摘要:

Purpose. To evaluate the effects of low-dose UVB irradiation of HLA and CDla expression and the toxic effects of UVB on human corneas.Methods. 24 pairs of human corneas from 24 donors were studied. One cornea from each pair was randomly irradiated with UVB (100 mJ/cm2) after enucleation. All corneas were then organ-cultured for 2, 7, 14 or 21 days. Endothelium was studied after enucleation and organ culture. Following preservation, corneas were evaluated by means of light microscopy, morphometry and TEM. HLA and CDla staining was performed using an immuno-alkaline-phosphatase technique.Results. Endothelial cell loss during organ culture averaged 9.1% in the UVB group and 9.2% in the control group (NS). The number of rosette and reformation figures (p = 0.004) and the coefficient of variation (p = 0.014) were higher in the control group. Epithelial sloughing was more accentuated in the UVB group. We observed the same moderate ultrastructural injuries in both groups. In the epithelium, the average number of HLA-DR + cells per field was 0.12 in the UVB group and 0.42 in the control group (p = 0.035). In the stroma, these figures were respectively 1.04 and 1.34 (p = 0.026). In the epithelium, the average number of CDla + cells was respectively 0.025 and 0.078 (p = 0.019). In the preservation mediums, the average percentage of CDla + cells was 0.07% in the UVB group and 0.27% in the control group (p = 0.014).Conclusions. Low-dose UVB (100 mJ/cm2) decreases HLA-DR and CDla expression of organ-cultured human corneas and induces moderate corneal injuries. Low-dose UVB might be useful for preventing allograft rejection.

ISSN:0271-3683    

DOI:10.3109/02713689609008908

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

Purpose. Hyperthermia has been shown to induce HSV-1 ocular shedding in mice. Systemic administration of propranolol significantly reduced the recovery of infectious virus in the tears, cornea, and trigeminal ganglia of mice subjected to hyperthermia. The present study was performed to determine the effects of systemic propranolol on ocular shedding and recurrent corneal epithelial lesions in the rabbit model.Methods. New Zealand white rabbits were infected with HSV-1 strain McKrae or 17Syn+. After latency was established, the animals were treated with systemic propranolol or saline (control) and examined by slit lamp biomicroscopy for corneal lesions. Tear film swabs were cultured to determine the frequency and duration of viral shedding.Results. Propranolol caused a significant reduction in the frequency and duration of ocular HSV-1 shedding and a reduction in the frequency of recurrent corneal epithelial disease, compared with saline treatment.Conclusions. These results suggest that beta-adrenergic receptor blockers such as propranolol could be useful in suppressing HSV-1 ocular recurrences and corneal disease.

ISSN:0271-3683    

DOI:10.3109/02713689609008909

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

Purpose. A Class 3 aldehyde dehydrogenase happens to be a major soluble protein constituent of the cornea. Its role is conjectured to be manifold: to protect the tissue from oxidative damage by eliminating the toxic aldehydes produced upon lipid perox-idation under oxidative stress, to act as an UV-absorber, and to maintain the level of the coenzyme NADH in the cornea. We have studied the effect of UVB on the structure and enzyme activity of corneal aldehyde dehydrogenase.Methods. Aldehyde dehydrogenase was irradiated at 295 nm for varying periods of time and change in its enzyme activity assayed. The structural changes in the molecule accompanying irradiation were monitored using fluorescence and circular dichroism spectroscopy, and its hydrodynamic behavior and surface hydrophobicity studied using gel filtration chromatog-raphy and binding of the hydrophobic fluorophore ANS. The protective ability of aldehyde dehydrogenase in preventing aggregation of photolabile proteins, such asΓ-crystallin of the eye lens, was studied by monitoring the scattering value of the test protein with irradiation by UVB.Results. Aldehyde dehydrogenase is seen to undergo photo-damage with alterations in its quaternary structure, though no significant change is noticed in the peptide chain conformation. Under such conditions the molecule continues to act as a protec-tant by preventing aggregation of photolabile proteins such as the eye lensΓ-crystallin.Conclusions. Our earlier studies have shown that the free sulfhy-dryl groups are important for the antioxidant abilities of aldehyde dehydrogenase. Its protective ability towards photoaggregation ofΓ-crystallin seen here might arise both due to: (i) oxyradical quenching and (ii) the increased surface hydrophobicity of the molecule upon irradiation, which allows it to bind to, and thus inhibit the aggregation of interacting proteins.

ISSN:0271-3683    

DOI:10.3109/02713689609008910

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

Purpose. Laser Doppler interferometry (LDI) permits the measurement of intraocular distances to a precision of better than 20μm. The signal complex from the posterior segment of the eye consists of four peaks in the chick, an animal frequently used in ocular development studies. The present study sought to identify anatomical landmarks corresponding to these LDI peaks.Methods. Distances obtained with LDI at the posterior pole were compared to axial length components measured with three independent methods: vernier calipers, tissue sections and high frequency A-scan ultrasound.Results. LDI reflections appear to originate from the retinal inner limiting membrane, Bruch's membrane and the inner and outer scleral surfaces.Conclusions. The non-invasive and highly precise nature of LDI measurements enables repetitive and accurate assessment of intraocular distances. Such measurements should prove particularly useful for the assessment of short-term cyclic variations in intraocular distances as well as post-natal eye growth.

ISSN:0271-3683    

DOI:10.3109/02713689609008911

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

Purpose. To investigate the occurrence of contaminated cultures of vitreous specimens from non-infected eyes obtained using anaerobic techniques employed for endophthalmitis.Methods. Vitreous specimens were obtained using meticulous sterile techniques employed for endophthalmitis from seventeen patients undergoing pars plana vitrectomy for non-infective indications: vitreous hemorrhage (12 eyes), retinal detachment (3), Coat's disease (1), and congenital dislocated lens (1). Vitreous specimens were inoculated in the operating room onto an anaerobic blood agar plate and into thioglycolate broth. Bacterial growth occurring before 10 days was considered positive.Results. Three organisms were isolated from three separate eyes. One colony of Staphylococcus species was isolated on an anaerobic blood agar plate on day 3. A single colony ofPropionibac-terium acnesgrew on an anaerobic blood agar plate on day 6. Alpha-hemolytic streptococci grew from thioglycolate broth on day 10.Conclusions. Growth as detected in this study might represent contamination rather than an infecting organism in an eye suspected of having endophthalmitis.

ISSN:0271-3683    

DOI:10.3109/02713689609008912

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor