. Pathologic (P < 0.01), but not physiologic (P > 0.05), retinal neovascularization was significantly suppressed in telmisartan-treated mice compared with vehicle-treated animals. The number of adherent leukocytes (P < 0.01) was also significantly reduced, together with retinal ICAM-1 levels (P < 0.01) in the telmisartan-treated group compared with the control group. No significant difference was detected in retinal VEGFR-2 levels between the two groups, whereas retinal VEGFR-1 levels in the telmisartan-treated group were significantly (P < 0.05) lower than in the vehicle-treated group. CONCLUSIONS: The present findings suggest that the AT1-R signaling blockade leads to the selective suppression of pathologic, but not physiological, retinal neovascularization through the inhibition of the inflammatory processes related to pathologic neovascularization.

Angiotensin II Type 1 Receptor Blockers↗
PubMed2005

Suppression of ocular inflammation in endotoxin-induced uveitis by blocking the angiotensin II type 1 receptor.

PURPOSE: To examine whether the angiotensin II type 1 receptor (AT1-R) signaling plays a role in ocular inflammation in endotoxin-induced uveitis (EIU). METHODS: EIU was induced in C57BL/6 mice by a single intraperitoneal injection of 150 mug lipopolysaccharide (LPS). Tissue localization, mRNA expression, and protein levels of AT1-R in murine retinas were examined by immunohistochemistry, RT-PCR, and Western blot analyses, respectively. Telmisartan, an AT1-R antagonist widely used as an antihypertensive agent, was administered intraperitoneally at a dose of 10 mg/kg daily for 5 days until the injection of LPS. Twenty-four hours after administration, leukocyte adhesion to the retinal vasculature was evaluated with a concanavalin A lectin perfusion-labeling technique. Retinal mRNA and protein levels of intercellular adhesion molecule (ICAM)-1 were examined by RT-PCR and ELISA, respectively. Protein concentration and inflammatory cells in the aqueous humor were also measured. RESULTS: Retinal vessels were positive for AT1-R. In mice with EIU, retinal AT1-R mRNA and protein levels were significantly increased when compared to the normal control. EIU animals also showed significant increases in the number of inflammatory cells infiltrating the anterior chamber and adhering to the retinal vessels and in retinal ICAM-1 levels. Administration of telmisartan to EIU mice resulted in significant suppression of retinal ICAM-1 expression and leukocyte adhesion and infiltration compared with vehicle treatment. Protein concentration in the aqueous humor of telmisartan-treated EIU mice tended to be lower than that of vehicle-treated EIU mice, but the difference was not statistically significant. CONCLUSIONS: AT1-R signaling blockade inhibited retinal ICAM-1 upregulation and leukocyte adhesion and infiltration in the EIU model. These results suggest the potential use of an AT1-R antagonist as a therapeutic agent to reduce ocular inflammation.

Angiotensin II Type 1 Receptor Blockers↗