摘要:

The ocular pathology of mannosidosis was studied In the bovine model. There was widespread vacuolation of many cell types including corneal epithelium, Bescemet's endothelium, corneal fibroblasts, pigraented cells, lens epithelium, lens fibres, pigment epithelium and all cell types of the neuroretina. On electron-microscopy most vacuoles were seen to be membrane bound vesicles compatible with being secondary lysosomes and similar to those previously described elsewhere in the body. Additional vacuoles were seen due to dilatations between lens epithelial cells and between lens fibres. The cause of lens and corneal opacities seen in human patients is unclear from the present study but are presumably a consequence of the lesions noted.

ISSN:0271-3683    

DOI:10.3109/02713688709034879

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

Latex beads coated with mucin (a sialic acid containing glycoconjugate), N-acetyl glucosamine (GlcNAc), or with the lectins, succinylated wheat germ agglutinin (sWGA) (binds to GlcNAc) orLimax flayvusagglutinin (LFA) (binds to sialic acid residues) were used as phagocytic particles-Phagocytosis of these coated beads by retinal pigment epithelial (RPE) explants was determined by bead uptake in normal (Long Evans) and dystrophic (Royal College of Surgeons, RCS/p+) rat retinas. Electron microscopy showed that beads coated with mucin or LFA lectin were not phagocytlzed by either dystrophic or normal RPE. sWGA-coated beads were phagocytized by both dystrophic and normal RPE, while GlcNAc-coated beads were taken up by dystrophic RPE only. Specificity of uptake for sWGA and GlcNAc bead coatings was shown by the reduction in the number of beads phagocytized in the presence of the appropriate competing sugar or lectin. The lack of phagocytic uptake of beads coated with a sialated glycoprotein or a sialic acid binding lectin suggests that sialic acid residues are not recognized as particulate ligands In this phagocytic assay. The data which show the uptake of beads coated with sWGA (binds only GlcNAc) together with results which showed WGA (binds both GlcNAc and sialic acid)-coated beads were not taken up, further suggest that GlcNAc residues may be involved in bead phagocytosis. The most striking difference between normal and dystrophic RPE engulfment of coated beads is the uptake of GlcNAc-coated beads by dystrophic RPE only. These results suggest that the receptor molecules on dystrophic RPE eell surface membranes may be different from those on normal RPE membranes.

ISSN:0271-3683    

DOI:10.3109/02713688709034880

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

Individual crystallins, urea-soluble and urea-insoluble proteins were isolated from the nucleus and cortex of types I-IV cataractous lenses and normal lenses. The levels of protein sulphydryis (P-SH), disulphides (S-S), as well as surface (F-SH) and buried (S-SH) in these proteins were determined by reaction with 5, 5′-dithiotris-(2-nitrobenzoic acid) or performic acid oxidation followed by amino acid analysis.During nuclear colour development there is a progressive decrease in the sulphydryl content of the crystallins. In the nuclei of advanced cataractous lenses, the P-SH decreases to 10% of the levels found in the normal nucleus. Similar but smaller changes take place in the cortex. No specific changes were found between the crystallins, with the exception ofβs crystallin.The cysteine remains constant in all lens types suggesting no higher oxidation products are formed.There is a significant shift in the distribution of cysteine in the nucleus of type III and IV lenses. Urea-insoluble proteins are the predominant species, accounting for about 70% of the total cysteine pool. This is consistent with the accumulation of modified insoluble polypeptides during senile nuclear cataract formation.

ISSN:0271-3683    

DOI:10.3109/02713688709034881

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

The nature of disulphide bonds in 3, 7 and 24 month old rat lens proteins has been determined in order to examine the possibility that there is a direct correlation between intermolecular disulphide bond formation and hardening of the lens during ageing.Significant levels of S-S were found in all of the crystallins, as well as in the insoluble proteins. However, no substantial changes in the molecular weight distribution of the proteins, or their constituent polypeptides, were observed after the reduction of these bonds. This indicates that almost all of the S-S bonds are intramolecular.It would appear that the hardening of the nucleus is not a result of intermolecular disulphide crosslinking during ageing. Instead, our observations suggest that intramolecular disulphide bonds may make the gamma-crystallin molecule more compact, thereby promoting closer packing in the nucleus where the concentration of this protein is highest.

ISSN:0271-3683    

DOI:10.3109/02713688709034882

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

In the experiments presented here we have used the isolated perfused eye technique to investigate the distribution of ERG potentials on the sclera over local retinal lesions induced by xenon arc photocoagulation. Three lesioned dog eyes were examined. In two cases the lesion was allowed 28 days to stabilize, whilst in the third the experiment was performed two hours after treatment. Immediately after enucleation, the eyes were placed in a perfusion system capable of maintaining retinal function for many hours. The scleral ERG profile was then measured on the scleral surface over both treated and untreated areas of retina in the same eye. It was found that the ERG amplitudes were consistently lower over the treated areas of retina when compared to the untreated side of the same eye. More surprising was the discovery that the ERG distribution on the untreated side was significantly different to that observed in control eyes. In particular it was found that the limbal areas of sclera on the untreated side now had significant ERG amplitudes present, whereas the control eyes had close to zero amplitude in this region. It is concluded that the induced retinal lesions caused a widespread redistribution of ERG potentials around the entire surface of the globe. The potential applications of these results in the assessment of local retinal function is discussed. A schematic model is presented for the distribution of ERG potentials on the surface of control and lesioned eyes.

ISSN:0271-3683    

DOI:10.3109/02713688709034883

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

The ironbinding protein lactoferrin is one of the main proteins in human tears. Until now no animal models are available to investigate the exact role of this protein on the ocular surface. We have therefore started investigations concerning the presence of ironbinding proteins in various laboratory animals.In this report the presence of lactoferrin and transferrin in guinea pig tears was investigated using an iron-binding assay, Ouchterlony immuno-diffusion, ELISA and immunoblotting techniques. Guinea pig tears contain a weak ironbinding activity, which is markedly lower than that observed in human tears.Lactoferrin and transferrin were identified using the fact that guinea pig lactoferrin reacts with monoclonal and polyclonal anti human lactoferrin antibodies and that guinea pig serum transferrin reacts with an anti rabbit transferrin serum. SDS-PAGE and immunoblotting showed that, guinea pig lactoferrin and transferrin have a similar molecular weight of approximately 75 kD, which is however, definitely smaller than that of human lactoferrin and transferrin (80 kD).The amount of lactoferrin in guinea pig tears, measured in an ELISA using anti human lactoferrin antisera, was very low (equalling 600 ng/ml of human lactoferrin immunoreactivity). Transferrin in guinea pig tears was measured with an ELISA in 10 guinea pigs and resulted in a mean concentration of 22.3 ug/ml. The species comparisons performed until now indicate that human tears remain unique in their high content of lactoferrin.

ISSN:0271-3683    

DOI:10.3109/02713688709034884

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

Corneal thickness is a reflection of endothelial barrier and pump functions. The corneal edema that occurs during intraocular inflammation is a consequence of the breakdown of one or both of these parameters. Results of this study demonstrate that, during intraocular inflammation induced by an intra-vitreal injection of bovine serum albumin (BSA), the permeability of rabbit corneal endothelia to inulin was increased. By comparison, treatment with oral aspirin and/or subconjunctival triamcinolone acetonide prevented the endothelial barrier breakdown induced by the BSA. Concomitant with the loss of the barrier function, endothelial ouabain binding decreased in the BSA injected eye, indicating a reduction in endothelial Na/K ATPase pump site density. A subconjunctival injection of triamcinolone prevented this decrease in pump sites. The increase in endotheliai permeability and the decrease in pump site density correlated with an increase in corneal thickness. It can be concluded that the intraocular inflammation induced by BSA effects corneal edema by both an increase in endothelial permeability and a decrease in Na/K ATPase pump site density. Subconjunctival triamcinolone is effective in preventing this response.

ISSN:0271-3683    

DOI:10.3109/02713688709034885

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

We retrospectively analyzed archival retinoblastomas from 44 eyes. The percentage of cycling cells were increased in younger patients, those with advanced disease, and cases with poor prognosis. These data suggest that all cell cycle studies may yield important insights in retinoblastoma.

ISSN:0271-3683    

DOI:10.3109/02713688709034886

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

Lectins were used as cytochemical probes to examine the relationship between normal retina and retinoblastoma. Cases of retinoblastoraa in which there were either Fiexner-Wintersteiner rosettes or fleurettes accompanied by nontumorous retina were studied with ten biotinylated lectins. Pineal and ocular tumors from cases of trilateral retinoblastoma were also studied. Con-A, LCA, PNA, WGA and RCA-I labeled tissue of each type to varying degrees, while BS-I, DBA, SBA, S-WGA and UEA-I bound neither tumor nor retina. The high degree of binding homology suggests biochemical as well as structural similarities between these tissues.

ISSN:0271-3683    

DOI:10.3109/02713688709034887

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

S-antigen (48K protein) is a photoreceptor cell protein highly pathogenic for the induction of experimental autoimmune uveitis (EAU) and intimately involved in the visual process. EAU is characterized, in part, as a T-cell mediated autoimmune disease which results in a severe inflammation of the uveal tract, and pineal gland. In order to determine specific sites in S-antigen responsible for its pathogenicity we synthesized twenty-three peptides, corresponding to the entire 404 amino acid sequence, and tested each peptide for its ability to induce EAU in Lewis rats. One peptide, peptide M (18 amino acids in length), was found to be highly pathogenic and consistently induced an EAU that was identical to the disease caused by native S-antigen. Clinically, the disease that developed in the eye was characterized by iris and pericorneal hyperemia, followed by inflammatory exudates in the anterior and vitreous chambers. Histopathologically a severe inflammatory response was observed which resulted in the complete destruction of the photo-receptor cell layer of the retina. In order to more fully characterize this pathogenic site, 14 additional smaller peptides (eight to eighteen amino acids in length) corresponding to the left and right portions of peptide M were synthesized. Of these peptides, peptide M16L, M15L, and M12L induced EAU, further localizing this pathogenic site to a small well-characterized region of S-antigen consisting of twelve amino acids. In addition, animals with ocular inflammatory disease had an associated pinealitis characterized by a lymphocytic infiltration of the subcapsular and central area of the pineal gland. The significance of these findings and the relationship of S-antigen in the pathogenesis of EAU and other autoimmune diseases is discussed.

ISSN:0271-3683    

DOI:10.3109/02713688709034888

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor