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Nagahisa Yoshimura

Publications and source records attributed to Nagahisa Yoshimura.

47 records · Page 3Linked to original sources
PubMed2002

Polypoidal choroidal vasculopathy with large vascular network.

PURPOSE: To report characteristics of polypoidal choroidal vasculopathy (PCV) of large vascular networks that expand across the retinal vascular arcade. METHODS: Among 60 consecutive eyes diagnosed as having PCV by fluorescein and indocyanine green (ICG) angiography, 12 eyes (9 patients) showed large lesions. The clinical and angiographic features of these 12 eyes were studied retrospectively. RESULTS: Cases of large PCV typically showed dilated network vessels, which spread radially, and multiple polypoidal dilations at the end of the network vessels. Most of the polypoidal dilations formed clusters resembling bunches of grapes and caused large serous and/or hemorrhagic pigment epithelial detachments (PEDs). Among the 12 eyes, 5 showed rapid expansion of the lesions and became large PCVs within 3-24 months. In these eyes, ICG angiography revealed mesh-like choroidal vessels beneath the retinal pigment epithelium. CONCLUSION: PCV with a large vascular network that expands across the vascular arcade is not uncommon. Some of these cases seems to have characteristics of choroidal neovascularization rather than choroidal vasculopathy. It is not easy to distinguish such cases from exudative age-related macular degeneration even though they showed typical findings of PCV on ICG angiography.

Aged↗
PubMed2002

Bcl-2 expression by CD4 T lymphocytes in Vogt-Koyanagi-Harada disease.

PURPOSE: To determine whether Bcl-2 is expressed on CD4(+ ) lymphocytes in the aqueous humor (AH) and cerebrospinal fluid (CSF) of patients with Vogt-Koyanagi-Harada (VKH) disease, and to determine whether Fas will induce apoptosis of lymphocytes in the CSF. METHODS: The percentages of CD4, CD8, CD45RO, Fas, and Bcl-2 positive T lymphocytes in the AH and CSF of eight patients with active VKH and five healthy controls were determined by flow cytometry. Soluble Fas ligand (sFasL) in the CSF was measured by ELISA. Freshly isolated cells from the CSF were cultured with anti-Fas antibody (Ab) and apoptosis was assessed by the TUNEL method. RESULTS: Fas(+) CD4(+) lymphocytes were the predominant lymphocytes in the AH and CSF of VKH patients. Bcl-2 was strongly expressed in these cells. Soluble FasL was also detected in the CSF. The number of apoptotic cells detected by anti-Fas Ab was not significantly increased in the CSF of VKH patients. CONCLUSIONS: In spite of the high expression of Fas antigen on CD4(+) cells and the presence of sFasL in the CSF, apoptosis was not observed. Bcl-2 expression may contribute to the regulation of apoptosis of inflammatory cells in the CSF of VKH patients.

Adult↗
PubMed2002

Role of PTB-like protein, a neuronal RNA-binding protein, during the differentiation of PC12 cells.

PTB-like protein (PTBLP) is a new homologue of pyrimidine tract binding protein (PTB), and has been cloned as a possible autoantigen in cancer-associated retinopathy. PTBLP has two functional domains, the nuclear localization signal and the RNA recognition motifs (RRMs). Full-length PTBLP (PTBLP-L) has four RRMs, and its alternative splicing product (PTBLP-S) lacks the third and fourth RRMs. Although PTBLPs are expressed in neuronal tissues, the function of PTBLPs has not been determined. We have studed whether PTBLP plays a role in neuronal differentiation using PC12 cells. During the process of nerve growth factor-induced neuronal differentiation of PC12 cells, PTBLP-L was down-regulated whereas PTBLP-S was up-regulated. Transfection of PTBLP-L into PC12 cells led to the suppression of neuronal differentiation. In PTBLP-S transfected cells, however, this suppression was not evident. When both PTBLP-L and PTBLP-S were co-transfected, the suppressive effect of PTBLP-L decreased. In differentiated cells, PTBLP-S localized in the nucleus and PTBLP-L was found dispersed throughout the cytoplasm and neuronal growth cone. These findings suggest that PTBLP-L acts as a negative regulator of neuronal differentiation and PTBLP-S acts as a competitor of PTBLP-L.

Animals↗
PubMed2002

Expression and neuroprotective effect of hepatocyte growth factor in retinal ischemia-reperfusion injury.

PURPOSE: To investigate the expression and possible neuroprotective effects of hepatocyte growth factor (HGF) in a rat model of retinal ischemia-reperfusion injury. METHODS: Retinal ischemia was induced in adult male Sprague-Dawley rats by raising the intraocular pressure to 110 mm Hg for 45 minutes. To study expression of HGF and its receptor c-Met, reverse transcription-polymerase chain reaction (RT-PCR), Western blot analysis, and immunohistochemical staining were performed on eyes enucleated at 6, 12, 24, 48, and 96 hours after reperfusion. To examine the neuroprotective effects of HGF, recombinant human (rh)HGF (1, 6, and 12 microg in 2 microL PBS) or vehicle was administered intravitreally 1 minute after reperfusion, and the eyes were enucleated at 6, 12, 24, 48, and 96 hours and 28 days after reperfusion. The retinal damage was assessed by electroretinogram (ERG) recordings, by measuring the inner retinal thickness, and by counting the number of TUNEL-positive cells in each retinal layer. RESULTS: RT-PCR and Western blot analyses showed upregulation of HGF and c-Met-HGF receptor mRNA at 6, 12, 24, and 48 hours after reperfusion, compared with the normal rat retina. Immunohistochemically, expression of HGF was found in the retinal pigment epithelial cells at 6 hours after reperfusion and in some cells in the ganglion cell layer and inner nuclear layer at 24 hours after reperfusion. The amplitudes of the ERG b-wave and oscillatory potentials were significantly larger in the eyes treated with 6 and 12 microg rhHGF than in those of vehicle-treated control rats (P < 0.01). On day 28, the thicknesses of the inner retina of vehicle-treated rats and that of 6-microg rhHGF-treated rats were 54.4 +/- 6.12 (mean +/- SD, n = 9) and 71.5 +/- 9.81 microm (n = 8), respectively (P < 0.01). The number of TUNEL-positive cells at 6, 12, 24, and 48 hours after reperfusion was decreased significantly by treatment with 6 microg rhHGF, compared with those in the control rats (P < 0.01). CONCLUSIONS: Upregulation of HGF in the retina may play a role in retinal ischemia-reperfusion injury. Intravitreal injection of rhHGF is neuroprotective against the injury.

Animals↗
PubMed2002

Inhibitory effects of pyrrolidine dithiocarbamate on endotoxin-induced uveitis in Lewis rats.

PURPOSE: To determine the effect of pyrrolidine dithiocarbamate (PDTC), an antioxidant nuclear factor (NF)-kappaB inhibitor, on the ocular inflammation induced by lipopolysaccharide (LPS). METHODS: Endotoxin-induced uveitis (EIU) was produced by a footpad injection of 200 microg LPS in male Lewis rats. PDTC (200 mg/kg) was injected intraperitoneally 30 minutes before the LPS administration. The number of infiltrating cells and protein concentration in the aqueous humor (AqH) was determined from the AqH collected at 24 hours. Immunohistochemical staining with a monoclonal antibody against activated NF-kappaB was performed to evaluate the effect of PDTC on NF-kappaB activation. Interleukin (IL)-1beta, IL-6, and tumor necrosis factor (TNF)-alpha mRNA expression in the iris-ciliary body (ICB) was determined by RNase protection assay (RPA). The levels of these cytokines and nitric oxide (NO) production were also determined. RESULTS: The number of cells in the AqH was 1100 +/- 254 cells/microL in rats injected with LPS and 90 +/- 43 cells/microL in rats pretreated with PDTC (P < 0.001). The concentration of proteins was significantly lower in the AqH of rats pretreated with PDTC than in those without PDTC. The number of activated NF-kappaB-positive cells in the ICB was reduced by the PDTC treatment. The ICB at 6 hours after LPS injection exhibited increased expression of IL-1beta, IL-6, and TNF-alpha mRNAs, which was decreased after PDTC pretreatment. PDTC also significantly diminished the levels of these cytokines and nitrite-nitrate in the AqH. CONCLUSIONS: These results suggest that PDTC reduces ocular inflammation in eyes with EIU by downregulating proinflammatory cytokine expression and by inhibiting the NF-kappaB-dependent signaling pathway.

Animals↗
PubMedDate not supplied

Expression of c-Jun and Bcl-2 family proteins in apoptotic photoreceptors of RCS rats.

PURPOSE: To determine if c-Jun and Bcl-2 family proteins play a role in photoreceptor apoptosis in Royal College of Surgeons (RCS) rats. METHODS: RCS and Sprague-Dawley rats were used. Cryosections of retinas harvested at various postnatal periods were immunostained with antibodies against c-Jun, Bcl-2, and Bax. Double staining with TdT-dUTP nick-end labeling (TUNEL) or propidium iodide (PI) and antibodies was also done. To study the time course of gene and protein expression, semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR) and immunoblotting analyses were carried out. RESULTS: TUNEL-positive photoreceptors of RCS rats were stained strongly with antibodies against c-Jun and Bax. The number of immunoreactive cells increased on days 21 and 28 after birth (P21 and P28) and decreased on P45. Semiquantitative RT-PCR analysis showed that mRNAs for c-Jun and Bax were upregulated at P21 and P28, but those for Bcl-2 were unchanged. On immunoblotting, a 43-kDa band was revealed by the anti-c-Jun antibody and a 21-kDa band, by the anti-Bax antibody. Protein expression of c-Jun and Bax were increased at both P21 and P28. The temporal profiles of immunoreactivity, protein expression, and mRNA expression were similar. CONCLUSION: c-Jun and Bax may play a role in photoreceptor apoptosis in RCS rats.

Animals↗
PubMedDate not supplied

Decreased retinal neuronal cell death in caspase-1 knockout mice.

PURPOSE: To determine whether apoptosis of retinal neurons induced by excessive light exposure and ischemia-reperfusion injury is altered in caspase-1 knockout mice. METHODS: Eight- to 10-week-old caspase-1 knockout mice (Casp1-/-) and wild-type (WT) mice (C57BL/6) were exposed to diffuse, cool, white fluorescent light of 25,000 lux for 2 h. Other mice were subjected to retinal ischemia by increasing the intraocular pressure to 110 mmHg for 45 min. Electroretinograms (ERGs) were recorded before and after the light exposure. TdT-dUTP terminal nick-end labeling (TUNEL) was performed to identify the apoptotic cells after the insults. The inner retinal thickness was measured to evaluate the retinal injury after the ischemia-reperfusion. Expression of caspase-1 protein was studied by immunohistochemical analysis and Western blotting. Caspase-1-like protease activity was determined by a colorimetric tetrapeptide substrate. RESULTS: The morphology of the retina and the amplitudes of the a and b waves of the ERGs of Casp1-/- mice did not differ from those of WT mice. After the light exposure, TUNEL-positive cells were observed in the outer nuclear layer of the WT mice retina. The number of TUNEL-positive photoreceptor nuclei after the light exposure, and the number of nuclei in the inner nuclear layer after the ischemia-reperfusion injury, were significantly less in Casp1-/- mice than in WT mice. There were more caspase-1-positive photoreceptor cells in WT mice after the light injury. The inner retinal layer of Casp1-/- mice was significantly thicker in Casp1-/- mice than in WT mice 2 weeks after the ischemic insult. CONCLUSIONS: Retinal neuronal apoptosis was less prominent in Casp1-/- mice after excessive light exposure and ischemia-reperfusion injury. These data indicate that caspase-1 plays a role in retinal neuronal apoptosis.

Animals↗
PubMedDate not supplied

Orbital amyloidosis-induced compressive optic neuropathy accompanied by characteristic eyelid pigmentation.

The deposition of amyloid protein in orbital tissue is called orbital amyloidosis. Orbital amyloidosis is a rare condition that usually affects older patients. Although the disease is slowly progressive, it rarely involves the optic nerve or threatens vision. We report a case of orbital amyloidosis that initially appeared as impressive eyelid pigmentation and blepharoptosis and then progressed to systemic amyloidosis. The orbital lesion induced compressive optic neuropathy. Surgical management enabled partial but not full recovery of vision.

Amyloidosis↗
PubMedDate not supplied

Neuronal differentiation of hippocampus-derived neural stem cells cultured in conditioned medium of embryonic rat retina.

PURPOSE: To investigate whether conditioned medium from embryonic rat retinas can induce differentiation of adult rat hippocampus-derived neural stem cells (AHSCs) into neurons and glia in vitro. METHODS: AHSCs were cultured in 3 types of media: standard culture medium, conditioned medium from embryonic rat retina, and standard culture medium with retinoic acid. Neuronal and glial differentiation of the cultured cells was assessed by cell growth analysis, flow cytometric analysis, immunofluorescent staining, and RT-PCR analysis. RESULTS: Cells cultured in the standard medium showed very little neuronal and glial differentiation. The cells cultured in the conditioned medium and the medium with retinoic acid showed neuronal morphology and growth inhibition. They also expressed mature neuronal markers and glial markers. In addition, the cells cultured in the conditioned medium expressed Thy-1, HPC-1, and calbindin, which were not found in the previous studies with postnatal retinas in vivo. Those cultured in the medium with retinoic acid expressed HPC-1 and calbindin, but not Thy-1. CONCLUSIONS: Conditioned medium from embryonic rat retina contains factors that induce neuronal and glial cell differentiation of AHSCs, and promote up-regulation of some types of retinal cell markers.

Animals↗
PubMedDate not supplied

Vitreous surgery for bilateral bullous retinal detachment in Vogt-Koyanagi-Harada syndrome.

A successful surgical treatment (vitrectomy) for bilateral bullous retinal detachment in a patient with Vogt-Koyanagi-Harada (VKH) disease is reported. A 78-year-old woman had severe reduction of visual acuity in both eyes because of an extremely bullous nonrhegmatogenous retinal detachment accompanied by VKH disease. We performed lens extraction and vitrectomy on both eyes combined with systemic and topical corticosteroid therapy. The retina was reattached immediately after the surgery and her visual acuity promptly improved in both eyes. She had no recurrence of retinal detachment even after tapering the dose of corticosteroid. We suggest that vitrectomy may be an effective therapeutic option in the treatment for severe bullous retinal detachment associated with VKH disease.

Aged↗