摘要:

Sulfated proteoglycans in the lamina cribrosa of the optic nerve head from individuals aged 2 months, 18 months, and 23, 35, 44, 55, 67, 74, and 88 years were studied by electron microscopy after cuprolinic blue dye binding. Within the cores of the laminar plates, cuprolinic blue-positive chondroitin/dermatan sulfate proteoglycan filaments of different sizes were found associated with collagen fibers. In addition, small punctate and filamentous structures that represented heparan sulfate roteoglycan molecules were associated with the basal Paminae of astrocytes and blood vessels. In the eyes of older individuals, the chondroitin/dermatan sulfate and heparan sulfate proteoglycan filaments were found to be shorter than those in younger persons. A mild decline with aging in the diameter of the filaments was also noted. Our findings illustrate the age-related changes in the proteoglycans in the human lamina cribrosa, which may help explain why the optic nerve head is more susceptible to damage with aging.

ISSN:0271-3683    

DOI:10.3109/02713689308995763

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

Culture of various types of cells on gelled, reconstituted extracellular matrices results in decreased cellular proliferation. In the present study, we evaluated several possible mechanisms for this inhibition, as applied to cultured bovine retinal microvascular endothelial cells (EC) or to retinal pigment epithelial (WE) cells: whether the inhibition might be related to (a) inactivation of fibroblast growth factor (FGF) by binding of the molecules present in the medium to a matrix component; (b) release of an inhibitor by the matrix in culture; or (c) inhibitory propehes of the matrix macromolecules themselves. Our results suggest that mechanism (c) is most likely. The reasons are, first, that culture of EC or WE cells on several different extracellular matrix substrates in the presence of logarithmically increasing concentrations of acidic or basic fibroblast growth factors (aFGF or bFGF) leads to a vertical shift of the plots of cell number after 4 days in culture vs. log growth factor concentration for both types of cells. The same result obtains when cells are cultured with logarithmically increasing concentrations of all-trans retinoic acid, which inhibits EC but not WE cell proliferation in a dosedependent fashion. This is consistent with mechanism (b) or (c), but not (a), for which one would expect a horizontal shift. Second, washing the matrices prior to the plating of cells with 1M NaC1, which elutes aFGF and partially elutes bFGF molecules from basement membranes, does not alter the growth of cells plated after the wash. This suggests also that growth factor binding to the matrix is not a likely mechanism for the observed inhibition. Incubation of matrices with culture medium prior to plating cells does not usually alter the ability of the medium thus“conditioned”to support cell growth, arguing against the possibility that the matrices release a soluble activator or inhibitor of such growth. However, in some experiments performed with lots of Matrigel®(a commercially available basement membrane extract from a murine tumor) obtained prior to mid-1991, media“conditioned”by incubation with this matrix did show enhanced ability to facilitate EC and RPE cell proliferation. Finally, if RPE cells or EC are plated on various substrates, allowed to attach for 24 hr., and then the same or other substrates are poured over the cells, the effect on proliferation of the matrices plated on the apical surfaces of the cells is often less than that of matrices plated adjacent to their basal surfaces. Although in most cases these differences are not statistically significant, there is an apparent trend. The overall results of this experiment suggest an asymmetrical cell-substrate interaction, mediated through receptors located predominantly on the basal surfaces of the cells.

ISSN:0271-3683    

DOI:10.3109/02713689308995764

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

The effects of transforming growth factor-β(TGFβ) and epidermal growth factor (EGF) on the synthesis of collagen and fibronectin, and on the proliferation of human corneal stromal fibroblastsin vitro, were evaluated. Human corneal stromal fibroblasts in culture were incubated for 48 hours with TGFβor EGF in the absence of serum. Collagen and fibronectin in the culture media were measured by a collagenase-digestion assay and a competitive ELISA, respectively. The effects of the growth factors on proliferation were assessed by3H-thymidine incorporation. Collagen synthesis was dose-dependently stimulated by TGFβ; at a concentration of 1 ng/ml of TGFβ, a 120% increase in collagen synthesis was seen over that of controls (p<0.01). EGF, at a concentration of 10 nglml, induced a 40% increase in collagen synthesis over that of controls (p<0.01). The maximum stimulation by TGFβwas greater than that by EGF (p<0.05). Fibronectin synthesis was stimulated by TGFβand EGF in a dose-dependent manner; 230% (p<0.001) and 210% (p<0.01) increases in fibronectin synthesis were caused by 10 ng/ml TGFβand EGF, respectively. TGFβand EGF dose-dependently stimulated3H-thymidine incorporation. The maximum increases in3H-thymidine incorporation reached 180% (p<0.001) and 190% (p<0.001) over that in controls, at 10 ng/ml concentrations of TGFβand EGF, respectively. In conclusion, both TGFβand EGF are potent stimulants of collagen and fibronectin synthesis and proliferation. Therefore, these two growth factors may be effective alternatives or additional choices for the treatment of corneal ulcer.

