摘要:

Keratoconus, a bilateral corneal disease, is characterized by modifications in corneal shape and thinning of the stroma. From a biochemical point of view, a decrease in collagen content, probably due to the high collagenase activity, has been reported.Gamma Interferon (γ-IFN), Tumor Necrosis Factor (TNF), and Interleukin 1 (IL1) are peptide regulatory factors involved in immunological responses, but they also play a role in the synthesis of collagen and prostaglandin E2 by fibroblasts.In these experiments, we have determined the number of membrane binding sites forγ-IFN, TNF, and IL1, and the dissociation constant (Kd) for each radiolabelled ligand. All experiments were carried out on cultured corneal stromal cells.Data from normal human corneas and from keratoconus were compared. No differences were found concerning y-IFN and TNF binding sites between normal corneas and keratoconus, while fibroblasts from keratoconus proved to bear four fold more IL1 binding sites than normal fibroblasts, with similar Kd.

ISSN:0271-3683    

DOI:10.3109/02713689109013850

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

Agonists and antagonists of histamine were used to characterize the stimulation of inositol phosphates formation and elevation of intracellular Ca2+by histamine in cultured non-pigmented epithelial (NPE) cells from human ciliary body. Agonists specific for the H1histamine receptor subtype were 20-to 200-fold more potent than the H2-specific agonists tested, and 5–16% as potent as histamine in inositol phosphates stimulation. An H1antagonist was 10,000-fold more potent than an H2antagonist in blocking histamine stimulation of inositol phosphates. H1agonists also mimicked and H1antagonists inhibited the elevation of intracellular Ca2+by histamine. The first phase of the Ca2+response to histamine was largely independent of extracellular Ca2+while the second phase required extracellular Ca2+. Dose-response curves for histamine elevation of intracellular Ca2+(EC50= 10μM, maximum at 100μM) and inositol phosphates (EC50= 2μM, maximum at 100μM) were similar. These data support the characterization of the NPE histamine receptor as an H1receptor linked to elevation of inositol phosphates and intracellular Ca2+.

ISSN:0271-3683    

DOI:10.3109/02713689109013851

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

Benomyl, a benzimidazole fungicide, produced ocular and craniocerebral malformations in fetal rats when administered to the dams by gavage in a dose of 62.4 mg/kg of maternal body weight/day on days 7–21 of gestation. Ocular anomalies included retinal dysplasia, cataracts, microphthalmia, and anophthalmia. These anomalies occurred in 43.3% of fetuses exposed to benomyl and a normal protein diet but increased to 62.5% when benomyl administration was combined with a protein deficient (8% casein) diet.Microscopic examination of the malformed eyes revealed that the most common abnormality, retinal dysplasia, consisted of rosettes of retinal cells and retinal infolding. The majority of rosettes had a single layer and a limiting membrane. Rosettes with two or three layers were also observed, particularly in fetuses exposed both to protein deficiency and benomyl. Although anophthalmia was identified macroscopically in five fetuses, only a single instance of true anophthalmia was found microscopically.These data support the results of previous investigators that benomyl induces ocular malformation and that protein deficiency enhances the teratogenic effects of benomyl. The disorderly proliferation of retinal cells and rosette formation resembled the periventricular cell masses that accumulate in brains exposed to benomyl and certain other teratogenic agents. The anti-tubulin action of benomyl is known to impair microtubule formation and it may produce brain and ocular malformations by disruption of neuronal proliferation and migration.

ISSN:0271-3683    

DOI:10.3109/02713689109013852

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

A chromatographic method for separating tear specific prealbumin (TSP) into six isoelectric forms is described. Size exclusion high performance liquid chromatography (SE-HPLC) was used to isolate TSP from whole tears, followed by chromatofocusing fast protein liquid chromatography (FPLC) of the SE-TSP fraction on a Mono P column. This yielded six fractions varying in isoelectric point (pI) between 5.3 and 4.6. Subsequent anion exchange FPLC (Mono Q column) allowed a slight further purification of each Mono P fraction and removed Polybuffer from the Mono P fractions. Isoelectric focusing (IEF) of the TSP isoforms verified that the heterogeneity was based on pI, and confirmed that the chromatofocusing separation was in many respects the same as an IEF separation. Purity of TSP isoforms was determined by SDS-polyacrylamide gel electrophoresis (SDS-PAGE), IEF, enzyme-linked immunosorbent assay (ELISA) and immunoblotting of samples separated by SDS-PAGE and IEF. Amino acid analysis and N-terminal amino acid sequencing revealed subtle differences between the TSP isoforms. The entire purification procedure was conducted both with and without the addition of reducing agents and protease inhibitors to tear samples and all buffers used in the purification process. Relatively little difference was seen in the TSP isoform profile under these two sets of conditions. However, the tendency of isolated TSP to aggregate and precipitate was dramatically decreased under reducing conditions, resulting in significantly higher protein recoveries. This chromatographic purification procedure provides a basis for further study of the nature of the heterogeneity of TSP and characterization of the properties of this protein.

ISSN:0271-3683    

DOI:10.3109/02713689109013853

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

Glucocorticoid-induced cataract formation appears to proceed via oxidation or peroxidation steps possibly caused by multiple activities of glucocorticoid in the living system. Attempts were made to modifiy GC-induced metabolic changes and prevent cataract formation using intermediates of the citric acid cycle. The compounds were applied to the embryos at 3, 10 and 20 hr after the administration of hydrocortisone succinate sodium (HC:0.25μmol/egg) to 15-day-old eggs. At 48 hr after HC treatment the lenses were classified and analyzed. Almost all lenses were classified as stage IV-V (>94%). However, the application of sodium isocitrate (IC:15μmol/egg) which was the most potent among several intermediates tested showed a significant preventive effect against cataract formation. The administration of IC prevented the decline of GSH, the elevations of LPO and reduced the marked elevation of glucose in the lens caused by HC. The IC treatment also diminished the elevation of LPO in blood and liver. The above effects by IC on HC-induced events may be due to the action of IC in preventing the early decline of hepatic GSH caused by HC. Possibly IC was utilized as an intermediate of the citric acid cycle and a substrate for isocitrate dehydrogenase in cytosol to modify GC-induced metabolic changes.

ISSN:0271-3683    

DOI:10.3109/02713689109013854

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

In searching for a clue to the role of actin filament bundles organized into polygonal arrays, or geodomes, in lens epithelial cells, we examined several physical events occurring in the young rabbit lens which may initiate their formation. We used NZW rabbits between the ages of 24 days gestation and 50 days postnatal. Data were obtained from TEM, SEM and fluorescence microscopy. Parameters measured were lens weights, apical surface areas of cells in epithelial whole mounts, epithelial cell thickness, and timing of eyelid opening, breakdown of the tunica vasculosa lentis (TVL) and formation of the ciliary zonules; these findings were correlated with the first signs of development of the arrays.Polygonal arrays formed slowly beginning at one to two days after birth, and with advancing time these thickened and made more numerous connections with the lateral plasma membranes. Development of the arrays was not correlated with onset of vision or disappearance of the TVL or a sudden increase in cell area, since these events occur postnatally at about 9–10 days, nor with the development of zonular fibers since these are already in place at 24 days of gestation. Only lens weights showed a dramatic increase between 24 days gestation and birth, it is surmised that the expanding lens mass may be involved in some way in signaling the organization of actin filaments into geodomes.

ISSN:0271-3683    

DOI:10.3109/02713689109013855

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

The effect of artificial tear solutions on the corneal epithelial barrier was evaluated by measuring corneal uptake of 5,6 carboxyfluorescein (CF) after exposure of rabbit corneas to various formulations in a conjunctival cup. Four tear solutions containing 0.01% benzalkonium chloride (BAC), a formulation containing 0.001% Polyquad, a contact lens re-wetting solution containing 0.004% thimerosal, and each of the above preservatives in balanced salt solution (BSS) were evaluated. Four non-preserved solutions were also tested. After treatment with the solutions corneas were exposed to the CF, removed from the eyes and dialyzed in balanced salt solution. The CF concentration in the dialysate was measured by fluorometry. Solutions containing 0.01% BAC caused a 9.24 to 99.28 fold increase in CF uptake as compared to control. Solutions preserved with Polyquad or thimerosal caused only a 0 to 4 fold increase in CF uptake while non-preserved solutions caused no change compared to control. Corneas prepared for transmission electron microscopy using fixative containing ruthenium red exhibited damage which correlated well with CF uptake; the ruthenium red penetrated the epithelium to the basal cell layer after corneal exposure to solutions containing BAC while only superficial cell layers were stained after exposure to the other test solutions. The method used in this study allows statistical comparison of artificial tear formulations. The data show that patients with severe dry-eye who use artificial tears frequently should avoid tear solutions containing BAC and that non-preserved solutions are preferable for treatment of these patients.

ISSN:0271-3683    

DOI:10.3109/02713689109013856

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

The purpose of this experiment was to test the effectiveness of E64 in prevention of selenite nuclear cataract in the whole animal. E64 is an inhibitor of cysteine proteases such as calpain (EC.3.4.22.17). In the whole animal, daily intraperitoneal injection of E64 was mildly effective in slowing the rate of formation of selenite nuclear cataract, although prevention was not permanent. Frequency of the nuclear cataract in selenite group at 5 days post selenite injection was significantly decreased from 40% to 17% in the selenite+E64 group, and the density of cataract in the Se+E64 group was reduced. However, crystallins and calpain were still degraded in the selenite+E64 group. E64 was more effective against selenite cataract when present continuously during lens culture, where it slowed the rate of formation of nuclear opacity. Amelioration of cataract occurred bothin vitroandin vivoeven though lens calcium concentrations were elevated. The results supported the idea that application of calpain inhibitor is beneficial hi prevention of rodent selenite cataracts.

ISSN:0271-3683    

DOI:10.3109/02713689109013857

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

Cytomegalovirus (CMV) retinitis is the most frequent infectious ocular complication of the acquired immune deficiency syndrome (AIDS). Currently, there are few animal models to study the virologic and immunologic factors which contribute to the pathogenesis of CMV retinitis. In these experiments, 1–2×104PFU of murine cytomegalovirus (MCMV) was inoculated into the supraciliary space of BALB/c mice. Within three days of inoculation, moderate iridocyclitis was observed which progressed to necrosis of the ciliary body by day 14. Approximately 60% of the mice developed typical retinitis characterized by virus-infected cytomegalic cells in the retina and retinal pigment epithelium, focal retinal infiltrates, transition zones between uninvolved and involved retina, and optic neuritis. The remaining animals exhibited atypical retinitis characterized by nonspecific retinal inflammation in the absence of obvious viral infection. This murine model of CMV retinitis shares some features with retinitis observed in AIDS patients with CMV retinitis and may be useful to evaluate the efficacy of immunologic and/or pharmacologic treatment strategies for CMV retinitis.

ISSN:0271-3683    

DOI:10.3109/02713689109013858

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

FK506 is a new immunosuppressive agent which has been found more potent than cyclosporine based on the dosage. FK506 was examined here for its effect on the development of uveitis in primates immunized with S-antigen. FK506 successfully inhibited uveitis in monkeys, even when administered three weeks after the first immunization, at the time when the immunopathogenic mechanism of uveitis is assumed to be developed. All four monkeys injected with 0.5 mg/kg/day of FK506 did not develop uveitis, 2 out of 4 treated with the 0.25 mg and 3 out of 4 of those receiving the 0.125 mg also did not develop disease. FK506 suppressed to some extent the cellular and humoral immune responses to S-antigen. The main side effect of FK506 was weight loss. We consider that this drug may be considered as a new potential therapeutic agent for immune-mediated ocular disease in humans.

ISSN:0271-3683    

DOI:10.3109/02713689109013859

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor