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Kouichi Ohta

Publications and source records attributed to Kouichi Ohta.

14 recordsLinked to original sources
PubMed2007

25-gauge vitrectomy to treat ocular complications of familial amyloid polyneuropathy.

PURPOSE: Secondary glaucoma and vitreous opacity with amyloid fibrils are the 2 major ocular complications of familial amyloid polyneuropathy (FAP). We investigated the feasibility of 25-gauge vitrectomy in excising the opaque vitreous into eyes that had already undergone trabeculectomy. METHODS: For the purpose of vision recovery, 25-gauge vitrectomy was performed in 2 eyes with vitreous amyloidosis. Both eyes had undergone trabeculectomy to treat glaucoma secondary to FAP. The survival of the filtration bleb after 25-gauge vitrectomy was also evaluated. RESULTS: Vision improved dramatically on the next day after the 25-gauge vitrectomy that causes minimal damage to the eye. No apparent complications including failure of the filtration bleb have been observed throughout the follow-up period of 6 months. CONCLUSIONS: 25-gauge vitrectomy has a potential to become a therapy of choice to excise opaque vitreous with amyloid fibrils in FAP, especially in the glaucomatous eyes that have already undergone trabeculectomy.

Amyloid↗
PubMed2005

DNA microarray analysis of gene expression in iris and ciliary body of rat eyes with endotoxin-induced uveitis.

The purposes of this study are to determine the genes that are up- or down-regulated in eyes with endotoxin-induced uveitis (EIU) by an oligonucleotide microarray system, and to determine the temporal and spatial changes in expression of selected genes that show strong up-regulation. EIU was induced by a footpad injection of lipopolysaccharide (LPS) in male Lewis rats. The expression of genes in the iris-ciliary body (ICB) at 2, 6, 12, and 24 hr after LPS injection was determined by oligonucleotide microarray analyses and compared to that in control rats. The microarray displayed 9911 genes and expressed sequence tags (ESTs). Cluster analysis was performed for highly up-regulated genes. Selected genes for cytokines (interleukin (IL)-1 beta and IL-6), chemokines (RANTES), and immediate early genes (Jun B, c-Fos, and c-Jun) were also studied by real-time polymerase chain reaction (PCR). Immunohistochemical studies were performed to localize the protein expression of some immediate early gene products. After LPS injection, the expression of 1930 genes were increased or decreased over 2-folds compared with normal controls by 24 hr. One hundred and seventeen genes were up-regulated over 10-fold, and these were classified into five clusters with similar expression pattern. The immediate early genes and transcription factors genes were included in one cluster of up-regulated genes peaking at 2 hr after the LPS injection. The expressions of cytokines, chemokines, and adhesion molecules were highly up-regulated. Real-time PCR analyses for selected genes showed similar expression changes as detected by the microarray analyses. Jun B immunoreactivity was found in the ICB cells at 3 and 6 hr after LPS injection. Gene expression changes after LPS injection were profiled by using an oligonucleotide microarray system. Our data suggest that the immediate early genes, such as Jun B, play an important role in inducing the inflammatory-related genes in the ICB.

Animals↗
PubMed2005

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephaloapthy (CADASIL): a hereditary cerebrovascular disease, which can be diagnosed by skin biopsy electron microscopy.

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an inherited cerebrovascular disease characterized by recurrent subcortical ischemic strokes starting in the third or fourth decade as a result of mutations in the Notch3 gene. Granular osmiophilic material (GOM) deposition around the vascular smooth muscle cells is a specific feature and electron microscopic observations of skin biopsies are useful for this diagnosis. A 39-year-old female with dizziness, abnormal visual fields, and hemiplegia, and a 42-year-old male with tinnitus and dizziness, were suspected of suffering from CADASIL based on MRI findings. Both cases were shown to have characteristic deposits of GOM, 200 to 800 nm in diameter, around the vascular smooth muscle cells of small arteries in the deep dermis, and thus the diagnoses of CADASIL were made, although there was no family history of cerebrovascular disorders or dementia. Dermatologists should be aware of these ultra-structural findings because this disease may occur sporadically and might be more common than initially thought.

Adult↗
PubMed2004

Heme oxygenase-1 induced in muller cells plays a protective role in retinal ischemia-reperfusion injury in rats.

PURPOSE: To investigate the protective roles played by heme oxygenase (HO)-1 and -2 in the rat retina after ischemia-reperfusion injury. METHODS: Retinal ischemia was induced in rats by increasing the intraocular pressure to 110 mmHg for 60 minutes. The expression of HO-1 and -2 in the retina was determined by Western blot, real-time polymerase chain reaction (PCR), and immunohistochemistry. To inhibit the upregulation of HO-1, short interfering (si)RNA of HO-1 was injected intravitreally before ischemia and that of green fluorescent protein (GFP) was used as the control. Muller cell damage was assessed by counting the number of S-100-positive cells. The number of macrophages invading the retina was determined by counting the number of ED-1-positive cells. RESULTS: The expression of HO-1 mRNA and protein was upregulated at 6 hours after reperfusion and peaked at 12 to 24 hours, whereas that of HO-2 was not altered. HO-1 immunoreactivities were detected in Muller cells at 24 hours after reperfusion, and HO-2 immunoreactivities were detected in retinal cells. The HO-1 expression in the retina treated with siRNA of HO-1 was reduced at 12 and 24 hours after reperfusion compared with that injected with siRNA of GFP. The number of S-100-positive cells at 24 hours after reperfusion decreased significantly in retinas treated with HO-1 siRNA (P <0.01). The number of macrophages that had infiltrated the retina was increased in retinas pretreated with the siRNA of HO-1 compared with those treated with siRNA of GFP. On day 14 after reperfusion, HO-1 siRNA-treated retinas showed severe retinal injury and destruction of the retinal architecture. CONCLUSIONS: HO-1 promotes the survival of Muller cells after ischemia-reperfusion injury. Because inhibition of the upregulation of HO-1 resulted in an infiltration of inflammatory cells and destruction of the retina, the authors conclude that HO-1 induced in Muller cells plays a protective role in retinal ischemia-reperfusion.

Animals↗
PubMed2003

Protective role of heme oxygenase-1 against endotoxin-induced uveitis in rats.

Endotoxin-induced uveitis (EIU) is an animal model of acute ocular inflammation. Cytokines, chemokines, and nitric oxide (NO) have been reported to play important roles. We have determined whether heme oxygenase (HO)-1, a heat shock protein, can suppress EIU. EIU was induced by a footpad injection of lipopolysaccharide (LPS) in male Lewis rats. Hemin, an inducer of HO-1, was injected intraperitoneally 1 hr prior to the LPS injection. HO-1 and HO-2 expression in the iris-ciliary body (ICB) was studied by real time PCR and Western blot analysis. The number of infiltrating cells and the protein concentration in the aqueous humor (AqH) were evaluated by microscopy and by protein assay. The expression of inducible nitric oxide synthase (iNOS), interleukin (IL)-6, tumor necrosis factor (TNF)-alpha, and IL-1beta mRNA was determined by real time PCR. The concentration of nitrate plus nitrite, and levels of IL-6 and TNF-alpha in the AqH were also evaluated by Griess reagents and by enzyme-linked immunosorbent assay, respectively. The expression of HO-1 mRNA and protein, induced by LPS, was enhanced significantly by pre-injection of hemin (P<0.001). HO-2 was constitutively present in the ICB and was not up-regulated by LPS or by hemin. The number of infiltrating cells and the concentration of protein in the AqH was significantly elevated by LPS injection, and hemin significantly reduced the number of cells and the protein concentration (P<0.0001). The expression of iNOS and IL-6 mRNA and protein were down-regulated by hemin (P<0.001). Hemin is effective in inducing HO-1 and in reducing the ocular inflammation induced by LPS probably by down-regulating NO and pro-inflammatory cytokine expression.

Animals↗
PubMed2003

Ocular manifestations in Blau syndrome associated with a CARD15/Nod2 mutation.

PURPOSE: To report cases of Blau syndrome with a CARD15/Nod2 mutation. DESIGN: Observational and interventional case report. PARTICIPANTS: A 10-year-old Japanese boy (proband) was seen with secondary angle-closure glaucoma (iris bombe), uveitis, skin rashes, and camptodactyly. His sister had posterior synechia and camptodactyly. She had iritis in both eyes during the follow-up period. Both eyes of the father were phthisical because of granulomatous uveitis and secondary glaucoma. The father also had camptodactyly. METHODS: Surgery was performed to release the iris bombe. Ocular inflammation was treated by topical and systemic steroids. Biopsy specimens from the skin rash and from the iris (from iridectomy) were obtained from the proband. Genetic analyses were performed on the proband, his sister, and their mother for a CARD15/Nod2 mutation. MAIN OUTCOME MEASURES: Clinical features, pathologic findings of the skin and iris specimens, and genetic analysis of the CARD15/Nod2 gene. RESULTS: Phacoemulsification, intraocular lens implantation, and peripheral iridectomy released the iris bombe. The biopsy specimen from the skin rash showed noncaseating, granulomatous infiltration with epithelioid cells and lymphocytes. The iridectomy specimen showed nonspecific inflammation. Systemic and topical steroid therapy partly reduced the ocular inflammation. Genetic analyses showed that the proband and his sister had an R334W mutation in the CARD15/Nod2 gene, but their mother was of the wild type. CONCLUSIONS: Blau syndrome should be considered in the differential diagnosis of childhood uveitis. Genetic analysis of the CARD15/Nod2 gene is helpful in the diagnosis.

Arthritis↗
PubMed2002

Chemokine gene expression in iris-ciliary body during experimental autoimmune uveoretinitis.

PURPOSE: To evaluate, through differential gene expression of chemokines in iris-ciliary body (I/CB), the extent to which leukocyte recruitment to the ocular anterior segment participates in the pathogenesis of experimental autoimmune uveoretinitis (EAU) in mice. METHODS: B10.A mice were immunized with 50 microg of interphotoreceptor retinoid binding protein (IRBP) mixed with complete Freund's adjuvant. Aqueous humor (AqH) was collected at 0, 11, 17, and 28 days and assayed for leukocyte content and protein levels. Enucleated eyes were subjected to histologic analysis. Chemokine gene expression in I/CB was determined at these same time points by a multiprobe ribonuclease protection assay (RPA) system. RESULTS: Inflammation was detected in the anterior chamber (AC) at 11 days and leukocyte recruitment continued thereafter. Polymorphonuclear neutrophils (PMN) were the predominant cell type in the AC, whereas macrophages/monocytes and lymphocytes were predominant in the retina/subretinal space at 17 days. Peak gene expression of macrophage inflammatory protein (MIP)-1alpha, MIP-1beta, and MIP-2 and interferon-gamma-inducible protein of 10 kd (IP-10) was detected in I/CB on day 11, whereas peak expression of RANTES and eotaxin was observed at 17 days. CONCLUSIONS: Early I/CB peak expression of mRNA for MIP-2 followed by PMN recruitment into the AC, suggests that PMN may play an important role in EAU pathogenesis.

Aging↗
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

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

Ocular immune privilege and the impact of intraocular inflammation.

Immune privilege, a characteristic of the internal compartments of the eye, is a physiologic mechanism that is designed to provide the eye with protection against pathogens while protecting the delicate visual axis from the sight-destroying potential of immunogenic inflammation. It is assumed that the presence of intraocular inflammation is incompatible with the existence of immune privilege. The validity of this assumption has been tested in four animal models of intraocular inflammation-systemic and local endotoxin-induced uveitis (EIU), mycobacterial adjuvant-induced uveitis (MAIU), and experimental autoimmune uveitis (EAU). Immune privilege was assessed in inflamed eyes by growth of intracamerally injected allogeneic tumor cells, by the capacity to support immune deviation following intracameral injection of antigen (ovalbumin, OVA), by assaying protein, leukocyte, and selected cytokine content of aqueous humor (AqH), and by capacity of inflamed AqH to suppress T cell activation in vitro. The results indicate that, irrespective of the type of inflammation, tumor cells formed progressively growing tumors in inflamed eyes. Moreover, OVA injected into the anterior chamber of eyes inflamed by MAIU and EAU failed to induce immune deviation. AqH from inflamed eyes reflected breakdown of the blood:ocular barrier as well as transient loss of its immunosuppressive properties. Immunosuppressive microenvironments routinely reemerged in inflamed eyes, and the immunosuppressive agent present under these circumstances in AqH was active TGF beta2. It is concluded that immune privilege is surprisingly resistant to abolition by intraocular inflammation, and that maintenance of immune privilege in the face of ongoing inflammation depends upon the emergence of progressive and partially different immunosuppressive mechanisms.

Animals↗
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↗