摘要:

The Zeiss Scheimpflug Cataract Video Camera was designed to photograph, store and analyze cataracts in a semi-automated fashion for cross-sectional and longitudinal studies. We conducted a reproducibility study of this system. Twenty-four normal and 61 cataractous eyes were photographed twice by each of two of the authors in the 90°meridian and microdensitometry was performed on each of the stored images. Reproducibility was then determined using the intraclass correlation coefficient to determine whether or not the differences encountered were due to variability in the system or due to actual differences among the images. The intraclass correlation in the lens nucleus was 0.995 with 95% confidence limits of. 992-.996. Therefore, reproducibility was 99.5%. In the anterior cortex, intraclass correlation was. 941 with 95% confidence limits of. 919-.959. In the posterior cortex intraclass correlation was. 905 with 95% confidence limits of. 870-.932. Reproducibility with this instrument was therefore excellent and with certain limitations, this may be a useful instrument in monitoring lens changes in certain diseases and the effects of anti-cataract agents.

ISSN:0271-3683    

DOI:10.3109/02713688809015140

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor

摘要:

Despite knowledge of the toxicity of oxygen to the retina, its effects on the retinal pigment epithelium have not been considered. We examined the effect of 20%, 10% and 5% oxygen on growth and superoxide dismutase (SOD) activity of porcine retinal pigment epithelial cells (RPE).Growth of RPE cells was very significantly lower in 20% oxygen than in either 10% or 5%; optimal growth occurred at 10% oxygen, the concentration most like their environment in vivo. Inclusion of SOD and catalase in the media very significantly stimulated growth in 20% oxygen.The SOD activity of RPE cells was significantly related to ambient oxygen. In first passage (P1) cells, SOD activity was 44% lower on day 7 than on day 1 of culture in 20% oxygen (p $ 0.05). Transfer of cells growing in 20% oxygen to 5% oxygen arrested the decrease in SOD and resulted in significantly higher SOD levels. In fourth passage (P4) cells grown in 20% oxygen, SOD was 25% and 44% lower than cells in 10% and 5% oxygen, respectively.After one week, SOD levels in the P4 cells were significantly higher than in P1. A statistical model of SOD activity in RPE cells indicated significant negative correlations with both oxygen concentration and the cell number. Growth of RPE cells was significantly influenced by oxygen level, days of culture and passage number, but not SOD activity.We conclude that traditional culture conditions support generation of free radicals in tissue culture media that suppress both growth and superoxide dismutase activity.

ISSN:0271-3683    

DOI:10.3109/02713688809015141

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor

摘要:

Rabbit lenses were incubated, in vitro, for 20 hr. During the first 60 min of the incubation period, the lenses were exposed to hydrogen peroxide at specified concentrations. Deranged electrolyte balance was observed in lenses exposed to hydrogen peroxide concentrations exceeding 0.1 mM.Lenticular sodium pump activity, as evidenced by lens86Rb uptake, was reduced to 61% of control when examined immediately after exposure to 0.5 mM hydrogen peroxide for 1 hr. Upon further incubation in peroxide-free medium, the sodium pump activity of hydrogen peroxide treated lenses continued to deteriorate. The deterioration of sodium pump activity in lenses transiently challenged with hydrogen peroxide was not altered by supplementation of the incubation medium with antioxidants or by substitution of calcium in the medium.Lenticular potassium permeability, as evidenced by the rate of86Rb efflux from the lens, was found to be elevated immediately after exposure to 0.5 mM hydrogen peroxide for 1 hr. However, no further change in the rate of86Rb efflux was noted when the hydrogen peroxide treated lens was incubated for an additional 19 hr in peroxide-free medium.Na, K-ATPase and Ca-ATPase activities were measured in membrane preparations isolated from lenses that had been exposed to 0.5 mM hydrogen peroxide and then cultured in control medium for 19 hr. Neither of the transport enzyme activities was diminished in the hydrogen peroxide treated lenses indicating that the deterioration in sodium pump activity in lenses temporarily exposed to hydrogen peroxide is not due to a progressive loss of Na, K-ATPase enzyme.

ISSN:0271-3683    

DOI:10.3109/02713688809015142

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor

摘要:

Quantitative fluorescence microscopy was used to study Carboxyfluorescein distribution across the blood-ocular barrier of control and streptozotocin diabetic rats at 2 min, 1 and 2 hr after dye injection (125 mg/kg iv). Measurement of dye concentrations in plasma, urine and feces demonstrated increased plasma clearance and increased urinary clearance of Carboxyfluorescein in diabetic rats. Unbound plasma dye concentration in the diabetic animals fell to 34% of the control level at 1 hr after injection; the corresponding plasma concentration vs. time integral was reduced to only 74% of the control value. The presence of a less fluorescent glucuronide conjugate of Carboxyfluorescein was not detected in plasma, urine or feces. Fluorescence intensity in the ocular tissues measured, including choriocapillaris, pigment epithelium, retina, ciliary epithelium, iris, and cornea, was not higher for diabetic than for control rats. In addition, there was no indication of localized dye leakage into retina through defects in the pigment epithelial and vascular endothelial barriers or of increased dye entry at the optic disc, a site of blood-retinal barrier discontinuity. Normalization of tissue fluorescence intensity measurements at the different time intervals to compensate for disparity in concurrent plasma dye concentrations resulted in significantly higher levels in diabetic retinas at 1 hr. However, because this difference was not manifest when the plasma dye concentration vs. time integral was used to normalize the data, it is concluded that no greater accumulation of Carboxyfluorescein occurs in the retina of diabetic rats over the time period studied.

ISSN:0271-3683    

DOI:10.3109/02713688809015143

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor

摘要:

Cataractous lenses produced by hydrocortisone or prednisolone treatment in developing chick embryos turned golden brown on heating at 100°C for 60 min. Analysis of an 80% ethanol fraction from the lenses, which contained the pigment-forming substance(s), demonstrated that the heat-induced pigmentation was related to the appearance of opacity of the lens after glucocorticoid administration and suggested that the pigmentation occurred by the Maillard reaction between glucose and amino acids.

ISSN:0271-3683    

DOI:10.3109/02713688809015144

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor

摘要:

Measurement of tear turnover rate using an automated scanning fluorophotometer (FluorotronR) was compared to Schirmer test results without anesthesia in young adults with no known ocular disorder. After the instillation of fluorescein, tear film fluorescence, expressed as fluorescein concentration equivalent, decreased exponentially in a linear fashion with time. The mean tear turnover rate was 30% per minute. Contact lens wearers had higher mean tear turnover rates when compared with non-contact lens wearers, but differences were not statistically significant. Half of tested eyes demonstrated total wetting of Schirmer Tear Test StripsR. Higher mean tear turnover rates were associated with complete wetting of the Schirmer test strips. There was no significant correlation between Schirmer paper wetting of<30 mm and fluorescein turnover rate.

ISSN:0271-3683    

DOI:10.3109/02713688809015145

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor

摘要:

Experimental ocular models of herpes simplex virus type 1 (HSV-1) reactivation have been used to monitor viral shedding in the tear film and the appearance of corneal epithelial lesions, but the temporal correlation between reactivation and the presence of viral particles in the corneal nerves has not been made. Two New Zealand white rabbits were inoculated with 20μl of HSV-1 McKrae strain (5.0↣106PFU/ml) in each eye. Beginning on postinfection day 82, ocular iontophoresis (0.8 mAmps for 8 min) of 0.01% epinephrine was done once a day for 3 consecutive days to induce reactivation. Ten limbal nerves from four corneas processed for transmission electron microscopy contained 883 unmyel inated and 40 myelinated axons. Seven nerves were positive for virus. Viral particles were found only in unmyel inated axons, and in low frequency (24/883). Virus was not found in Schwann cells, perineurium, or adjacent stroma nor were virus particles seen exiting axons. No enveloped virions were found. Axons from six nerves of four control corneas from rabbits with latent, but not reactivated, HSV-1 did not contain virus particles. Induction by corneal iontophoresis of epinephrine suggests that HSV-1 is translocated from the ganglion to the cornea through axonal transport mechanisms. For the first time, evidence of anterograde, intra-axonal transport of HSV-1 particles in response to epinephrine reactivation is demonstrated.

ISSN:0271-3683    

DOI:10.3109/02713688809015146

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor

摘要:

Many tissues which require vitamin A store the vitamin as long-chain fatty acyl esters of retinol. As part of a study designed to characterize vitamin A metabolism in the lacrimal gland, which transports retinol from blood to lacrimal gland fluid, extracts from lacrimal glands of rabbits and rats were analyzed by non-aqueous high performance liquid chromatography. Retinyl linoleate, retinyl palmitate, and retinyl stearate were identified in these extracts by their co-elution with standards, their retention time relative to retinyl palmitate, and their susceptibility to hydrolysis by saponification. Retinyl palmitate was present in rabbit lacrimal gland at 51.0↣10.1 ng/g tissue. After treatment of vitamin A-deficient rabbits with orally administered [11, 12-3H] retinyl acetate, the radiolabeled esters retinyl linoleate, palmitate, and stearate were extracted from the lacrimal glands. These data show that the lacrimal gland stores vitamin A as fatty acyl esters of retinol.

ISSN:0271-3683    

DOI:10.3109/02713688809015147

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor

摘要:

Lens crystallins were isolated from the homogenates of mammalian eye lenses derived from three different species by gel permeation chromatography and characterized by SDS-gel electrophoresis, isoelectric focusing, amino acid analysis and N-terminal sequence analysis. Five fractions corresponding to HMα-,α-,βH-,βL-andγ-crystallins were obtained for the crystallins from these phylogenetically distant species. The native molecular masses for these purified fractions and their polypeptide compositions were determined by gel filtration and SDS-gel electrophoresis respectively, revealing the typical subunit compositions for each classified crystallin. The gel pattern ofγ-crystallins from the marmot lens appeared to be more complex than those of gibbon and deer lenses. Comparison of the amino acid contents of each orthologous class of mammalian crystallins with those of evolutionarily distant species still exhibited similarity in their amino acid compositions. The charge heterogeneity of each crystallin fraction can be detected by isoelectric focusing under denaturing conditions. N-terminal sequence analysis of the crystallin fractions revealed that all fractions except that ofγ-crystallin are N-terminally blocked. Extensive sequence similarity between mammalianγ-crystallin polypeptides were found, which suggested the close relatedness ofγ-crystallins amongst different species of mammals and also established the heterogeneous nature of this multigene family.

ISSN:0271-3683    

DOI:10.3109/02713688809015148

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor

摘要:

In this study enzyme glutathione peroxidase was localized in ocular tissue of Lewis rats using the peroxidase antiperoxidase immunohistochemical technique. Antisera to glutathione peroxidase was raised in a rabbit. Immunoreactive glutathione peroxidase was found to be distributed predominantly in the corneal epithelium and endothelium, choroid, inner segment of photoreceptors and retinal pigmented epithelium. Its presence in these sites suggests an adaptation to oxidative stress where this antioxidant enzyme along with other antioxidant systems serves to prevent damage.

ISSN:0271-3683    

DOI:10.3109/02713688809015149

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor