摘要:

The retinal pigment epithelium (RPE) is clinically involved in diverse ocular inflammatory diseases. Because perturbed RPE cells produce a variety of inflammatory substances, RPE cells may play an integral part in these diseases. Interleukin-1 (IL-1) and granulocyte-macrophage colony-stimulating factor (GM-CSF) are pleiotropic cytokines with the ability to trigger numerous inflammatory responses. This report shows that cultured human RPE cells synthesize interleukin-1β(IL-1β) and GM-CSF in response to the potentially inflammatory cytokine, IL-1α, but not toE. coliendotoxin. Control RPE cells made little or no mRNA or protein for either IL-1βor GM-CSF. Upon stimulation of the cells by IL-1α, both IL-1βand GM-CSF mRNAs were readily apparent by 3 hours, persisted for over 24 hours, and were translated into immunologically detectable proteins. GM-CSF protein was secreted into the culture medium, whereas IL-1βprotein remained cell associated. The IL-1α-induced mRNA and protein production were inhibited by dexamethasone. These observations provide additional evidence that RPE cells are capable of playing a pivotal role during ocular inflammation.

ISSN:0271-3683    

DOI:10.3109/02713689308999465

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

Calcium permeability was significantly increased in lenses from rats 36 h following a single injection of a cataractogenic dose of sodium selenite (30 nmol/g body weight) and this permeability returned to control values by 72 h post-injection (PI). The greater Ca2+permeability could be partially reversed by incubating lenses in medium containing 2 mM dithiothreitol (DTT). Estimations of Ca-ATPase activity revealed the greatest level occurred in the epithelial layer and that the nucleus had no detectable activity. By 48 h PI both Ca2+-pump activity and the Ca2+-dependent ATP hydrolytic activity were less compared to controls in membrane preparations from rat lenses. Only the hydrolytic activity could be partially restored by treatment with 5 mM DTT. Both permeability and active Ca2+transport were affected by selenite in a manner that would lead to increased Ca2+accumulation in lenses from rats treated with selenite. It is suggested that the oxidative damage that accompanies in vivo exposure to selenite could affect Ca2+homeostasis in the lens by directly altering permeability and Ca-ATPase.

ISSN:0271-3683    

DOI:10.3109/02713689308999466

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

Goggles that degrade the retinal image produce axial enlargement of the ocular globe and large myopic refractive errors. Many authors have assumed that visual image degradation itself leads to myopia. Hodos and co-authors have shown, however, that goggled eyes in chicks are considerably warmer than normal. Such temperature changes may either underlie or be a consequence of alterations in choroidal blood flow (CBF). Since alterations in CBF could affect eye growth, we explored the effect of monocular goggling on CBF in chicks. Plastic goggles were glued over one eye in four-day old chicks and the goggles were left in place for 12 or 14 days. Fourteen days after the goggling, CBF was measured using laser Doppler velocimetry. Three groups of chicks were studied: 1) chicks with goggles for 14 days; 2) chicks with goggles for 12 days followed by no goggles for the two days; 3) age matched non-goggled chicks. A-scan ultrasonography confirmed that the visual deprivation produced vitreous chamber elongation in the goggled eye and that the degree of elongation for the goggled eye was the same for the two goggled groups. The results were : 1) blood flow in non-goggled chicks was similar in both eyes; 2) blood flow was significantly reduced in the goggled eye in chicks wearing goggles for 14 days- 37% of control; and 3) blood flow was still significantly reduced in the goggled eye in chicks whose goggles were removed two days before measurement- 51% of control. These results show that CBF is reduced by goggles that result in myopic eye growth. These findings have implications for the mechanisms underlying myopic eye growth and for the retinopathy that often attends high myopia.

ISSN:0271-3683    

DOI:10.3109/02713689308999467

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

We have previously reported decreased choroidal blood flow (CBF) associated with goggle-induced ocular enlargement and myopia. It was uncertain, however, if this change in CBF was related to the occurrence of ocular enlargement or the increased ocular temperature produced by the goggle. We therefore used corneal surgery-induced ocular enlargement that eliminated the thermal effects observed with goggles to investigate the effects of ocular enlargement on CBF. Central corneal incisions (2 mm in length) were made in the right eye of 4 day old chicks and the wound sutured. In one group, the incision was oriented along the vertical meridian (with the head in its natural position -beak tip 30–45 degrees below horizontal), while in another group the incision was oriented along the horizontal meridian (with the head in its natural position). Age matched controls received no corneal incision. Two weeks later, CBF was measured using laser Doppler velocimetry. After determining CBF, the eyes were removed and axial length, nasotemporal length and dorsoventral length were measured. Ocular enlargement was induced in 11 out of 12 chicks with vertical cuts. The CBF in the operated eye of these 11 animals was 62% of that in the nonoperated eye. Ocular enlargement was also induced in eight of 14 chicks with horizontal cuts. The CBF in the operated eye in these eight chicks was 60% of that in the nonoperated eye. The extent of eye growth was greater in all dimensions in the vertical cut chicks with ocular enlargement than in the horizontal cut chicks with ocular enlargement. Chicks without ocular enlargement that had received corneal surgery showed no alteration in CBF in the operated eye. These results indicate that CBF is reduced as a consequence of ocular enlargement. The greater efficacy of the vertical cuts in yielding eye growth suggests differential control of eye growth by retinal image disturbance in different parts of the visual field.

ISSN:0271-3683    

DOI:10.3109/02713689308999468

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

αB-crystallin is a major lens protein that is a member of the heat-shock family of proteins. Using immunohisto-chemical and northern blot techniques, we now demonstrate its presence in freshly-fixed retinoblastoma tissue. The protein is also abundantly expressed in cultured human retinoblastoma cells (Y-79 NEI, WERI Rb-1) as well as two subcultured Y-79 lines (ATCC and GM01232C). High expression ofαB-crystallin may be involved in tumor growth and/or be a marker for general oncogenic“stress”in the tumor tissue.

ISSN:0271-3683    

DOI:10.3109/02713689308999469

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

An instrument, the Meibometer, is described for estimating the casual level of meibomian lipid on the human eyelid margins, adapted from a commercially-available instrument used for measurement of skin surface lipid. A loop of plastic tape is pressed onto the everted lower lid margin to lift off a blot of lipid. The resultant change in light transmission of the tape is read by a photometer. Readings are not affected by side (R or L), time of day or lid surface temperature. After cleaning lipid from the lid margins with hexane, the rate of recovery per 10 blinks, as a percentage of the pre-cleaned level, was measured as 33.7±5.8 (mean±SE). This rate of delivery appears to provide enough lipid for complete resurfacing of the preocular tear film with every blink. Over short periods no detectable lipid was delivered in the absence of blinking.

ISSN:0271-3683    

DOI:10.3109/02713689308999470

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

Using a modified skin surface lipid measuring instrument. the Meibometer, the amounts of meibomian lipid on the lid margins (the casual levels) of 421 subjects aged 1 to 94 years were measured. The lowest levels were found in children younger than 14 years (means±S.E.: males = 1.48±0.17, females = 1.53±0.17μg lipid/mm2lid margin surface) and rose with age, the highest levels being found in males aged 60–69 years (mean±S.E. = 3.26±0.18μg lipid/mm2lid margin surface). Male levels were higher than females in the 20–29 years age group but male and female levels became indistinguishable above the age of 50. These age- and sex-related changes differed markedly from those seen in skin surface lipid levels. The age-related changes in the casual levels of lid lipids remain unexplained although an endocrinological mechanism modified by morphological factors is considered.

ISSN:0271-3683    

DOI:10.3109/02713689308999471

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

The retinal pigment epithelium (RPE) lying between the neural retina and the choroid, performs as a transport organ for solutes and water between the choriocapillaries and the subretinal space. It also has the function to maintain the microenvironment of photoreceptors including the regulation of calcium ions during light or dark adaptation. In order to further elucidate the transport functions of the RPE, apical membranes were isolated from RPE by differential precipitation with divalent ions. In this work bovine tissues were used as well as elasmobranch tissues. For the latter, we have already purified and characterized membrane vesicles in a previous paper. Na+-K+-ATPase, alkaline phosphatase, and 5'-nucleotidase, which are marker enzymes of the apical membrane, were highly enriched in the final membrane fraction. The majority of the fraction consists of right side out vesicles. The fluorescent indicator for sodium, SBFI, or the calcium specific indicator, Fura-2, were pre-loaded into the apical membrane vesicles of RPE of either dogfish eyes or bovine eyes. When anoutwardly-directed Ca2+gradient was formed across the vesicular membranes, the influx of Na+was stimulated 155% and 142% for dogfish and bovine species, respectively. When an outwardly-directed Na+gradient was formed across the vesicular membranes, the Ca2+influx was also enhanced by 136% for dogfish RPE and 167% for bovine RPE. This Na+gradient dependent Ca2+influx was blocked by bepridil, an antiarrhythmic agent which is a Na+/Ca2+exchanger inhibitor. These results indicate that a Na+/Ca2+exchanger is present in the apical membrane of bovine and dogfish RPE.

ISSN:0271-3683    

DOI:10.3109/02713689308999472

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

Arylamine N-acetyltransferase (NAT) activity was identified and characterized in bovine retinal pigment epithelium (RPE) cells. Upon examining the RPE supernatant for multiple ionic species, one major NAT activity peak was detected. Based upon its substrate specificity, it is best described as an arylamine NAT. However, there was detectable arylalkylamine NAT activity within this peak. Further purification via size-exclusion HPLC revealed multiple peaks of NAT activity, although the major peak (around 30 kDa) again predominantly exhibits arylamine NAT activity. However, substrate specificity studies indicate that this arylamine NAT activity is able to acetylate specific arylalkylamine substrates. This arylamine NAT demonstrates a monomorphic pattern of acetylation since it acetylates p-aminobenzoic acid rather than sulfamethazine. It also demonstrates a low sensitivity to methotrexate inhibition indicated by the high IC50value (570μM). The mode of inhibition by methotrexate is uncompetitive as demonstrated by kinetic analysis.

ISSN:0271-3683    

DOI:10.3109/02713689308999473

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

Raman spectroscopy was used for the first time to characterize the structure of lipid membranes prepared from the nuclear and cortical regions of 48 and 69 year old clear human lenses. The interface region carbonyl band appears as a doublet at 1742 and 1728 cm-1. The lower frequency band is characteristic of a hydrogen bonded carbonyl group, perhaps to bilayer water. From the intensity of the curve fit bands, we calculate that 43% of the carbonyl groups are hydrogen bonded. Our data show that the hydrocarbon chains of the nuclear lipids are 1.4 times more saturated than those of the cortical lipids. The molar ratio of phospholipid CH2/=C-H groups was calculated to be 13 ana 18 for cortical and nuclear lipids, respectively. Hydrocarbon chain disorder was estimated to be 72 and 58% (±8% disorder) for the cortical and the nuclear lipids, respectively. Raman spectroscopy is sensitive to structural differences in various regions of the lipid bilayer and could be an effective tool to explore lipid and protein interactions in terms of lens region, age and opacity.

ISSN:0271-3683    

DOI:10.3109/02713689308999474

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor