摘要:

Attenuation of the rat conjunctival response by repeated topical challenge with dinitrophenyl (DNP) hapten was demonstrated in our study. Adult rats were immunized by intraperitoneal injections of dinitrophenylatedAscaris suumextract (DNP-Asc) and alum. Serum levels of anti-DNP homocytotropic antibody were determined by passive cutaneous anaphylaxis in rats prepared with antibody 48 hours earlier. In other animals, topical challenge was performed by applying N,N′-di-2,4-DNP-L-lysine (di-DNP-lysine) in phosphate-buffered saline (PBS) to one eye; PBS alone was applied to the fellow eye. The degree of conjunctival reaction was assessed clinically, and ocular tissues were processed for histological evaluation. The intensity of the conjunctival reaction and extent of mast cell degranulation were significantly greater after one challenge with di-DNP-lysine than after multiple challenges. In the multiple-challenge group, the contralateral eye remained responsive to a single challenge with di-DNP-lysine. These results may have implications for therapeutic interventions in ocular anaphylaxis.

ISSN:0271-3683    

DOI:10.3109/02713688808997241

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor

摘要:

The present study demonstrates an experimental set-up to study light injury with defined parameters including retinal irradiance levels and spectral composition of the damaging light. The time-course of acute morphological changes at constant light intensity and increasing exposure durations (from 5–30 minutes) was evaluated, the wavelength of the damaging light being 400–550 nm. Pigment epithelial lesions appeared already after 5 minutes, and rod outer segment membrane disruptions after 15–20 minutes of light exposure. Striking was the observation of disruption and vesiculation of disk membranes at the base of rod outer segments. This“clear zone”was consistently observed beginning after twenty minutes of light exposure. The comparison of morphological changes in pigmented and albinotic eyes revealed no essential differences. This result confirms the observations of other laboratories that pigment epithelial melanin neither protects against nor promotes light damage to a significant extent. Long-term changes after light exposure revealed pigment epithelial lesions and rod outer segment disruptions, followed by macrophage invasion and pigment epithelial proliferation with subsequent loss of photoreceptor cells.

ISSN:0271-3683    

DOI:10.3109/02713688808997242

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor

摘要:

Glutathione-insulin transhydrogenase (GIT, thiol:protein-disulfide isomerase/oxidoreductase, E.C. 5.3.4.1/1.8.4.2) catalyzes via sulfhydryl-disulfide interchange, the scission as well as formation of disulfide bonds in many diverse proteins. Using insulin as a substrate, the lens epithelial layer of cows, rats and rabbits was found to contain GIT activity. The enzyme's activity is activated by GSH and inhibited by M-ethylmaleimide. Subcellular distribution of bovine lens epithelial homogenates showed that the majority of GIT activity is located in the insoluble fraction (10,000 g pellet) and in the high molecular weight fraction (60,000 g pellet). Lens epithelial extracts were subjected to SDS-PAGE followed by Western blot, and probed with a polyclonal antibody to rat liver GIT, or with either of two monoclonal antibodies directed against different epitopes of the enzyme. Lens epithelium was found to contain two forms of GIT, one with the same molecular weight as the purified enzyme (Mr 56Kd), and a second having an Mr of 67Kd. Immunoblots using polyclonal antibodies revealed an additional major immunoreactive band of 32Kd in the cow lens epithelial layer as well as in the isolated cortical and nuclear portions. Rat lenses showed no immunoreactive 32Kd band. Using a bovine cortical/nuclear fraction the 32Kd reactivity was found to be associated with theβH-crystallin fraction, but the extract failed to show GIT activity with the insulin substrate. This suggests thatβH-crystallin may share a common epitope with GIT.

ISSN:0271-3683    

DOI:10.3109/02713688808997243

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor

摘要:

Five major crystallin fractions were found in camel lens fractionated by Sepharose CL-6B column chromatography. These crystallin fractions were named alpha high (αH), alpha low (αL), beta high (βH), beta low (βL) and gamma (γ) by comparison with the elution profiles and molecular weights of rabbit crystallins. The amino acid composition and isoelectric focusing bands for crystallins of camel and rabbit were remarkably similar, but individual differences were found. By means of sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), two alpha H crystallin subunits, of 23K and 20K molecular weight, were found in camel and rabbit. Likewise, a single 21K molecular weight band was found in the gamma crystallin of camel and rabbit. In camel, the beta high crystallin consisted of five major subunits, while rabbit beta high crystallin consisted of only three subunits. On SDS-PAGE, camel and rabbit beta low crystallins both showed two major subunits of 27K and 23K molecular weight but camel beta low crystallin showed an additional 35K molecular weight subunit. Characterization of camel lens crystallins may contribute to understanding the effect of aging on aggregation of camel crystallins.

ISSN:0271-3683    

DOI:10.3109/02713688808997244

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor

摘要:

Single or multiple (3) injections of“Shigella”endotoxin were administered into the rabbit vitreous body to investigate the development of epiretinal membranes following intraocular inflammation. The evaluation included clinical assessment of the resulting traction retinal detachments, together with histological, autoradiographic, immunohistochemical and ultrastructural studies. Traction retinal detachments were found beneath fibroglial epiretinal membranes (being more extensive in eyes which had received 3 endotoxin injections) in the vicinity of the medullary rays, while purely glial membranes occurred over attached peripheral retina. The primary change at the vitreoretinal interface was an elevation of the inner limiting lamina of the retina followed by the extension of glial cells onto the retinal surface. It is postulated that glial cells breach the inner limiting lamina as a sequel to inflammation involving the vitreoretinal interface and form a scaffold upon which fibroblast-like cells migrate.

ISSN:0271-3683    

DOI:10.3109/02713688808997245

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor

摘要:

HPLC analysis of human tears allows tear protein profiles to be obtained within ten minutes. A tear protein profile normally consists of 4 major peaks: IgA, lactoferrin, protein G and lysozyme. Although it is a rapid method, the use of High Performance Liquid Chromatography in the (quantitative) determination of proteins in tears is influenced by various factors. The day to day variability of the quantitative use, ranges between 7 and 9% for the various tear proteins. Combining the HPLC method with a convenient collection method such as sponges or Schirmer strips, showed that the sponges and some of the Schirmer strips used in this study eluted significant material absorbing light at 280 nm. No statistical difference was observed in the HPLC protein profiles of tears collected with Schirmer strips or with sponges.Using sponges has the advantage that they can absorb almost twice as much tears in a same period of time as Schirmer strips.HPLC analysis of human tear proteins is not accurate when there is albumin leakage as in traumatic sampling with Schirmer strips or in inflammatory states. The I-125 column which was used in our study is not able to separate lactoferrin and albumin, which may cause an overestimation of lactoferrin in inflammatory conditions. The study presented here indicates that for quantitative use of HPLC in epidemiological tear protein research better separating protein gel filtration columns are needed.

ISSN:0271-3683    

DOI:10.3109/02713688808997246

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor

摘要:

HLA DR and DQ distribution was investigated in normal human ocular tissues, together with class I antigens and immunocompetent cell subsets, by immunofluorescence and immunoperoxidase procedures. In the anterior segment, our findings, consistent with those of previous reports, showed the wide distribution of class I antigens, specially in the corneal epithelium, while class II antigens were restricted to very rare cells scattered in the conjunctiva, the peripheral cornea and the stroma of the ciliary processes. Some non pigmented epithelial cells of the ciliary processes were HLA DR and DQ positive. In the posterior segment, class I antigens were abundantly represented in the choroid and the retinal layers. Few HLA DR and DQ positive cells were seen in the choroid, similar to those found in the anterior segment. Normal RPE did not react with any monoclonal antibody, but numerous cells located in the retina were strongly HLA DR and DQ positive, all around the blood vessels, and not at the sites of endothelial cells. The characterization of those cells, which could be hypothetized as pericytes needs further studies but suggests close relationships between neuroretina and the immune system. This study may provide insight in the implication of the immune system in many poorly understood ocular diseases.

ISSN:0271-3683    

DOI:10.3109/02713688808997247

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor

摘要:

We studied ultrastructurally the development of rabbit corneal endothelium from the 13th day of gestation to 3 days after birth. Precursor corneal endothelial cells, stromal cells, and a vascular network migrate in close association with each other between the developing corneal and lens epithelia. During development, newly deposited extracellular fibrous matrices separate the prospective endothelium from the capillaries and corneal stroma. The extracellular matrix between the apical endothelial surface and the vascular network loses its fibrous appearance early in development. Simultaneously, randomly organized fibrils are deposited on the basal endothelial surface facing the stroma. These fibrils, gradually obscured by the deposition of a nonfibrous component, eventually become part of Descemet's membrane. Early in development, prospective endothelial cells cannot be distinguished morphologically from the overlying corneal stromal cells. Morphologic differentiation of the endothelial cell is characterizd by the formation of sinuous lateral borders that interdigitate with those of adjacent cells to form a continuous single-cell layer of tissue. The basal endothelial membrane forms a pitted surface, distinguishing it from the apical cell membrane. Intercellular junctions between lateral membranes, a cilium projecting into the anterior chamber, and deposition of Descemet's membrane on the basal endothelial surface contribute to the polarization of the endothelium. Throughout most of corneal development the vascular pupillary membrane maintains a close association with the apical surface of the differentiating endothelium. We conclude that fetal corneal endothelium develops within a complex extracellular matrix environment and in proximity to the underlying vascular network. These structures play an important role in the morphogenesis of corneal endothelium.

ISSN:0271-3683    

DOI:10.3109/02713688808997248

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor

摘要:

A reduced nicotinamide adenine dinucleotide phosphate (NAD(P)H)-dependent hydrogen peroxide-generating activity of rat ocular tissue was investigated cytochemically utilizing the cerium method. NADPH or NADH oxidation resulted in electron-dense fine granular deposits on the corneal epithelial and endothelial plasma membranes, around the photoreceptors of the retina, and on the processes of the retinal pigmented epithelium. Control specimens incubated in a substrate-free medium did not show any such deposits. These results suggest that, under normal conditions, there is generation of oxidants, such as hydrogen peroxide, in the ocular structures, and that such oxidants can be visualized by cytochemical techniques.

ISSN:0271-3683    

DOI:10.3109/02713688808997249

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor

摘要:

A developmentally regulated, cytoskeletal-associated protein was identified and partially characterized using a monoclonal antibody developed for this study. Based on the distinctive fibrous pattern of distribution of this antigen in the cytoskeletons of cultured corneal fibroblasts, and a characteristic reorganization of these fibers into perinuclear whorls in response to colchicine treatment, this protein was found to be associated with the intermediate filaments (vimentin filaments). Chronological distribution of this intermediate filament-associated protein (IFAP) and vimentin during fetal development of the cornea in rabbit was analysed immunohistochemically. During an early stage of corneal development (day 13 of gestation), both this IFAP and vimentin were present in the stromal cells in the presumptive corneal region. The IFAP was also present in the surface epithelium. At day 17 and 21, the corneal endothelial layer was developed and contained both the IFAP and vimentin. However, in the corneal stromal cells, the concentration of IFAP (based on the densities of the immunostaining reaction) progressively decreased during the later stages of fetal development (day 24 to day 28), while relative concentrations of vimentin were not reduced significantly. In the corneal stromal cells in the adult rabbit, the IFAP was not detectable while vimentin was still present. For further characterization of this protein, extracts of cultured corneal fibroblasts and fetal corneas were analysed by SDS-PAGE followed by an immunotransblot technique. These analyses indicated that the IFAP was a polypeptide with a Mrof 130k. Therefore, this protein was not vimentin (Mr55–58k). The presence of this IFAP in the fetal corneas and stromal cells and its absence in the quiescent stromal cells in the adult cornea indicated that this unique IFAP is developmentally regulated in corneal stromal cells, and its association with vimentin filaments may be important during the active state of corneal stromal cells.

ISSN:0271-3683    

DOI:10.3109/02713688808997250

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor