Hiroyuki Namba

Yamagata University, Ямагата, Yamagata, Japan

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Publications (4)6.45 Total impact

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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: 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