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Biomedical subjects

K Tsubota

Publications and source records attributed to K Tsubota.

At least 109 records · Page 6Linked to original sources
PubMed1998

[Cytologic evaluation of dry eye by brushing procedure: value of slide preparation by ThinPrep technique].

Recent clinical trials have indicated that an automated smear apparatus (ThinPrep process) of sample preparation has great diagnostic sensitivity. In this study, conjunctival brush cytology prepared using the ThinPrep method was applied in ocular surface disorders especially for dry eye status. To assess its diagnostic value in cellular samples, 35 patients with keratoconjunctivitis sicca (KCS) and 12 normal volunteer patients were examined using this technique. Conjunctival cells from normal controls revealed fine chromatin and polyhedral cytoplasm without keratinized cytoplasm. However, cellular samples from KCS revealed increased keratinized cells with pyknotic nuclei. They also contained extremely elongated cells. In KCS patients, the mean numbers of keratinized cells were significantly higher (32.3 cells/300 cells) than those of the normal control group (0.2 cells/300 cells). In patients with KCS, inflammatory cell counts were also higher than those of normal controls. Conjunctival cytology by the ThinPrep method obviously deserves additional trials as an adjunct to cytological evaluation of dry eye status, especially for quantitative ocular evaluation of various ocular lesions.

Cell Count↗
PubMed1998

Trabeculectomy with the use of amniotic membrane for uncontrollable glaucoma.

Although trabeculectomy is an established surgical technique for glaucoma, in some cases it does not achieve a good filtering effect despite the use of mitomycin-C (MMC). The authors have developed a new surgical technique for uncontrollable glaucoma that uses amniotic membrane to prevent postoperative adhesion of conjunctiva and sclera. They performed trabeculectomy with a limbal-based conjunctival flap using 0.4 mg/ml of MMC for 2 minutes. Amniotic membrane was then placed under the scleral flap and sutured using 10-0 nylon. Among 14 eyes of 13 patients who underwent this procedure, intraocular pressure was controlled to less than 20 mm Hg after surgery in 13 eyes, including 3 eyes that underwent a second surgery with the same technique and 2 eyes that underwent laser trabeculoplasty. The authors' results suggest that this technique is efficacious for the reduction of intraocular pressure in high-risk glaucoma patients.

Adult↗
PubMed1998

Terrien's marginal degeneration associated with erythema elevatum diutinum.

PURPOSE: To describe a patient with Terrien's marginal degeneration associated with a chronic skin disease, erythema elevatum diutinum. METHODS: A 27-year-old woman with peripheral thinning of her left cornea associated with adjacent conjunctival and episcleral inflammation was clinically examined. RESULTS: Episodes of worsening skin lesions were associated with development of inflammation in her left eye. Administration of sulfones was effective for reducing both skin and ocular inflammation. CONCLUSION: Erythema elevatum diutinum should be considered an underlying systemic disease of Terrien's marginal degeneration.

Adult↗
PubMed1998

Reoxygenation injury in a cultured corneal epithelial cell line protected by the uptake of lactoferrin.

PURPOSE: To investigate whether reoxygenation after extended hypoxia causes cellular damage in cultured corneal epithelial cells and to demonstrate the protective effects of lactoferrin. METHODS: Immortalized human corneal epithelial cells (T-HCECs) were cultured to confluence in 96-well culture plates, subjected to stringent hypoxia (1% O2, 5% CO2, 94% N2 at 37 degrees C) for 24 hours, and returned to normoxic conditions (5% CO2, 95% air at 37 degrees C). Cell viability was observed by 1 microM propidium iodide staining 0, 2, 4, and 6 hours after reoxygenation. Inhibition studies were performed after 2 hours' reoxygenation, using 2 mM iron chelator desferrioxamine and 0.2 mg/ml lactoferrin. Confocal immunocytochemistry for human lactoferrin and western blot analysis for lactoferrin-induced ferritin were performed in cultured T-HCECs to demonstrate the internalization of lactoferrin after application. RESULTS: After 2 hours, reoxygenation of T-HCECs after hypoxia produced an increase in cell death that was significantly greater than that observed in normoxic control cells or in cells subjected to hypoxia for the same time span without reoxygenation. The addition of desferrioxamine and lactoferrin at the time of reoxygenation significantly attenuated cellular damage. Confocal immunocytochemistry revealed that lactoferrin is taken into the cytoplasm of T-HCECs as early as 30 minutes after application. This was also demonstrated in western blot analysis by the upregulation of intracellular ferritin at 18 hours by the addition of iron-bound lactoferrin but not by iron-free lactoferrin. CONCLUSION: Reoxygenation is responsible for increased cellular damage after extensive hypoxia, which is attenuated by chelators of free iron in the cytosol, including the major tear protein lactoferrin.

Blotting, Western↗
PubMed1998

Respiratory syncytial virus-induced interleukin-4 production by human conjunctival epithelial cells contributes to allergy: preliminary study.

PURPOSE: We previously reported allergic conjunctivitis was associated with a local pattern of cytokines and identified respiratory syncytial virus (RSV) in the conjunctival epithelium, in patients with allergic conjunctivitis. We hypothesized that RSV infected the normal conjunctival epithelium and produced interleukin-4 (IL-4), causing an allergic reaction. To determine this event, we studied production of IL-4 by human conjunctival epithelial cells, after infection with RSV. METHODS: Conjunctival samples were collected with a special brush and were challenged with 5 x 10(6) pfu/ml of live RSV. RSV infection was detected by immunocytochemical study and RT-PCR. HLA-DR antigen was expressed by flow cytometry. IL-4 was assayed by a sandwich ELISA. RESULTS: Immunocytochemical study and RT-PCR showed that RSV infected the conjunctival epithelial cells. HLA-DR was demonstrated in the RSV-infected conjunctival epithelial cells. Average concentrations of IL-4 in culture supernatants in infected cells were 3.8 +/- 1.8, 3.6 +/- 1.1, and 5.4 +/- 1.8 pg/ml at 24, 48, and 72 h, respectively. Levels in non-infected cells were 0.33 +/- 0.0, 0.59 +/- 0.69, and 0.4 +/- 0.22 pg/ml, respectively (p > 0.001). CONCLUSION: Findings suggest that the expression of IL-4 is associated with intracellular infection by RSV in conjunctiva. With our former reports, RSV infection in conjunctival epithelial cells can be suggested as one of the possible environmental pathogens of allergic conjunctivitis.

Adolescent↗
PubMed1998

Use of topical cyclosporin A in a primary Sjögren's syndrome mouse model.

PURPOSE: A new animal model, the NFS/sld mutant mouse, was used for primary Sjögren's syndrome to investigate the efficacy of topical and systemic cyclosporin A (CyA) in preventing inflammation of the exocrine glands. METHODS: Cyclosporin A was applied topically (0.01% and 0.1%, three times a day) or administered orally (10 mg/kg and 100 mg/kg, once a day) to mice from 6 to 16 weeks of age, after which the mice were killed. RESULTS: Topical CyA reduced lacrimal gland and submandibular gland inflammation without causing pathologic changes in other organs. Flow cytometry showed that CD44 expression of CD4 T cells from the submandibular lymph nodes was downregulated, whereas that of Mel14+ was upregulated. Using a reverse transcription-polymerase chain reaction assay, we determined that topical CyA significantly decreased the expression of mRNA of IL-2 and T-cell receptor-constant beta-chain. CONCLUSIONS: Topical CyA may be clinically useful in reducing the lymphocyte infiltration of lacrimal glands associated with Sjögren's syndrome.

Administration, Oral↗
PubMed1997

Association between HLA-DPB1 matching and 1-year rejection-free graft survival in high-risk corneal transplantation.

We analyzed the effect of matching for HLA class II alleles on corneal graft outcome in a single-center, retrospective study from January 1991 through April 1996. The study involved 81 transplant recipients at high and low risk of corneal graft rejection, who were typed by the polymerase chain reaction-restriction fragment length polymorphism method and who completed at least 1-year of follow-up. The DRB1, DQB1, and DPB1 alleles were analyzed together and transplant recipients were subdivided into groups with matching (one to four alleles matched in the high risk or one to five alleles matched in the low risk) and without matching (no allele matched) for HLA class II. A significantly higher rate of 1-year rejection-free graft survival was revealed in high-risk transplant recipients with matching, compared with those without matching (P=0.0238). We have shown that matching for at least one HLA class II allele was actually beneficial in high-risk transplants. An analysis of matching for each allele separately, detected that only HLA-DPB1 matching was significantly associated with a higher rate of 1-year rejection-free graft survival in high-risk transplant recipients with matching (one or two alleles matched) compared with those without matching (no allele matched) (P=0.0139). In particular, matching for one DPB1 allele was significantly beneficial compared with no matching (P=0.0140). There was no significant effect of HLA-DRB1 and -DQB1 matching (P=0.3177 and P=0.2878, respectively). Furthermore, a strong association between DPB1 matching and 1-year rejection-free graft survival was observed in DRB1-incompatible high-risk transplant recipients (P=0.0308). Nevertheless, no significant effect of DPB1 matching was detected in DQB1-incompatible transplant recipients. Our findings indicate that HLA class II DNA typing is clinically relevant for corneal transplant recipients and that especially HLA-DPB1 matching has a beneficial effect in high-risk corneal transplantation.

Adolescent↗
PubMed1997

Evaluation of human conjunctival epithelium by a combination of brush cytology and flow cytometry: an approach to the quantitative technique.

Cytology using the brush technique is readily available and is a rapid means of establishing a presumptive diagnosis of ocular surface changes. However, those techniques have some limitations when obtaining cells from certain localized areas particularly if using the Cytobrush-S. We have described here a new type of brush (Accellon-M), which can collect the local cells using its spherical tip, and evaluated them by comparing with Cytobrush-S. Furthermore, we differentiated epithelial cells from nonepithelial cells that were collected by brushing, and by a combination of brush cytology and flow cytometry using an anti-keratin antibody, AE-3, which reacts with all basic epithelial keratins. Accellon-M could collect the epithelial cells from conjunctiva as effectively as with the Cytobrush-S, and there were no statistical differences between both groups. AE-3, which is reported as the marker of epithelial cells, were detected quantitatively by a combination of brush cytology and flow cytometry techniques. The result of the present study emphasizes that both the Cytobrush-S and the Accellon-M are valuable for conjunctival brush cytology. An additional positive feature of the Accellon-M may be improved cell collection from the conjunctival epithelium especially when the target cells are in a limited area. The combination of the brush cytology and the flow cytometry technique appears to be a useful adjunct as an additional diagnostic or research tool for use in the detection of various antigens in the conjunctival epithelium.

Adult↗
PubMed1997

Ex vivo phosphorus magnetic resonance spectroscopy on eye bank corneas and corneal metabolic health.

BACKGROUND: Since a potential exists for untoward effects on the cornea from the high magnetic fields and radio-frequency energies, and the further manipulation required for phosphorus-31 magnetic resonance spectroscopy (31P-MRS), we determined the effects of this technology on tissues using paired human corneas (n = 4) meeting criteria acceptable for transplantation. METHODS: Slit-lamp biomicroscopy, pachometry, specular microscopy, and redux fluorophotometry were performed on all corneas. One cornea of each pair was examined (< 30 min) by 31P-MRS. Following 31P-MRS, slit-lamp biomicroscopy, pachometry, and redox fluorophotometry were again performed. RESULTS: Data tabulated included the 31P energy modulus (1.37 +/- 0.28), the ATP/Pi (2.92 +/- 0.59) and SP/Pi (0.76 +/- 0.04) ratios, and the intracorneal pH (7.24 +/- 0.09). CONCLUSION: Since there were no significant differences in slit-lamp biomicroscopy, endothelial density and morphometry, cell counts, and pachometric and redox fluorophotometric measurements between corneas of each pair before and after 31P-MRS analysis, it was concluded that there was no detectable metabolic damage secondary to such analysis. This study suggests that MRS analysis of human eye-bank tissues does not damage the cornea metabolically and may provide a practical evaluation of the health of the cornea at the biochemical level.

Adenosine Triphosphate↗
PubMed1997

Blinking is controlled primarily by ocular surface conditions.

PURPOSE: To investigate the relation between blinking and ocular surface conditions and to introduce and examine a new index, the maximum blink interval. METHODS: In a prospective study, the blink rate of subjects under relaxed conditions was determined from a video recording taken by a hidden observer. The maximum blink interval was defined as the longest time subjects can avoid blinking without feeling uncomfortable. RESULTS: Significant changes in the blink rate and maximum blink interval were induced by factors that directly or indirectly affect the ocular surface: topical anesthesia, changing exposed ocular surface area, and wind. Moreover, the blink rate and maximum blink interval were significantly different in dry eye patients compared with healthy volunteers, with the values of the former approaching the values of the latter after use of artificial tears. The maximum blink interval was decreased by the same factors that increased the blink rate, and there was a significant inverse correlation between blink rate and maximum blink interval. Use of video display terminals was associated with decreased maximum blink interval and, hence, the development of dry eye symptoms. CONCLUSIONS: There was an important association among blink rate, maximum blink interval, and ocular surface conditions. The blink rate and our newly introduced measurement, the maximum blink interval, should prove useful in assessing factors that cause dry eye. This prospective study should contribute to the understanding and treatment of dry eyes.

Administration, Topical↗
PubMed1997

Lacrimal punctal occlusion for the treatment of superior limbic keratoconjunctivitis.

PURPOSE: To test the hypothesis that superior limbic keratoconjunctivitis is caused by insufficient tear supply to the superior keratoconjunctiva. METHODS: We used cautery and sutures to permanently occlude the lacrimal puncta of 11 patients (22 eyes) with superior limbic keratoconjunctivitis for whom topical treatment was ineffective. RESULTS: All 11 patients (22 eyes) responded favorably to lacrimal punctal occlusion. After lacrimal punctal occlusion, rose bengal and fluorescein staining (both on a scale of 0 [no staining] to 9 [complete staining]) were reduced (mean +/- SD, 2.7 +/- 1.6 to 1.1 +/- 1.8 and 1.4 +/- 1.2 to 0.4 +/- 0.8, respectively). Impression cytology disclosed improvement of squamous metaplasia in the superior conjunctiva as well as increased goblet cells in nine of 13 eyes (69%) examined. Subjective symptoms improved in all 22 eyes (100%). CONCLUSIONS: Improvement of local tear deficiency to the superior limbic portion by punctal occlusion was an effective treatment in this small series. Superior limbic keratoconjunctivitis might be caused by the insufficient local tear supply.

Adult↗
PubMed1997

Use of high-speed, high-resolution thermography to evaluate the tear film layer.

PURPOSE: To evaluate the tear film layer in patients with dry eye and in normal subjects by measuring the corneal temperature with infrared radiation thermography. METHODS: One eye of each of 13 patients with dry eye and one eye of each of seven normal subjects were evaluated randomly. The corneal temperature was measured continuously with a recently improved infrared radiation thermography technique. We calculated the k value, which reflected the steepness of the corneal temperature change. The bigger the k value was, the more rapid was the decrease in corneal temperature, and this was directly related to increased evaporation. RESULTS: With normal blinking, the mean k value for patients with dry eye (5.6 +/- 2.9 per second) was significantly less than that in the control subjects (9.3 +/- 5.0 per second; P < .05). Keeping the eyes open after closing the eyes significantly decreased the k values compared with normal blinking in both groups (P < .05). CONCLUSIONS: Our findings demonstrate the usefulness of this method of measuring corneal temperature to evaluate the tear film layer. High-speed, high-resolution thermography detected subtle changes in corneal temperature with enhanced sensitivity and spatial and temporal resolution. We found that the mean k value, and therefore the rate of decline in corneal temperature in patients with dry eye, was significantly less than that in normal subjects. The k value may therefore reflect tear film layer stability. The measurement of the changes in the corneal temperature can thus give us valuable information on the tear film layer.

Adult↗
PubMed1997

Important concepts for treating ocular surface and tear disorders.

PURPOSE: To outline important concepts for treating ocular surface and tear disorders. METHOD: A review was conducted of recently published findings. RESULTS: Five concepts were delineated: ocular surface health is ensured by a close relationship between ocular surface epithelia and the preocular tear film; a stable tear film is inherently maintained by external adnexae; the intact protective mechanism is controlled by effective neuroanatomic integration; corneal epithelial stem cells are located at the corneoscleral limbus; and ocular surface epithelial cell function is supported by stromal fibroblasts and matrix. CONCLUSIONS: These concepts stress that ocular surface epithelia and the preocular tear film function as a unit and, furthermore, that several corneal and external diseases can be categorized as ocular surface and tear disorders. These concepts also help one formulate unified diagnostic and therapeutic strategies for management of these diseases.

Animals↗
PubMed1997

Analysis of videokeratography after penetrating keratoplasty: topographic characteristics and effects of removing running sutures.

OBJECTIVE: Previous studies have shown that removal of running sutures after penetrating keratoplasty causes unpredictable changes in astigmatism. The current study was conducted to investigate whether computer-assisted videokeratography is beneficial for predicting visual outcomes after running sutures are removed. DESIGN: The design was that of a prospective clinical study. PARTICIPANTS: The authors prospectively studied 29 consecutive eyes undergoing a 10-0 nylon running suture removal after penetrating keratoplasty. INTERVENTIONS: Videokeratography was performed before, 1 week, 1 month, and 3 months after removal of sutures. MAIN OUTCOME MEASURES: Changes in refractive and topographic astigmatism after suture removal were measured. Topographic patterns and their quantitative descriptors also were analyzed. RESULTS: An asymmetric bowtie was the most common videokeratography pattern both before and after suture removal. After suture removal, the incidence of peripheral corneal steepening increased significantly (2 vs. 21 eyes, P < 0.0001), and that of focal flattening of the midperipheral cornea decreased (13 vs. 5 eyes, P = 0.046). The mean topographic astigmatism, surface regularity index, and corrected visual acuity were improved significantly by suture removal in eyes that had localized flattening but not in eyes without this finding. Eyes having either skewed axis in astigmatism or topographic astigmatism of more than 9 diopters also showed significant decreases in astigmatism. CONCLUSIONS: Suture removal after keratoplasty is advantageous for both reducing astigmatism and normalizing topography, especially in eyes that have localized flattening of the midperipheral cornea. Predictability of visual outcomes of a running suture removal in postkeratoplasty eyes may be improved by the use of videokeratography.

Adolescent↗
PubMed1997

Amniotic membrane transplantation for ocular surface reconstruction in patients with chemical and thermal burns.

OBJECTIVE: The purpose of the study is to examine the usefulness of preserved human amniotic membrane transplantation in patients with chemical and thermal burns. DESIGN: The study design was a nonrandomized clinical trial. PARTICIPANTS: Seven eyes of six patients with severe chemical (n = 5) and thermal (n = 2) burns were studied. INTERVENTION: Eyes were treated with excision of cicatricial tissues followed by a placement of amniotic membrane on the sclera. Transplantation of limbal grafts from an opposite eye (n = 4) or from donor eyes preserved at -80 degrees C (n = 2) was performed simultaneously. MAIN OUTCOME MEASURES: Reconstruction of ocular surface epithelia and visual acuity were measured. RESULTS: With the mean observation period of 53.3 weeks, central corneal epithelium was reconstructed successfully in all eyes. Neither amniotic membrane nor limbal grafts were rejected. A persistent epithelial defect developed in one eye, which was treated successfully by tarsorrhaphy. After surgery, the corneal epithelium showed normal arrangements on specular microscopy, and its barrier function recovered to seminormal. Corrected visual acuity markedly improved in each eye. Regenerated conjunctiva on the amniotic membrane was stable and uninflammed with minimum-to-mild scarring. Slight recurrence of conjunctivalization was noted in three eyes. However, because these eyes were stable and central cornea was clear, no further surgery was needed. CONCLUSIONS: Amniotic membrane transplantation promotes normal conjunctival epithelialization while suppressing fibrosis formation. The procedure, especially when performed with limbal autograft transplantation, appears to be effective for the treatment of chemical or thermal burns of the ocular surface.

Adolescent↗
PubMed1997

Cytologic evaluation of conjunctival epithelium using Cytobrush-S: value of slide preparation by ThinPrep technique.

Recent clinical trials have indicated that an automated smear apparatus (ThinPrep process) of sample preparation has great diagnostic sensitivity. In this study, conjunctival brush cytology prepared using the ThinPrep method was applied in ocular surface disorders especially for dry eye status. To assess its diagnostic value in cellular samples, 17 patients with keratoconjunctivitis sicca (KCS) and 10 normal volunteer patients were examined using this technique. Conjunctival cells from normal controls revealed fine chromatin and polyhedral cytoplasm without having keratinized cytoplasm. On the other hand, the cellular samples from KCS revealed increased keratinized cells with pyknotic nuclei. They also contained extremely elongated cells. In KCS patients, the mean number of keratinized cells was significantly higher (34.1 cells/300 cells) than that of the normal control group (0.2 cells/300 cells). In patients with KCS, inflammatory cell counts were also higher than those of normal controls. Conjunctival cytology by means of the ThinPrep method obviously deserves additional trials as an adjunct in the cytology of dry eye states, especially in quantitative ocular evaluation for various ocular lesions.

Conjunctiva↗