摘要:

Tear prealbumin was purified from crude tear prealbumin previously isolated from the saline soluble human ocular mucus. Purification was achieved by further column chromatographies on DEAE Sephadex A-25 and Sephadex G-75. Preliminary characterization included amino acid analysis, gel electrophoresis, and isoelectric focusing. Unlike serum prealbumin, the purified tear prealbumin showed a predominance of acidic residues and a trace amount of tryptophan. It exhibited polymorphic nature, with pi values of 4.8 and 4.9. The possibility of a tear prealbumin/retinol complex was also examined. The protein was found to incorporate with 3H retinol. The % retinol-incorporated tear prealbumin did not exhibit the characteristic UV spectrum of retinol; however, it did display emission and excitation fluorescence spectra at high concentrations similar to serum retinol-binding protein.

ISSN:0271-3683    

DOI:10.3109/02713688608995169

出版商:Taylor&Francis    

年代:1986

数据来源: Taylor

摘要:

The cytoskeletal pattern of the most superficial layers (cortex and epithelium) of senile cataractous lenses has been analyzed by PAGE-SDS. While the nuclear type of cataract and age-matched transparent human lenses have super-imposable protein patterns, lenses with cortical cataract demonstrate appreciable modifications of their cytoskeletal composition. The most evident change is the decrease of fodrin and the marked reduction or even the absence of the 98 Kd band. Fodrin may be completely removed from the water insoluble fraction (WIF) of cortical cataract by extraction in low ionic strenght buffer, a treatment which only partially solubilizes this protein in transparent control lenses.

ISSN:0271-3683    

DOI:10.3109/02713688608995170

出版商:Taylor&Francis    

年代:1986

数据来源: Taylor

摘要:

In the retina, the membranous outer segments shed from the photoreceptors are phagocytized by the adjacent retinal pigment epithelial cells. These cells are some of the most active phagocytic cells in the body and like photoreceptors must survive the lifetime of the organism. The initiation of engulfment by the pigment epithelial cells occurs by an unidentified mechanism. The ingestion of particles by many, but not all phagocytic cells, is mediated by Fc and C3 receptors located on the external plasma membrane. The present experiment reports our unsuccessful attempt to demonstrate either the Fc or C3b receptor on the plasma membrane of RCS rat pigment epithelial cells.

ISSN:0271-3683    

DOI:10.3109/02713688608995171

出版商:Taylor&Francis    

年代:1986

数据来源: Taylor

摘要:

Sodium selenite has been shown to inhibit Na, K-ATPase. Glutathione, at sufficient excess, is able to prevent or reverse the inhibition. Dithiothreitol can also reverse much of the inhibition, but KCN cannot. Selenomethionine does not inhibit Na, K-ATPase. The interactions of sodium selenite with Na, K-ATPase and glutathione may aid in understanding the early events in selenium cataractogenesis.

ISSN:0271-3683    

DOI:10.3109/02713688608995172

出版商:Taylor&Francis    

年代:1986

数据来源: Taylor

摘要:

Eight intracapsular and 18 extracapsular human surgical specimens were stereophotographed. Each lens was divided into 10 areas, separating those which appeared transparent from those that showed opacities. Samples weighing 6-12 mg from each area were investigated. The total water content was determined by thermogravimetric analysis; the freezable water content was measured by differential scanning calorimetry. The difference between the two provided the non-freezable water content. Graphic presentation illustrates the correspondence of high total water, low non-freezable water content with location of the turbidity in the lens.Pairwise, statistical comparison shows that in intracapsular human surgical specimens the non-freezable water content in the clear areas of both cortex and nucleus was significantly greater than in the opaque areas.

ISSN:0271-3683    

DOI:10.3109/02713688608995173

出版商:Taylor&Francis    

年代:1986

数据来源: Taylor

摘要:

The posterior segment of the eye was divided into four compartments: retinal cytosol (R), subretinal fluid on the retinal surface (S/R), retinal pigment epithelial (RPE) cytosol, and subretinal fluid on the RPE surface (S/RPE). The volume of each compartment was estimated from the dilution of creatinine (in the extraction buffer) by the endogenous tissue fluid.The ascorbate concentrations in R, S/R, S/RPE, and RPE were 20.6, 12.3, 3.7, and 5.8 mg/dl respectively. Dehydroascorbate was observed only in the RPE and S/RPE. The decreasing ascorbate concentration from the retina to RPE, and the distribution of dehydroascorbate suggest a movement of ascorbate from the vitreous cavity into the subretinal space.The permeability of retinal cell layers to ascorbate was confirmed by the high radioactivity observed in the subretinal space after an intravitreal injection of C14-ascorbate. The occurrence of dehydroascorbate in the RPE and the S/RPE indicates the presence of oxidative reaction of ascorbate in these compartments, where light induced free radicals are located.

ISSN:0271-3683    

DOI:10.3109/02713688608995174

出版商:Taylor&Francis    

年代:1986

数据来源: Taylor

摘要:

The normal human corneal endothelial monolayer maintains stromal water equll Ibrlum and thus, transparency, by means of a pump-leak mechanism (1-3). Water leaks into the stroma through non-tight lateral cell junctional complexes and is drawn out by an energy dependent cell membrane ion pump. We investigated the histochemical localization of cytochrome oxidase activity (CO), an important energy-deriving mitochondrial enzyme in dysfunctional corneas with Fuchs endothelial dystrophy (ED), which is a regionally distributed disease. Keratoconus corneas were used as controls for functional control endothelium. In the central area of the corneal button, decreased CO activity was demonstrated which correlated clinically with central corneal edema. This reflects decreased metabolic activity and/or decreased numbers of mitochondria in the attenuated dysfunctional cells. In the mid-periphery, CO activity was increased in the cellular rosettes surrounding guttata, which may be related to increased synthesis of abnormal Descemet's membrane and guttata. Peripherally, the large polygonal cells resembled functional endothelium in their morphology and CO activity. We have, therefore, demonstrated regional differences in energy metabolism in endothelium from Fuchs' ED patients which may be related to decreased numbers of mitochondria in the dysfunctional cells, and/or to synthesis of abnormal Descemet's membrane material.

ISSN:0271-3683    

DOI:10.3109/02713688608995175

出版商:Taylor&Francis    

年代:1986

数据来源: Taylor

摘要:

A major glycoprotein of relative molecular weight of 130,000 daltons of chick lens cell membranes was identified by Concanavalin-A staining and enriched for by Con A-Sepharose chromatography. Using both Con A binding and immunological analyses with a specific polyclonal antibody, the glycoprotein was detected in chick lens epithelium, annular pad, cortex and nucleus. Localization to the plasma membranes of lens cells was demonstrated by immunofluorescence. A similar protein, which cross-reacts with the antibody to the chick protein and also binds Con A was demonstrated in human and bovine lenses.

ISSN:0271-3683    

DOI:10.3109/02713688608995176

出版商:Taylor&Francis    

年代:1986

数据来源: Taylor

摘要:

The isolated arterially perfused eye preparation has become a valuable tool in the investigation of ocular function. Normal retinal function can be maintained for several hours with the measurement of the gross electroretinogram (ERG) serving as a useful monitor of the electrophysiological condition of the preparation. This paper deals with the manner in which the amplitude of the ERG is affected by the electrode recording locations and describes the characteristic distribution of potentials on the surface of the isolated arterially perfused dog eye. The ERG is recorded between a fixed corneal contact lens electrode and a movable electrode on the uppermost surface of the sclera. The scleral electrode is moved in small increments parallel to the optic axis and lowered onto the uppermost surface of the sclera on a line from the corneal limbus to the optic nerve. The resulting ERG profile is characterised by minimal b-wave amplitude at the corneal limbus and little growth until a point 5 or 6 mm from the corneal limbus is reached, followed by a region of rapidly increasing amplitude up to a maximum at the point where the optic nerve exits from the globe. There follows a region of large but stable signal amplitude along the optic nerve. The ERG profile is largely unaffected by a reorientation of the globe about the optic axis, demonstrating that the potential distribution on the surface of the globe may be described in terms of points equidistant from the limbus being isopotential. A similar distribution of potentials is shown to exist with two types of retinal illumination, that from a simple flash lamp and that from a more uniform retinal stimulation provided by the incorporation of a ganzfeld sphere. The implications of this finding are discussed with reference to clinical and experimental electroretinography.

ISSN:0271-3683    

DOI:10.3109/02713688608995177

出版商:Taylor&Francis    

年代:1986

数据来源: Taylor

摘要:

Human neonatal corneal endothelial cells were successfully maintained in tissue culture, morphologically resembling adult corneal endothelium. Eyebank donor corneas were obtained, denuded of their native endothelium and seeded with a suspension of the cultivated neonatal endothelial cells. After 48 hours, the eye-bank tissue was then transplanted into the eyes of Rhesus monkeys. Over a five month period, five of eight transplants cleared, with a mean central corneal thickness of 0.480 mm and endothelial cell densities ranging from 560 to 1650 cells/mm2. All control eyes without donor endothelium remained cloudy. In the experimental group three eyes initially thinned but subsequently became edematous. Further studies are needed to improve the seeding procedure and to assess the long-term viability of transplanted endothelium.

ISSN:0271-3683    

DOI:10.3109/02713688608995178

出版商:Taylor&Francis    

年代:1986

数据来源: Taylor