ISSN:0271-3683    

DOI:10.3109/02713689308995765

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

The capacity of photoreceptor cells to synthesize opsin was evaluated in a newly-described mouse model of retinal degeneration, the C57BL/6-mivtt/mivit. The mivit/mivitmouse loses photoreceptor cells at a rate of about one row per month beginning at 8 weeks, ROS are severely disrupted at 4 months, RPE is unevenly pigmented. Retinas of affected and control mice ages 4, 6, 8, 12, 16, 20, 24, 28, 32 and 52 weeks were incubated for 2 hours in medium containing [3H] leucine. Homogenates of retina samples were subjected to SDS-PAGE using disc gels. The gels were sliced and counted by scintillation. The incorporation of [3H] leucine into opsin was compared with its incorporation into other retinal proteins. During the early time points studied, mivit/mivitretinas incorporated proportionately similar amounts of [3H] leucine into opsin versus other retinal proteins as did controls. At 12 weeks, the percentage was about 80% and it continued to decline over the succeeding weeks studied. By 1 year, the proportion of leucine incorporated into opsin versus other proteins was only about 23 % the amount incorporated in controls. The results of the present study suggest that the mivit/mivitphotoreceptor cells are able to synthesize opsin and the gradual decline in synthetic ability follows the gradual loss of cells and is not correlated with the disruption of ROS.

ISSN:0271-3683    

DOI:10.3109/02713689308995766

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

Previously we have presented the morphological features of a neonatal mouse retinal explant kept in culture for 3 to 4 weeks. To further evaluate the organotypic parameters of the tissue we have examined the presence of opsin, S-antigen, and interphotoreceptor retinoid-binding protein (IRBP) in the same experimental paradigm, using light microscopic immunocytochemistry.In vitro, opsin and S-antigen staining is found in photoreceptor somata from genetically normal explants and those derived from mice with the rd or the rds mutation. when present, inner and outer segments label more intensely. No IRBP staining has been found in cell bodies of any genotype. However, some labeling is found in the plexiform layers and in the inner segments. The results indicate that photoreceptor proteins are continuously producedin vitro. This further establishes the organotypic nature of the retinal explant in culture. The administration of growth factors to these explants has been investigated. Neither basic fibroblast growth factor nor nerve growth factor alone has affected the explants phenotype. However, the combination of these proteins has significantly retarded rd cell lossin vitro.

ISSN:0271-3683    

DOI:10.3109/02713689308995767

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

Light exposure not only elicits a photic response but may also alter the metabolism and functional properties of the retina. This may be evoked by the stimulation of phospholipid derived second messenger systems. In this study, we investigated the light-evoked release of inositol 1,4,5-trisphosphate in the isolated rat retina in vitro by means of high performance liquid chromatography (HPLC) detection. After prelabelling of isolated retinae with tritiated myo-inositol in darkness, they were exposed to no light or to white fluorescent light of 10,000 lux illuminance for 3,5 and 10 sec, respectively. We observed a 200% increase in the release of inositol 1,4,5-trisphosphate compared to basal values in darkness after 3 sec of light exposure with a decline after 5 sec and a return to basal values after 10 sec indicating a rapid breakdown of inositol 1,4,5-trisphosphate. Our data confirm previous studies in the amphibian retina and photoreceptors and demonstrate for the first time a light evoked inositol 1,4,5-trisphosphate release in the mammalian retina.

