摘要:

Retinal cryoapplication accelerates blood resorption of experimental vitreous hemorrhages shortening the time until fundus visualization is possible. For the animals that underwent cryoapplication five days after blood injection into the vitreous cavity, the mean time to fundus visualization was 3.75 weeks versus 5.06 weeks for the control group (p<0.001).Retinal cryoapplication also causes an increase in the concentration of fibrin degradation products in the vitreous cavity, indicating an activation of fibrinolysis, one of the most important processes involved in hemorrhage resolution.Use of topical indomethacin slightly lessens the effect of cryoapplication on acceleration of blood resorption (mean 4.06 weeks until visualization), but does not influence the effect on fibrinolysis.

ISSN:0271-3683    

DOI:10.3109/02713689109013863

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

The effect of increased intraocular pressure (IOP) on stimulated aqueous humor flow (AHF) was studied in cynomolgus monkeys. Two experimental series were performed, one with unilateral VIP-treatment (60μg intracamerally) and one with unilateral terbutaline-treatment (10μg.ml−1perfusion fluid). The AHF was determined with a labelled albumin dilution method, and an artificial increase in IOP was produced by clamping the outlet of the perfusion system, thus causing a net inflow of perfusion fluid.The initial AHF was significantly higher in the VIP-treated eye than in the control eye-1.568±0.095 as compared to 1.112±0.103μl.min−1(P<0.01). The spontaneous IOP was 5.8±0.4 mmHg (P<0.001) higher in the VIP-treated eye. There was no difference in pseudo-facility between the VIP-treated eye (0.063±0.016μl.min−1.mmHg−1) and the control eye (0.065±0.022μl.min−1.mmHg−1). but the total and true outflow facilities were higher in the VIP-treated eye.In the experiments with terbutaline, the initial AHF was 1.729±0.114 for the experimental eye and 1.262+0.104μl.min−1for the control eye (P<0.01). The pseudofacility tended to be higher in the terbutaline-treated eye (0.072±0.026μl.min−1.mrnHg−1) than in the control eye (0.048±10.012μl.min−1.mmHg−1), but the difference was not statistically significant. There was no difference in total and true outflow facility between the experimental and control eye.The results indicate that the pressure sensitivity of the AHF is independent of the initial level of the AHF. VIP increases true outflow facility, possibly via a direct effect on the trabecular meshwork. VIP also appears to rise the IOP due to an increase in episcleral venous pressure, which could be secondary to vasodilatation in the anterior segment.

ISSN:0271-3683    

DOI:10.3109/02713689109013864

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

The presence of histamine Hi-receptors in the bovine retinal blood vessels was studied with a [3H]mepyramine binding assay. The membranes of purified vessels obtained from bovine retinas showed specific [3H]mepyramine binding sites with a dissociation constant(K0) of 2.78±0.32 nM. This was similar to values obtained from the retinal neuronal fractions. The binding capacity(Bmax) was 53.8±1.7 f'mol/mg protein, which was about a half that of the retinal neuronal fractions (108.9±3.1 f'mol/mg protein). Some Ht-antagonists proved to be potent competitors for [3H]mepyramine binding sites in bovine retinal blood vessels. These results indicate that histamine Hi-receptors exist in the retinal blood vessels which may be involved in the physiological and the pathological responses of blood circulation in retinas.

ISSN:0271-3683    

DOI:10.3109/02713689109013865

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

The pathogenesis of proliferative vitreoretinopathy (PVR) membranes remains poorly understood. We have studied the presence of acidic fibroblast growth factor (aFGF), a potent mitogen for many cells, within these membranes. We have used affinity purified monospecific anti-aFGF polyclonal antibodies, in conjunction with highly sensitive immunofluorescence techniques. The labelling was exclusively localized to cell bodies and was absent from the extracellular matrix. Double labelling techniques revealed that all cytokeratin positive cells (probably pigmented epithelial cells) and macrophages contained aFGF-like immunoreactivity, whilst glial cells were unlabelled. Appropriate controls indicated the specificity of the antibodies. Hence, the presence of this mitogenic molecule within certain cell types constituting PVR membranes may contribute to the pathogenesis.

ISSN:0271-3683    

DOI:10.3109/02713689109013866

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

Cell-attached and excised inside-out membrane patches were used to study single channel currents in a cell line derived from human non-pigmented ciliary epithelium. Most of the patches contained a Ca2+-dependent K+channel with large unitary conductance (200 pS in symmetrical K+solutions). Single channel current in cell-attached patches exposed to high K+solution in the pipette showed a null potential of-36 mV. This value, which should yield an approximate estimation of cell membrane potential, was reversibly increased by-30 to-40 mV in the presence of Ca29+ionophores, Tetraethylammonium up to 10 mM applied at the membrane cytoplasmic face had no effect on the channel. Addition of 1 mM BaCl2to excised patches caused a voltage-dependent blockade of the channel. In the presence of barium the unit currents were not altered, but the channel remained closed for long periods of time and the open state probability decreased with depolarization. The possibility that this channel participates in regulation of transepithelial ciliary body secretion is discussed.

ISSN:0271-3683    

DOI:10.3109/02713689109013867

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

Air/liquid organ culture of tissues with stratified epithelial layers has been shown to encourage tight packing of cells and promote cellular differentiation. In this study human corneas cultured in a air/liquid environment were compared to paired, conventionally-cultured corneas to determine if the long-term morphology could be improved. Fourteen paired human corneas were cultured at 37+C in covered culture dishes for 1 to 3 weeks. Air/liquid cultured corneas were placed epithelial-side up in a fixed position and culture medium was added to a level so that during rocking the corneal epithelia were intermittently exposed to air/liquid environments. Mate corneas were cultured using the conventional method. In this method corneas are fully submerged, epithelial-side down, in culture medium. After 3 weeks of culture significantly less epithelial intercellular edema was noted for the air/liquid cultures (p = 0.033), compared to conventional cultures. Significant improvements in cellular structure of the endothelial layers, after 1 and 3 weeks incubation (p = 0.029 and 0.000) and stromal layers, after 3 weeks in culture (p = 0.024), were also noted. We have shown that slight modifications of the organ culture environment lead to improvements in corneal morphology. Air/liquid corneal organ culture has promise for use in corneal wound healing studies and long-term culture.

ISSN:0271-3683    

DOI:10.3109/02713689109013868

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

The relationships between plasma, aqueous humor and lens ascorbic acid levels are examined in 131 samples from 127 patients. Mean ascorbate intake for nonsupplemented individuals was 148 mg/day or over two times the recommended daily allowance. A subset of 44 patients participated in a trial to assess the impact of vitamin C supplementation of 2 grams per day on aqueous and lens ascorbic acid levels. Such supplementation significantly increased both total and reduced ascorbic acid levels in plasma and aqueous and total ascorbic acid in the lens. Correlation coefficients relating total and reduced ascorbic acid levels in the three tissues ranged from 0.42 to 0.19 (p<0.05 for all correlation coefficients). Over 60% of the ascorbate was present in the reduced form in plasma and aqueous, and about 50% of the lens ascorbate was in the reduced form.

ISSN:0271-3683    

DOI:10.3109/02713689109013869

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

Aqueous humor contains transforming growth factor-β(TGF-β) and other inhibitory factors for cellular proliferation. In the present study we investigated the possibility that these factors are produced locally by cells found within the iris and ciliary body. Iris and ciliary body (I/C-B) cells or whole tissue explants from C57BL/6 mice produced soluble factors which inhibited both murine thymocyte and mink lung epithelial cell proliferation. Indomethacin partially blocked inhibition of thymocyte proliferation, but did not affect inhibition of Mv1 Lu proliferation. The inhibitory activity of culture supernatants was not blocked by neutralizing antibodies to TGF-β1or TGF-β2. However, following acid activation of culture supernatants from both I/CB and corneal tissue, increased inhibitory activity consistent with activation of latent TGB-βwas detected. Antibody neutralization experiments demonstrated that this increase in activity was due primarily to TGF-β2for I/CB tissue. Polymerase chain reaction (PCR) analysis of cDNA generated from I/CB tissue mRNA showed prominent fragments representing both TGF-β1and TGF-β2mRNA. Corneal tissue, however, showed a prominent fragment for TGF-β1mRNA, but either no band or a barely detectable fragment for TGF-β2mRNA. Therefore, it remains uncertain whether TGF-β2mRNA is produced by the cornea in this strain. Overall, these results demonstrated that three distinct categories of substances inhibitory to proliferation may be locally produced by resident iris and ciliary body cells: 1) indomethacin sensitive products, 2) TGF-β2in latent form, and 3) factors not blocked by indomethacin or anti-TGF-βneutralizing antibodies. Products generated by these tissues may have important regulatory properties in the development of immune responses to antigens introduced into the anterior chamber.

ISSN:0271-3683    

DOI:10.3109/02713689109013870

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

The mechanisms involved in the clearance of immune deposits in tissues are not yet clear. The cornea was chosen as a model to examine this question due to its avascularity and transparency. Bovine serum albumin (BSA) and rabbit antl BSA serum were injected at opposite sites into the corneal stroma of unsensitized rabbits. Within a day, a sharp opaque line was seen macroscopically between the two injection sites. Sections of the corneas were examined by light microscopy and electron microscopy; furthermore, immunohistochemical techniques were used. With the light microscope, a precipitation line was seen in the corneal stroma, which was identified as an antigen-antibody complex by immunofluorescence techniques. In the same area infiltrating polymorphonuclear cells and swollen keratocytes were observed. In the ultrathin sections precipitates were seen lying between the collagen fibrils without affecting the structure of the collagen. The swollen keratocytes had an activated rough endoplasmic reticulum. In certain cases the precipitates appeared to be intracellular, both in the polymorphonuclear cells, as well as in the keratocytes. These findings suggest that stromal keratocytes may play an important role in the degradation of corneal immune deposits.

ISSN:0271-3683    

DOI:10.3109/02713689109013871

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

We found in the previous study that the induction of 7-pentoxyresorufin O-dealkylase and 7-ethoxyresorufin O-dealkylase activities by phenobarbital and 3-methylcholanthrene, respectively, is more pronounced in porcine ciliary nonpigmented epithelial cells than in pigmented epithelial cells. In order to determine whether cytochrome P450 isozymes that mediate the O-dealkylase activities are also induced in nonpigmented cells under the conditions, primary cultures of porcine ciliary processes were treated with phenobarbital and 3-methylcholanthrene and the expression and localization of cytochrome P450 isozymes induced by these compounds were investigated by immunocytochemical methods using antibodies against the individual P450 isozymes. Intense labeling of nonpigmented epithelial cells was observed when ciliary processes treated with phenobarbirtal were reacted with anti-P450 (phenobarbital) antibody and when the processes treated with 3-methylcholanthrene were incubated with anti-P450 (methylcholanthrene) antibody. The labeling patterns supported the conculsion that the O-dealkylase activities and P450 isozymes specific for these activities are co-induced in and localized to the endoplasmic reticulum. This study is the first report presenting direct evidence of cytochrome P450 induction in primary cultures of ocular tissues and demonstrates the usefulness of porcine ciliary epithelial cells for studying the induction of ocular drug metabolizing enzymes.

ISSN:0271-3683    

DOI:10.3109/02713689109013872

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor