Biomedical subjects

Kazuo Tsubota

Publications and source records attributed to Kazuo Tsubota.

At least 109 records · Page 6Linked to original sources

PubMed2004

UV dose-dependent caspase activation in a corneal epithelial cell line.

PURPOSE: To characterize the UVB radiation-dependent patterns of caspase activation and cell death in SV 40 immortalized corneal epithelial cells. METHODS: Cell death in immortalized human corneal epithelial cells (T-HCEC) was induced by exposure to low (50 mJ/cm2) and high (450 mJ/cm2) doses of UVB. Cell death morphology was examined by fluorescence microscopy using the cell death marker propidium iodide (PI). Apoptosis of T-HCEC was analyzed by DNA fragmentation assays, and enzyme activity was measured for caspase 3 and 9 by fluorophotometry. Changes in mitochondrial inner membrane potential were measured by flow cytometry using the fluorescent marker, rhodamine 123. Redistribution of cytochrome c, the upstream trigger of caspase 9, was measured in the cytosol fraction of T-HCEC following irradiation. RESULTS: PI staining revealed a fragmented staining pattern of the nucleus consistent with apoptosis in detached cells irradiated with low-dose UVB, while cells receiving high dose UVB demonstrated round, well bordered staining of the nucleus. Flow cytometry revealed irreversible mitochondrial damage in the high dose group shown by decreased levels of rhodamine 123 fluorescence. Cells in the low-dose group had intact mitochondrial inner membrane potential, increased cytosolic cytochrome c, and showed a significantly higher rate of DNA fragmentation and caspase activation than the high dose group. CONCLUSION: Low dose UVB caused cytochrome c redistribution, caspase activation and apoptosis of corneal epithelial cells, which was not observed at high irradiation levels of UVB.

Apoptosis↗

PubMed2004

Detection of neutrophils in late-onset interface inflammation associated with flap injury after laser in situ keratomileusis.

OBJECTIVE: To report a case with late-onset interface inflammation associated with traumatic flap injury at 7 months after laser in situ keratomileusis (LASIK) and to describe the type of infiltrating cells in the tears of the patient. METHODS: Interventional case report. A 24-year-old male patient who underwent uneventful LASIK on both eyes received blunt trauma from the tip of a shoe in the left eye 7 months after surgery. The corneal flap of his left eye was lacerated across the pupillary area. Inflammatory cells were observed under the lacerated flap segment. Tear fluid was collected from his left eye 3 days after the injury and assessed by tear cytology. For controls, tears of 2 patients who underwent LASIK and developed no interface inflammation were collected the next day after their surgeries and examined. RESULTS: Tear fluid of the patient with interface inflammation contained numerous neutrophils. Tears of control patients contained only a few epithelial cells and cell debris but no inflammatory cells. The inflammation was decreased by systemic and topical steroids. However, irregular astigmatism caused by stromal scarring remained, resulting in decreased best-corrected visual acuity. CONCLUSIONS: Interface inflammation can be caused by late-onset flap injury. Neutrophils detected in the tears may reflect a major component of cells infiltrating the interface after LASIK.

Adult↗

PubMed2004

A comparative evaluation of the efficacy of intraoperative mitomycin C use after the excision of cobblestone-like papillae in severe atopic and vernal keratoconjunctivitis.

OBJECTIVE: To evaluate the effect of intraoperative 0.02% mitomycin-C (MMC) use after excision of cobblestone-like papillae on preventing corneal recurrences compared with simple papillary resection. METHODS: Thirteen cases of atopic keratoconjunctivitis (AKC) and 6 cases of vernal keratoconjunctivitis (VKC) with a mean age of 12.0 +/- 3.4 years participated in this study. All patients had cobblestone-like papillae on the upper tarsal conjunctiva and corneal ulcers or erosions that were refractory to conventional treatment. Seventeen eyes received simple papillary excision. Papillary excision with intraoperative application of MMC was performed in 7 eyes: 0.02% MMC was applied for 2 minutes to the upper palpebral conjunctiva immediately after papillary excision. Recurrence of corneal lesions and regrowth of papillae were evaluated and compared retrospectively between the 2 groups. Postoperative follow-up ranged from 12 to 18 months. RESULTS: Papillary regrowth was observed in 14 out of 17 eyes (82.4%) in the simple resection group, whereas regrowth was noted in 4 out of 7 eyes (57.1%) in the MMC group (P > 0.05). The recurrence of corneal lesions was observed in 8 out of 17 eyes (47.1%) in the simple resection group (mean onset 1.5 +/- 1.7 months) compared with 1 eye with corneal recurrence 6 months after surgery in the MMC group (14.3%). The difference was statistically significant (P < 0.05). No complications related to MMC use were observed during the follow-up period. CONCLUSION: MMC-aided papillary resection may be rewarding in well-selected severe AKC and VKC cases in preventing recurrence of corneal complications, but the potential complications of MMC use would suggest caution in its consideration.

Adolescent↗

PubMed2004

Same-size donor corneas for myopic keratoconus.

OBJECTIVE: To determine the efficacy of using same-size donor grafts for keratoconus patients with axial myopia. METHODS: A prospective noncomparative interventional case series was performed on 142 eyes of 136 consecutive keratoconus patients. Penetrating keratoplasty (PKP) was performed by 3 skilled surgeons using the same technique with a single running 10-0 nylon suture. Donor button size was determined by a study protocol, where a same-size donor was used for eyes with an axial length (AXL) longer than 24.50 mm, whereas a 0.25-mm-oversized donor was used for eyes shorter than 24.49 mm. Postoperative spherical equivalent (SE) and incidence of postoperative complications were analyzed. RESULTS: Of the 142 consecutive eyes, 123 eyes were operated according to protocol. The average postoperative SE on last visit was -3.94 +/- 3.21 D, with an average uncorrected visual acuity of 0.28 (0.90 average corrected). Postoperative SE correlated inversely (r = 0.46) with preoperative axial length (AXL) expressed by the equation: SE = -0.15 (AXL)2+6.40 (AXL)-71.82. Graft rejection was observed in 7 eyes (5.7%), and glaucoma in 2 eyes that required surgery. CONCLUSIONS: Using same-size donor grafts in keratoconus patients with a long visual axis is a safe and effective procedure in reducing postoperative myopia.

Adolescent↗

PubMed2004

The relation of conjunctival and corneal findings in severe ocular allergies.

OBJECTIVE: Corneal lesions such as ulcers and erosions are major complications observed in patients with severe ocular allergic diseases. We aimed to look into the relationship between specific clinical conjunctival findings and the severity of corneal complications. METHODS: Thirty eyes of 6 patients with vernal keratoconjunctivitis (VKC) and 13 patients with atopic keratoconjunctivitis (AKC) were evaluated in this study. Slit-lamp photographs of upper tarsal conjunctiva and cornea were used to evaluate the clinical findings objectively. The corneal findings and clinical findings of upper tarsal conjunctiva such as conjunctival injection, edema, the height of papillae, and mucous discharge were evaluated and graded. Statistical correlations between conjunctival findings and the severity of corneal damage were analyzed. RESULTS: Conjunctival injection and edema significantly correlated with the severity of corneal complications. The height of the papillae and the amount of mucous discharge did not correlate with the severity of corneal complications. CONCLUSION: Direct signs of inflammation such as injection and edema correlated with corneal damage. The height of papillae did not show a significant correlation with the corneal findings. Our results suggest that inflammation of the conjunctiva rather than mechanical factors may play a greater role in the formation of corneal damage in severe ocular allergies.

Adolescent↗

PubMed2004

Quantitative evaluation of eyelid elasticity using the cutometer SEM575 and its clinical application in assessing the efficacy of tacrolimus ointment treatment in eyelid atopic dermatitis.

PURPOSE: To study the clinical efficacy of a noninvasive suction device that measures eyelid skin elasticity in the treatment of eyelid atopic dermatitis using tacrolimus (FK-506) ointment. METHODS: Ten patients with eyelid atopic dermatitis treated with tacrolimus ointment and 10 normal volunteers participated in this study. The cutometer SEM575 was used to quantitatively evaluate eyelid skin elasticity. Severity of the eyelid atopic dermatitis was scored, and comparisons were made before and after treatment. RESULTS: Skin elasticity of patients with eyelid atopic dermatitis was significantly lower than that of normal volunteers (31.3 +/- 5.2% vs 40.2 +/- 7.8%, respectively). Skin elasticity of patients with eyelid atopic dermatitis improved significantly to 37.5 +/- 6.3% after treatment with tacrolimus ointment. The total severity score for eyelid atopic dermatitis also improved from 2.77 +/- 1.11 to 1.77 +/- 1.15. CONCLUSION: Measurement of skin elasticity using the cutometer SEM575 is a useful and reliable method for objective and quantitative evaluation of eyelid skin condition in patients with eyelid atopic dermatitis. The efficacy of short-term tacrolimus ointment treatment in patients with eyelid atopic dermatitis was confirmed quantitatively using this apparatus.

Adult↗

PubMed2004

Dramatic healing of an allergic corneal ulcer persistent for 6 months by amniotic membrane patching in a patient with atopic keratoconjunctivitis: a case report.

PURPOSE: To present a case of allergic corneal ulcer in a patient with atopic keratoconjunctivitis (AKC) that was persistent for 6 months and healed by amniotic membrane patching. CASE REPORT: A 27-year-old male patient with a corneal ulcer associated with AKC persistent for 6 months despite conventional treatment underwent amniotic membrane patching. On removal of the amniotic membrane patch after 1 week, the corneal ulcer that had been persistent for 6 months had healed completely. CONCLUSION: We experienced a case with corneal ulcer that was persistent for 6 months and healed dramatically within 1 week with improved vision and corneal clarity. In such severe and persistent cases requiring rapid epithelialization, amniotic membrane should be considered as an adjunct to conventional therapy.

Adult↗

PubMed2004

A new noninvasive tear stability analysis system for the assessment of dry eyes.

PURPOSE: This was a prospective case-control study conducted to evaluate the effectiveness of the Tear Stability Analysis System (TSAS) for the assessment of patients with dry eye. METHODS: The TSAS can take 10 consecutive corneal topograms at one per second for 10 seconds. Examinations using the TSAS were conducted in 26 eyes of 26 healthy control subjects and in 27 eyes of 27 patients with dry eye. Examinations were also conducted in 14 eyes of 14 patients before and after the insertion of punctum plugs. Surface regularity and asymmetry indices (SRI, SAI), as well as new tear stability regularity and asymmetry indices (TSRI, TSAI), derived from SRI and SAI, were analyzed. RESULTS: The mean SRI and SAI in dry eyes were significantly greater than in control eyes (P < 0.05). The time-wise change of SRI and SAI was significantly different between dry eyes and control eyes (P < 0.05). TSRI and TSAI in dry eyes were also significantly greater than in control eyes. Punctum plug insertion was associated with a significant decrease in SRI and SAI (P < 0.05). CONCLUSIONS: TSAS was effective in objectively assessing the tear stability in patients with dry eye. This system may be useful in noninvasive diagnosis of dry eye and evaluation of treatment effects.

Case-Control Studies↗

PubMed2004

Induction of epithelial progenitors in vitro from mouse embryonic stem cells and application for reconstruction of damaged cornea in mice.

PURPOSE: Severe ocular surface diseases and injuries cause loss of the corneal limbal epithelium, leading to re-epithelialization by bulbar conjunctival cells, resulting in vascularization of the cornea, conjunctival scarring, and loss of visual acuity. In this study, the optimal culture condition for induction of differentiation of epithelial progenitor cells from embryonic stem (ES) cells was determined for use in transplantation to damaged cornea in mice. METHODS: Mouse ES cells were cultured on Petri dishes coated with several extracellular matrix proteins, and the markers for epithelial cells were analyzed with RT-PCR and Western blot analysis. The optimal condition for induction of epithelial progenitor cells was determined, and the progenitors were transplanted onto mouse eyes with corneal epithelia that had been damaged by exposure to n-heptanol. RESULTS: Epithelial progenitors were successfully induced by culturing mouse ES cells on type IV collagen for 8 days. These progenitors expressed keratin (K)12, which is specific to corneal epithelial cells, and cell surface CD44 and E-cadherin, both of which are essential in corneal epithelial wound healing. Complete re-epithelialization of the corneal surface occurred within 24 hours after transplantation. The resultant corneal epithelial cells expressed markers of the grafted cells, and no teratomata were observed during the follow-up period. CONCLUSIONS: Epithelial progenitors were successfully induced in vitro from ES cells and were applicable as grafts for treating corneal epithelial injury. ES cells may become an unlimited donor source of corneal epithelial cells for corneal transplantation and may restore useful vision in patients with a deficiency of limbal epithelial cells. This is an important first trial toward assessing the use of ES cells to reconstruct corneal epithelial cells.

Animals↗

PubMed2004

[Basic and clinical research in dry eye syndrome].

Explore the source record for details and available documents.

Dry Eye Syndromes↗

PubMed2003

Visualization of gaseous monoxide reception by soluble guanylate cyclase in the rat retina.

Immunohistochemistry using novel monoclonal antibodies (mAbs) allowed us to uncover tissue activities of soluble guanylate cyclase (sGC) fine tuned by NO and CO. Upon NO and CO applications in vitro, purified sGC increased the affinity to mAb3221 by 100- and 10-fold, respectively, but not to mAb28131. Immunohistochemistry for gas-generating enzymes revealed that NO occurred in amacrine, bipolar, and Müller's glia cells (MGCs), whereas CO was derived mostly from heme oxygenase (HO)-2 in MGCs. Basal sGC immunoreactivities in vivo to mAb3221 but not to mAb28131 were enhanced by injecting L-arginine and attenuated by blocking NO synthases, suggesting the ability of the former mAb to sense NO. Comparison of mAb-assisted immunohistochemistry suggested that sGC activities were enhanced by zinc protoporphyrin-IX, an HO inhibitor, and repressed completely by blocking NO. However, suggested roles of CO played in situ varied among different retinal layers. In inner plexiform and inner nuclear layers located in the proximity of the cellular NO sources, CO serves as a simple inhibitor of local sGC, while playing roles in housekeeping sGC activation in external limiting membrane standing far from them. These results suggest that CO generated in MGCs is a diffusible gas mediator regulating sGC in both autocrine and paracrine manners.

Animals↗

PubMed2003

Improved functional visual acuity after punctal occlusion in dry eye patients.

PURPOSE: To report an increased functional visual acuity, which was recently reported as a simulation of visual function of daily acts of gazing, in dry eye patients after punctal occlusion. DESIGN: Prospective comparative interventional study. METHODS: We measured ordinary best-corrected visual acuity and functional visual acuity in eight eyes of eight dry eye patients after punctal occlusion, and compared the results with those of 22 eyes of 22 dry eye patients without punctal occlusion. RESULTS: Functional visual acuity in dry eye patients after punctal occlusion was 0.962 in decimal notation, which was significantly higher than that of patients without punctal occlusion, 0.283 (P <.0001). CONCLUSIONS: This study shows that punctal occlusion can improve the impaired functional visual acuity of dry eye patients.

Dry Eye Syndromes↗

PubMed2003

Lecithin-bound superoxide dismutase in the treatment of noninfectious corneal ulcers.

PURPOSE: To evaluate the effects of a lipophilic analog of superoxide dismutase in the treatment of persistent epithelial defects of the cornea. DESIGN: Interventional case series. METHODS: Nineteen eyes of 19 patients with noninfectious corneal ulcers were enrolled. Patient profiles consisted of seven cases with Mooren-type peripheral ulcers, three cases with chemical or thermal burns, two cases with vernal keratoconjunctivitis, four cases with cicatricial keratoconjunctivitis, and three cases with sterile ulcers after corneal surgery. Patients consisted of 11 men and 8 women, with a mean age of 51.5 +/- 17.9 years (range, 14-77). Only patients who did not respond to conventional therapy were recruited for the study. Lecithinated superoxide dismutase was applied for 2 weeks, and sketches and/or fluorescein slit micrographs were recorded before and at the end of the study. The main outcome measure was decrease in ulcer size. RESULTS: As a group, the average ulcer size relative to the entire cornea decreased from 18.2 +/- 15.1% to 10.0 +/- 15.0% after 2 weeks (P <.05). A dramatic effect (>90% decrease in ulcer size) was observed in eight cases (100% in six cases), whereas no apparent change was found (<30% decrease in ulcer size) in five cases. The presence of polymorphonucleocytes within the ulcerated tissue was confirmed by brush cytology. CONCLUSION: Lecinthinated superoxide dismutase was effective in decreasing persistent epithelial defect size in a subset of patients with sterile corneal ulcers refractive to conventional therapy. A large-scale clinical investigation is merited.

Adolescent↗

PubMed2003

Therapeutic deep lamellar keratoplasty for cornea perforation.

PURPOSE: To present the efficacy of performing deep lamellar keratoplasty as an emergency measure following perforation of the cornea. DESIGN: Interventional case report. METHOD: Deep lamellar keratoplasty was performed in two cases of perforated cornea. Following incarceration of the iris within the perforated area, The Descemet membrane was exposed except for strands of stroma surrounding the perforation. A fresh donor cornea stripped of the Descemet membrane was then sutured in place. RESULTS: Both cases have attained clear corneas in areas other than the original perforation. CONCLUSIONS: Deep lamellar keratoplasty is a safe technique for the treatment of cornea perforation.

Adolescent↗

PubMed2003

A new method for tear film stability analysis using videokeratography.

PURPOSE: To report a new tear film stability analysis system using videokeratography. DESIGN: Observational case series. METHODS: New videokeratography software for TMS-2N (topographic modeling system; TOMEY Corporation, Nagoya, Japan) was developed that can automatically capture consecutive corneal surface images every second for 10 seconds. Forty-eight adult volunteers (80 eyes) were recruited for this study, and all subjects were examined with the new system. Corneal topographs were analyzed for tear breakup time (TMS-BUT) and the ratio of breakup area to entire color-code area (TMS-BUA) was calculated. Routine methods for tear film breakup time evaluation using slit-lamp microscope and fluorescence staining (SLE-BUT) were performed for comparison purposes. Regressive correlations of TMS-BUT or TMS-BUA with SLE-BUT were analyzed. Based on SLE results, subjects were separated into two groups with normal and short BUT, respectively. TMS-BUT and TMS-BUA were compared with SLE-BUT data with regard to the sensitivity and specificity of evaluation of dry eye symptoms. RESULTS: Topographic modeling system-tear breakup time (TMS-BUT) had a positive correlation with SLE-BUT (R = 0.7219, P <.0001), whereas TMS-BUA showed a negative correlation (R = 0.6317, P <.0001). Among 34 eyes with normal SLE-BUT, 11 eyes (32.35%) displayed abnormal TMS-BUT, 9 (81.82%) of which were associated with dry eye symptoms. The sensitivities of TMS-BUT and TMS-BUA were 97.5% and 95%, respectively, significantly higher than that of SLE-BUT (75%), with P =.008 and 0.01, respectively. Topographic modeling system-BUT and TMS-BUA displayed a similar rate of specificity in comparison with SLE-BUT. CONCLUSIONS: This new videokeratography system is a noninvasive and objective method with increased sensitivity for tear film stability analysis.

Adolescent↗

PubMed2003

Abnormal protein profiles in tears with dry eye syndrome.

PURPOSE: To verify the hypothesis that protein concentrations, such as lactoferrin, epidermal growth factor (EGF), and aquaporin 5 (AQP5), in tears are abnormal in patients with dry eye. DESIGN: Prospective case-control study. METHODS: One hundred three dry eye patients were divided into three groups: dry eye not associated with the Sjögren syndrome (non-SS; n = 71), Sjögren syndrome (SS; n = 23), and Stevens-Johnson syndrome (SJS; n = 9). Sixteen normal control subjects were also checked. The concentrations of lactoerrin, EGF, and AQP5 were measured by enzyme-linked immunosorbent assay. RESULTS: The concentration of lactoferrin was significantly decreased in tears of non-SS (P =.0001), SS (P =.00005), and SJS (P =.0006) patients compared with control subjects. The concentration of EGF was significantly decreased in non-SS (P =.0005), SS (P =.00002), and SJS (P =.0001) patients compared with control subjects. The concentration of AQP5 was significantly increased in tears of only SS patients (P =.01) compared with control subjects and increased in tears of only SS patients compared with non-SS patients (P =.007). CONCLUSIONS: The decrease in both lactoferrin and EGF was found not only in SS patients but also in non-SS patients, indicating that tear components in dry eyes differ in their quantity and quality. Quantification of AQP5 increased only in SS patients, suggesting that AQP5 protein leaks into the tears when acinar cells of the lacrimal gland are damaged by lymphocytic infiltration.

Adolescent↗

PubMed2003

Quantitative analysis of lacrimal gland function, apoptotic figures, Fas and Fas ligand expression of lacrimal glands in dry eye patients.

The purpose of our study was to examine the correlation between the lacrimal gland function and apoptotic figure, Fas and Fas ligand (FasL) expression in the lacrimal gland. A total of 15 dry eye patients (nine Sjögren's syndrome and six non-Sjögren's syndrome-type dry eye) were recruited for the study. Lacrimal function was evaluated by Schirmer tests 1 and 2. Lacrimal gland biopsies were performed and sections were analyzed by immunohistochemistry using APO2.7, an antibody to Fas and FasL. Quantitative analysis of fluorescein staining was performed by a scanning laser microscopy. Schirmer test 2 results were lower in Sjögren's syndrome-type dry eye and were associated with positive staining of acinar cells with APO2.7 and of infiltrating lymphocytes with FasL. There was a good correlation between the results of Schirmer test 2 and APO2.7 and FasL staining. Lacrimal gland dysfunction is related to the apoptotic figure of acinar cells possibly induced by FasL on the infiltrating lymphocytes.

Adult↗

PubMed2003

Amniotic membrane transplantation with conjunctival autograft for recurrent pterygium.

OBJECTIVE: To study the effect of amniotic membrane transplantation (AMT) combined with either limbal autograft transplantation (LAT) or conjunctival autograft transplantation (CAT) in recurrent pterygium. DESIGN: Retrospective, noncomparative, interventional case series. PARTICIPANTS: Twenty-seven eyes of 27 patients with recurrent pterygium. The mean number of prior surgeries was 3.1 (range, 1-10). Fifteen eyes each had restriction of ocular movement and symblepharon before surgery. INTERVENTION: Patients were treated by AMT with either LAT (n = 15) or CAT (n = 12). MAIN OUTCOME MEASURES: Recurrence of pterygium, improvement in ocular movement, and symblepharon formation. RESULTS: Twenty-three (85.2%) of 27 eyes showed no recurrence with a mean observation period of 67.0 weeks. Fourteen eyes (93.3%) each showed improvement in ocular movement restriction and symblepharon after AMT. In four eyes that developed recurrence, three had LAT and one had CAT combined with AMT, suggesting that there was no difference in surgical outcome between LAT and CAT. CONCLUSIONS: AMT with CAT is a safe and effective method for recurrent pterygium, especially that associated with ocular movement restriction and symblepharon. Considering the potential adverse effects associated with limbal excision, AMT plus CAT may be preferred over AMT plus LAT.

Adolescent↗