ISSN:0271-3683    

DOI:10.3109/02713689308995768

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

The slowed healing rates observed by some investigators may he caused by vehicles or preservatives in the antimicrobials preparations tested. To determine whether antimicrobials directly inhibit corneal epithelial wound healing, we cultured blocks of the rabhit cornea in media containing various concentrations of antibiotics or antimicrobials (at 1, 10, or 100μg/ml); after 24 hours, we measured the distance of epithelium that had migrated down the side of each block. The higher concentrations of fluoroquinolones (ofloxacin; 74±5.8 % of control at 100μg/ml, p<0.05, ciprofloxacin; 4.4±1.5 %1 of control at 100μg/ml, p<0. 01, or norfloxacin; 71±7.0 % at 10μg/ml, p<0.01, and 1.5±0.4 % of control at 100μg/ml, p<0.01) and the highest concentrations of peptides (polymyxin B; 64±3.0 % of control at 100μg/ml, p<0.01, or colistin; 67±5.7 % of control at 100μg/mI, p<0.01) or fosfomycin (79±6.2 % of control at 100μg/ml, p<0.05) had an inhibitory effect on corneal epithelial migration. Among aminoglycosides tested, sisomicin (85±10.0 % of control, not significant), dibekacin (76±11.6 % of control, p<0.05) and streptomycin (77±9.4 %, of control, not significant) were inhibitory at 100μg/ml, but tobramycin had no effect. Penicillins (aspoxicillin, subenicillin or ampicillin), cephalosporins (cefmenoxime or cefminox), oxytetracycline, erythromycin and chloramphenicol did not affect epithelial migration at all. These results demonstrate that some antimicrobials are inhibitory at high concentrations, but penicillins, cephalosporins, oxytetracycline, erythromycin or chloramphenicol has no inhibitory effect on corneal epithelial migration.

ISSN:0271-3683    

DOI:10.3109/02713689308995769

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

Ocular cicatricial pemphigoid (OCP) is a chronic autoimmune inflammatory disease which affects the conjunctiva and other squamous epithelial mucous membranes resulting in a scarring process. It is characterized by the deposition of an antibasement membrane zone (BMZ) antibodyIn vivo. Sera from 11 patients with active OCP were studied. Using monkey esophagus and normal skin as substrate. weak staining of the BMZ was observed in conventional indirect immunofluorescence (IIF) assay. Using salt split human skin as substrate, the OCP sera demonstrated binding to the epidermal side of the split, in low titers with weak staining. Ten of the 11 sera were positive on an immunoblot assay using COLO and SCaBER tumor cell lysates demonstrating 230, 205. 160, and 85 kD proteins. Sera from six bullous pemphigoid (BP) patients, with only cutaneous involvement and high titer of anti-BMZ antibody. as detected by IIF, also bound to 230. 160. and 85 kD proteins on both lysates in comigration experiments. Serum from five normal individuals and two patients each with severe atopic conjunctival disease, erythema multiforme with chronic conjunctivitis and systemic lupus erythematosus (SLE). did not demonstrate those bands. When the two lysates were first absorbed with BP sera and then the same lysates were immunoblotted with OCP sera, in all ten OCP sera the 230, 160. and 85 kD bands were eliminated and only a single 205 kD band was uniformly present. These results indicate that OCP sera recognize peptide(s) present in 230, 205 and 160 kD proteins in lysates from COLO and SCaBER tumor cells. These proteins contain the immunodominant region of the BMZ molecule(s) in which the OCP antigen(s) reside. The OCP antigen(s) appears to be distinct from the BP antigen(s).

ISSN:0271-3683    

DOI:10.3109/02713689308995770

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

In primate eyes the injection of Endothelin (ET) 1 into the anterior chamber lowers the intraocular pressure by increasing outflow facility. A possible source for aqueous ET is the ciliary epithelium, since virus transformed human nonpigmented ciliary epithelial cells secrete ET into the medium and immunohistochemically stain with antibodies against ET 1.This study demonstrates that human ciliary epithelium exhibits positive endothelin-like immunoreactivity with antibodies against ET 1. There are, however, regional differences with regard to the staining intensity. Pronouced staining was observed in the nonpigmented and pigmented epithelium at the crests of the pars plicata. In the valleys of the pars plicata and in the pars plana no immunolabeling was found.

ISSN:0271-3683    

DOI:10.3109/02713689308995771

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

Protein phosphorylation plays a critical role in the control of growth and regulation of many eukaryotic cells. Members of the protein tyrosine kinase (PTK) family of peptides function as growth factor receptors and oncoproteins. A common feature of members of the PTK family is a highly conserved intracellular catalytic domain. We analyzed the chicken lens epithelium, which responds to several known growth factors, for the presence of receptor PTK's. Using reverse transcription polymerase chain reaction (rtPCR) and degenerate primers made to conserved regions within kinase domains, we amplified RNA from embryonic day 6 (E6) lens epithleium and sequenced 135 cDNA clones. Sixteen distinct kinase sequences were obtained. Eight of these sequences represented kinase domains of known mammalian growth factor receptors, and six represented intercellular kinases. Two sequences appeared to code for new kinases. The amino acid identity of the chicken homologs ranged from 80–100% when compared to their mammalian counterparts.

ISSN:0271-3683    

DOI:10.3109/02713689308995772

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor