摘要:

Ciliary body explants from 30 human eyes were maintained in organ culture up to 14 days. The age of the donors ranged from 4 5 to 85 years, the post mortem time from 4 to 22 hours. The ciliary epithelium as well as the underlying stroma were studied light- and electronmicro-scopically before incubation and after 1, 3, 5, 7 and 14 days of culture. At the same time intervals, the localization of Na/K-ATPase and carbonic anhydrase (CA) were examined histochemically.If the cells were already damaged before incubation in medium (9 cases), they did not recover in culture. Best results were obtained after 3 to 5 days of culture with a survival rate of more than 90 % after 3 days and more than 70 % after 5 days, respectively. Both the nonpigmented (NPE) and the pigmented epithelium (PE) of the pars plicata in culture retained the morphological characteristics of epithelia involved in active secretion, namely elaborate in-foldings of the cell membranes, numerous mitochondria in the cytoplasm and high activity of Na/K-ATPase and CA. In addition the adjacent capillaries were still fenestrated.After longer incubation times (7–14 days) the NPE and PE cells were filled with increasing amounts of lipid droplets and glycogen granules, indicating changes in metabolism.

ISSN:0271-3683    

DOI:10.3109/02713689108996333

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

Immunologic privilege of the anterior chamber has been associated with the capacity to induce a unique form of deviant systemic immunity after anterior chamber (AC) immunization. However, the capacity of privilege to suppress expression of immunity in the AC has not been examined. We studied the ability of the AC to sustain immunogenic inflammation after direct antigen challenge (delayed hypersensitivity-DH) in C57BL/6 mice primed to M tuberculosis (MT) antigens. Compared to subcutaneous and subconjunctival sites where primed mice demonstrated vigorous and significant DH, the anterior chambers of these mice failed to develop signs of inflammation unless toxic doses of antigen were injected. In an attempt to promote intraocular DH, the AC's of MT-primed mice were pre-treated with subinflammatory intracameral injections of IFN-γ, a cytokine that antagonizes TGF-β, recruits antigen presetting cells (APC) from the blood and activates resident APC precursors. It was observed that AC injection of IFN-γ, followed 3 days later by AC challenge with 200 ng of MT, resulted in severe intraocular inflammation only in primed (but not naive) mice. We conclude that the normal mouse AC resists DH unless its immunosuppressive microenvironment is abolished, as in these experiments by IFN-γ. We propose that impaired expression of cell-mediated immunity is an important component of immune privilege of the AC.

ISSN:0271-3683    

DOI:10.3109/02713689108996334

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

The inhibitory effects of sulfhydryl reagents on Ca-ATPase activity in the rabbit lens epithelium were assessed. Test conpounds used in this study were selected on their ability to cause a calcium increase in cultured lenses. Under conditions in which lenses were cultured in the presence of the test compound, epithelial Ca-ATPase was inhibited markedly by diamide, t-BHP, IAA and slightly by selenite. The findings demonstrated that hydrogen peroxide caused little inhibition of Ca-ATPase in the lens epithelium, both when the intact lens was cultured in the presence of the oxidant or when the epithelial homcgenate contained peroxide during the assay of enzyme activity. The study suggests that if a thiol-modifying compound can reach Ca-ATPase or its critical SH groups, inhibition is likely.

ISSN:0271-3683    

DOI:10.3109/02713689108996335

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

The morphologic changes in ciliary processes and the associated intraocular pressure (IOP) were observed in owl and squirrel monkeys after intravitreal (IVT) and intravenous (IV) injections of water soluble marijuana-derived material (MDM). The response in monkeys differed from that reported in rabbits wherein IV injection induced severe ciliary swelling and a significant decrease in IOP. Only moderate swelling occurs in monkey processes after IV injection of relatively high dose of MDM, and this change, which includes disruption of the basal lamina of the pigment epithelium, is not associated with a change in IOP. Severe swelling occurs in the crests of monkey ciliary processes after IVT injection, which is accompanied by a fall in IOP. The difference in the response in monkey versus rabbit ciliary processes after IV injection of MDM may be due to a more compact stroma in the monkey processes.

ISSN:0271-3683    

DOI:10.3109/02713689108996336

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

In soluble extracts of bird lenses, crystallin subunits of apparent sizes between 30kDa and 40kDa show considerable variability in both abundance and mobility in sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS PAGE). This is only partly due to the taxon-specific distribution of lactate dehydrogenase-B (LDH-B)/e-crystallin. Here we show that, in spite of high conservation in primary sequence,βB1-crystallin subunits of avian lenses have a markedly slower migration in SDS PAGE than those of mammals and that the apparent subunit size ofβB1-crystallin varies among birds. This may be at least partly due to unusual post-translational modifications, sinceβB1-crystallins of adult birds react strongly in a glycan detection procedure. No other crystallins in birds or mammals share this strong reaction. Modification ofβB1-crystallin could have interesting consequences for the formation of high molecular weightβ-crystallin aggregates in bird lenses.

ISSN:0271-3683    

DOI:10.3109/02713689108996337

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

Exposure of cultured bovine lens epithelial cells (BLECs) to minimal essential medium (MEM) containing 40 mM galactose (Gal) promotes a decrease in the cellular content of reduced glutathione (GSH) as galactitol increases. Incubation of BLECs with Gal also leads to a reduction in3H-myo-inositol (3H-MI) concentrating capability. Studies were therefore initiated to determine the nature of the relationship between polyol accumulation, GSH content and the attenuation of the active transport of myo-inositol. The inhibitor of glutathione biosynthesis, L-buthionine sulfoximine (L-BSO) was used in order to lower the intracellular pool of GSH in MEM-maintained cells to a concentration below that characteristically observed in Gal-treated cells, under conditions whereby no galactitol accumulation could or had occurred. L-BSO (0.5 mM) was simultaneously administered to BLECs maintained in either MEM or Gal for up to five days. The cellular content of GSH after five days of continuous incubation was 3.3μg GSH/μg PO4in MEM alone and 0.45μg GSH/μg PO4 in MEM + BSO. Moreover, the GSH content in BLECs exposed to Gal for five days was 1.9μg GSH/μg PO4and was not detectable in the Gal + BSO-treated cells. However, the ability to concentrate3H-MI in MEM + BSO-treated BLECs was equivalent to that observed with MEM-maintained cells regardless of the significant difference in GSH content. Likewise, L-BSO addition to Gal-treated cells, while virtually depleting the intracellular GSH content, did not further decrease the ability of the cells to accumulate H-MI compared to that observed with BLECs in Gal alone. Indeed, supplementation of Gal-treated cells with exogenous GSH failed to correct the Gal-induced attenuation in myo-inositol concentrating ability. These studies demonstrate that the Gal-induced depletion of cellular GSH and the Gal-induced deficit in ability to concentrate myoinositol are not associated and represent independent events. That is, depletion of lens cell GSH does not lead to the attenuation of myo-inositol uptake in cultured lens epithelial cells.

ISSN:0271-3683    

DOI:10.3109/02713689108996338

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

Evidence is presented indicating that young rat lens has the capacity to synthesize 12(S)-hydroxyeicosatetraenoic acid (12(S)-HETE) from exogenous arachidonic acid (AA). A 9,000 xg supernatant prepared from 15 day old rat lenses, when incubated with calcium and U-[14C]-AA, generated a radiolabelled product with a retention time identical to authentic unlabelled 12-HETE in two different HPLC solvent systems. Mass spectral analysis provided evidence that the metabolite was 12-HETE while chiral studies demonstrated the exclusive presence of the 12(S) isomer. Radiolabelled 12-HETE synthesis was inhibited by preincubating the 15 day old rat lens supernatant with 0.2 Mm curcumin, a mixed cyclooxygenase/ lipoxygenase inhibitor. Radiolabelled 12(S)-HETE synthetic capacity was highest in the A day old rat lens, the earliest time period measured, and rapidly declined with age reaching negligible levels at about 4 months. These results suggest that the young rat lens possess the biosynthetic capacity to generate radiolabelled 12(S)-HETE from U-[l4]C-AA. The profile of 12-HETE synthetic activity suggests a possible regulatory function of the hydroxylated AA metabolite in the developing lens.

ISSN:0271-3683    

DOI:10.3109/02713689108996339

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

One of the earliest histopathological signs of diabetic retinopathy is a selective loss of intramural pericytes from retinal capillaries. In the present study, the retinal vessels of rats with streptozotocin-induced diabetes (STZ Wistar) and rats with genetically-induced insulin dependent diabetes mellitus (BB Wistar) and non-insulin dependent diabetes mellitus (SHR/N-corpulent) were examined after 6 to 8 months duration for diabetes-related retinal microangiopathies. The SHR/N-corpulent (cp_) rats were fed a 54% sucrose diet, whereas the STZ Wistar and BB Wistar rats were fed laboratory chow for 32 to 36 weeks. In all the diabetic rats, the retinal capillaries in enzyme-digested flat mounts exhibited an increase in periodic-acid-Schiff (PAS) staining and loss of pericytes compared to their respective euglycemic controls. Pericyte“ghosts”, like those defined in human diabetes as intramural pockets lacking normal cell contents, were documented by high resolution micrographs in all the diabetic rats. Endothelial cell proliferation, capillary dilation, and varicose loop formation were noted in some of the diabetic rats. Hence, similar capillary lesions were found in very different groups of diabetic rats. The findings suggest that a chronic high tissue concentration of glucose is the underlying factor which triggers pathogenesis in the pericyte. Hyperglycemia-induced activation of endogenous aldose reductase of the polyol pathway is probably the initial insult, but other factors such as advanced glycosylation products may affect the final outcome.

ISSN:0271-3683    

DOI:10.3109/02713689108996340

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

The role of bacterial piliation and protease production in Pseudomonas aeruginosa adhesion to the injured corneal epithelial surface and subsequent infectivity was examined using several bacterial strains, including three that were hyperpiliated. To initiate this study, bacteria were examined by transmission EM to confirm their piliation characteristics. The PAK strain, like pseudomonas ATCC 19660, possessed about 1–4 polar pili. The mutant PAK/PR11 lacked pili while PAK/PR1, DB2, a mutant of PAOl, and PA1244, a wild-type clinical isolate, were hyperpiliated. Ocular infectivity of these bacterial strains and mutants was examined macroscopically and histo-pathologically in mice and these data compared to the well-characterized ocular disease response of a murine model of infection with pseudomonas ATCC 19660. The PAK strain was infective, but less virulent than strain 19660 by both macroscopic grading and histopathological analysis of infected eyes. Infectivity of the PR11 mutant was similar to the PAK parent strain, while PR1, DB2 and 1244, all hyperpiliated, were not infective. To explore the hypothesis that hyperpiliated bacteria bound less well to cornea and thus failed to induce corneal disease, in vitro quantitative studies of bacterial adhesion were done using an ocular organ culture model. The PR1 hyperpiliated mutant bound significantly less well to cornea than the PAK parent strain, PR11 mutant or pseudomonas 19660, while DB2 and 1244 binding did not differ significantly from 19660 or PAK. Examination of protease production, another factor which may influence adhesion, revealed that only 19660 and DB2 produced detectable protease. This study provides evidence that non-piliated, non-protease producing strains such as PAK/PR11 possess alternate virulence mechanisms to facilitate binding to and infectivity of corneal tissue.

ISSN:0271-3683    

DOI:10.3109/02713689108996341

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

The mechanisms by which the eye maintains an immunosuppressive environment has been the subject of recent investigations. In this report we investigated the ability of resident ocular cells from the iris, choroid, and retina to inhibit lymphocyte responses in vitro. Our results demonstrate that single cell suspensions derived from iris and choroid to inhibit alloantigen induced lymphocyte proliferation. We show that this inhibition was mediated by soluble factors which are low (<10,000) and intermediate (10,000–30,000) molecular weight molecules. This capacity is limited to iris and choroid and is not demonstrable in cell preparations derived from the retina. We conclude from our studies that cells derived from iris and choroid are capable of regulating immune responses and suggest that these cells (or their soluble products) may play a role in the immunosuppressive environment of the eye.

ISSN:0271-3683    

DOI:10.3109/02713689108996342

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor