摘要:

Pathological changes in the retinal pigment epithelium (RPE) in a strain of chickens having hereditary blindness and retinal degeneration were described at the ultrastructural level. Photoreceptors in the retinal degenerate (rd) chicken had previously been noted to degenerate within a week after hatching. Affected chicks have neural retinas that are morphologically comparable to normal animals prior to that time despite an obvious lack of vision. In the present study, no pathological changes were noted inrdRPE prior to the time of photoreceptor degeneration. However, while mitochondria in the normal chick's RPE underwent diurnal changes in morphology within a few days of hatching, pleomorphic or ring mitochondria were not seen with high frequency in therdchick. After photoreceptors began degenerating, changes were seen in therdRPE. By 2 weeks of age, we noted a reduction in the depth and number of basal infoldings, an increase in number and size of atrophic vacuoles and large whorls of membranous material withinrdRPE cells. Membranous debris and what appeared to be broken off outer segments were seen in the subretinal space at that time. These phenomena became more prominent and prevalent with time. In 3–4 week old specimens, nearly intact outer segments were seen within RPE cytoplasm. At the same time very few intact outer segments were present on photoreceptors. After this time degenerative changes were seen in the RPE: a thinning of cells (apical to basal cell width), spreading out of cells (increased distance between intercellular junctional complexes), hypopigmentation of cells and presence of free cells in the sub-retinal space. Some RPE cells appeared in a rounded up configuration, bulging into the subretinal space and making junctional complexes with remaining photoreceptor inner segments or Mueller cell processes. Many RPE cells did appear to maintain their phagocytic abilities, as evidenced by presence of many microvilli and pinocytotic vacuoles in the apical cytoplasm.

ISSN:0271-3683    

DOI:10.3109/02713688509003346

出版商:Taylor&Francis    

年代:1985

数据来源: Taylor

摘要:

A radioimmunoassay was developed for detection of immunoglobulin in the aqueous of normal horses and horses with intraocular diseases. Levels of albumin were detected by radial immunodiffusion. Results of assays on samples from normal eyes from which aqueous was obtained by paracentesis under anesthesia were 32.10±21.50µg/ml for IgG, 0.05±0.01µg/ml for IgM, 0.04±0.02µg/ml for IgA and 34.0±38.0µg/ml for albumin. Results in 138 normal eyes sampled post mortem were 41.56±38.65µg/ml for IgG, 0.18±0.43µg/ml for IgM, 0.46±1.45µg/ml for IgE and 184±240µg/ml for albumin. Levels in abnormal eyes were some 50–120% greater, and very high levels were noted in cases of clinically documented uveitis.The aqueous to serum ratio of the proteins measured generally varied in relation to the molecular weights and was increased in diseased eyes. The ratio of IgG/albumin in the diseased eyes was less which suggested leakage of protein from an impaired blood/aqueous barrier rather than intraocular antibody synthesis.

ISSN:0271-3683    

DOI:10.3109/02713688509003347

出版商:Taylor&Francis    

年代:1985

数据来源: Taylor

摘要:

An enzyme linked immunosorbent assay was developed for the detection of immunoglobulin class specific antibodies toLeptospira interrogansserovarpomonain the serum and aqueous humor of horses. Serum antibody was also assayed by microscopic agglutination tests.Although higher levels of antibody were found in sera from horses with signs of uveitis, the association was not statistically significant. Antibodies topomonawere detected in the aqueous of 12 eyes from the 101 horses sampled at a slaughterhouse, and in most instances, a comparison of the aqueous/serum antibody level with that of the total aqueous/serum IgG level indicated intraocular antibody synthesis. Antibodies were also found in 4 aqueous (or vitreous) samples out of 9 obtained from horses with clinically documented uveitis and the above comparison again indicated intraocular antibody synthesis.The data point to an important role forpomonaas an etiology of equine recurrent uveitis but also emphasize that the initiating cause for this disease is often obscure in that association with leptospirosis cannot be shown in many instances.

ISSN:0271-3683    

DOI:10.3109/02713688509003348

出版商:Taylor&Francis    

年代:1985

数据来源: Taylor

摘要:

Following single drop instillation of pilocarpine, drug levels in individual aqueous humor samples of rabbits were determined by high-performance liquid chromatrography and correlated with changes in pupillary diameter and intraocular pressure (IOP). Application of higher concentrations of pilocarpine resulted in higher drug levels but these differences were neither statistically significant nor consistently proportional to the strength applied. Maximum miosis occurred between 30 and 60 minutes and the maximum fall in IOP occurred between 1 and 2 hours. The influence of contact lenses with varying water content and thickness upon intraocular penetration of pilocarpine was studied. Contact lenses did not affect 30-minute concentrations of pilocarpine in aqueous humor. Although two-hour levels were significantly lower with contact lenses, miosis and IOP at these time periods were comparable with and without lenses. Neither water content nor thickness appreciably influenced miosis and IOP.

ISSN:0271-3683    

DOI:10.3109/02713688509003349

出版商:Taylor&Francis    

年代:1985

数据来源: Taylor

摘要:

In previous studies of topical application of retinoic acid to the eye, retinoic acid in an oil vehicle has been used. An all-trans-retinoic acid (Tretinoin, USP) formulation in a petrolatum-based ophthalmic ointment vehicle has now been developed which is chemically stable for at least one year. The ointment is effective at retinoic acid concentrations of 0.01–0.1% in reversing corneal keratinization in vitamin Adeficient, xerophthalmic rabbits. At 0.1% it also stimulates the healing rate of corneal epithelial wounds in rabbits and monkeys. Retinoic acid ointment may prove to be valuable clinically in the treatment of xerophthalmia, corneal epithelial erosions, and related ocular surface abnormalities.

ISSN:0271-3683    

DOI:10.3109/02713688509003350

出版商:Taylor&Francis    

年代:1985

数据来源: Taylor

摘要:

Intense ultraviolet (UV) and blue stimulation decreases visual pigment concentration and increases long wavelength fluorescent emission in R1–6 photoreceptors in the white eyed fruit flyDrosophila melanogaster.We used microspectrophotometry to show that the threshold for visual pigment decrease is about 1 log unit lower for UV than for blue light (18.7 vs approximately 19.9 log quanta/cm2respectively). UV and blue stimuli about 0.2 log units brighter had been shown to cause structural degeneration. Above the threshold for structural damage, visual pigment is decreased permanently while below this level, a recovery of visual pigment was achieved within several hours. Microspectrofluorometric data are partially consistent with the hypothesis that the visual pigment is converted into a fluorescent product which had been named M'. M' had been proposed to be a new form of metarhodopsin which absorbs chiefly in the yellow and which has a fluorescent emission in the red; long wavelength stimulation had been reported to regenerate the native visual pigment from M'. Our data suggest that the situation is significantly more complex than this simple model. For instance, we report that long wavelength stimulation regenerates only a small fraction of the visual pigment which had been decreased by UV or blue stimulation. Furthermore, several lines of evidence suggest that other fluorescent products are also created by intense UV and blue stimulation. We were particularly interested in the lower damage threshold for UV light because of the hypothesis that UV visual sensitivity is mediated by a sensitizing pigment which absorbs UV light and transfers its energy to the blue absorbing rhodopsin. Our data suggest that the UV light decreases the rhodopsin without preferentially decreasing the sensitizing pigment.

ISSN:0271-3683    

DOI:10.3109/02713688509003351

出版商:Taylor&Francis    

年代:1985

数据来源: Taylor

摘要:

In the bovine lens theγIV-crystallin fraction is a principal determinant of the phase separation and opacification temperature, TC(Siezen et al, Proc. Natl. Acad. Sci. USA 82, 1985, 1701). We have now measured the effect on TCof purifiedγIV-crystallin solutions produced by a variety of reagents which affect protein-protein, protein-water and water-water interactions.Ionic strengths less than physiological increase TCdramatically, while higher ionic strength has very little effect. Calcium ion concentrations up to 8 mM produce no change in TC. Glycerol and acrylamide both depress TClinearly with reagent concentrations; TCdepression ofγIV-crystallin by these compounds is quantitatively the same as for whole lens.Sulfhydryl reducing agents such as glutathione and dithiothreitol lower TC, while hydrogen peroxide increases TC. Changes in opacification temperature ofγIV-crystallin produced by oxidizing and reducing agents are time-dependent and highly non-linear with reagent concentration.Our results clearly show that bovineγIV-crystallin is an important target protein for various reagents which are known perturbants of the opacification temperature of whole lens.The relevance of these findings to human diabetic and senile cataract formation is discussed.

ISSN:0271-3683    

DOI:10.3109/02713688509003352

出版商:Taylor&Francis    

年代:1985

数据来源: Taylor

摘要:

The pathoqenesis of diabetic retinopathy has not been fully explained. The earliest histological lesion is the loss of intramural pericytes and thickening of the basement membrane. Increased activity of the polyol pathway is a probable mechanism for these two abnormalities. Investigations have suffered from the lack of an exact animal model simulating the human condition.Examination of the retina in the spontaneously diabetic BB-rat demonstrated degeneration and loss of intramural pericytes, a progressive increase in basement membrane thickness, and microinfarctions with areas of non-perfusion. Therefore, this model may be used to clarify the biochemical mechanism(s) linking the metabolic abnormalities of diabetes and the retinopathy.

ISSN:0271-3683    

DOI:10.3109/02713688509003353

出版商:Taylor&Francis    

年代:1985

数据来源: Taylor

摘要:

An earlier report described the presence of high concentrations of lead in the bovine eye. However, we have been unable to detect this heavy metal in the ocular fluids or lenses of rabbits dosed with Pb, despite the appearance of high concentrations in blood, liver, and brain. We were also unable to detect it in lenses from cattle, horses, dogs, or four elderly humans. The possibility of environmental lead exerting toxic effects in the eye thus appears to be minimal.

ISSN:0271-3683    

DOI:10.3109/02713688509003354

出版商:Taylor&Francis    

年代:1985

数据来源: Taylor

摘要:

LASER TfiERAPY IN GLAUCOMA by Jacob T. Wilensky, Appleton-Century-Crofts, Norwalk, CT; 1985

ISSN:0271-3683    

DOI:10.3109/02713688509003355

出版商:Taylor&Francis    

年代:1985

数据来源: Taylor