Biomedical subjects

Yusuke Oshima

Publications and source records attributed to Yusuke Oshima.

14 recordsLinked to original sources

PubMed2007

Residual indocyanine green fluorescence pattern after vitrectomy for idiopathic macular hole with internal limiting membrane peeling.

BACKGROUND: Internal limiting membrane (ILM) peeling with indocyanine green (ICG) staining is a commonly used procedure to treat idiopathic macular holes (MH). AIM: To report changes in the patterns of residual ICG fluorescence over time after vitrectomy using the Heidelberg Retina Angiograph 2 (HRA2, Heidelberg Engineering, Heidelberg, Germany). METHODS: 10 patients (10 eyes) who had undergone vitrectomy for MH with ILM peeling were included. 9 (90%) patients underwent ILM peeling with ICG, and 1 (10%) patient had it with triamcinolone acetonide (TA). We observed residual ICG using HRA2, postoperatively. Autofluorescence, optical coherence tomography images and best-corrected visual acuity (BCVA) measurements were also obtained. The minimal follow-up was 3 months. RESULTS: The MHs were closed postoperatively in all patients (100%). In eyes that underwent ILM peeling with ICG, the BCVA improved significantly (p<0.001) in 8 (89%) eyes and was unchanged in 1 (11%) eye. HRA2 showed the ICG fluorescence patterns but not TA postoperatively. The ICG hyperfluorescent signal was typically diffuse at the posterior retina and was hypofluorescent around the fovea. The hyperfluorescence then migrated towards the optic nerve disc presumably along the nerve fibre, and the area of ILM peeling was clearly identified. A large number of hyperfluorescent dots were observed instead of diffuse hyperfluorescence that was observed just after surgery. CONCLUSIONS: Patterns of residual ICG fluorescence were sequentially observed with HRA2 after vitrectomy for MH with ICG-assisted ILM peeling.

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PubMed2006

Self-retaining 27-gauge transconjunctival chandelier endoillumination for panoramic viewing during vitreous surgery.

PURPOSE: To report the development of a 27-gauge self-retaining transconjunctival chandelier endoilluminator for panoramic viewing during vitrectomy. DESIGN: New surgical instrument. METHODS: The tip of the illuminating fiber is 27-gauge (0.35 mm) and shaped like a cone to provide wide-angle illumination. The tip, inserted approximately 3 mm into the vitreous cavity transconjunctivally, provides diffuse illumination. The optical fiber covered by a malleable sleeve can be retained in the eyeball without a suture. RESULTS: The slim light fiber design (0.35 mm) stabilizes the 27-gauge tip in the eye and provides up to 25 lumens of measured illumination. The adequate lighting potential and self-retaining design allow wide-angle visualization and bimanual manipulation in challenging cases. Easy insertion and removal without suture placement make it convenient to change the position of the device during surgery and efficiently shorten surgical time. CONCLUSIONS: This suture-free 27-gauge endoillumination chandelier improves the efficacy and efficiency of vitreous surgery.

Conjunctiva↗

PubMed2006

Regression of iris neovascularization after intravitreal injection of bevacizumab in patients with proliferative diabetic retinopathy.

PURPOSE: To assess the short-term safety and efficacy of intravitreal injection of bevacizumab for iris neovascularization (INV). DESIGN: Noncomparative, interventional case series. METHODS: Intravitreal bevacizumab was injected in seven eyes of five patients with INV that was associated with proliferative diabetic retinopathy (PDR). The main outcome measurements were visual acuity, intraocular pressure (IOP), and regression of INV by fluorescein angiography before and one week, one month, and two months after injection. RESULTS: Regression of INV was confirmed in all eyes (100%) from one week after injection. Repeated injections stabilized the recurrence (two eyes; 29%) that was observed two months after the initial injection. The visual acuity remained stable or improved, and the intraocular pressure was controlled in six eyes (86%) throughout the follow-up period. No inflammation or complications were observed. CONCLUSIONS: Intravitreal injection of bevacizumab may be an effective and safe alternative for patients with INV that is refractory to conventional treatments.

Adult↗

PubMed2006

Fluorescence-suppressed Raman technique for quantitative analysis of protein solution using a micro-Raman probe, the shifted excitation method, and partial least squares regression analysis.

A practical Raman analyzing technique with suppression of the strong fluorescent background in order to obtain quantitative information is proposed in the present study. The technique is based on the shifted excitation method and partial least squares regression (PLSR) analysis. The Raman system consists of a single Raman spectrometer, a background-free electrically tunable Ti:Sapphire laser (BF-ETL), and a micro-Raman probe (MRP). The system allows one to obtain reliable shifted excitation Raman spectra with a simple operation. The PLSR analysis successfully provides quantitative information from the obtained spectra with the suppression of random noise including photon shot noise. The present study demonstrates that the technique is effective for extracting quantitative information concealed behind a fluorescent background that is more than 200 times stronger than the Raman signal.

Animals↗

PubMed2006

[Sub-Tenon's injection of triamcinolone acetonide for choroidal neovascularization].

PURPOSE: To evaluate the efficacy of sub-Tenon's injection of triamcinolone acetonide for age-related macular degeneration (AMD) and polypoidal choroidal vasculopathy (PCV). METHOD: Sub-Tenon's injection of triamcinolone acetonide was performed in patients (27 eyes) with the subfoveal choroidal neovascularization of AMD and in patients (10 eyes) with PCV, and its efficacy was evaluated. The visual acuity and the exudation from lesions evaluated by fluorescein angiography or optical coherence tomography (OCT) at three months or six months after injection were compared to the baseline values. RESULTS: Visual acuity was maintained in 23 of the 27 eyes (85.0%) with AMD and in 8 of the 10 eyes (80.0%) with PCV at three months after injection. Six months after infusion, the rate declined to 76.0% and 66.7%, respectively. Exudation from lesions had decreased in 10 eyes of 25 eyes(40.0%) with AMD and in 2 eyes of 9 eyes (22.2%) with PCV by six months after injection. Complete suppression of the lesions was observed in seven eyes (18.9%) with relatively small lesions. CONCLUSION: Sub-Tenon's injection of triamcinolone acetonide is useful as a treatment modality for AMD and PCV.

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PubMed2006

Surgical outcomes of 25-gauge transconjunctival vitrectomy combined with cataract surgery for vitreoretinal diseases.

INTRODUCTION: To report surgical outcomes of 25-gauge transconjunctival vitrectomy combined with cataract surgery for the management of a variety of vitreoretinal diseases. MATERIALS AND METHODS: A retrospective, interventional case study was conducted. Chart review of a consecutive series of 150 eyes of 144 patients who underwent 25-gauge vitrectomy combined with phacoemulsification and intraocular lens implantation for epiretinal membrane (n = 62), refractory macular oedema associated with retinal vascular disorders (n = 29), idiopathic macular hole (n = 21), non-clearing vitreous haemorrhage (n = 18), rhegmatogenous retinal detachment (n = 11), tractional retinal detachment associated with proliferative diabetic retinopathy (n = 7), and subretinal haemorrhage (n = 2). Main outcome measures included preand postoperative visual acuity, operating time, intraocular pressure, intra- and postoperative complications. RESULTS: The mean follow-up period was 9.7 months (range, 6 to 26). The mean overall visual acuity improved from 20/100 preoperatively to 20/38 at final visit (P <0.001). Statistically significant improvement of visual acuity was also observed in each subgroup. Operative time was shortened in macular surgery. No intraoperative complications were noted attributable to small-gauge instruments and no cases required conversion to 20-gauge standard instrumentation. However, 12 eyes (8%) required suture placement to at least one sclerotomy site. Postoperative intraocular pressure remained stable in most cases except 18 eyes (13%) with transient hypotony during the first week after surgery. One case of retinal detachment but no case of endophthalmitis was observed throughout the follow-up period. CONCLUSIONS: 25-gauge vitrectomy combined with cataract surgery is a safe and effective system for the management of a variety of vitreoretinal diseases, especially cases requiring minimal intraocular manipulation. Further study is recommended to evaluate potential postoperative complications.

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PubMed2005

Chondromodulin-I and tenomodulin: a new class of tissue-specific angiogenesis inhibitors found in hypovascular connective tissues.

In tissues and/or organs of mesenchymal origin, the vasculature is usually well developed. However, there are certain hypovascular tissues that exhibit powerful anti-angiogenic resistance, implying the presence of tissue-type specific inhibitors of angiogenesis. Hyaline cartilage is one example, and several anti-angiogenic factors have been purified from cartilage. We previously identified chondromodulin-I (ChM-I) as a tissue-specific inhibitor of angiogenesis in fetal bovine cartilage. ChM-I is specifically expressed in the avascular regions of the growth-plate and cartilaginous bone rudiments in embryos. Recently, we cloned a novel type II transmembrane protein, tenomodulin (TeM), having a domain homologous to ChM-I at its C-terminus. TeM turned out to be expressed specifically in other hypovascular structures in the mesenchyme, such as the epimysium, tendon, and ligaments. In this overview, we discuss the structural characteristics of this class of anti-angiogenic molecules and their pathophysiological role in the control of vascularity.

Angiogenesis Inhibitors↗

PubMed2005

New micro vertical scissors for the surgical ablation of retinal angiomatous proliferation.

PURPOSE: To develop new micro vertical scissors for the ablation of retinal angiomatous proliferation (RAP) to minimize possible retinal damage. DESIGN: Interventional case report. METHODS: New micro vertical scissors were developed and used for the ablation of RAP vessels. RESULTS: The length of the inner side of the tip is 180 microm, which is approximately one seventh that of regular vertical scissors. The scissors handled easily and the RAP vessels were ablated with less retinal damage compared with that associated with use of standard vertical scissors. Postoperatively, intraretinal hemorrhage was reduced and hyperfluorescence seen on indocyanine green angiography resolved. CONCLUSIONS: The new micro vertical scissors developed for the ablation of RAP vessels can be used safely and effectively during this surgical procedure.

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PubMed2005

Vascular endothelial growth factor reduced and connective tissue growth factor induced by triamcinolone in ARPE19 cells under oxidative stress.

PURPOSE: To investigate whether triamcinolone acetonide (TA) affects the expression of vascular endothelial growth factor (VEGF) and connective tissue growth factor (CTGF) in retinal pigment epithelial (RPE) cells exposed to oxidative stress. METHODS: TA (10 nM, 1 microM, or 100 microM) was added to ARPE19 cells exposed to oxidative stress induced by hypoxia-reoxygenation and paraquat. Cellular expression of VEGF, CTGF, and an inducer of both growth factors, transforming growth factor (TGF)-beta was investigated with real-time reverse transcription-polymerase chain reaction and Western blot analysis. Tube-forming assays were conducted with human umbilical vein endothelial cells (HUVECs) in conditioned medium from RPE cells exposed to oxidative stress, with or without TA treatment. RESULTS: Oxidative stress induced mRNA expression of VEGF, CTGF, and TGF-beta by RPE cells. TA reduced upregulation of VEGF and TGF-beta in a concentration-dependent manner. In contrast, upregulation of CTGF by oxidative stress was accelerated by TA concentrations of 10 nM and 1 muM. Tube formation by HUVECs was strongly inhibited by exposure to conditioned medium from oxidative stress-stimulated ARPE19 cells treated with 1 muM TA compared with cells not treated with TA. CONCLUSIONS: TA reduced VEGF expression and induced CTGF expression in ARPE19 cells exposed to oxidative stress, and conditioned medium from these cells inhibited tube formation by HUVECs. Because VEGF is a major cytokine involved in angiogenesis, and CTGF is a main cytokine related to fibrosis, these results suggest that changes in their expression may be important mechanisms underlying the decreased choroidal neovascularization and fibrosis after administration of TA.

Blotting, Western↗

PubMed2004

Anti-angiogenic action of the C-terminal domain of tenomodulin that shares homology with chondromodulin-I.

Tenomodulin (TeM) is a type II transmembrane glycoprotein that contains a C-terminal domain with homology to the mature, secreted form of chondromodulin-I (ChM-I), a cartilage-derived angiogenesis inhibitor. TeM transcripts have been found in hypovascular tissues such as tendons and ligaments but the biological activity of TeM has not yet been fully explored. Using an adenovirus expression system, we utilized the forced expression and subsequent secretion of the human TeM C-terminal 116 amino acids (Ad-shTeM) in human umbilical vein endothelial cells (HUVECs) to assess the anti-angiogenic properties of TeM. The C-terminal 120 amino acids of the human ChM-I precursor (Ad-shChM-I) was similarly expressed in HUVECs as a comparison study. Transduction of both Ad-shTeM and Ad-shChM-I resulted in significant impairment of the tube-forming activity of HUVECs, when cultured in Matrigel. Similarly, conditioned medium from COS7 cells, transfected with plasmid DNA encoding shTeM or shChM-I, inhibited tube formation of HUVECs when compared to medium derived from either COS7 cells transfected with control vector or from non-transfected cells. Upon infection of HUVECs with Ad-shTeM or Ad-shChM-I, DNA synthesis stimulated by vascular endothelial growth factor (VEGF) was reduced to 40-50% of normal levels. Additionally, in a modified Boyden chamber assay, migration of HUVECs in response to VEGF was significantly affected following transduction of either Ad-shTeM or Ad-shChM-I and these transduced HUVECs were found to spread well on type I collagen or fibronectin, but not on vitronectin. Furthermore, the transduction of either Ad-shTeM or Ad-shChM-I in human melanoma cells resulted in suppression of tumor growth in association with decreased vessel density in vivo. Hence, we have demonstrated that, similarly to ChM-1, the C-terminal domain of TeM exhibits both anti-angiogenic and anti-tumor activities when expressed in a secreted form.

Adenoviridae↗

PubMed2004

Involvement of rho-kinase pathway in contractile activity of rabbit RPE cells in vivo and in vitro.

PURPOSE: Increased alpha-smooth muscle actin (alpha-SMA) expression in epiretinal membranes causes tractional retinal detachment (TRD) in proliferative vitreoretinopathy (PVR). The Rho-A/Rho-associated kinase signaling pathway is a principal mediator of contractile force generation in nonmuscle cells. In the current study, the relation between the Rho-kinase pathway and alpha-SMA expression and type I collagen gel contractile activity in retinal pigment epithelial (RPE) cells was investigated, using Y27632, a specific inhibitor of p160ROCK, and the involvement of the Rho-kinase pathway was evaluated in a rabbit PVR model with cultured RPE cells and platelet-rich plasma (PRP). METHODS: RPE cells were obtained from rabbits and cultured. The number of passages and the effect of Y27632 on alpha-SMA expression were studied by immunohistochemistry and immunoblot analysis. An in vitro type I collagen gel contraction assay and MTT assay evaluated the effect of Y27632 on RPE cell contractile force and proliferation. Cultured sixth-passage rabbit RPE cells were coinjected with PRP intravitreally, followed by 50 micro M of Y27632, injected weekly. The presence of TRD was assessed until 28 days to evaluate the effect of Y27632 in vivo. RESULTS: Expression of alpha-SMA was increased according to the passages. Y27632 suppressed alpha-SMA expression in cultured RPE cells and impaired contractile force. Y27632 did not affect the proliferative potential. Y27632 significantly (P < 0.01) reduced TRD development. CONCLUSIONS: Y27632 decreased alpha-SMA expression and the contractile force generated by RPE cells and attenuated PVR, indicating the involvement of the Rho-kinase pathway in cell-dependent collagen contraction in vitro and in vivo. The drug may affect the biological event by inhibiting alpha-SMA expression, and Y27632 could be useful for preventing PVR.

Actins↗

PubMed2003

Expression and localization of tenomodulin, a transmembrane type chondromodulin-I-related angiogenesis inhibitor, in mouse eyes.

PURPOSE: To explore the role in the eye of tenomodulin (TeM), a chondromodulin (ChM)-I-related glycoprotein, the expression, localization, and antiangiogenic potential of TeM were investigated. METHODS: Gene expression and protein localization of TeM in mouse eyes were examined by Northern blot analysis, in situ hybridization, and immunohistochemical analysis. Antiangiogenic function included in the C terminus of TeM and ChM-I was examined in vascular endothelial cells through adenoviral gene transduction. RESULTS: TeM expression was detectable from day 15 of the embryonic stage and was clearly present in the eye and skin. In situ hybridization of the eye tissues revealed TeM mRNA in the tendon of the extraocular muscle, the sclerocornea, the lens fiber cells, and the ganglion cell layer, inner nuclear layer cells, and pigment epithelium of the retina. Corresponding immunoreactivity of TeM was present in most of these cells. Western blot detected 40- and 45-kDa immunoreactive bands of TeM in the eye as differently glycosylated forms of the transmembrane protein. Production of a secreted form of TeM and ChM-I through adenoviral gene transfer caused effective autocrine suppression of cell proliferation and capillary-like morphogenesis of retina vascular endothelial cells. The condition media from soluble TeM- and ChM-I-overexpressing cells also showed a marked inhibitory effect on in vitro angiogenesis. CONCLUSIONS: These results indicate a potential role for TeM in prevention of vascular invasion in the mouse eye and the possibility of both TeM and ChM-I as candidates for use in gene therapy approaches to treatment of ocular angiogenesis.

Adenoviridae↗

PubMed2002

[Chondromodulin-I and its related gene Tenomodulin].

During endochondral bone formation, vascular invasion into the cartilaginous rudiments triggers the subsequent replacement of cartilage by bone. We have found that the cartilage-derived glycoprotein, Chondromodulin- I (ChM- I ), is involved in the anti-angiogenic property of cartilage, and that its absence creates a permissive microenvironment for vascular invasion in cartilage. Recently, we reported that a novel ChM- I related molecule, Tenomodulin (TeM), is specifically expressed in tendon, epimysium, ligaments, sclera, and cornea, all of which are hypovascular or avascular. In contrast to ChM- I that is secreted and accumulates in the extracellular matrix, TeM is expressed on the cell surface as a type II transmembrane protein. Anti-angiogenic properties of TeM and ChM- I in mesenchyme will be reviewed.

English Abstract↗

PubMedDate not supplied

Radial optic neurotomy for the management of hemicentral retinal vein occlusion: long-term follow-up study.

PURPOSE: To assess the efficacy of radial optic neurotomy (RON) for hemicentral retinal vein occlusion (hemi-CRVO) in patients with follow-up of >12 months. METHODS: Five consecutive patients with hemi-CRVO were enrolled in the study and underwent vitrectomy with RON. The effects of this treatment were assessed by visual acuity, optical coherence tomography, indocyanine green angiography, and kinetic visual field testing. RESULTS: The median and mean visual acuities improved from 20/250 to 20/50 and from 20/286 to 20/51, respectively. Four patients (80%) had visual acuity improvement of > or =3 lines; visual acuity in 1 patient (20%) remained the same. Visual acuity in all four eyes with preoperative visual acuity of <20/200 improved to >20/200 12 months after surgery. Foveal thickness was gradually reduced during the follow-up period. Chorioretinal anastomosis was detected by indocyanine green angiography in 3 eyes (60%). A temporal visual field defect was found in two eyes. No neovascularization on the iris, angle, optic disk, or retina was detected postoperatively. CONCLUSION: Visual acuity may improve more with RON compared with the natural history of the disease, and no neovascular formation may occur after RON, suggesting that this procedure may be an effective treatment for hemi-CRVO.

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