摘要:

Proliferative vitreoretinopathy (PVR) involves the formation of intravitreal fibrocellular membranes which may lead to traction retinal detachment and blindness. The cellular component of epiretinal membranes originates from the proliferation and migration of cells within the eye. Several growth factors and other cytokines are plausible candidates for directing the processes leading to membrane formation. A reproducible animal model is needed for experimental studies of cytokine expression during PVR induction or treatment.We found that intravitreal injection of>106mixed mononuclear leukocytes or adherent monocytes along with a trans-scleral incision through the pars plana leads to the development of PVR-like disease in rabbit eyes. The severity of the disease was related to the number of monocytes injected. Typically, organized membranes extending from the incision toward the optic nerve formed within one week. Progression to extensive traction retinal detachment required 1 to 4 weeks. Injection of up to 5×106lymphocytes or freeze-thaw killed monocytes was ineffective, and coinjecting 100μg endotoxin with the monocytes did not result in enhanced disease.The histological appearance of the epiretinal membranes was similar to human PVR membranes. Macrophage, cytokeratin-positive (epithelial), and fibroblast-like cells were present. Northern blot analysis of RNA extracted from the rabbit membranes revealed the presence of mRNA for acidic fibroblast growth factor (aFGF). Acidic FGF mRNA was not expressed by the injected monocytes. A comparable level of aFGF mRNA and also mRNAs for basic FGF, platelet-derived growth factor-B, and transforming growth factor beta were found in epiretinal membranes induced by a scleral incision in association with cryopexy. These model systems will be valuable for studying cytokine-mediated regulation of epiretinal membrane development.

ISSN:0271-3683    

DOI:10.3109/02713689209015074

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

Endothelin-like immunoreactivity was detected in human (15.6±2.7 pg/ml) and bovine (11.1±0.98 pg/ml) aqueous humour of the eye. These concentrations are 2-3 times higher than the corresponding plasma levels. Cultured human nonpigmented ciliary epithelial cells released endothelin-like immunoreactivity with a maximum of 2.1±0.32 pg/(cm248 h). The release was stimulated by fetal calf serum, thrombin, carbachol and phorbol ester and blocked by cycloheximide. Immunocytochemistry showed cytoplasmic staining of cultured human nonpigmented ciliary epithelial cells for endothelin-1. Endothelin-1 was shown to induce contractions in isolated human ciliary muscle by isometric force measurements. Endothelin in the aqueous humour may play a role in the regulation of intraocular pressure.

ISSN:0271-3683    

DOI:10.3109/02713689209015075

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

We developed an experimental model of proliferative vitreoretinopathy (PVR) in albino rabbits by combining some factors suspected of causing the di sease. Sixty nine eyes divided into six groups served as controls (Groups C 1–6). Forty nine eyes were divided into four experimental groups (Groups E 1-4). Group El (n=12) was injected with 0.15 ml of platelet-rich plasma. In addition, Groups E2 (n=12) and E3 (n=12) underwent cryotherapy or vitrectomy. Group E4 (n=13) underwent both procedures. Seven of the 13 Group 4 experimental eyes developed total retinal detachment and giant holes. None of the other groups developed more than two total retinal detachments or giant holes (P<0.05). Light and electron microscopy showed Intravitreal or freretinal proliferation composed of ibroblast-like cells. Retroretinal membranes appeared only in Group E4 eyes, composed of elongated cells with oval nuclei and abundant organelles in the cytoplasm. We believe these lesions mimic human PVR more closely than other models previously developed.

ISSN:0271-3683    

DOI:10.3109/02713689209015076

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

One-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis (1D-SDS PAGE) of the non-denatured low molecular weight (MW) tear proteins (dilution in phosphate buffered saline or in the non-ionic detergent Triton (100) revealed no protein G but a strongly marked 23-kD related to a tear specific prealbumin (TSP) subunit coming with the known 15, 17, 18 and 20-kD TSP subunits. Under mild denaturating conditions of sample preparation with SDS dilution just before electrophoresis, 23-kD protein decreased and a faint 32-kD protein G appeared. Under stronger denaturing conditions of sample preparation with SDS treatment (boiling or freeze-thaw cycles), 23-kD protein disappeared and two main protein G forms (32 and 34-kD) and additional bands (29, 36, 39, 42, 57 and 60-kD) appeared depending on the sample treatment. The isoelectric pH (pi) of these proteins ranged from pH 5.2 to pH 5.4.Different two-dimensional electrophoresis methods revealed that:-in presence of SDS, 23-kD protein was spontaneously changed into 17-kD TSP and such a phenomenon was partially reversible by using a non-ionic detergent (Triton X100), new proteins appeared under denaturating processes were related to various protein G forms and originated from TSP group, proteins G were produced by the aggregation of TSP subunit related to MW 17-kD/pI 5.0 corresponding to the major TSP subunit,-disulfide bond formation was shown to play a major role in the aggregation process although protein G group was not totally reduced by dithiotreitol.Such results suggest that protein G is anin vitroexperimental artifact due to denaturing conditions with SDS treatment. Protein G originates in the aggregation of 17-kD TSP partly formed by denaturation of 23-kD TSP.

ISSN:0271-3683    

DOI:10.3109/02713689209015077

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

An inflammatory response was elicited in the rabbit eye by intracameral injection of platelet activating factor (PAF). PAF induced severe aqueous flare, corneal edema, pupillary constriction and marked biphasic changes in intraocular pressure (IOP) in a dose-dependent manner. All of the responses to PAF were inhibited by the PAF receptor antagonist, BN 52021 (20 mg/kg, i.p.). The cyclooxygenase inhibitor, indomethacin (30 mg/kg, i.p.) caused significant inhibition of the early phase PAF-induced aqueous flare, pupillary constriction and intraocular hypertension, but did not effect PAF-induced corneal edema or intraocular hypotension. NDGA (10 mg/kg, i.p.), a lipoxygenase inhibitor, did not inhibit the inflammatory effects of PAF. PAF-induced chemotactic response was evaluated by tissue chemiluminescence. Intracamerally injected PAF did not significantly increase chemiluminescence in cornea or iris-ciliary body, but intracorneal injection of PAF did cause a chemotactic response in both the conjunctiva and cornea. These data suggest that PAF may be an important mediator of intraocular inflammation and that some PAF-induced effects are prostaglandin dependent, while others may be independent of eicosanoid synthesis and release.

ISSN:0271-3683    

DOI:10.3109/02713689209015078

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

Calcitonin gene-related peptide (CGRP) is a mediator of intraocular inflammatory responses, but it may also affect aqueous humour dynamics. The aim of the present work was to characterize CGRP binding sites in the eyes of various mammals. The binding of radiolabelled human CGRP to membranes from the ciliary body-iris (c + i) block of porcine eye showed characteristics expected of an interaction with a receptor site: it was reversible, saturable and displaced by rat CGRP and calcitonin. Studies with CGRP fragments demonstrated the importance of rather long carboxyterminal sequences of the CGRP molecule for high-affinity binding to the receptor. Rat islet amyloid polypeptide (IAPP), which has about 50% structural similarity to CGRP, displaced radioligand binding nearly as efficiently as CGRP, while human IAPP was about twenty-fold less potent. No displaceable CGRP binding could be reliably demonstrated by the present method in c + i membranes from cat, rabbit and bovine eyes, thus indicating differences in the number or localization of CGRP receptors between different mammalian species.

ISSN:0271-3683    

DOI:10.3109/02713689209015079

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

Experimental autoimmune uveoretinitis was induced in female Lewis rats with bovine retinal soluble antigen (S-antigen). Tissue changes and immunoreactivities of transforming growth factor-β(TGF-β), epidermal growth factor (EGF), and extracellular matrix compounds in the anterior segment (ciliary body) were investigated by immunocytochemical methods. Control animals received adjuvant only. The immunized animals were sacrificed at day 0, 3, 7, 14, 20, and 30 postimmunization. Tissue changes that occurred at the peak of inflammation (day 14) included destruction of the inner basement membrane, epithelial cell loss, distortion of the ciliary stroma, and loss of epithelial basal infoldings. Ciliary body architecture was regenerated almost completely by day 30. Basement membrane laminin and collagen type IV levels did not change much during the inflammatory process. Fibronectin labeling level peaked at day 14 postimmunization. Collagen type V level was low at day 14 and elevated at day 20 and day 30. TGF-βimmunoreactivity peaked at day 14 and remained elevated thereafter. EGF labeling did not increase until day 20 and was maximal at day 30. Labeling of both growth factors was principally confinded to the stromal regions. The presence of TGF-βand EGF in the ciliary stroma at well defined intervals suggests a coordinated effect upon the synthesis and reorganization of the extracellular matrix and possibly upon the inflammatory cell population in the anterior tissue.

ISSN:0271-3683    

DOI:10.3109/02713689209015080

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

The effect of 2-mercaptopropionylglycine on the development of cataract induced by a single dose of X-ray (10 Gy) was investigated in rats. Intraperitoneal injection of 20 mg/kg, three times weekly starting 1 day after irradiation delayed the development of X-ray-induced cataracts significantly. The amounts of non-protein SH groups, malondialdehyde and the Na+/K+ratio, in the lenses of rats post-treated with the drug were significantly maintained at normal levels even at 27 weeks after irradiation.On the other hand, a single administration of 250 mg/kg of the compound, 30 min prior to irradiation had no effect on cataract progression induced by X-ray.

ISSN:0271-3683    

DOI:10.3109/02713689209015081

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

PurifiedPseudomonas aeruginosaelastase cleaved a 65 kDa gelatinase [inactive proenzyme form of matrix metalloproteinase (MMP-2)] from human corneal fibroblasts into a biologically active fragment with an approximate molecular mass of 58 kDa. However, purified pseudomonal alkaline protease did not cleave MMP-2 appreciably. Since activated MMP-2 is known to degrade native type IV, V and VII collagens, all components of the corneal basement membrane or stroma, our results suggest a new role for pseudomonal elastase in the pathogenesis of corneal infection, inflammation and ulceration.

ISSN:0271-3683    

DOI:10.3109/02713689209015082

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

To determine the efficacy of a fluoroquinolone antibiotic in the treatment of methicillin-resistantStaphylococcus aureus(MRSA) keratitis, topical administration of 0.3% ciprofloxacin was compared with topical 5.0% vancomycin or 5.0% cefazolin in experimental infections in the rabbit eye. The infections were established by intrastromal injection of 100 colony forming units (CPU) of MRSA, which resulted in greater than 106CFU per cornea by 12 hr postinfection. Chemotherapy (one drop every 15 min) was given from 4–9, 10–15, or 10–20 hr postinfection. Early therapy (4–9 hr postinfection) with ciprofloxacin rendered all eyes free of bacteria; ciprofloxacin was significantly more effective than vancomycin or cefazolin. When treatment was initiated 6 hr later (10–15 hr postinfection), no corneas became free of bacteria, but ciprofloxacin was again more effective than vancomycin or cefazolin. Bacterial killing by ciprofloxacin after treatment from 10–20 hr postinfection was also significantly greater than that of vancomycin. Overall, the results show that ciprofloxacin is effective in killing methicillin-resistantStaphylococcus aureus, and is most effective when applied during the very early stages of infection.

ISSN:0271-3683    

DOI:10.3109/02713689209015083

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor