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Biomedical subjects

Shin Yoneya

Publications and source records attributed to Shin Yoneya.

27 records · Page 2Linked to original sources
PubMed2003

Retinal neuroprotection against ischemic injury mediated by intraocular gene transfer of pigment epithelium-derived factor.

PURPOSE: To determine whether intraocular gene transfer of pigment epithelium-derived factor (PEDF) protects the retina from ischemia-reperfusion injury. METHODS: Four days before induction of pressure-induced ischemia, Lewis rats received intravitreous injection of 3 x 10(9) particles of an adenovirus vector expressing PEDF (AdPEDF.11) in one eye and 3 x 10(9) particles of an empty adenovirus vector (AdNull.11) in the contralateral eye. Seven days after reperfusion, eyes were enucleated and processed for morphometric analysis. Apoptotic cells stained by TdT-dUTP terminal nick-end labeling (TUNEL) in the retina were counted 12 hours after initiation of reperfusion. Retina levels of PEDF were measured by enzyme-linked immunosorbent assay. RESULTS: PEDF levels in retinal homogenates from eyes receiving AdPEDF.11 injection were well above the background levels in the untreated baseline and control eyes (P = 0.04). Retinal thickness was preserved in AdPEDF.11-treated eyes. Retinal cell density was significantly greater in the ganglion cell layer (GCL; P = 0.014), inner nuclear layer (INL; P = 0.008), and outer nuclear layer (ONL; P = 0.008) of AdPEDF.11-treated eyes compared with the corresponding layers in AdNull.11-treated eyes. AdNull.11-treated eyes also had significantly more TUNEL-positive cells in these layers than AdPEDF.11-treated eyes (P < 0.05). CONCLUSIONS: Adenoviral vector-mediated intraocular expression of PEDF significantly increases cell survival after ischemia-reperfusion injury of the retina. The protective effect may result from inhibition of ischemia-induced apoptosis. This study provides proof of concept for a gene transfer approach directed at interrupting programmed cell death induced by retinal ischemic insult.

Adenoviridae↗
PubMed2002

Retinal oxygen saturation levels in patients with central retinal vein occlusion.

PURPOSE: To validate the efficacy of Fourier transform-based spectral retinal imaging (SRI) in quantifying retinal ischemia. DESIGN: Prospective, observational case series. PATIENTS AND METHODS: Eleven eyes of 10 patients with central retinal vein occlusion (CRVO) and 4 fellow unaffected eyes of selected patients were examined by both fluorescein angiography and SRI. The fluorescein angiograms were correlated with oxygen saturation maps that were calculated from the SRI. RESULTS: Oxygen saturation levels in the fundus were shown as color grading in 35 degrees fundus images processed by SRI. This grading correlated well with the severity of CRVO, as estimated by fluorescein angiography. CONCLUSIONS: The severity of circulatory disturbances in CRVO may be graded by applying SRI.

Blood Flow Velocity↗
PubMed2002

The ultra-late phase of indocyanine green angiography for healthy subjects and patients with age-related macular degeneration.

PURPOSE: To compare the characteristics of residual fundus fluorescence observed in the ultra-late phase of indocyanine green (ICG) angiography, in normal subjects and in patients with age-related macular degeneration (ARMD). METHODS: ICG angiography was performed on 38 patients, 21 had ARMD, 9 were normal subjects aged >62, and 8 were normal subjects aged <36. The intensity and pattern of fluorescence from angiograms obtained in the ultra-late phase, 24 hours after dye injection, was also recorded and analyzed. RESULTS: In the ultra-late phase, 95% of ARMD eyes with CNV showed geographic hypofluorescent lesions. All of the CNV that could be delineated with fluorescein and/or ICG angiography were located in these geographic lesions. In 73% of ARMD eyes without CNV, these hypofluorescent lesions occurred, while age-matched normal subjects had no hypofluorescent lesions. The mean intensity of fluorescence in the normal older subject group was significantly higher than that seen in the normal young subject group. CONCLUSIONS: Increased fluorescence, associated with older subjects, in the ultra-late phase of ICG angiography may reflect aging changes in the chorioretinal complex. Geographic hypofluorescent areas, demonstrated only in the ultra-late phase, associate with ARMD and may represent areas predisposed to CNV development.

Adult↗
PubMed2002

[Clinical dose finding study of indocyanine green to detect choroidal neovascularization in patients with exudative age-related macular degeneration].

PURPOSE: To evaluate the proper clinical dosage of indocyanine green(ICG) in angiography for detecting choroidal neovascularization(CNV) of exudative age-related macular degeneration(AMD). SUBJECTS AND METHODS: Indocyanine green angiography (IA) was performed using a randomized crossover method with two different doses on two occasions. Ease of detection, side effects and clinical serum data were also evaluated. RESULTS: Among the 39 eyes, detection of CNV using 12.5 mg and 25 mg was most effective in 21 and 31 eyes respectively, showing a statistically significant difference. Slight vomiting was observed temporarily in one patient who had taken 25 mg. CONCLUSION: A dose of 25 mg is appropriate for detection of CNV of exudative AMD and this dosage raises no safety concerns.

Aged↗
PubMed2002

[Retinal thickness and changes with age].

PURPOSE: We studied the morphological changes occurring with aging in the macula using optical coherence tomography(OCT). METHODS: Forty-seven eyes from 47 normal volunteers were studied. The subjects ranged in age from 21 to 79 years and their refractive errors were within +/- 3.00 diopters. The measurement of the retinal thickness was done by OCT. The retinal thickness was evaluated at five points: the foveola, and 1 mm superior, inferior, nasal, and temporal to the foveola. The axial length of the eye and the refraction were also measured in all subjects. RESULTS: The retinal thickness was 142 +/- 15 microns at the foveola, 257 +/- 18 microns at the superior point, 255 +/- 18 microns at the inferior point, 246 +/- 20 microns at the temporal point, and 261 +/- 21 microns at the nasal point (mean +/- standard deviation). All points except the foveola showed reduced retinal thickness with age. Thus, attenuation of the retinal thickness in the parafoveal area was correlated significantly with age. However, no change in the retinal thickness at the foveola was observed with increasing age. Neither axial length nor refractive error biased this result. CONCLUSION: Our results demonstrated that the macular thickness changes with aging, but no obvious change could be detected in the foveola.

Adult↗
PubMed2002

[Quantitative analysis of indocyanine green angiography in multifocal posterior pigment epitheliopathy and its related diseases].

PURPOSE: To clarify the indocyanine green(ICG) angiographic features in multifocal posterior pigment epitheliopathy(MPPE), we measured the maximum diameter of the choroidal vein and mean fluorescence intensity within the vascular arcade. METHODS: ICG angiography was performed in 40 eyes of 20 patients with MPPE and 10 age-matched normal controls, and quantified by IMAGEnet. RESULTS: The mean maximum choroidal venous diameter was 544 +/- 162(mean +/- standard deviation) microns in eyes with MPPE and 278 +/- 55 microns in healthy age-matched control eyes. The mean fluorescence intensity was 106.9 +/- 52.5 and 86.5 +/- 32.5, respectively. Both the mean maximum choroidal venous diameter and the mean fluorescence intensity showed statistical difference between the two groups. In contrast, there was no statistically significant difference between the eyes with serous retinal detachment and without detachment in the MPPE group. CONCLUSIONS: These results show that choroidal venous dilation and choroidal hyperfluorescence in MPPE are clearly distinguished from choroidal aging changes. Additionally, these pathological angiographic changes seemingly do not delineate the activity of MPPE, but demonstrate the background factor of the pathogenesis of MPPE.

Adult↗
PubMedDate not supplied

Enhanced documentation of slit-lamp images of the human vitreous stained with fluorescein sodium.

BACKGROUND AND OBJECTIVE: To develop a new method to document the slit-lamp image of the vitreous body as stained with fluorescein sodium. PATIENTS AND METHODS: The system consists of a Goldmann-type slit-lamp biomicroscope, a highly sensitive monochromatic charge-coupled device camera, and a video attachment for real-time observation and recording. As a standard procedure, observation of the vitreous was conducted 60 minutes after intravenous administration of 500 mg of fluorescein sodium. This method was applied to 19 eyes with various eye diseases. RESULTS: Fine details of the vitreous were observed in all of the eyes. Posterior vitreous detachment could be recorded in 5 of the 19 eyes examined. Vitreoschisis and large lacunae were documented in 11 eyes. CONCLUSION: This method promises to be of value in detecting early age-related and pathological changes of the vitreous such as posterior vitreous detachment and vitreoschisis in clinics.

Adult↗