Search PubMed⌕ Search

Biomedical subjects

T Oshika

Publications and source records attributed to T Oshika.

At least 37 records · Page 2Linked to original sources
PubMed2001

Risk factors for corneal graft failure and rejection in penetrating keratoplasty.

PURPOSE: To evaluate risk factors for graft failure and allograft rejection after penetrating keratoplasty (PK). METHODS: We retrospectively studied clinical results of PKs in terms of graft survival and rejection-free graft survival rates. PKs were done on 271 eyes between 1987 and 1997. Clinical results were analyzed by Kaplan-Meier's life table method and the log-rank test. Relative risks and adjusted survival probabilities for each value of the factor were compared with the risk for a specified reference value. RESULTS: The overall rates of graft survival and rejection-free graft survival in 10 years after PK were 79.3% and 77.9%, respectively. Higher relative risk of graft failure was associated with corneal vascularization (relative risk for within one quadrant = 1.67, two quadrants = 2.37, three or more quadrants = 3.39), regraft (relative risk for one failed previously graft = 2.08, two or more failed previously graft = 2.65), aphakia (relative risk = 2.17) or pseudophakia (relative risk = 3.02), presence of anterior synechia (relative risk = 2.91), presence of posterior synechia (relative risk = 2.56), long (more than 85 minutes) operation time (relative risk = 2.20), and older (more than 50 years) recipient age (relative risk = 2.38). Higher relative risk of rejection was associated with corneal vascularization (relative risk for within one quadrant = 2.35, two quadrants = 2.03, three or more quadrants = 2.63), long (more than 85 minutes) operation time (relative risk = 1.47), and younger (less than 60 years) donor age (relative risk = 2.10). There was no association between graft failure or allograft rejection and graft size or suture technique, respectively. CONCLUSION: The risk factors for graft failure after PK were corneal vascularization, regraft, aphakia or pseudophakia, presence of anterior synechia, presence of posterior synechia, long operation time, and older recipient age. The risk factors after PK for allograft rejection were corneal vascularization, long operation time, and younger donor age.

Adolescent↗
PubMed2001

Influence of subconjunctival steroid injection on blood glucose profile in diabetic rats.

PURPOSE: The influence of subconjunctival steroid injection on blood glucose concentration was investigated in rats with streptozotocin (STZ)-induced diabetes. METHODS: Adult male Wistar rats with STZ-induced diabetes (n = 10) and normal controls (n = 10) received subconjunctival injections of 0.1 ml of 0.4% dexamethasone or saline. Blood glucose concentrations were measured before and 3, 6, 12, 18 and 24 h after treatment. RESULTS: In the STZ group, subconjunctival injection of steroids (p = 0.0013) or saline (p = 0.0037) significantly increased the blood glucose level 3 h after treatment. In the control group, the blood glucose concentration was not elevated by subconjunctival injection. In both STZ and control groups, the blood glucose concentration was significantly higher after steroid injection than after saline injection throughout the 24 h study period. CONCLUSIONS: Subconjunctival steroid injection induced a significant blood glucose increase in both diabetic and control rats. For diabetic rats, the subconjunctival injection itself constituted stress that resulted in glucose elevation.

Administration, Topical↗
PubMed2001

Presumed interference colours at the level of the human anterior lens capsule.

PURPOSE: To assess the incidence and related factors of the presumed interference colour phenomenon at the anterior lens capsule. METHODS: In 274 eyes of 137 normal subjects, ranging in age from 4 to 83 years old (50.1 +/- 24.9 years, mean +/- standard deviation), the anterior lens capsule was observed with slit-lamp microscopy under specular conditions to assess the presence and degree of presumed interference colours. RESULTS: The colouring phenomenon, which was thought to be relevant to the interference phenomenon induced at the level of the anterior lens capsule, was found in 67.5% of eyes. Typically, there was a colour spectrum with a greenish tint in the central area and a reddish tint at the periphery, which coincided with the area of capsular shagreen. Multiple regression analysis revealed a signigificant positive correlation between the degree of the interference colour phenomenon and the age of the subjects (r = 0.45, p < 0.0001, R2 = 0.713). CONCLUSION: Presumed interference colours are frequently seen at the human anterior lens capsule. Interference colours and capsular shagreen seem to reflect age-related changes in the lens.

Adolescent↗
PubMed2001

Advanced glycation end products in Descemet's membrane and their effect on corneal endothelial cell.

PURPOSE: [corrected] The purpose of this study was to evaluate the effect of advanced glycation end products (AGEs) in Descemet's membrane on the attachment and spreading of the corneal endothelial cells. METHODS: An anti-AGEs monoclonal antibody (6D12), which recognizes a N(epsilon)-carboxymethyl lysine (CML)-protein adduct as an epitope, was used for immunohistochemistry and enzyme-linked immunosorbent assay (ELISA). Fresh bovine Descemet's membrane was incubated for 4 weeks in the buffered solution with 500 mM of glucose-6-phosphate (G-6-P). In the incubated Descemet's membrane, the immunohistochemical localization of CML was examined. Type I collagen-, type IV collagen-, fibronectin-, or laminin-coated 96-well plates were glycated by G-6-P. The amount of CML was determined by ELISA using 6D12. Cultured bovine corneal endothelial cells were seeded onto glycated or non-glycated extracellular matrix (ECM) in 96-well plates and allowed to attach for 3 hours. The number and the surface area of the attached cells were examined. RESULTS: Immunoreactivity to CML was detected in Descemet's membrane incubated in the buffered solution containing G-6-P. Glycation of fibronectin and laminin decreased the number and the surface area of the attached corneal endothelial cells. Aminoguanidine in the incubation mixture inhibited CML formation of ECM components and increased the number and the surface area of the attached corneal endothelial cells in a dose-dependent manner. CONCLUSIONS: AGE formation on fibronectin and laminin attenuated the attachment and spreading of the corneal endothelial cells. AGEs' formation in Descemet's membrane may be responsible for the corneal endothelial cell loss with aging and corneal endothelial abnormalities in diabetic patients

Animals↗
PubMed2001

Effect of donor age on morphologic variation of cultured human corneal endothelial cells.

PURPOSE: To examine the effect of donor age on the morphologic variation of cultured human corneal endothelial cells (HCEC). METHODS: HCEC were obtained from the remaining corneoscleral rims of seven human corneas used for penetrating keratoplasty. The donor age ranged from 2 to 75 years. Primary cultures were established from explants of the endothelial cell layer, including the Descemet's membrane, and were propagated on culture dishes coated with bovine corneal endothelial extracellular matrix. At the fourth passage, frequency distribution of cell area in the confluent monolayer was calculated and the effect of donor age on cell area was analyzed. RESULTS: The percentage of HCEC with cell area over 2000 microm2 significantly increased with donor age (r = 0.935, p = 0.0007). CONCLUSION: Cultured HCEC established from older donor tissue display greater heterogeneity. The use of HCEC from younger donors may be preferable to maximize the benefits of HCEC transplantation.

Adolescent↗
PubMed2001

Ocular and systemic factors relevant to diabetic keratoepitheliopathy.

PURPOSE: This study examines the contribution of ocular and systemic factors to diabetic keratoepitheliopathy. METHODS: The presence and severity of keratoepitheliopathy was investigated in 114 eyes of patients with diabetes and 59 eyes of patients without diabetes. The ocular factors examined were the status of the lipid layer of the tear fluid assessed with the specular reflection video-recording system, corneal sensitivity using the Cochet-Bonnet method, tear volume by the cotton thread test, tear film stability by tear breakup time, and grade of diabetic retinopathy. The systemic factors examined included patient age, hemoglobin A1c value, and duration of diabetes mellitus. Multivariate regression analysis was performed to assess the factors related to keratoepitheliopathy. RESULTS: The incidence of keratoepitheliopathy was 22.8% and 8.5% in patients with and without diabetes, respectively. Ocular measures, such as nonuniformity of tear lipid layer, corneal sensitivity, and tear breakup time, were significantly worse in patients with diabetes than in patients without diabetes ( p < 0.05). Multivariate regression analysis showed that the status of the tear lipid layer was significantly relevant to diabetic keratoepitheliopathy ( p < 0.05). CONCLUSION: Qualitative abnormalities in tear secretion seem relevant to the development of diabetic keratoepitheliopathy. The tear lipid layer interference pattern may yield useful information for the elucidation of the mechanism and treatment of diabetic keratoepitheliopathy.

Adult↗
PubMed2001

Anterior capsular contraction after cataract surgery in eyes of diabetic patients.

AIM: To investigate change in the area of anterior capsular opening (ACO) after cataract surgery and its relation to the degree of postoperative anterior inflammation in patients with diabetes mellitus (DM). METHODS: 31 eyes of 31 patients with DM and 30 eyes of 30 normal controls scheduled to undergo cataract surgery were examined prospectively. The area of ACO was measured with an anterior eye segment analysis system (EAS-1000) on the day following surgery and 3, 6, and 12 months after surgery. Comparative analyses were made on the area of ACO relative to the presence of DM and diabetic retinopathy (DR). The percentage reduction of area of ACO was calculated from values 1 day and 12 months after surgery, and multiple regression analysis was performed on the presence of DM, patient age, ACO area on the first postoperative day, and aqueous flare intensity 1 day and 12 months after surgery. RESULTS: The area was significantly smaller in the DM group at 3 (p=0.015, Student's t test), 6 (p=0.011), and 12 (p=0.010) months postoperatively. Patients having DR showed significantly smaller ACO area than the non-DR group 3 (p=0.039), 6 (p=0.033), and 12 (p=0.028) months after surgery. Multiple regression analysis revealed that presence of DM (p=0.003) and aqueous flare intensity 12 months after surgery (p=0.039) significantly correlated with the percentage reduction of area of ACO. Age, ACO area at 1 day postoperatively, and aqueous flare intensity immediately after surgery were not relevant to ACO contraction. CONCLUSIONS: Anterior capsular contraction after cataract surgery was greater in eyes of DM patients, especially in those with DR and increased permeability of the blood-aqueous barrier.

Aged↗
PubMed2001

Advanced glycation end products in human optic nerve head.

AIMS: To localise advanced glycation end products (AGEs) in human optic nerve head. METHODS: Optic nerve samples from 13 elderly individuals (seven diabetics and six non-diabetics) were obtained at necropsy. Pyrraline, an advanced glycation end product, was immunohistochemically localised in the optic nerve heads. RESULTS: In the diabetic subjects, moderate to intense immunoreactivity for pyrraline was detected in sclera, pia mater, cribriform plates, connective tissues in the optic nerve, and around vessels in the optic nerve and pia mater. Immunoreactivity for pyrraline was also detected around retinal vessels. In the non-diabetic subjects, slight or no immunoreactivity for pyrraline was found in cribriform plates and around the optic nerve vessels. CONCLUSION: Accumulation of AGEs in cribriform plates and around vessels in the optic nerve may contribute to the development of optic neuropathy in diabetic patients.

Aged↗
PubMed2001

Corneal irregular astigmatism after laser in situ keratomileusis for myopia.

AIMS: To quantitatively evaluate the changes in corneal irregular astigmatism after laser in situ keratomileusis (LASIK) in relation to the amount of laser ablation. METHODS: In 189 eyes of 116 patients undergoing LASIK for myopia, corneal topography was obtained before and 1 month after surgery. Using Fourier harmonic analysis of the topography data, corneal irregular astigmatism (asymmetry and higher order irregularity) was calculated. RESULTS: By surgery, asymmetry component significantly increased (p < 0.0001, Wilcoxon signed rank test), while higher order irregularity did not (p = 0.767). The increases in the asymmetry component significantly correlated with ablation depth (Spearman rank correlation coefficient r(s) = 0.440, p < 0.0001). No significant correlation was found between changes in higher order irregularity and ablation depth (r(s) = 0.137, p = 0.074). CONCLUSION: LASIK significantly increases the asymmetry component of the cornea which is dependent on the amount of laser ablation.

Adult↗
PubMed2001

Influence of glistenings on the optical quality of acrylic foldable intraocular lens.

AIMS: To assess the influence of glistenings on the optical quality of acrylic foldable intraocular lens. METHODS: Several degrees of glistenings in the optic were experimentally created by immersing the lens in water at 37 degrees C for 48 hours and then at 25 degrees C for 24 hours. Optical bench tests were carried out in water including measurements of spectral transmittance with the spectrophotometer, intensity of forward scattering using the integrating sphere photometer, modulation transfer function, and resolving power at various contrasts with and without the veiling glare light source. RESULTS: Glistenings of 1+ to 4+ degrees were created, among which the 4+ glistenings seemed to be extremely intense and thought to be beyond the range of clinical settings. Clinically feasible level of glistenings, up to 3+, did not adversely influence spectral transmittance, scattering, modulation transfer function, and resolving power at various contrasts. The 4+ glistenings caused mild to moderate deteriorations of the optical quality of the lens. CONCLUSION: The optical quality of the acrylic foldable intraocular lens is not significantly affected by the level of glistenings usually seen in the clinical setting.

Acrylates↗
PubMed2001

Molecular basis of ocular abnormalities associated with proximal renal tubular acidosis.

Proximal renal tubular acidosis associated with ocular abnormalities such as band keratopathy, glaucoma, and cataracts is caused by mutations in the Na(+)-HCO(3)(-) cotransporter (NBC-1). However, the mechanism by which NBC-1 inactivation leads to such ocular abnormalities remains to be elucidated. By immunological analysis of human and rat eyes, we demonstrate that both kidney type (kNBC-1) and pancreatic type (pNBC-1) transporters are present in the corneal endothelium, trabecular meshwork, ciliary epithelium, and lens epithelium. In the human lens epithelial (HLE) cells, RT-PCR detected mRNAs of both kNBC-1 and pNBC-1. Although a Na(+)-HCO(3)-cotransport activity has not been detected in mammalian lens epithelia, cell pH (pH(i)) measurements revealed the presence of Cl(-)-independent, electrogenic Na(+)-HCO(3)-cotransport activity in HLE cells. In addition, up to 80% of amiloride-insensitive pH(i) recovery from acid load in the presence of HCO(3)(-)/CO(2) was inhibited by adenovirus-mediated transfer of a specific hammerhead ribozyme against NBC-1, consistent with a major role of NBC-1 in overall HCO(3)-transport by the lens epithelium. These results indicate that the normal transport activity of NBC-1 is indispensable not only for the maintenance of corneal and lenticular transparency but also for the regulation of aqueous humor outflow.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed2000

Preservation of donor cornea prevents corneal allograft rejection by inhibiting induction of alloimmunity.

To determine whether preservation of the donor cornea prevents allograft rejection, orthotopic corneal transplantation was performed using corneas preserved in storage medium (Optisol-GS((R))). Donor corneas harvested from C3H/He (H-2(k)) mice and B10.D2 (H-2(d)) mice were preserved in storage medium for 0, 3, 7 and 14 days, and then transplanted into the corneal beds of the recipient BALB/c (H-2(d)) mice. Graft survival was determined clinically and histologically. The expression of major histocompatibility complex (MHC) molecules in the preserved corneas was analysed by immunohistochemistry and Western blotting. Donor-specific cytotoxic T lymphocyte (CTL) and delayed-type hypersensitivity (DTH) responses were assessed 3 weeks after grafting. Active suppression of DTH in the recipient mice was also examined 3 weeks after grafting. The survival of 14 day preserved allografts was significantly higher than that of the non-preserved allografts in both MHC and minor histocompatibility (H) antigens, and minor H only disparate combination. The recipients of the preserved allografts failed to induce both CTL and DTH. The active suppression of DTH was not acquired in these recipients. The expression of donor-derived MHC class I antigens was markedly reduced in the corneas after preservation. Preservation of the donor cornea had a remarkable effect on the prevention of corneal allograft rejection. Since the preserved allografts failed to induce donor-specific CTL and DTH, and active suppression of DTH was not acquired in the recipients, the prevention of allo-rejection is due to a failure of allo-sensitization. These results indicate that the reduction of MHC class I antigens and minor H antigens expression in the preserved grafts induces a failure of allo-sensitization and leads to the high rate of acceptance in corneal allografts.

Animals↗
PubMed2000

Analgesic effects of sub-Tenon's versus retrobulbar anesthesia in planned extracapsular cataract extraction.

BACKGROUND: A prospective study was conducted to compare the analgesic effects of sub-Tenon's and retrobulbar anesthesia by assessing patients' response to the visceral stimulus. METHODS: Seven hundred and twenty eyes of 720 patients underwent extracapsular cataract extraction and posterior chamber intraocular lens implantation. They received retrobulbar anesthesia with 3 ml lidocaine (225 eyes), retrobulbar anesthesia with 5 ml lidocaine (216 eyes), or sub-Tenon's anesthesia with 3 ml lidocaine (279 eyes). Pain scores were recorded when an acetylcholine chloride solution was injected into the anterior chamber to attain miosis after lens implantation. RESULTS: Pain scores were significantly different among the three anesthesia groups (P<0.0001, Kruskal-Wallis test). The multiple comparison revealed that analgesic effects were highest with sub-Tenon's anesthesia, followed by 5-ml retrobulbar and 3-ml retrobulbar anesthesia. CONCLUSION: Sub-Tenon's anesthesia is an effective and reliable anesthetic method in cataract surgery.

Acetylcholine↗
PubMed2000

Chronic clinical course of two patients with severe corneal dystrophy caused by homozygous R124H mutations in the betaig-h3 gene.

PURPOSE: To report the chronic clinical course of two patients with homozygous R124H mutations in the betaig-h3 gene. METHODS: Case reports. RESULTS: Two patients with homozygous R124H mutations in the betaig-h3 gene developed severe juvenile corneal opacities that required keratoplasty. After surgery, corneal opacities recurred and limited the recovery of visual acuity in the chronic follow-up. CONCLUSION: In patients with homozygous R124H mutations in the betaig-h3 gene, recurrence of corneal opacities after keratoplasty limits the recovery of visual acuity in the chronic follow-up.

Child↗
PubMed2000

Influence of rapid glycemic control on lens opacity in patients with diabetes mellitus.

PURPOSE: To report the influence of rapid glycemic control on lens opacity in patients with diabetes mellitus. METHODS: In a prospective study, nine patients with adult onset diabetes mellitus and glycosylated hemoglobin values over 9% were divided into two groups, rapid glycemic control and slow glycemic control groups, based on the time course of glycosylated hemoglobin values after the initiation of glycemic control. The lens thickness and opacity were measured using the anterior eye segment analysis system. RESULTS: One week after onset of treatment, the lens in rapid glycemic control group became significantly thicker than in pretreatment, but returned to the baseline level at the subsequent measurement points. The lens opacity index in the rapid glycemic control group increased significantly (P <.01, paired t test) 4 months after the glycemic control, which persisted throughout the 1-year study period. The lens thickness and opacity in the slow glycemic control group did not change significantly. CONCLUSION: It was suggested that rapid glycemic control can induce an irreversible increase in lens opacification.

Adult↗
PubMed2000

Changes in anterior and posterior corneal curvatures in keratoconus.

OBJECTIVE: To quantitatively evaluate the changes in anterior and posterior corneal curvatures of eyes with keratoconus. DESIGN: Case-control retrospective and observational study. PARTICIPANTS: Thirty-one patients who were clinically diagnosed to have unilateral or bilateral keratoconus and 18 normal subjects. INTERVENTION: The anterior and posterior topographies were obtained using scanning-slit videokeratography and assessed by Fourier series harmonic analysis. MAIN OUTCOME MEASURES: Quantitative descriptors of the topography data, spherical power, regular astigmatism, and irregular astigmatism (asymmetry and higher order irregularity) components were compared between the anterior and posterior surfaces and among groups of clinically diagnosed keratoconus (33 eyes), keratoconus suspect (13 eyes), and normal subjects (36 eyes). RESULTS: Spherical power (P = 0.0003, Mann-Whitney U test with Bonferroni's correction of P values), regular astigmatism (P = 0.0166), and asymmetry (P = 0.0031) of the anterior surface were significantly greater in the keratoconus eyes than in the normal controls. For the posterior surface, spherical power (P<0.0001), regular astigmatism (P = 0.0143), asymmetry (P< 0.0001), and higher order irregularity (P = 0.0032) of the keratoconus group were significantly greater than those of the control group. The keratoconus suspect eyes, when compared with the normal controls, showed a significantly greater amount of spherical power (P = 0. 0166) and asymmetry (P<0.0001) in the anterior surface and spherical power (P <0.0001), regular astigmatism (P = 0.0244), asymmetry (P<0.0001), and higher order irregularity (P = 0.0276) in the posterior surface. All refractive components demonstrated statistically significant correlations between the anterior and posterior surfaces (P<0.0001, Spearman's rank correlation). CONCLUSIONS: Not only the anterior but also the posterior corneal curvature is affected in keratoconus. These changes are observed from the early stage of this disorder.

Adolescent↗