摘要:

Three hours to 14 days following the intravitreal injection of 10 ng ofE. coliendotoxin into the vitreal chamber of one eye of the New Zealand white rabbit, ocular inflammation was evaluated by clinical and biochemical criteria and prostaglandins were measured in the intraocular fluids and in the incubation medium of the intact lens. Increased synthesis of PGE2 was detected for lenses from inflamed eyes beginning at 18 h post-endotoxin injection. Lenticular PGE2synthesis remained above control levels for the duration of the time course. Lenses also exhibited increased PGF2αsynthesis, which began at 18 h and returned to control levels by day 7. At the times of peak production, aqueous humor PGE2concentration correlated with lenticular PGE2synthesis and with aqueous humor leukocyte number. No correlations were found for lenticular PGE2vs. cell number, or vitreous humor PGE2vs. aqueous humor PGE2.These results suggest that during ocular inflammation, aqueous humor PGE2may be derived, at least in part, from the lens and leukocytes.

ISSN:0271-3683    

DOI:10.3109/02713688609015129

出版商:Taylor&Francis    

年代:1986

数据来源: Taylor

摘要:

The axial elongation of high myopia is known to induce tangential stretching forces on the retina. Such forces might be expected to compromise retinal circuitry and thus affect the temporal and spatial contrast sensitivity function. In fact, we find that simple high myopes have normal contrast sensitivity for stationary gratings, moving gratings, and uniform field flicker. This suggests that, unlike many other retinal disease processes, the high myope's retina retains its normal integrity until the outer retina is compromised.

ISSN:0271-3683    

DOI:10.3109/02713688609015130

出版商:Taylor&Francis    

年代:1986

数据来源: Taylor

摘要:

The effects of aqueous and vitreous humors and plasma on the rate of auto-oxidation of a rabbit brain homogenate were measured. Both aqueous and vitreous humors from normal eyes increased, while plasma decreased the rate of oxidation in the homogenate. During endotoxin-induced ocular inflammation the copper (Cu) and iron (Fe) concentrations of both the aqueous and vitreous humors increased, most likely due to the influx of their plasma binding proteins, ceruloplasmin (Cu) and transferrin (Fe). As both proteins are known to be antioxidants, it was not surprising to find that the aqueous and vitreous humor from the inflamed eyes had significant antioxidant activity. This antioxidant activity correlated well with the concentrations of Cu and Fe in aqueous humor and Cu but not Fe in the vitreous humor throughout the time course of the inflammatory response. Thus, entry of plasma proteins through disrupted blood ocular barriers may function in protecting ocular tissues against the increased oxidation which occurs during inflammation.

ISSN:0271-3683    

DOI:10.3109/02713688609015131

出版商:Taylor&Francis    

年代:1986

数据来源: Taylor

摘要:

The rabbit defense system has a number of specific features: no lactoferrin and lysozyme are detectable and peroxidase activity is only demonstrated in the cubic epithelial cells of the ducts. Experiments carried out with radioactive amino acid, demonstrate the absence of secreted proteins with molecular weights corresponding to those of albumin and transferrin, indicating that these proteins are not synthesized by the lacrimal gland tissue. Rabbit tear pattern presents a set of acidic proteins secreted by the lacrimal gland tissue, with small molecular weight and acidic pl's.

ISSN:0271-3683    

DOI:10.3109/02713688609015132

出版商:Taylor&Francis    

年代:1986

数据来源: Taylor

摘要:

The extent of plasma proteins in the vitreous humor of the rat was determined. Disc gel electrophoresis of the soluble proteins of the rat vitreous humor showed many protein bands, but most of the bands did not coincide with those of rat plasma. Using antibodies to rat plasma proteins, immunological analyses of vitreous and plasma, including fractions separated by high-pressure gel permeation chromatography, showed that several vitreous proteins react with plasma protein antibodies. However, only albumin and transferrin were found to be completely identical in both fluids. The concentration of albumin in vitreous was about 625µg/ml and that of transferrin was 61.6±19.1 (S. D.)µg/al. The total protein concentration in vitreous was 9.5±0.5(S. D.) mg/ml. The ratio of transferrin to albumin in the vitreous was approximate to that of plasma, but the sum of the two proteins accounted for less than 10% of the total protein. These data indicate that in the rat some plasma proteins, particularly albumin and transferrin, are found in the vitreous, but most of the soluble proteins appear to originate from sources other than plasma, such as the vitreous itself or in surrounding tissues including the ciliary body and the retina.

ISSN:0271-3683    

DOI:10.3109/02713688609015133

出版商:Taylor&Francis    

年代:1986

数据来源: Taylor

摘要:

UK-14, 304-18 (UK), a relatively selectiveα2- agonist, was examined for its effects on intraocular pressure (TOP) and pupil diameter (PD) in rabbits, cats and monkeys and on noradrenergic function in the cat nictitating membrane (CNM) preparation. Topical, unilateral administration of UK (0.0005-0.5 mg) produced dose-dependent decreases in IOP and pupil size in normal, unanesthetized rabbits, cats and monkeys. The ocular hypotensive effect of UK in the ipsilateral eye was delayed relative to the contralateral eye in all three species; UK produced an initial transient ocular hypertension in rabbits which was abolished by surgical transaction of three major extraocular muscles. Mean arterial blood pressure in rabbits was not affected by 0.005 mg UK topically. The ocular hypotensive and miotic effects of UK were attenuated in superior cervical ganglionectomized (SX) cats and rabbits. Intra-arterially administered UK (0.33, 1.0, 3.3 and 10µg) produced dose-related systemic hypotension and inhibition of contractions of the CNM elicited by electrically stimulating the pre-and postganglionic sympathetic trunks in the urethane/chloralose anesthetized cat. This inhibition was reversed and prevented by 300µg rauwolscine but not by 300µg domperidone. UK also enhanced the contractile response of the CNM to injected norepinephrine (10µg), UK suppressed ocular hypertension induced by water loading and IOP recovery rate following hypertonic saline infusion in rabbits suggesting that aqueous flow was inhibited. These results indicate that UK lowers IOP, in part, by suppressing sympathetic neuronal function which causes a reduction in aqueous flow.

ISSN:0271-3683    

DOI:10.3109/02713688609015134

出版商:Taylor&Francis    

年代:1986

数据来源: Taylor

摘要:

The technique of tear film osmolality determination using a nanoliter freezing point depression type osmometer was studied to determine what factors affect the accuracy of the technique. Reflex tearing during microcapillary sampling of the tears caused a 5% decrease in tear film osmolality. Evaporation effects of sampling, retrieval and osmolality determination of samples resulted in an increase of 0.2% for one ul volumes and 1.2% and 1.3% for 0.50 and 0.25 ul volumes of samples, respectively. Evaporation of the sample during storage between layers of immersion oil resulted in increasing osmolalities of 0.5, 0.2 and 0.2%/day for sample volumes of 0.25, 0.50 and 1.0 ul respectively over 14 days. Samples (1.0 ul) stored at 4®C showed an increase in osmolality of 1.25 mos/kg/day. These results suggest that reflex tearing is one major source of variation in tear film osmolality determiniations and that avoidance of reflex tearing is critical to the accuracy of the technique.

ISSN:0271-3683    

DOI:10.3109/02713688609015135

出版商:Taylor&Francis    

年代:1986

数据来源: Taylor

摘要:

Rat urethane retinopathy produces sequential and progressive loss of the photoreceptor cells, proceeding from the posterior to the peripheral retina. The inner retina, the retinal pigment epithelium and the choriocapillaris are spared. After loss of the photoreceptor cells, a vasculopathy develops which includes progressive retinal capillary loss and formation of coil-like tufts of retinal vessels which are embedded in the retinal pigment epithelium. Some of the retinal vessels within the retinal pigment epithelium have changed their phenotype from continuous to fenestrated endothelial cells.To elucidate whether DNA synthesis was necessary for formation of the coil-like vessel tuft formation, an autoradiographic study was performed. At 12,14,16 and 20 weeks of age, times during which the vasculopathy is known to be forming, urethane and control rats were injected with 3 successive doses of methyl-3H-thymidine. Autoradiography oftrypsin-digested retinal vessel preparations was compared with histological sections of the paired eye.The frequency of tritium labelled endothelial cells was much higher in the urethane rats than control animals, and were predominantly in the posterior pole, rather than the periphery. Labelled endothelial cells tended to be associated with, or near, the coil-like vessel tufts. Capillary dropout was observed in urethane, but not control animals. Frequently, adjacent endothelial cells were labelled, suggestive of mitosis. The occurrence of thymidine uptake and a change in phenotype of the endothelial cells leads us to suggest that new cell synthesis, or neovascularization, has occurred in these vessels. Since the retina is less than half the normal thickness and the choriocapillar is is intact, it appears unlikely that ischemia is responsible for inducing these pathological responses. We suggest that the retinal pigment epithelial cell is responsible for the increase in DNA synthesis and change in phenotype of the retinal endothelial cell.

ISSN:0271-3683    

DOI:10.3109/02713688609015136

出版商:Taylor&Francis    

年代:1986

数据来源: Taylor

摘要:

Lenses of rats maintained on a 50% galactose diet displayed the development of a progressive cataract which was cortical at 3-11 days, and progressively internalized (nuclear as well) and mature at 16-20 days of feeding. Lens fiber plasma membranes were isolated from female rats subjected to the galactose diet and from controls at 11, 19, and 31 days of feeding, and analyzed by SDS-PAGE. Examination of the fiber plasma membranes from whole lenses of galactose-fed rats demonstrated the limited proteolysis of MP26 into MP23-24, in both the cortical and mature stages of the resultant cataracts. The limited proteolysis of MP26 was first evident in the lens cortex at 11 days of galactose feeding, and was evident as well, and more severe in proportion, in the lens nucleus at 19 days of feeding. The greatest proportion in MP26 limited proteolysis was observed in whole lenses at 31 days of galactose feeding. The regional progression of MP26 limited proteolysis closely paralleled the morphological progression of the galactose-induced cataract in the rat. The proportion of lens MP26 which underwent limited proteolysis into MP23-24 increased the longer the animals were kept on the galactose diet.

ISSN:0271-3683    

DOI:10.3109/02713688609015137

出版商:Taylor&Francis    

年代:1986

数据来源: Taylor

摘要:

The distribution of a steroid antagonist, RU486, that is known to reduce rabbit intraocular pressure has been examined in the eye. On an equal tissue weight basis, the corneal epithelium is the site of maximal absorption followed by conjunctival tissues (bulbar and palpebral) and the rest of the cornea. Aqueous humor concentrations of drug vary between 5×10-−6and 5×10-−8M at 1 and 24 hours, respectively: these concentrations have been shown by others to inhibit dexamethasone binding to rat thymocytes, and are sufficient to act as an antagonist at steroid receptors in the eye. Multiple drop administration for 10 days (3 drops per day) revealed no accumulation in the treated eye, but did show the presence of drug in the untreated contralateral eye that could explain the contralateral pharmacological effect seen on intraocular pressure after several days of treatment.

ISSN:0271-3683    

DOI:10.3109/02713688609015138

出版商:Taylor&Francis    

年代:1986

数据来源: Taylor