Hiroyuki Namba

Yamagata University, Ямагата, Yamagata, Japan

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Publications (6)9.99 Total impact

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    ABSTRACT: Purpose: To investigate the relationship between age and ocular higher-order wavefront aberrations (HOAs) in an adult Japanese population, as well as factors associated with HOA variations. Methods: In the Yamagata Study (Funagata) cohort, 227 adult Japanese participants (aged 37-86 years) were recruited, and they underwent systemic and ophthalmologic examinations in 2012. Ocular, corneal, and internal HOAs were measured. From the Zernike coefficients, we calculated the root mean square of the total HOA, coma, and spherical aberration for a pupil diameter of 4 mm. Linear regression analyses were used to determine whether HOAs were associated with age or other factors. Results: Multiple adjusted linear regression analyses demonstrated that all components of logarithmic HOAs increase with age. Ocular, corneal, and internal HOAs increased by 0.012/year (P < 0.001), 0.007/year (P = 0.010), and 0.014/year (P < 0.001), respectively. Ocular coma also significantly increased with age (0.010/ year, P = 0.007), but corneal (P = 0.963) and internal (P = 0.476) coma did not. Age-related spherical aberration increased only in the internal component (0.019/year, P = 0.001). In addition to age, ocular and corneal HOAs were mainly affected by corneal indexes. Conclusion: Age is associated with increases in ocular HOAs, independent of other possible confounding factors. Associations of ocular HOAs with corneal parameters indicate that ocular HOAs are mainly generated by the cornea. Internal HOAs, supposedly generated from cataract progression, may be associated with systemic factors, including serum creatinine and blood pressure. Copyright © 2014 by Association for Research in Vision and Ophthalmology.
    Investigative ophthalmology & visual science. 12/2014;
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    ABSTRACT: The aim of this study was to examine the efficacy and surgical success rates of amniotic membrane (AM) transplantation performed for corneal perforation closure using a novel technique. This study included 6 eyes from 6 patients with corneal perforation who had received AM transplantation between May 2011 and April 2012. The AM was collected from human placenta shortly after cesarean section. In surgery, the AM was folded into pleats and used to plug the wound using 10-0 nylon suture. The wound was then covered with an AM seal. After reepithelialization and AM scarring, sutures were removed. All 6 patients had successful wound closure with 1 surgery. One patient underwent optical keratoplasty later, and 1 patient required combined preserved sclera transplantation. The absolute value of astigmatism decreased to <3.50 diopters (D) 3 months after surgery and to <3.00 D 6 months after surgery in patients with peripheral AM transplants. The visual acuity gradually improved over the first 3 months after surgery, and visual acuity gains were maintained at the 6-month postoperative mark. The AM transplantation procedure may be an effective option for treating corneal perforations when the wound is circular or irregular, except for incised wounds. Our "Pleats Fold" AM transplantation technique can achieve definite closure and effectively repair wounds of various sizes. Postoperative astigmatic values were acceptable. Therefore, we recommend this procedure for repairing lesions <3 mm in diameter that do not involve the central cornea and that are infection free.
    Cornea 04/2014; · 1.75 Impact Factor
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    ABSTRACT: Compared with the peripheral corneal limbus, the human central cornea lacks blood vessels, which is responsible for its immunologically privileged status and high transparency. Dendritic cells (DCs) are present in the central avascular area of inflamed corneas, but the mechanisms of their migration to this location are poorly understood. Here, we investigated the contribution of vessel formation to DC migration into the central cornea, and analyzed the DC chemotactic factors produced by human corneal epithelial (HCE) cells. Using human eyes obtained from surgical procedures, we then assessed vessel formation, DC distribution, and activin A expression immunohistochemically. The results demonstrated increased numbers of vessels and DCs in the central area of inflamed corneas, and a positive correlation between the number of vessels and DCs. Activin A was expressed in the subepithelial space and the endothelium of newly formed blood vessels in the inflamed cornea. In infected corneas, DCs were present in the central area but no vascularization was observed, suggesting the presence of chemotactic factors that induced DC migration from the limbal vessels. To test this hypothesis, we assessed the migration of monocyte-derived DCs toward HCE cell supernatants with or without lipopolysaccharide (LPS) stimulation of HCE cells and inflammatory cytokines (released by HCE cells). DCs migrated toward tumor necrosis factor alpha (TNF-α), interleukin (IL)-6, and activin A, as well as LPS-stimulated HCE cell supernatants. The supernatant contained elevated TNF-α, IL-6, and activin A levels, suggesting that they were produced by HCE cells after LPS stimulation. Therefore, vessels in the central cornea might constitute a DC migration route, and activin A expressed in the endothelium of newly formed vessels might contribute to corneal vascularization. Activin A also functions as a chemotactic factor, similar to HCE-produced TNF-α and IL-6. These findings enhance our understanding of the pathophysiology of corneal inflammation during infection.
    PLoS ONE 01/2014; 9(10):e109859. · 3.53 Impact Factor
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    ABSTRACT: To describe the pathophysiological findings of a patient with pemphigus vulgaris (PV) showing giant conjunctival papillae. A 64-year-old man who had mucosal-dominant PV with giant conjunctival papillae, resembling those of vernal keratoconjunctivitis (VKC), underwent an ophthalmological workup. The clinical and pathological findings were investigated. Ophthalmic interventions were unable to provide the desired beneficial effects, and multiple excisions were necessary to remove the proliferative conjunctival lesions. Histopathological investigations of the excised tissues demonstrated acantholysis and a subconjunctival infiltration with numerous inflammatory cells such as lymphocytes, plasma cells, and neutrophils. However, in contrast to typical VKC, mast cells and eosinophils were rarely found in the subconjunctival tissues. Direct immunofluorescent staining showed a significant deposition of immunoglobulin G and complement component 3 in the epithelial intercellular substance, consistent with mucosal-dominant PV. Then, the patient was hospitalized because of oral erosion exacerbation and malnutrition. Because of the patient's declining general condition, we administered an increasing dose of a systemic steroid with an intravenous immunoglobulin, after which his ocular lesions and symptoms improved. The histological conjunctival papilla findings were quite different from those of VKC papillae. If PV causes a lesion in a patient, systemic immunosuppression might be more effective than topical ophthalmic treatment because of overall immunological involvement.
    Case reports in ophthalmology. 01/2013; 4(3):114-21.
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    ABSTRACT: The responses of corneal and scleral stromal cells to platelet-derived growth factor (PDGF)-BB were assessed and inflammatory reactions in the cornea and sclera were investigated. Primary cultures of cells obtained from human subjects and strains derived from human corneal or scleral stromal cells (Cs3 and Sc1, respectively) were used. Changes in gene expression after 24 hours of exposure to 10 ng/mL PDGF-BB were analyzed with an Sc1 DNA microarray. The upregulation of several genes in Cs3 and Sc1 was confirmed by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot analysis. The expression of bioactive factors was detected immunohistochemically in nine different clinical specimens. DNA microarray analysis revealed that the gene encoding thrombomodulin (TM) was induced in Sc1 by PDGF-BB. RT-PCR confirmed that TM expression at the mRNA level was increased in both corneal and scleral stromal cells. At the protein level, TM expression was increased in scleral stromal cells, but not in corneal cells, and TM was detected in both the membrane and cytoplasmic compartments. TM was detected immunohistochemically in inflamed scleral and several corneal specimens. After TM stimulation, interleukin (IL)-18 transcription was increased in Sc1. PDGF-BB induced TM mRNA expression in scleral and corneal stromal cells, but Western blot analysis revealed the increase in TM expression only in the scleral cells. TM induced IL-18 in scleral stromal cells. A cascade involving these biologically active factors may regulate scleral and corneal inflammation. The results also reveal differences in the biological response of scleral and corneal stromal cells.
    Investigative ophthalmology & visual science 11/2010; 51(11):5460-9. · 3.43 Impact Factor
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    ABSTRACT: To establish human corneal stroma- and sclera-derived cells as models for studying diseases of the anterior segment of the eye. Using a recombinant retrovirus system, we transfected human papilloma virus 16 E6 and E7 (HPV16 E6/E7) into human corneal stroma- and sclera-derived cells. The primary cells and established cell strains were characterized by assessing the mRNA expression of collagen, matrix metalloproteinase, and tissue inhibitor of metalloproteinase by reverse transcription-polymerase chain reaction. We also examined the effects of inflammatory cytokines on hyaluronan synthase expression and hyaluronan products. Both a corneal stroma-derived cell strain, Cs3, and a sclera-derived cell strain, Sc1, were obtained, and both cell strains could be passaged up to 25 times. The mRNA expression pattern observed in the primary cells was identical to that observed in the cell strains. Hyaluronan synthase 1 and 2 mRNAs were increased by transforming growth factor beta and platelet-derived growth factor BB. Significant differences were observed between the hyaluronan products with and without cytokine treatment. Cell strains derived from corneal stroma and sclera fibroblast cells can be established using HPV16 E6/E7 immortalized genes of the same origin. The phenotypic cell characteristics did not change after transfection, immortalization, or successive passages in culture.
    Japanese Journal of Ophthalmology 01/2010; 54(1):74-80. · 1.27 Impact Factor