Biomedical subjects

Tohru Sakimoto

Publications and source records attributed to Tohru Sakimoto.

9 recordsLinked to original sources

PubMed2006

Laser eye surgery for refractive errors.

Several laser and non-laser refractive surgical procedures have been used to modify the shape of the cornea and correct myopia, hyperopia, astigmatism, and presbyopia. Introduction of the excimer laser to reshape the cornea has resulted in remarkable developments in the correction of these refractive errors. Combined with other advanced ophthalmological instruments, laser refractive eye surgery has resulted in a substantial rise in the safety, efficacy, and predictability of surgical outcomes. Despite these advances, certain limitations and complications persist. In this review, we describe the history, preoperative assessment, surgical techniques, outcomes, and complications of laser refractive surgery.

Astigmatism↗

PubMed2002

[Histological study of conjunctiva-associated lymphoid tissue in mice].

PURPOSE: To investigate conjunctiva-associated lymphoid tissue (CALT) in mouse conjunctiva. METHOD: We examined normal mice, ranging in age from 4 to 6 weeks, to investigate the presence of follicular tissue histologically. Next, we treated mice by topical instillation of ovalbumin and cholera toxin B, and then examined conjunctival follicles by immunohistological methods. RESULTS: Follicular tissue was present at the nictitating membrane. Both size and amount of follicular tissue was increased by the topical ovalbumin treatment. Immunohistological examination revealed CD4, CD8, and S-100 protein positive cells in follicular tissue. The epithelial layer, corresponding to follicular tissue, had intraepithelial pockets and CD4 positive cells in the pockets. CONCLUSION: It was concluded that the follicular tissue at the nictitating membrane is CALT in mice.

Animals↗

PubMedDate not supplied

Gelatinase expression in ocular surface disorders.

PURPOSE: To determine the expression of gelatinase A [matrix metalloproteinase (MMP)-2] and gelatinase B (MMP-9) in ocular surface disorders, we carried out examinations of the eyes of patients with such disorders. METHODS: The cases consisted of a normal group comprising three eyes as the control and a patient group comprising six eyes of patients with ocular surface disorders. These groups underwent the following examinations. (1) Gelatin zymography: Tear samples taken by using the Schirmer I test were eluted and analyzed by gelatin zymography. (2) Immunohistochemical study: By using the alkaline phosphate-anti-alkaline phosphatase or avidin-biotin complex method, corneal or conjunctival tissue was examined for the presence of MMP-2, MMP-9, and membrane type 1 (MT1)-MMP, which activates MMP-2. (3) Reverse transcription-polymerase chain reaction (RT-PCR): Total RNA was eluted from the specimens, and the expression patterns of MMP-2, MMP-9, and MT1-MMP mRNA were analyzed. RESULTS: (1) Gelatin zymography: Only the proforms of MMP-2 and MMP-9 were detected in the normal group. Both active MMP-2 and active MMP-9 were detected in all studied cases in the patient group. (2) Immunohistochemical study: In the normal group, only MMP-2-positive cells were present in conjunctival epithelium. In the patient group, cells positive for MMP-2, MMP-9 and MT1-MMP were present in the epithelium of the conjunctiva or cornea except in one thermal burn case. (3) RT-PCR: In the normal group, only MMP-2 expression was observed. MMP-2, MMP-9, and MT1-MMP mRNA expression was observed in three cases in the patient group. CONCLUSIONS: MMP-2, MMP-9, and MT1-MMP, which activates MMP-2, were expressed in the patients with various ocular surface disorders. In ocular surface disorders, therefore, the expression of gelatinases is upgraded.

Conjunctival Diseases↗

PubMedDate not supplied

Expression of alpha- and beta-defensins in human ocular surface tissue.

PURPOSE: Defensins are antimicrobial peptides and are classified into three groups, alpha-, beta- and theta-defensins. We investigated the localization of human neutrophil peptides (HNP) 1-3, which are members of the alpha-defensin subfamily, and the expression of human beta-defensin 1 (hBD-1) and hBD-2 in the ocular surface tissues. METHODS: Corneal or conjunctival tissues were obtained from 17 patients undergoing surgery. The reasons for surgery were thermal burns (two patients), acid burn (one patient), corneal perforation (one patient), corneal abscess (one patient), and pterygium (two patients). As a control, tissue samples were collected from ten patients undergoing cataract surgery. The samples were examined for HNP 1-3 by immunohistochemical analysis, and for hBD-1 and hBD-2 by the reverse transcriptase-polymerase chain reaction (RT-PCR) method. RESULTS: Results of staining for HNP 1-3 were positive in all of the six tested samples. The RT-PCR method detected hBD-1 mRNA in all samples. However, hBD-2 was detected in only 7 of the 17 samples. In eight of the ten normal conjunctiva samples and in the two samples from conjunctiva with thermal burn or pterygium, hBD-2 mRNA was not detected. CONCLUSIONS: We concluded that HNP 1-3 and hBD-1 are constitutively expressed in the ocular surface. However, hBD-2 may or may not be expressed, depending on the stage of ocular surface diseases.

Adult↗

PubMedDate not supplied

Comparison of topical dexamethasone and topical FK506 treatment for the experimental allergic conjunctivitis model in BALB/c mice.

PURPOSE: To evaluate the efficacy of topical dexamethasone and topical FK506 treatment on allergic inflammation in conjunctiva, we performed a comparative study using a mouse experimental allergic conjunctivitis model. METHODS: The experimental allergic conjunctivitis model was developed by ovalbumin (OVA) instillation after OVA sensitization by intraperitoneal application of a mixed solution of OVA and aluminum hydroxide. The Balb/c mice of the experimental allergic conjunctivitis model were divided into three groups, depending on whether or not they received topical treatment and which type of treatment they received. The allergy group comprised six mice without topical treatment; the dexamethasone (Dx) group comprised six mice receiving topical 0.1% dexamethasone ointment treatment; and the FK506 (FK) group comprised six mice receiving topical 0.1% FK506 ointment treatment. The negative control group comprised six mice with neither sensitization nor topical treatment. For the histological examination, frozen sections of the eyelids, eyeballs, and lacrimal glands were stained with acid Giemsa stain or, in the immunohistochemical method, with alkaline phosphatase-antialkaline phosphatase (APAAP), for CD4. Densities of eosinophils and CD4-positive lymphocytes in the conjunctival tissue were counted. Productive C epsilon gene expression in the conjunctival tissue, including the lacrimal gland, was also evaluated by reverse transcriptase polymerase chain reaction (RT-PCR). RESULTS: In the histological study, the cell density of eosinophils infiltrating into subconjunctival tissues was 66.3 +/- 34.7 cells/mm(2) (mean +/- SD) for the allergy group, 2.5 +/- 4.2 cells/mm(2) for the Dx group, 4.2 +/- 8.6 cells/mm(2) for the FK group, and 3.7 +/- 7.6 cells/mm(2) for the negative control group. The cell density of CD4-positive cells infiltrating into subconjuctival tissues was 145.9 +/- 66.4 cells/mm(2) for the allergy group, 10.0 +/- 12.9 cells/mm(2) for the Dx group, 10.1 +/- 15.5 cells/mm(2) for the FK group, and 21.7 +/- 17.8 cells/mm(2) for the negative control group. The allergy group showed significant differences in the density of eosinophils and CD4-positive cells compared with those of the Dx (P < 0.0001) and FK (P < 0.0001) groups. In the RT-PCR study, the expression of productive C epsilon gene was positive in the Dx group, but negative in the allergy group, the FK group, and the negative control group. CONCLUSIONS: Topical Dx and FK506 treatments were both efficacious in suppressing eosinophil and lymphocyte infiltration into subconjunctival tissue in the mouse experimental allergic conjunctivitis model. However, the influence of their IgE productive mechanisms seemed to differ, causing different efficacy of productive C epsilon gene expression in the conjunctival tissue.

Administration, Topical↗

PubMedDate not supplied

Expression of beta defensins in ocular surface tissue of experimentally developed allergic conjunctivitis mouse model.

PURPOSE: To investigate the expression of beta-defensin in the ocular surface of a mouse experimental allergic conjunctivitis (EAC) model. METHODS: Mouse beta-defensin (mBD)-1 and -2 mRNA expressed in conjunctival tissue of both the EAC and the control group were analyzed by real-time reverse transcriptase-polymerase chain reaction (RT-PCR) analysis. mBD-1 and mBD-2 mRNA expressed in cornea, limbus, and conjunctival epithelium of the EAC and the control group were also analyzed using a laser-assisted microdissection technique and the RT-PCR method. RESULTS: There was no significant difference in the amount of mBD-1 between the EAC and the control group. However, the EAC group had significantly less mBD-2 (0.23 +/- 0.15 x 10(4) copy/microl) than the control group (3.61 +/- 4.87 x 10(4) copy/microl) (P < 0.01, Mann-Whitney U test). mBD-1 mRNA was positive for all examined tissue in both groups. The expression of mBD-2 mRNA in the EAC group was definitely positive for the corneal and conjunctival epithelium and negative for the limbus. CONCLUSION: mBD-2 mRNA was expressed significantly less in the EAC model than in the control. Analysis by site in the ocular surface tissue revealed that this reduction was caused by the diminished expression of mBD-2 in the limbus.

Animals↗

PubMedDate not supplied

Histological study of conjunctiva-associated lymphoid tissue in mouse.

PURPOSE: To investigate conjunctiva-associated lymphoid tissue (CALT) in the mouse conjunctiva by histological methods. METHODS: The presumed follicular tissue in the conjunctiva of normal mice, age ranging from 4 to 6 weeks, was histologically investigated by the hematoxylin-eosin staining method. Next, we treated the mice with topical instillation of a combined solution of ovalbumin and cholera toxin B to investigate the morphological changes of conjunctival follicles to antigen challenge. The treated mice underwent sequential clinical examinations, and the conjunctival follicular tissue was examined by an immunohistochemical method using anti-CD4 antibody, anti-CD8 antibody, and anti-S-100 antibody. RESULTS: Follicular tissue was present on the mouse nictitating membrane. Both size and number of follicular tissue areas increased with topical ovalbumin treatment. Immunohistochemical study revealed CD4, CD8, and S-100 positive cells in the follicular tissue. The epithelial layer, corresponding to follicular tissue, demonstrated intra-epithelial pocket and the presence of CD4-positive cells in the intra-epithelial pocket. CONCLUSION: Follicular tissue at the nictitating membrane is CALT in the mouse.

Animals↗

PubMedDate not supplied

A novel nonsense mutation with a compound heterozygous mutation in TGFBI gene in lattice corneal dystrophy type I.

PURPOSE: We examined transforming growth factor beta-induced (TGFBI) gene mutations in a family with lattice corneal dystrophy type I. METHODS: The proband was one of the offspring of a consanguineous marriage; 4 affected and 3 unaffected individuals of the family were investigated. Genomic DNA of each case was extracted and used for polymerase chain reaction (PCR). The exon 4, 11, and 12 of the TGFBI gene were directly sequenced. The mutations were confirmed by PCR restriction fragment length polymorphism analysis. RESULTS: There was no significant difference in phenotype between the proband and the other 2 patients, except for progression of the corneal opacity with age. R124C mutation was detected in all affected individuals. In addition, G470X, a novel nonsense mutation, was detected in the proband, resulting in the proband being a compound heterozygote with the TGFBI gene. Her unaffected daughter was found to be heterozygous for G470X. CONCLUSION: It is most likely that the novel nonsense mutation is not pathogenic, and that the mutant keratoepithelin protein with R124C is responsible for the phenotype.

Adolescent↗

PubMedDate not supplied

Active form of gelatinases in tear fluidin patients with corneal ulcer or ocular burn.

PURPOSE: To investigate the expression of the active form of gelatinases (gelatinase A: matrix metalloproteinase-2 [MMP-2] and gelatinase B: matrix metalloproteinase-9 [MMP-9]) in ocular surface disorders, we determined the presence of the active form of these gelatinases in the tear fluid of patients with corneal ulcer or ocular burn. METHODS: The subjects consisted of the ulcer group comprising 13 eyes, the burn group comprising 6 eyes, and the normal group comprising 10 eyes. Tear samples were taken by the method of the Schirmer test I. The tears were eluted using extraction buffer containing 0.01 M phosphate buffer solution (pH 7.2), 1% Tween 20 and 1 M NaCl, and analyzed by gelatin zymography. RESULTS: Only the proforms of MMP-2, and MMP-9 were detected in the normal group and in uncomplicated herpetic keratitis or herpetic keratitis cases complicated by mixed infection in the ulcer group. Active MMP-9 was detected in mild corneal ulcer cases and mild ocular burn cases. Both active MMP-2 and active MMP-9 were detected in endogenous corneal ulcer cases and severe burn cases, including perforation cases. CONCLUSIONS: Both active gelatinases were detected in tears of severe corneal ulcer or severe ocular burn cases. The active form of gelatinase expression may be related to the severity of ulceration.

Abscess↗