Biomedical subjects

Shiro Amano

Publications and source records attributed to Shiro Amano.

At least 37 records · Page 2Linked to original sources

PubMed2005

Corneal irregular astigmatism after hyperopic laser in situ keratomileusis.

PURPOSE: To evaluate the changes in irregular astigmatism after hyperopic laser in situ keratomileusis (LASIK). METHODS: In a prospective case series, 15 eyes of 12 patients who had hyperopic LASIK were evaluated. Corneal topography was obtained before and after hyperopic LASIK. Corneal irregular astigmatism (asymmetry and higher-order irregularity) was calculated using Fourier harmonic analysis of the topography data. RESULTS: Hyperopic LASIK significantly increased the asymmetry component at 3 (P = 0.0085) and 6 months (P = 0.0307) postoperatively. The mean higher-order irregularity was not significantly changed at any postoperative time-point (P = 0.222). The achieved change in the spherical equivalent was significantly correlated with the post/preoperative ratio of asymmetry (R = 0.695, P = 0.0030). CONCLUSION: Hyperopic LASIK significantly increases the asymmetry component of the cornea, which is correlated with the achieved change in the spherical equivalent.

Adult↗

PubMed2005

Corneal endothelial cell protection with Viscoat and Healon or Healon alone during penetrating keratoplasty.

PURPOSE: To determine the influence of dispersive ophthalmic viscosurgical products (OVPs) on corneal endothelial cell (CEC) density during penetrating keratoplasty (PKP) and on the postoperative intraocular pressure (IOP). METHODS: In 117 eyes of 113 patients, PKP was performed by a single surgeon from April 1, 1998 to April 30, 2002. Loss of CECs and postoperative IOP were evaluated retrospectively after use of Viscoat (sodium hyaluronate 3.0%, chondroitin sulfate 4.0%) plus Healon (sodium hyaluronate 1.0%) (Viscoat/Healon group) or Healon alone (Healon group) during surgery. RESULTS: The average CEC loss was 14.6 +/- 15.5% and 9.0 +/- 10.5% at 1 month, 18.1 +/- 14.6% and 10.1 +/- 7.3% at 3 months, 20.1 +/- 16.3% and 12.2 +/- 10.9% at 6 months, and 31.7 +/- 21.4% and 18.1 +/- 15.5% at 12 months in the Healon (n = 74) and Viscoat/Healon (n = 43) groups, respectively. Patients were stratified into groups with corneal leukoma (n = 61) or bullous keratopathy (n = 56). Loss of CECs was significantly smaller in the Viscoat/Healon group compared with the Healon group irrespective of whether patients had corneal leukoma or bullous keratopathy at 3, 6, and 12 months postoperatively. There was no significant difference of postoperative IOP between the Healon and Viscoat/Healon groups over 12 months of follow-up. CONCLUSION: These results suggest that the addition of Viscoat to Healon decreases CEC loss during PKP and does not affect postoperative IOP.

Adjuvants, Immunologic↗

PubMed2005

Intraocular pressure measurement over amniotic membrane patch in human subjects.

PURPOSE: To investigate the accuracy of intraocular pressure (IOP) measurement over amniotic membrane patching on human ocular surface using Tono-Pen tonometry. METHODS: The IOP of 28 normal eyes in 14 volunteers (mean age, 27.6 years; range, 25-34) was measured by a handy applanation tonometer and the Tono-Pen XL. Then, a single layer of amniotic membrane (approximately 50 microm) was placed onto the corneal surface of the volunteers and the IOP was again measured using the Tono-Pen XL. RESULTS: The average IOP using handy applanation tonometry and the Tono-Pen was 14.3 +/- 2.1 and 14.3 +/- 2.4 mm Hg, respectively. In the presence of amniotic membrane, the average IOP was not significantly overestimated (14.7 +/- 2.6 mm Hg). The bias between handy applanation tonometry or the Tono-Pen XL without amniotic membrane and the Tono-Pen XL with amniotic membrane was only -0.40 and -0.18 mm Hg, respectively. CONCLUSIONS: The Tono-Pen XL is accurate and useful for IOP monitoring even in eyes with amniotic membrane patching.

Adult↗

PubMed2005

Bone marrow-derived cells in mouse and human cornea.

Recently published experimental data on the distribution of bone marrow (BM)-derived cells in human and mouse corneas in comparison with in human skin/oral mucosa are reviewed. In mouse corneal epithelium, major histocompatibility complex (MHC) class II-negative dendritic cells (DC) are present. Immature MHC class II-negative and mature MHC class II-positive DC are present in the center and periphery of the anterior corneal stroma, respectively. Monocyte (Mo)/macrophage (MPhi) lineage cells including the MPhi marker F4/80-expressing cells reside in the posterior stroma. In human cornea, MHC class II (HLA-DR)-positive immature myeloid DC (CD11cCD16, CD11cCD16, and CD11cCD1c) and Mo/MPhi lineage cells are detectable in the corneal epithelium and stroma, respectively. Distribution of Mo/MPhi lineage cells (HLA.DRCD11bCD11cCD14) is predominant in the anterior stroma of the central cornea and all layers of the peripheral cornea. Both the phenotypes and distribution pattern of these cells in human cornea are different from those of human skin and nasal mucosa. These findings suggest that BM-derived cells in normal human cornea are present in situ in preparation for foreign antigen and pathogens and have critical roles in innate and acquired immunity of the ocular surface.

Animals↗

PubMed2005

New drug delivery for corneal neovascularization using polyion complex micelles.

PURPOSE: To introduce photodynamic therapy (PDT) for corneal neovascularization (NV) by polyion complex (PIC) micelles, a novel drug delivery system. METHODS AND RESULTS: Development of specific drug delivery systems to corneal NV sites is an important part of next-generation photodynamic therapy. Nanocarriers consisting of PIC micelles bound by polyethylene glycol (PEG) shell exhibit good stability, high drug-loading capacity, and excellent potential for controlled drug release. Encapsulation of the photosensitizer dendrimer porphyrin (DP) into PIC micelles (DP-micelles) conveys adequate stability and increased photocytotoxicity without compromising photophysical properties of DP stability. We assessed the accumulation of DP-micelles and observed that the DP-micelles were incorporated into the corneal NV area. CONCLUSIONS: PIC micelles possess attractive features of selective accumulation at the corneal NV site. PDT using DP-micelles appears to be effective and safe for the treatment of corneal NV.

Animals↗

PubMed2005

Management of subconjunctival haematoma by tissue plasminogen activator.

A patient with subconjunctival haematoma related to enterovirus 70 who was treated with tissue plasminogen activator (tPA) is reported. A 46-year-old man developed a severe subconjunctival haematoma and discharge in the left eye. Investigations, including coagulation tests, showed no abnormalities apart from a high-serum antibody titre for enterovirus 70. The polymerase chain reaction demonstrated enterovirus 70 DNA in resected conjunctival tissue, leading to a diagnosis of acute haemorrhagic conjunctivitis. The left eye was treated with a single subconjunctival injection of tPA (16 000 IU) and the subconjunctival haematoma resolved completely after 3 days. Severe subconjunctival haematoma can occur in patients with acute haemorrhagic conjunctivitis due to enterovirus 70. Subconjunctival injection of tPA may be useful for the treatment of severe subconjunctival haematoma.

Conjunctivitis, Acute Hemorrhagic↗

PubMed2005

Vasovagal syncope evoked by needle phobia when inserting a contact lens.

PURPOSE: To report a patient who fell unconscious because of vasovagal syncope evoked by needle phobia when he tried to wear contact lenses. CASE REPORTS: A 16-year-old healthy boy had sometimes experienced dizziness when looking at the tips of pens. When he put his finger and the lens close to his eye to insert a soft contact lens, he felt sick and dizzy and fell unconscious. CONCLUSION: Our experience suggests that patients with needle phobia may develop vasovagal syncope by concentrating on a fingertip when inserting a contact lens. We need to be aware of unconsciousness because of phobia when trying to insert contact lenses.

Adolescent↗

PubMed2005

Sphere formation and expression of neural proteins by human corneal stromal cells in vitro.

PURPOSE: To demonstrate the presence of corneal stromal precursors that express neural markers in vitro. METHODS: To isolate sphere-forming cells, human corneal stromal cells were subjected to a reaggregation-free neurosphere assay in medium containing methylcellulose gel matrix. To promote differentiation, the isolated sphere colonies were plated in wells with medium containing fetal bovine serum. Expression of nestin, vimentin, keratocan, alpha-smooth muscle actin (alphaSMA), beta-III tubulin, neurofilament M (NFM), and glial fibrillary acidic protein (GFAP) was examined in the sphere colonies and their progeny (i.e., cells migrated from sphere colonies), by immunocytochemistry and/or reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: Human corneal stromal cells formed sphere colonies that had no self-renewal capability. The frequency of sphere-forming cells was 1.5% +/- 0.1% (range, 1.3%-1.6%). Most of the cells within these colonies expressed nestin and vimentin, whereas some expressed beta-III tubulin, NFM, GFAP, and alphaSMA by immunocytochemistry. Ninety-one percent and 89% of the progeny expressed vimentin and alphaSMA, respectively, whereas nestin was undetectable. beta-III tubulin-, NFM-, and GFAP-positive cells were detected in the progeny at the frequency of 7.2%, 0.9%, and 0.5%, respectively. Semiquantitative RT-PCR showed that nestin, NFM, GFAP, and keratocan gene expression was higher in the sphere colonies, whereas vimentin and alphaSMA expression increased in the progeny. CONCLUSIONS: Adult human corneal stroma contains precursor cells that express neural markers.

Adult↗

PubMed2005

Human corneal endothelial cell precursors isolated by sphere-forming assay.

PURPOSE: To isolate precursors of human corneal endothelial cells (HCECs) in vitro. METHODS: HCECs were subjected to a sphere-forming assay in which spheres floated in serum-free medium containing growth factors. To promote differentiation, the isolated sphere colonies were plated in dishes coated with poly-L-lysine (PLL)/laminin or fetal bovine endothelium extracellular matrix. Marker expression of neural and mesenchymal cells was examined in the sphere colonies and their progenies by immunocytochemistry and/or reverse transcription-polymerase chain reaction (RT-PCR). Adherent differentiated cells from the sphere colonies were evaluated morphologically and functionally. RESULTS: HCECs formed primary and secondary spherical colonies, as shown by sphere-forming assay in vitro. The colonies expressed nestin, beta3-tublin, glial fibrillary acidic protein, and alpha-smooth muscle actin on immunocytochemistry. The progeny, proliferating on extracellular matrix derived from bovine corneal endothelium, but not on PLL/laminin-coated and noncoated dishes, expressed nestin and beta3-tublin. These markers were confirmed by RT-PCR. Adherent differentiated cells from the sphere colonies had an HCEC-like hexagonal shape and satisfactory transport activity that is essential in HCECs. CONCLUSIONS: These findings indicate that the HCEC contains precursor cells with a propensity to differentiate into HCECs and that these cells can also produce neuronal and mesenchymal cell proteins.

Actins↗

PubMed2005

Distinct populations of dendritic cells in the normal human donor corneal epithelium.

PURPOSE: To characterize dendritic cells (DC) in normal human corneal epithelium. METHODS: Normal human donor corneal epithelium was examined by fluorescence microscopy with single and double staining for multiple markers. Morphologic studies were also performed by confocal microscopy. HLA-DRa, CD1c, and CD16 mRNA expression in the corneal epithelium was examined by RT-PCR. CD45+ cells were separated from the corneal epithelium with magnetic beads and then were stimulated with TNF-alpha and lipopolysaccharide in vitro. RESULTS: CD45+ cells were mainly located in the basal-cell layer of the corneal epithelium and partly in the wing/surface layers. CD45-positive cell numbers were significantly higher in the peripheral cornea (3-6 mm from the center) than in the central cornea (0-3 mm from the center). All these cells expressed HLA-DR and CD11c but not CD3, CD11b, CD14, CD19, CD56, or CD66, suggesting that these were bone marrow-derived myeloid DC. Some DR+CD11c+ DCs from the periphery expressed CD1c and CD16. HLA-DRa, CD1c, and CD16 mRNAs were detected in normal corneal epithelium. These CD11c+ DCs did not express CD123, CD1a, DC marker (CMRF56), CD40, CD80, or CD86. When CD45+ cells were isolated from the corneal epithelium by magnetic cell sorting, CD40 and CD86 expression were detected after in vitro stimulation with TNF-alpha and lipopolysaccharide. CONCLUSIONS: These findings demonstrate that normal human corneal epithelium contains at least three DC phenotypes, with HLA-DR+ myeloid lineage CD11c+CD16- DCs as the main population plus a small number of CD11c+CD16+ DCs and CD11c+CD1c+ DCs. These cells can be discriminated from bone marrow-derived cells in the human corneal stroma.

Aged↗

PubMed2005

Sphere therapy for corneal endothelium deficiency in a rabbit model.

PURPOSE: To isolate precursor cells derived from rabbit corneal endothelium (CE) and to use them for the treatment of CE deficiency in a rabbit model. METHODS: A sphere-forming assay was performed to isolate precursor cells from rabbit CE. Immunocytochemistry was used to examine marker expressions of neural and mesenchymal cells in the sphere colonies and their progenies. The pump function of the CE sheet was evaluated by measurement of the potential difference and short circuit current. Precursors obtained from rabbit CE by a sphere-forming assay were injected into the anterior chamber of the eye, after which an eye-down (i.e., CE up) position was maintained for 24 hours to allow attachment by gravitation (sphere eye-down group). The sphere eye-down and control groups, observed for 28 days after surgery, underwent histologic and fluorescence microscopic examinations. RESULTS: Rabbit CE formed primary and secondary sphere colonies. The progeny expressed alpha-smooth muscle actin, nestin, and neural markers and showed a CE-like hexagonal shape and adequate transport activity. Mean corneal thickness in the sphere eye-down group was significantly less than in the other control groups 3, 7, 14, 21, and 28 days (P < 0.05) after surgery. CE-like hexagonal cells were detected on Descemet's membrane, and corneal edema was substantially suppressed. DiI-labeled cells were spread over the rear corneal surface in the sphere eye-down group only. CONCLUSIONS: Precursors from rabbit CE were isolated by a sphere-forming assay. Rabbit CE-derived sphere therapy is an effective treatment in a rabbit CE deficiency model.

Actins↗

PubMed2005

Treatment of rabbit bullous keratopathy with precursors derived from cultured human corneal endothelium.

PURPOSE: To establish a method for the mass production of human corneal endothelium (HCE) precursors and the therapeutic application of these cells in a rabbit CE-deficiency model. METHODS: A sphere-forming assay was performed to produce precursors from cultured HCE. Various marker expressions were examined in the sphere colonies, and their progenies by immunocytochemistry and reverse transcription-polymerase chain reaction (RT-PCR). The transport activity of the sphere-derived cell sheet was evaluated by the Ussing chamber system. DiI-labeled precursors obtained from cultured HCE were injected the anterior chamber of the eye in a rabbit CE-deficiency model, and the eye-down position was maintained for 24 hours for attachment to Descemet's membrane (sphere eye-down group). The sphere eye-down and control groups, observed for 28 days after surgery, underwent histologic and fluorescence microscopic examinations. RESULTS: Cultured HCE formed primary and secondary sphere colonies. The spheres expressed alpha-smooth muscle actin and nestin, and progeny expressed alpha-smooth muscle actin, confirmed by RT-PCR. The progeny showed an HCE-like hexagonal shape, were confluent, and had adequate transport activity. Mean corneal thickness in the sphere eye-down group was significantly less than in the other control groups 14, 21, and 28 days (P < 0.006) after surgery. The HCE-like hexagonal cells detected on the Descemet's membrane are DiI-positive in the sphere eye-down group. CONCLUSIONS: The findings demonstrate that culture of HCE can promote mass production of HCE precursors, determined by sphere-forming assay. Injection of precursors derived from cultured HCE into the anterior chamber is an effective treatment strategy for CE deficiency in a rabbit model.

Actins↗

PubMed2005

Comparison of rabbit corneal endothelial cell precursors in the central and peripheral cornea.

PURPOSE: To compare the distribution and self-renewal capacity of rabbit corneal endothelial cell precursors in the central and peripheral regions of the cornea. METHODS: The corneal endothelium (CE) and Descemet's membrane of New Zealand White rabbit corneas were divided into a peripheral region (6.0-10.0 mm in diameter) and a central region (6.0 mm in diameter). Then a sphere-forming assay was performed to isolate precursors from the CE of each region. Numbers of primary and secondary sphere colonies and sizes of primary spheres were compared between the central and peripheral regions. RESULTS: Primary spheres were isolated from the peripheral and the central regions of the CE. The rate of primary sphere formation in the peripheral region (34.4 +/- 10.4/10,000 cells) was significantly higher than in the central cornea (26.8 +/- 6.6/10,000 cells; P = 0.0042), but there was no significant difference in the size of primary spheres between the two regions. Self-renewal capacity was higher in the peripheral region than in the central region, as evidenced by a significantly higher secondary sphere formation rate for cells from the periphery (39.0 +/- 8.8/10,000 cells) compared with that for cells from the central region (25.4 +/- 4.2/10,000 cells; P = 0.00028). CONCLUSIONS: These findings demonstrate that peripheral and central rabbit corneal epithelia contain a significant number of precursors but that the peripheral endothelium contains more precursors and has a stronger self-renewal capacity than the central region.

Animals↗

PubMed2005

[Clinical results of amniotic membrane transplantation in Miyata Eye Hospital according to surgical methods].

PURPOSE: To evaluate clinical results of amniotic membrane transplantation according to three methods : graft, patching, and stuffing. SUBJECT AND METHODS: We retrospectively reviewed 65 patients(65 eyes) who received amniotic membrane transplantation by the three methods, graft, patching or stuffing during the period of March 1998 to May 2003 in the Miyata Eye Hospital. Application of surgery was determined as follows : graft with limbal transplantation for limbal dysfunction, patching for prolonged epithelial defect, and stuffing for corneal perforation. The criteria of success were defined as corneal and conjunctival epithelialization and prevention of invasion of proliferative tissues beyond the limbus for graft, corneal epithelialization for patching, and occlusion of perforated cornea at first use for stuffing, respectively.

Adult↗

PubMed2004

Gene expression profile in corneal neovascularization identified by immunology related macroarray.

PURPOSE: To identify differentially expressed genes in corneal neovascularization using cDNA macroarray. METHODS: Mechanical denudation of corneal and limbal epithelium was performed to induce corneal vascularization in mice. Corneas were harvested 4 days after operation. Total RNA was isolated from both normal and vascularized corneas and used for the synthesis of cDNA probes. 32P labeled exponential cDNA probes were hybridized to mouse cDNA immunology arrays. To validate the gene expression patterns revealed by the cDNA expression array analysis, semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) and statistical analysis were performed to compare the normal and vascularized corneal samples. RESULTS: Of 545 immunology related genes on the arrays, 6 genes were upregulated and 1 gene was downregulated in the vascularized corneas compared with the normal corneas. Semi-quantitative RT-PCR was performed on the 6 genes selected in the arrays study, and showed that calreticulin (calregulin), apolipoprotein E, HSP84 (HSP90beta), and pleiotrophin were upregulated while interferon regulatory factor-1 was downregulated in the vascularized corneas compared with the normal corneas. These genes possess a number of biological functions including molecular chaperon, growth factor, and transcriptional factors. CONCLUSIONS: The differentially expressed genes newly identified in the context of corneal neovascularization represent novel candidate factors for further functional studies of the mechanisms of corneal neovascularization. Our data may provide new insight into the biological process of inflammation induced corneal neovascularization.

Animals↗

PubMed2004

Limitation of Scheimpflug videophotography system in quantifying posterior capsule opacification after intraocular lens implantation.

PURPOSE: To assess the applicability of Scheimpflug videophotography system for the quantitative comparison of posterior capsule opacification after intraocular lens (IOL) implantation of different materials. DESIGN: Retrospective, nonrandomized, interventional case series. METHODS: Three groups (n = 15 eyes, each) underwent cataract surgery with implantation of acrylic, silicone, or hydrogel IOL. One year after surgery, the scatter light density at the anterior IOL surface level was measured using EAS-1000. Another three groups (n = 32 eyes, each) received acrylic, silicone, or hydrogel lens. One week after surgery, the scatter light density at the posterior capsule was measured. RESULTS: Scatter light density at the anterior IOL surface 1 year after implantation was 7.5 +/- 3.0 computer-compatible tape (CCT) steps in the acrylic group, 6.0 +/- 2.3 CCT steps in the silicone group, and 5.0 +/- 3.2 CCT steps in the hydrogel group; the density in the acrylic group was significantly greater than that in the hydrogel group (P =.026). Scatter light density at the posterior capsule level 1 week after surgery was 28.3 +/- 8.9 CCT steps in the acrylic group, 22.2 +/- 2.0 CCT steps in the silicone group, and 26.7 +/- 6.7 CCT steps in the hydrogel group; there was a significant difference between the acrylic and silicone groups (P =.0005) and between the silicone and hydrogel groups (P =.008). CONCLUSIONS: The IOL material significantly influences the scatter light density measurements of Scheimpflug videophotography system, and thus the intensity of posterior capsule opacification quantified by this system cannot be directly compared with different optic materials.

Acrylic Resins↗

PubMed2004

Age-related changes in corneal and ocular higher-order wavefront aberrations.

PURPOSE: To investigate age-related changes in ocular and corneal higher-order wavefront aberrations and elucidate relative contributions of the cornea and the lens in the age-related changes. DESIGN: Observational case series. METHODS: Corneal and ocular higher-order wavefront aberrations in the central 6 mm diameter were measured with videokeratography and the Hartmann-Shack wavefront aberrometer in 75 normal eyes of 75 patients with a mean age of 43.5 +/- 11.7 years (range, 18-69 years). Higher-order wavefront aberrations were calculated with Zernike polynomials up to sixth order. From the Zernike coefficients, we calculated root mean square (RMS) of coma and spherical aberration. To examine age-related changes of the polarity of spherical aberration, the changes of the Zernike coefficient Z(4)(0) was also investigated. RESULTS: Both corneal (r =.307, P =.007) and ocular (r =.334, P =.0033) coma RMS showed positive correlations with age. There was a positive correlation between corneal and ocular coma RMS (r =.468, P <.0001). The RMS of corneal spherical aberration did not change with aging (r =.153, P =.1895), whereas the RMS of ocular spherical aberration had a positive correlation with aging (r =.308, P =.0068). CONCLUSIONS: These results suggest that the ocular coma increases with age, mainly because of the increase in the corneal coma, and the ocular spherical aberration increases with age, mainly because of the increase in the spherical aberration in the internal optics.

Adolescent↗

PubMed2004

Transplantation of corneas reconstructed with cultured adult human corneal endothelial cells in nude rats.

PURPOSE: The feasibility of corneal reconstruction with cultured adult human corneal endothelial cells (HCEC) was examined in a nude rat model. METHODS: Endothelial cells were removed from the corneas of Lewis rats using a sterile cotton swab. Cultured adult HCEC labelled with a fluorescent marker chloromethyl-benzamidodialkylcarbocyanine (CM-Dil) were seeded onto the denuded Descemet's membrane. Then the corneas were centrifuged, incubated for 2 days, and transplanted into the eyes of nude rats using the penetrating keratoplasty technique (HCEC group). Control nude received corneas denuded of endothelium and without HCEC. The operated eyes were observed for 28 days after transplantation, and then were subjected to histological and fluorescein microscopic examination. RESULTS: The mean corneal thickness was significantly smaller in the HCEC group than in the control group throughout the observation period. The corneal endothelial cell density of the grafts at 28 days postoperatively ranged from 2425 to 3250 cells mm(-2) (mean+/-sd, 2744+/-337 cells mm(-2)). Fluorescein microscopy at 28 days after surgery showed numerous DiI-labelled cells on the posterior corneal surface in the HCEC group. Frozen sections showed a monolayer of DiI-labelled cells on Descemet's membrane. CONCLUSIONS: Cultured adult HCEC function well and maintain corneal transparency for 1 month after transplantation in nude rats.

Adult↗