摘要:

Lenses fixed in formaldehyde or glutaraldehyde can be embedded in plastic, and sections as large as 3–4 mm across can be cut with glass knives on an ultramicrotome. When these sections are stained with 25% sodium fluorescein and allowed to bleach in a fluorescence microscope, high contrast images of essentially every cell in the section, including cells very near the lens center, can be seen. The method is effective with lenses from a number of species, and should be useful for a wide variety of morphological studies of normal and cataractous lenses.

ISSN:0271-3683    

DOI:10.3109/02713688208998374

出版商:Taylor&Francis    

年代:1982

数据来源: Taylor

摘要:

Enzyme-linked immunosorbent assay was applied to the determination of the serum IgG antibody contents in rats immunized with the organ-specific autoantigen (S antigen) of the retina.Optimal conditions (i.e. S antigen concentration, serum and conjugate dilutions, enzymatic reaction time) were determined. The assay required only a single serum dilution and was well reproducible. It was very sensitive, allowing the detection of low antibody contents in animals immunized with 1μg of S antigen.The time course of the antibody response and its variations according to the dose and the species of the immunizing S antigen were considered.

ISSN:0271-3683    

DOI:10.3109/02713688208998375

出版商:Taylor&Francis    

年代:1982

数据来源: Taylor

摘要:

In an attempt to determine the factors involved in ocular pigment variation, the eyes of pallid mice (C57BL/6J–Pa/Pa), and those of littermate black mice (C57BL/6J–+/Pa) were examined ultrastructurally, histochemically, and biochemically. As controls, the eyes of black and congenic albino mice (C57BL/6J +/C2Jand–C2J/C2J) were also examined. In the developing pallid mouse eye the retinal pigment epithelium (RPE) and choroid contained immature melanosomes with incomplete melanization. In the adult pallid RPE, numerous lysosomal structures containing melanin components were present, while in choroid, melanosome numbers not only increased but many were aggregated in large membrane–bound granules. These RPE and choroidal structures may be melanolysosomes because of their histochemical acid phosphatase positive reactions. Biochemically, the activity of acid phosphatase in ocular homogenates of pallid eyes was significantly higher than in either the black eyes of +/Pa or in the albino and black eyes of the C2Jgenotypes.Dopa reactions at the light and electron microscopic levels indicated that Dopa oxidase activity was present in the cells of the RPE and choroid of both pallid and black mice. Histochemically the Dopa reaction of pallid pigment cells seemed to be equal to that of black ones, suggesting that tyrosinase production might be normal in pallid pigment cells. Biochemically, however, tyrosinase activity in the pallid eye was significantly lower than in the black control.It is concluded that the active digestion of melanosomes, as well as the low ocular tyrosinase activity and the immaturity of pallid melanosomes, may contribute to the pigment dilution observed in the pallid mouse eye.

ISSN:0271-3683    

DOI:10.3109/02713688208998376

出版商:Taylor&Francis    

年代:1982

数据来源: Taylor

摘要:

Refractive keratoplasty procedures for large dioptric corrections utilize a lenticular addition to the cornea which is typically cut from a donor cornea, but can also be fabricated from hydrogel plastics (1). The success of an intrastromal hydrogel implant depends on the nonreactiveness of both the hydrogel to the stroma tissue and the tissue environment to the hydrogel. Permalens hydrogel (Cooper Labs, Inc.) was fabricated into 6 mm diameter, 0.24 mm thick, and +15.00 diopter lenticules and surgically implanted into intracorneal pockets of rabbit corneas for eleven months. Light and electron microscopy revealed scattered zones of abnormal fibroblast activity at the posterior interface of the hydrogel and stroma. The anterior pocket lining was covered with a single cell layer of keratocytes, but there were no irregular areas that might be light scattering. The remaining ultrastructure appeared normal. Preliminary work with primates did not reveal this type of abnormal fibroblast activity. The data indicates that hydrogels for intrastromal implantation in refractive keratoplasty have a promising future.

ISSN:0271-3683    

DOI:10.3109/02713688208998377

出版商:Taylor&Francis    

年代:1982

数据来源: Taylor

摘要:

Monocularly aphakic guinea pigs (Cavia porcellis), prepared by removing the lens by phacoemulsification, were maintained under near-UV lighting conditions for several months. Exposure to near-UV energy was at much lower irradiance levels than that of sunlight, and was at lower than the threshold level for near-UV damage to the aphakic monkey retina as reported by Ham, et al (1). In some aphakic eyes, regenerated lens-like structures formed which scattered light appreciably. After increasing light exposure periods, the eyes of control and irradiated animals were studied histologically. Other animals were periodically examined by electroretinographic (ERG) techniques. While there was no observable histopathological damage, aphakic-UV irradiated eyes with little or no lens regrowth exhibited depressed b-waves, late time constants and altered wave forms when compared with control eyes. The results demonstrate that ambient near-UV light exposure can adversely influence retinal electrical activity in aphakic eyes at irradiance levels below threshold for morphological damage. The protective function of the lens is also supported by these findings.

ISSN:0271-3683    

DOI:10.3109/02713688208998378

出版商:Taylor&Francis    

年代:1982

数据来源: Taylor

摘要:

Rabbit antisera to bovine lens leucine aminopeptidase (LAP) have been prepared. These LAP-specific antisera cross-react with a component, LAP, in human lens homogenates. Bovine and human lens LAP are similar but not identical. Immuno-diffusion tests show that LAP is present in a vast majority if not all cataractous and normal human lens homogenates. Results from immunoelectrophoresis indicate that LAP is found in these homogenates as several metazymes as well as in an albuminoid - and possibly membrane-associated form. In contrast to many activity-based studies which imply that very little LAP is present in human lenses, micro-complement fixation tests indicate that the concentration of LAP in aged human lenses is similar to that found in calf lenses. Taken together, these data indicate that LAP undergoes age-related changes. These alterations of enzyme (or environment) result in an enzyme of markedly reduced activity, hence, the discrepancy between amount of LAP and the amount of enzymatic activity in aged human lenses.Active LAP is shown to enhance the rate of hydrolysis ofα-2 andα-B crystallins but notα-A2,βH,βLorγcrystallins. The ramifications of LAP inactivation with respect to cataractogenesis are discussed.

ISSN:0271-3683    

DOI:10.3109/02713688208998379

出版商:Taylor&Francis    

年代:1982

数据来源: Taylor

摘要:

The popular Schirmer test of tearing ability heretofore has never been analyzed kinetically and the interpretation of the results is usually based on implicit, often erroneous assumptions. We have analyzed the capillary flow of fluids in filter paper stripsin vitrosystems for the cases of unlimited supply and limited supply at constant rates, andin vivousing human subjects, who kinetically corresponded to limited supply having variable rates. The effects of evaporation, surface tension, viscosity, paper pore-size, and the wettability of the cellulose fibers in the paper were also studied. The results show that in the case of unlimited supply, the fluid absorption is kinetically identical to fluid uptake by a horizontal capillary. This implies that the paper strip can absorb fluids only at a certain maximum rate which decreases with time. At lower secretion rates, the rate of wetting length increase is linearly proportional to the secretion rate provided that evaporation is prevented. Evaporation increases with increased wetting length until a steady state is reached where the length of wetting remains constant in time. As long as the secretion rate remains below the maximum uptake rate of the paper strip, the paper and fluid characteristics have a negligible influence on the wetting rate thus the rate of wetting can provide quantitative information on the secretion rate.Wetting length versus time curves obtainedin vivocan be best described mathematically by assuming that the initially high secretion rate exponentially decays to a lower, final value. From the data, the magnitude of the initial and final tear secretion rates as well as the secretion rate decay coefficient can be calculated. These physiologically relevant values quantitatively characterize the functioning of the lacrimal system and may have diagnostic value in detecting marginal lacrimal deficiencies and predicting poor contact lens tolerance.

ISSN:0271-3683    

DOI:10.3109/02713688208998380

出版商:Taylor&Francis    

年代:1982

数据来源: Taylor

摘要:

The present study demonstrated numerous LH-RH—positive structures in the paddy-bird (padda orizivora) retina. LH-RH-positive cells were seen in the ganglion cell layer (GL), inner plexiform layer (IPL) and inner nuclear layer (INL). Judging from the morphological features, the former two types of cells may belong to the displaced amacrine cells and the latter to the amacrine cells. LH-RH-positive fibers were found in the nerve fiber layer, GL, IPL, INL and outer plexiform layer.

ISSN:0271-3683    

DOI:10.3109/02713688208998381

出版商:Taylor&Francis    

年代:1982

数据来源: Taylor

摘要:

The synthesis of cytoskeletal and membrane polypeptides of the chick lens epithelium, superficial cortical fiber cells and deep cortical fiber cells was studied in the organ-cultured lens. The synthetic activity of the cytoskeletal polypeptides was restricted to the epithelium and superficial cortical fiber cells while membrane polypeptides were synthesized by deep cortical fiber cells as well. None of the polypeptides was observed to be synthesized by the lens nuclear fiber cells.

ISSN:0271-3683    

DOI:10.3109/02713688208998382

出版商:Taylor&Francis    

年代:1982

数据来源: Taylor