摘要:

Purpose.To describe the differences of corneal endothelial cell densities, cell size variability and cell hexagonality in cataract populations of south Asia between sexes and ethnic groups.Methods.1,235 eyes of 1,235 male and female patients 40–75 years of age with senile cataract were examined with non contact specular microscopy with semi-automated analysis technique. The cell data of the study population was analyzed in relation to age, sex, and ethnic groups. Mean arithmetic differences and the coefficient of variation of repeated observations were calculated to estimate precision of the technique utilized. The main outcome measures were corneal endothelial cell density, cell size variability and cell hexagonality.Results.The mean corneal endothelial cell density was 2,720 cells/mm2, mean cell size variability was 37.8% and percent cell hexagonality 40%. We found statistical significant difference between the three ethnic populations in all the corneal endothelial cell measurements (p< 0.0001). Females had a 2.9% greater cell density than males (p= 0.0001). There was no significant difference in mean cell density according to age. Variability of cell size, however, increased with age (p< 0.001). These findings were consistent across the three ethnic groups.Conclusions.In a total sample of 1,235 eyes distributed evenly in three cataract patient populations of south Asia, we found statistically significant differences of corneal endothelial cell densities of cell size variability and cell hexagonality between sexes and ethnic groups.

ISSN:0277-3740    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

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 &mgr;m2significantly 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.

ISSN:0277-3740    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Purpose.To identify the mutation in the keratoepithelin gene for proper diagnosis of granular corneal dystrophies.Methods.Four generations of a single family with corneal dystrophy were analyzed. Fourteen family members were examined and 11 were found to be affected by clinical evaluation. Genetic DNA was extracted from proband's leukocytes for molecular analysis. Exons 4 and 12 of the BIGH3gene were amplified then directly sequenced.Results.The clinical appearance of corneas consisted of grayish white granules with sharp borders, fine dots, and radial lines in the superficial part of the central corneal stroma, which resembles granular and Avellino corneal dystrophies. Performing BIGH3gene analysis, we observed a C-to-T transition at position 1710 (CGG to TGG) producing R555W mutation, which is a hot spot for granular corneal dystrophy.Conclusion.Direct clinical examination may be insignificant in the proper diagnosis of corneal dystrophies, and molecular genetic approach may be required.

ISSN:0277-3740    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Purpose.To study the effects of antiviral agents on human keratocytes in vitro.Methods.Cultured human keratocytes were incubated with either ganciclovir, idoxuridine, trifluridine, or cidofovir at concentrations from 0.0001 to 10 mg/mL. Phase-contrast microscopy and XTT (sodium [2,3-bis [2-methoxy-4-nitro-5-sulphophenyl]-2h-tetrazolium-5-carboxanilide, inner salt) colorimetric assay were performed after 24, 48, and 72 hours of incubation.Results.When adjustments were made for time of incubation and concentration, trifluridine reduced cell viability significantly more than ganciclovir, idoxuridine, and cidofovir (p< 0.001, three-way analysis of variance). There was significant time-and dose-dependent reduction of cell viability (p< 0.001) with trifluridine and cidofovir. After a 72-hour incubation with ganciclovir or idoxuridine, cell viability was reduced as compared with 24-and 48-hour incubation (p< 0.001); only the effects of the highest concentration tested (1.0 mg/mL) were significantly different from those of the lower concentrations (p< 0.002). At a concentration of 1.0 mg/mL, trifluridine and cidofovir produced moderate to severe signs of cytotoxicity, whereas ganciclovir and idoxuridine displayed much less severe morphologic signs.Conclusions.Our results indicate that antiviral agents may have both time-and concentration-related toxic effects on stromal keratocytes. These findings may impact the selection of the most appropriate antiviral drug when it is needed to treat infections involving the corneal stroma.

ISSN:0277-3740    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Purpose.To evaluate for the first time cell junctional protein organization in proliferating corneal endothelial cells during in vivo wound healing.Methods.A total of 16 cats (32 eyes) were used in this study. A single 3-mm diameter (n= 24) or 1-to 2-mm diameter (n= 8) scrape injury was created in the central corneal endothelium of each eye. Twenty-four, 48, 72 hours or 5 days after scrape injury, eyes were collected for in situ double-or triple-labeling with phalloidin, anti-ZO-1, &agr;-catenin, &bgr;-catenin, and MIB-1 (monoclonal antibody to Ki67, a marker for actively cycling cells) and were imaged using confocal laser microscopy.Results.In 3-mm diameter injuries, endothelial cells completely resurfaced the wound 48 to 72 hours after scrape injury; smaller wounds resurfaced by 48 hours. Ki67 staining was negative 24 hours after scrape injury in all cases. Ki67-positive cells were observed in the central region of the wounds after 48 and 72 hours, and mitotic figures and pairs of postmitotic cells were observed. On day 5, Ki67-positive cells were rarely detected, and no mitotic figures were observed. In the wound area, a significant increase in cell area and a reduction in hexagonality were observed in cycling cells after 48 and 72 hours. Normal apical, pericellular staining of f-actin, ZO-1, &agr;-catenin, and &bgr;-catenin was partially maintained at all times during wound healing of small and large wounds. Double-labeling confirmed that these proteins were also present along the apical cell border in Ki67-positive cells.Conclusions.After in vivo scrape injury, proliferation is limited temporally and spatially to spreading endothelial cells within the wound. Cell junctional connections appear to be maintained in actively cycling cells during healing.

ISSN:0277-3740    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Purpose.To investigate the distribution and relative level of expression of the receptor tyrosine kinases, epidermal growth factor receptor (EGFR), ErbB2 and ErbB3, in human ocular surface epithelia.Methods.Immunofluorescent staining was performed to identify expression of the EGFR, ErbB2 and ErbB3 in the corneal, limbal and conjunctival epithelium in tissue sections and impression cytologies taken from normal human eyes. Western blotting was undertaken to confirm the results of immunofluorescent staining.Results.The three receptor tyrosine kinases, EGFR, ErbB2 and ErbB3, were detected in human corneal, limbal and conjunctival epithelia by immunofluorescent staining. Strong staining for the EGFR was observed in the basal epithelial cells at all 3 sites and throughout the corneal epithelium. Minimal or no staining for the EGFR was observed in the superficial conjunctival and limbal epithelia. The strongest staining for ErbB2 and ErbB3 was observed in the superficial ocular surface epithelium. All three receptors were detected in the corneal, limbal and conjunctival epithelium by western blot.Conclusion.EGFR, ErbB2 and ErbB3 are expressed by the ocular surface epithelia. EGFR is preferentially expressed by the basal epithelial cells that have the greatest proliferative potential. In contrast, ErbB2 and ErbB3 are preferentially expressed by the superficial differentiated ocular surface epithelia.

ISSN:0277-3740    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Purpose.Keratocytes are important in regaining corneal transparency during wound healing after surgery or trauma. Hitherto, there are still controversies concerning the effects of organ culture on the density and integrity of keratocytes and collagen fibers. The current study aimed at a systematic analysis of the effects of organ-culture on the morphology and density of keratocytes and collagen fibers.Methods.Human corneas were organ-cultured in MEM for 7 (n=17, 3 pairs), 14 (n=18, 9 pairs) and 21days (n=18, 9 pairs). Of the pairs one cornea was processed in swollen condition and the fellow cornea after reversal of swelling in MEM plus Dextran. Eleven post-mortem corneas (PM) and 11 fresh corneas obtained from melanoma patients were used as controls. Stromal thickness, number of keratocyte profiles (corrected for swelling), number and diameter of collagen fibers were measured in light microscopical sections and electron micrographs.Results.Stromal swelling due to organ-culture resulted in large keratocyte profiles with many vacuoles and large distances between collagen fibers in the posterior stroma. In contrast both keratocytes and distances between collagen fibers were not affected in the anterior stroma. After reversed-swelling the posterior corneal stroma was similar to that in fresh controls, indicating that the swelling process is largely reversible. The initial decrease in keratocyte density (18%) in the early post-mortem period did not progress during 21 days of organ culture.Conclusion.With respect to the morphology and density of keratocytes and collagen fibers it can be concluded that donor corneas remain suitable for transplantation up to at least 21days after organ-culture.

ISSN:0277-3740    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Purpose.To study the early events in corneal neovascularization after alkali injury and their relationship to the presence and absence of leukocytes.Methods.A standardized 5.5-mm diameter penetrating central corneal alkali wound was induced in one eye in each of ten New Zealand white rabbits (2.5 kg). In five of the ten rabbits, 1.5 mL 5% fucoidin was given intravenously every 2 hours to prevent leukocytes from leaving the blood stream. Presence of hyaluronan (HA) and proliferating cell nuclear antigen (PCNA) in the corneas were analyzed using immunohistochemical staining 36 hours after injury.Results.In the alkali wounded corneas, HA was expressed intensively in the limbal area where a massive infiltration of leukocytes was seen. PCNA was expressed in the vascular endothelium as well as in the corneal cells. In the leukocyte-free corneas, HA staining intensity and distribution were the same as in uninjured corneas. No positive PCNA staining was seen in the vascular endothelial cells in these corneas.Conclusions.Extravasated leukocytes in the alkali-burned corneas caused enhanced production of HA and proliferation of vascular endothelial cells.

ISSN:0277-3740    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Purpose.A web-like retrocorneal membrane (RCM) is an uncommon complication of chronic syphilitic interstitial keratitis. Extracellular matrix components have not yet been defined in this structure, although previous histologic examinations have suggested the presence of collagen. We examined the presence and distribution of extracellular matrix components in a patient with an RCM.Methods.A specimen of the opaque cornea affected by syphilitic interstitial keratitis with RCM formation was obtained during penetrating keratoplasty in a 62-year-old woman and was evaluated by histology, immunohistochemistry, and scanning electron microscopy (SEM). Antibodies against collagen types I, III, and IV; fibronectin; vimentin; &agr;-smooth muscle actin (&agr;-SMA); heat shock protein 47 (Hsp 47); proliferating cell nuclear antigen (PCNA); and Ki67 were used.Results.Histologic analysis detected multiple concentric, acellular layers positive for collagen types I, III, and IV. The corneal endothelial cells (CECs) were positive for vimentin, collagen I, fibronectin, and Hsp 47 but not for &agr;-SMA. Furthermore, the CECs were negative for PCNA and Ki67, indicating that they were not proliferating. SEM revealed the RCM was covered by CECs with a fibroblastic appearance.Conclusion.RCM associated with syphilitic interstitial keratitis contained collagen types I, III, and IV and fibroblast-like CECs. These CECs may secrete the extracellular matrix components found in the RCM. Hsp 47 up-regulation in the CECs may play an important role in RCM formation. These findings provide further insights into the phenotypic modulation of CECs.

ISSN:0277-3740    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Purpose.Although oxygen transmissibility has been a favored index to describe the physiologic performance of contact lenses, it has been maintained by some that the flux through a contact lens would be a more useful guide. Here, a model is described that allows contact lens oxygen flux to be estimated under open and closed eye wearing conditions.Methods.The equivalent oxygen potential (EOP) was used to approximate the oxygen concentration beneath a contact lens. A logarithmic relation between corneal oxygen consumption and this oxygen level was substituted into Fick's Law to provide a mathematical model. Paired data of EOP and oxygen transmissibility (Dk/t), from a previous empiric derivation, were entered into a nonlinear regression analysis of this model.Results.The modelling procedure produces a good fit to the selected data. The estimated maximum flux during open eye wear is 7.5 &mgr;L/cm2.h, consistent with previous determinations. Error estimates increased from 0 to 0.55 &mgr;L/cm2/h atDk/tvalues of 0 and 200 × 10−9Barrer/cm, respectively, for the open eye.Conclusion.This study provides a workable model for estimating the oxygen flux through contact lenses. Varying the underlying relation between the oxygen tension beneath a lens and the oxygen flux produces minimal variation to the result. The model has a number of clinical applications, such as demonstrating the advantages of highly transmissible contact lenses and the limits to which increasing oxygen transmissibility can alter the corneal physiologic environment.

ISSN:0277-3740    

出版商:OVID    

年代:2001

数据来源: OVID