摘要:

Degeneration and loss of retinal capillary pericytes are characteristic features of diabetic retinopathy. The effect of pancreatic islet cell allotransplantation across a major histocompatibility barrier on diabetic pericyte changes was examined in streptozotocin induced diabetic rats 14 months post-transplantation. Morphological studies of the retinal microvasculature were carried out using qualitative and quantitative morphological techniques.We describe significant prevention of pericyte degeneration and loss after successful allotransplantation suggesting that pancreatic islet allograft is a promising therapeutical approach in the prevention of diabetic retinopathy.

ISSN:0271-3683    

DOI:10.3109/02713688709034827

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

Tear fluid cytology is described for the early and late phases of ocular anaphylaxis in actively immunized Sprague-Dawley rats. Tears were collected from both eyes of the rats before challenge and at 1, 2, 4, 6, 8, 10, 12, 24, and 48 h after topical challenge with di-DNP-lysine in one eye and PBS in the fellow eye. Results showed a statistically significant increase in the Aggregate Cell Rating, which represents the aggregate scores in neutrophil, eosinophil, lymphocyte, and atypical epithelial cell levels, in antigen-treated vs control eyes. This report is the first to use a cytologic study of tear film to detect the late phase of ocular anaphylaxis in the rat. Cytology of the tear film could be applied to the study of allergic conjunctivitis in both animals and humans.

ISSN:0271-3683    

DOI:10.3109/02713688709034828

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

The signaling messengers for the regulation of intracellular calcium-dependent functions involve a phospholipid-sensitive protein kinase (protein kinase C) modulated by diacylglycerol, which is a product of phosphoinositide degradation. We found that protein kinase C activity is two times higher in the epithelium than in the stroma-endothelial layers of the rabbit cornea. 12-0-tetradecanoylphorbol-13-acetate (TPA) and phosphati-dylserine stimulate protein kinase C at low Ca2+concentrations. The TPA-phosphatidyl-serine stimulated activity of corneal epithelium was recovered in the soluble fraction; in the membrane-bound fraction, a very active phosphatidylinositol kinase accounted for half the basal phosphorylation of the corneal epithelium.

ISSN:0271-3683    

DOI:10.3109/02713688709034829

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

Rabbit corneal endothelia were subjected to a cryoinjury (-70°C for 15 sec) and sodium and bicarbonate fluxes were determined at various times after induction of the endothelial destruction. A complete monolayer of cells was present by 4 days that consisted of large cells that underwent division over the next 16 days-Unidirectional sodium fluxes were unaltered by the transformation from large to normal sized hexagonal cells. Unidirectional bicarbonate fluxes showed an increase in J endo coupled with a decrease in the net J str, flux. As the cells became smaller these bicarbonate endo fluxes returned to normal values. The data indicate that the cell margin/cell size ratio is not related to the flux rates, thus the paracellular pathway increase with healing is not related to the passage of either sodium or bicarbonate. Secondly, the data indicate separate effects on both sodium and bicarbonate, suggesting that transendothelial movement of the ions can be separated and that they are not necessarily linked in passage across the endothelium.

ISSN:0271-3683    

DOI:10.3109/02713688709034830

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

The effect of cyclosporine (CsA) treatment in both primary and secondaryChlamydia trachomatisocular infection in cynomolgus monkeys was studied. Following primary infection, CsA-treated animals developed severe clinical symptoms which persisted for up to 12 weeks compared to control animals which developed less severe inflammation lasting only 4 to 6 weeks. CsA treatment had no effect on the clinical course of a second ocular infection. Antigen-specific antibodies developed normally in the serum and tears of all animals, but the titer of IgM in serum and secreted IgA in tears of CsA-treated animals was significantly lower than control animals. Chlamydia-specific cell-mediated immunity, as determined by in vitro lymphoproliferation assays of peripheral blood, did not develop in either group of animals.

ISSN:0271-3683    

DOI:10.3109/02713688709034831

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

Phosphatidic acid (PA) is an obligate intermediate in the phosphatidylinositol (PI) cycle and may serve as a sensitive marker for this pathway of reactions. Previously, we have shown that acetylcholine (ACh) stimulates formation of labeled PA in whole rat corneas whose.phospholipids were prelabeled with [14C]arachidonate. To determine which layer of the cornea exhibits the ACh effect, intact epithelium was isolated from the rest of the corneal tissue (designated“stroma/ endothelium”) by incubating rat corneas with neutral protease and then stripping off the epithelium using forceps. The epithelium was ultra-structurally normal and avidly incorporated [14C]arachidonate into phospholipids; the stroma/endothelium had only trace incorporation. [14C]Arachidonyl-PA formation by the epithelium was significantly increased after a 37 second (+58%) and was maximal after a 5.0 minute (+188%) incubation in the presence of 1 mM ACh. The stimulation by ACh was blocked by atropine and scopolamine but not by d-tubocurarine. The epithelium also incorporated significant quantities of [3H]inositol into phosphatidylinositol (PI), phosphatidylinositol monophosphate (PIP), and phosphatidyl-inositol bisphosphate (PIP.). When [3H]inositol-labeled epithelia were incubated for 5 minutes with 1 mM ACh, [3H]inositol monophosphate (IP) was increased 200%, [3H]inositol bisphosphate (IP2) was increased 225%, and [3H]inositol trisphosphate (IP3) was increased 74%. These results suggest that muscarinic cholinergic receptors may be an important regulator of the PI cycle in corneal epithelium and thus may affect intracellular calcium mobilization and epithelial proliferation and regeneration.

ISSN:0271-3683    

DOI:10.3109/02713688709034832

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

In vitro differentiation of embryonic chicken lens epithelial explants to form lens fiber cells is accompanied by an increase in protein synthesis without a corresponding increase in mRNA levels. This apparent increase in translational efficiency is correlated with a specific enhancement of phosphorylation of a 32K protein, which we identify as ribosomal protein S6 by two dimensional gel electrophoresis of purified ribosomal proteins. Serum, insulin, and chicken vitreous humor, three agents known to initiate differentiation in this system, all lead to enhanced S6 phosphorylation. Maximal enhancement of phosphorylation is reached within the first hour after the onset of differentiation, and is not blocked by inhibitors of RNA and protein synthesis.

ISSN:0271-3683    

DOI:10.3109/02713688709034833

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

The maximal velocity (Vmax) and the apparent dissociation constant (K0.5) of Na+K+-ATPase have each been estimated with respect to sodium and potassium ion activation. These estimations were made from the enzymatic activity of plasma membrane preparations derived from bovine corneal endothelial cells. The determinations were made on cells obtained from fresh tissue and from secondary tissue cultures. Two methods were used to obtain the estimates: the first used a combination of Eadle-Hofstee and Hill plots; the second used Eisenthal-Cornish-Bowden plots. The Vmaxfor sodium was 5.58–5.60μmoles Pj/mg protein/30 min for fresh tissue vs. 2.00–1.80μmoles Pi/mg protein/30 min for tissue cultures. The corresponding K0.5values were 62–57 mM (fresh tissue) vs. 7.9–6.7 mM (tissue culture). Vmaxfor potassium was 4.28–4.00μmoles Pi/mg protein/30 min for fresh tissue vs. 1.37–1.34μmoles Pi/mg protein/30 min for tissue cultures. The corresponding Ko.5 values were 3.3–3.1 mM (fresh tissue) and 1.7–1.7 mM (tissue culture). The results indicate a lowered activity and change in affinity of the enzyme for the two ions in tissue cultures compared to fresh tissues. The detergent Lubrol W-X increased activity in both tissue sources. Sonication had no significant effect on the activity. Variations in pH (7–9) indicated that the highest activity was obtained at pH 7.8 for the enzyme in tissue culture while activity was highest at pH 8.0 for the enzyme in fresh tissues. These differences in kinetic activity suggest a response to changes in the ion requirements of these cells due to their environment, developmental stage or some other parameter.

ISSN:0271-3683    

DOI:10.3109/02713688709034834

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

Fibroblast proliferation with subsequent bleb scarring is a major cause of filtering surgery failure. To investigate possible antiproliferative effects of beta radiation, owl monkey Tenon's capsule fibroblasts in tissue culture were irradiated to doses of 30, 100, 300, 1,000, and 3,000 rads with a linear accelerator and to doses of 95,285, and 950 rads with a Strontium-90 applicator. The irradiated cell proliferation expressed as the percentage of the non-irradiated control growth on the third and seventh days, respectively, after beta irradiation was: 97% and 96% after 30 rads; 72% and 90% after 100 rads; 48% and 44% after 300 rads; 39% and 14% after 1,000 rads; and 39% and 14% after 3,000 rads. Similar effects on cell proliferation were observed with the Strontium-90 applicator. The inhibitory effect of beta irradiation on fibroblast proliferation in tissue culture suggests that beta irradiation after filtering surgery may reduce postoperative bleb scarring.

ISSN:0271-3683    

DOI:10.3109/02713688709034835

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

Lens proteins from the guinea pig (Cavia porcellus) were found to be similar to those of other mammals with the exception of the presence of a previously undescribed constituent comprising about 10% of the total soluble lens proteins. This oligomeric protein is composed of polypeptides with apparent molecular weight of 38,000 and elutes from gel exclusion chromatography columns in the BH-crystallin fraction. Following purification by ion exchange chromatography an antibody was raised against the protein. Using that antibody and antibodies specific for other crystallins we could detect no cross-reactivity between the guinea pig protein and any other reported lens cystallin. This protein, which we have named zeta (ζ)-crystallin, is the first reported mammalian lens crystallin which is not part of theα−orβ-γfamilies of crystallins. Unlike all other known mammalian crystallins, which have little or no a-helical structure, zeta-crystallin is estimated to be approximately 30–40%α-helix.

ISSN:0271-3683    

DOI:10.3109/02713688709034836

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor