摘要:

Several growth factors have been evaluated for their effects on corneal wound healing but few studies have yet demonstrated an acceleration of endothelial repairin vivo.Mesodermal Growth Factor (MGF) was testedin vivoby making standardized freeze wounds in cat corneas and immediately injecting one of four concentrations of MGF in sterile phosphate buffered saline (PBS), or PBS alone, into the anterior chamber. Seven days later, the animals were sacrificed and the corneas excised and stained. Descemet's membrane and endothelium were dissected and mounted onto glass slides. The wound areas were photographed, measured and compared statistically.Those cats receiving the three lowest doses of MGF had significantly smaller wounds than controls (p<0.05).

ISSN:0271-3683    

DOI:10.3109/02713689008999590

出版商:Taylor&Francis    

年代:1990

数据来源: Taylor

摘要:

156 eyes of patients and normal volunteers were classified at the slit lamp into the following pure groups: normal (n=50), nuclear (n=39), cortical (n=33) and PSC (n=34). The eyes were photographed with the Topcon SL-45 Scheimpflug camera and the images scanned and processed to obtain one dimensional profiles through a 40×440 micron axial window. Of the 156 profiles, 90 were used as reference samples and were processed to obtain average profiles. The remaining 66“unknown”profiles and each of the reference profiles, were classified into the four groups based on their distance from the average profiles in Euclidean space. The system was found to be very sensitive (98%) in detecting the presence of cataracts and specific (100%) in identifying normal, i.e. cataract negative lenses. In classifying pure cataracts into the various classes 98% of answers were correct.

ISSN:0271-3683    

DOI:10.3109/02713689008999591

出版商:Taylor&Francis    

年代:1990

数据来源: Taylor

摘要:

Resting refractive correction in ketamine-, pentobarbital-, or halothane-anesthetized rhesus and cynomolgus monkeys was∼1–3 diopters myopic, with little difference under the various anesthetic regimens. Topical cyclopentolate or atropine, or systemic hexamethonium eliminated much of the myopia, while epinephrine, phenylephrine and thymoxamine had little effect. Anesthesia-induced myopia in monkeys thus seems comparable to tonic accommodation (“night myopia”) in the human. Accommodation induced by electrical stimulation of the Edinger-Westphal nucleus averaged∼50% less under halothane than under pentobarbital, possibly due to halothane-induced systemic arterial hypotension.

ISSN:0271-3683    

DOI:10.3109/02713689008999592

出版商:Taylor&Francis    

年代:1990

数据来源: Taylor

摘要:

The relationship between Ca2+ and lens fiber cell communication was investigated in the isolated intact rat lens by using radiotracer and electrophysiological techniques. The lens internal calcium was increased by adding the SH oxidant diamide (1 mM), by incubating in a sodium-free (n-methylglucamine/ solution or by increasing external calcium from 1 to 10 mM. A 12 hours incubation in diamide produced a ten-fold increase in 45Ca uptake into the lens which was accompanied by a ten-fold increase in internal resistance. Incubation in Na-free solution or in 10 mM Ca2+ both produced a 5-fold increase in 45Ca content, while the increase in internal resistance was five and six fold respectively. This uncoupling was prevented in the diamide and Na-free treated lenses by omitting Ca2+ from the incubation medium.Fiber cell uncoupling was noticed in each of these experimental conditions after approximately 5 hours incubation, and good recovery was obtained in the high calcium solution if the stress was removed.The calmodulin antagonists calmidazolium (3μM) and W7 (100μM) both prevented uncoupling in the high calcium solution, provided there was a 2 hours preincubation period in calcium-free solution containing antagonist before the stress was applied.These data indicate that lens fiber cell communication is regulated by Ca2+ and calmodulin.

ISSN:0271-3683    

DOI:10.3109/02713689008999593

出版商:Taylor&Francis    

年代:1990

数据来源: Taylor

摘要:

Enkephalinase (EC 3.4.24.11) is a naturally occurring, membrane-bound peptidase that degrades substance Pin vivoandin vitro.Addition of this neutral endopeptidase to a rabbit eye cup model partially inhibits substance P-induced contraction of the iris sphincter muscle. Inactivation of substance P is reversed by thiorphan, a specific inhibitor of enkephalinase. These results show that enkephalinase degradation of substance P produces metabolites that are physiologically inactive in iris contraction. We also observed that atropine acts synergistically with enkephalinase to completely abolish substance P-induced iris contraction suggesting that the action of substance P on the iris contains an acetylcholine-stimulatory effect which is not lost by enkephalinase treatment.

ISSN:0271-3683    

DOI:10.3109/02713689008999594

出版商:Taylor&Francis    

年代:1990

数据来源: Taylor

摘要:

Blue light, but not green or red light, inhibited growth of retinal pigment epithelial (RPE) cells, aortic endothelial cells, and fibroblasts in vitro. Significant inhibition was observed in all 3 cell types exposed for 18 hr to blue light (425–500 nm) at 42 J/cm2. Damage was prevented by inclusion of superoxide dismutase (SOD) and catalase, providing evidence for a photooxidative mechanism. Dopa (100μM) also caused oxidative damage that suppressed growth of all 3 cell types. A synergism of dopa and light effects was observed in endothelial cells and fibroblasts, but the agents caused additive effects on RPE cells. Endothelial cells were the most sensitive to dopa, light, and the two combined. Fibroblasts were the only cell type that exhibited greater sensitivity to light than to dopa. These data suggest that oxygen-mediated damage to the growing blood vessels in the retina of a premature infant may be exacerbated by exposure to blue light. A further implication is that restriction of RPE melano-genesis to the prenatal period of darkness and lower oxygen protects the retina from simultaneous oxidative challenge by light and by reactive species generated during oxidation of dopa released to the extracellular environment.

ISSN:0271-3683    

DOI:10.3109/02713689008999595

出版商:Taylor&Francis    

年代:1990

数据来源: Taylor

摘要:

The synthesis of phosphatidylinositol, phospha-tidylinositol-4-phosphate and phosphatidylinositol-4-5-bisphosphate was studied using3H-myo-inositol (3H-MI) as precursor in cultured bovine lens epithelial cells (BLECs) maintained in galactose-free, physiological medium or 40 mM galactose (Gal)±sorbinil for six days. The formation of inositol polyphosphates from phosphoinositides was also shown. Galactitol did not exceed 2mM in Gal-incubated cells after six days of exposure; no galactitol was observed in BLECs maintained in galactose-free, physiological medium or Gal supplemented with sorbinil. Uptake of3H-myo-inositol(3H-MI) into BLECs was significantly reduced in cells exposed to Gal. A concomitant reduction in3H-MI incorporation was observed in the phos-phoinositides, as well as with the released inositol phosphates. The simultaneous addition of sorbinil to the Gal medium corrected the drop in3H-MI uptake and normalized3H-MI incorporation into the phos-phoinositides and inositol phosphates. While an apparent decrease in the three inositol-containing lipids was observed with the Gal-incubated cells, based on3H-MI incorporation, there was no change in total membrane phosphatidylinositol content when compared to cells maintained in physiological medium as determined by theμg PI PO4perμgj total membrane PO4. The apparent loss of radiolabeled phosphoinositides was attributed to the decreased specific activity resulting from the lower internal pool of3H-MI in the Gal-exposed cells available for incorporation into the phosophoinositides. Our observations support the contention that the net cellular content of inositol-con-taining lipids does not vary significantly between control cells and those exposed to hypergalactosemic conditions for six days. These studies demonstrate that activation of the polyol pathway interferes with lens myo-inositol uptake and that the co-administration of sorbinil to the Gal medium protects against the attendant decrease.

ISSN:0271-3683    

DOI:10.3109/02713689008999596

出版商:Taylor&Francis    

年代:1990

数据来源: Taylor

摘要:

Herpetic ocular disease is one of the major causes of corneal blindness. Clinical diagnosis of corneal disease is based principally on corneal appearance. However, abnormal morphology of the corneal epithelium (CE) is not an indicator for the presence of a herpes virus. Further, it has not been established if herpes viruses are present in normal corneal epithelial tissue. In these studies, the polymerase chain reaction was used to evaluate normal and diseased corneal epithelium for the presence of herpes simplex virus type 1 (HSV-1), Epstein-Barr virus (EBV) and cytomegalovirus (CMV) genomic sequences. Thirty-two normal corneal epithelium specimens obtained from cadavers shortly after death were analyzed for HSV-1, EBV and CMV genomic sequences. Three of the 32 normal CE specimens were positive for amplified EBV DNA, 1 was positive for HSV-1 DNA, and none was positive for CMV DNA. We also tested eight herpetic dendritic lesions of which 3 were HSV-1 culture and PCR positive. The remaining five dendritic lesions were HSV-1 culture and PCR negative. Since these lesions were not evaluated for other herpesviruses, the etiology of these dendritic lesions is unknown. Six corneal epithelium samples from HIV-infected donors were negative for EBV, CMV and HSV-1 amplified sequences. Positive EBV, CMV and HSV-1 serology on all normal donors and on donors with clinically apparent disease did not correlate with positive PCR results. The results of these studies suggest that EBV and HSV-1 DNA can be amplified from a small percentage of apparently normal corneal epithelium.

ISSN:0271-3683    

DOI:10.3109/02713689008999597

出版商:Taylor&Francis    

年代:1990

数据来源: Taylor

摘要:

Choroidal blood flow in pigeons is regulated by the medial part of the nucleus of Edinger-Westphal (EW) via the ipsilateral ciliary ganglion. Interruption of this circuit by unilateral lesions of EW results in pathological modifications in the morphology of retinal photoreceptors in the ipsilateral eye in pigeons housed under 12hr light (400 lux)/12hr dark conditions. In the present study, we examined the effects of unilateral EW lesions on glial fibrillary acidic protein (GFAP) expression by retinal Müller cells in pigeons housed under the same lighting conditions. Since Müller cells in the retina of land vertebrates express increased GFAP during conditions of retinal pathology or stress (e.g., inflammation or hypoxia), this study would enable us to further evaluate the effects of disruption in the neural regulation of choroidal blood flow on the retina. We found that following EW lesions, retinal Müller cells expressed GFAP, with the precise intracellular location of the GFAP dependent on the amount of time elapsed following the lesion. One week after the EW lesions, GFAP labelling was restricted to the Müller cell endfeet in the nerve fiber layer and ganglion cell layer. By two-three weeks, the labelling had extended outward (or sclerad) into the portions of the Müller cells spanning the inner plexiform layer. Finally, by six weeks post-lesion, the entire extent of the Müller cell from the nerve fiber layer to the outer limiting membrane contained GFAP. No GFAP immunoreactivity in Müller cells was observed in the eyes contralateral to the EW lesions or in eyes in which the pupil had been fixed and dilated by lesions of the pretectal region. Our results suggest that the retina is in a state of physiological stress following interruption of the neural regulation of choroidal blood flow by EW lesions. Although the precise mechanisms by which altered choroidal blood flow regulation affects Müller cell GFAP production require elucidation, the results nonetheless highlight the importance of intact neural regulation of choroidal blood flow for retinal health.

ISSN:0271-3683    

DOI:10.3109/02713689008999598

出版商:Taylor&Francis    

年代:1990

数据来源: Taylor

摘要:

Utilizing a rapid colorimetric assay that relates cell number to cytoplasmic hexosaminidase activity, we conducted drug-induced cytotoxicity experiments on human ocular fibroblasts cultured from Tenon's capsule specimens. The effects of two different agents–dimethyl sulfoxide (DMSO) or mitomycin C–on the proliferation of human ocular fibroblasts were studied. Simultaneously the sensitivity of this technique was compared to electronic cell counting with a Coulter counter, a conventional means of quantifying proliferation.Known numbers of cells were exposed to varied concentrations of either DMSO or mitomycin C for 11 days. Cell attachment was quantified after 24 hours, and proliferation was quantified periodically thereafter over the remaining 10 days. Colorimetric data contained a similar or smaller amount of random error than corresponding Coulter values. Both assays identified statistically significant antiproliferative effects and inhibitory effects on cell attachment at higher drug doses; however, Coulter counting alone detected many additional significant effects among lower-dose DMSO and mitomycin treatment groups. Although the hexosaminidase assay displayed lower sensitivity than Coulter counting, it may still be useful to rapidly screen new compounds for strong antifibroblastic effects.

ISSN:0271-3683    

DOI:10.3109/02713689008999599

出版商:Taylor&Francis    

年代:1990

数据来源: Taylor